<?xml version="1.0" encoding="latin1" ?>
<!DOCTYPE chapter SYSTEM "chapter.dtd">
<chapter>
<header>
<copyright>
<year>2004</year><year>2011</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
The contents of this file are subject to the Erlang Public License,
Version 1.1, (the "License"); you may not use this file except in
compliance with the License. You should have received a copy of the
Erlang Public License along with this software. If not, it can be
retrieved online at http://www.erlang.org/.
Software distributed under the License is distributed on an "AS IS"
basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
the License for the specific language governing rights and limitations
under the License.
</legalnotice>
<title>ERTS Release Notes</title>
<prepared>otp_appnotes</prepared>
<docno>nil</docno>
<date>nil</date>
<rev>nil</rev>
<file>notes.xml</file>
</header>
<p>This document describes the changes made to the ERTS application.</p>
<section><title>Erts 5.8.3</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
The scroll wheel now scrolls the werl window on Windows.</p>
<p>
Own Id: OTP-8985</p>
</item>
<item>
<p>
Some malformed distribution messages could cause VM to
crash, this is now corrected.</p>
<p>
Own Id: OTP-8993</p>
</item>
<item>
<p>
The OS function getifaddrs() can return NULL in some
address fields for e.g PPP and tunnel devices which
caused the emulator to segfault. This bug has now been
corrected.</p>
<p>
Own Id: OTP-8996</p>
</item>
<item>
<p>
The expression <<A:0>> would always produce
an empty binary, even if <c>A</c> was not an integer.
Corrected to cause a <c>badarg</c> exception if the type
of <c>A</c> is invalid. (Thanks to Zvi.)</p>
<p>
Own Id: OTP-8997</p>
</item>
<item>
<p>
A bug that potentially could cause an emulator crash when
deleting an ETS-table has been fixed. A resource leak
when hitting the maximum amount of ETS-tables allowed has
also been fixed.</p>
<p>
Own Id: OTP-8999</p>
</item>
<item>
<p>
A bug in the <c>exit/2</c> BIF could potentially cause an
emulator crash.</p>
<p>
Own Id: OTP-9005</p>
</item>
<item>
<p>
Due to a bug in glibc the runtime system could abort
while trying to destroy a mutex. The runtime system will
now issue a warning instead of aborting.</p>
<p>
Own Id: OTP-9009</p>
</item>
<item>
<p>
A bug in epmd could create strange behaviour when
listen() calls failed. This is now corrected thanks to
Steve Vinoski.</p>
<p>
Own Id: OTP-9024</p>
</item>
<item>
<p>When setting file_info the win32_driver will now
correctly set access and modified time. Previously these
entities were swapped.</p>
<p>
Own Id: OTP-9046</p>
</item>
<item>
<p>
Setting scheduler bind type to <c>unbound</c> failed if
binding of schedulers wasn't supported, or if CPU
topology wasn't present. This even though the
documentation stated that it is possible to set the bind
type to <c>unbound</c>.</p>
<p>
Own Id: OTP-9056 Aux Id: Seq11779 </p>
</item>
<item>
<p>Two problems were fixed in crash dump: The time left
for timers are now shown as unsigned integers and the
contents of ordered_set ETS tables is no longer
included.</p>
<p>
Own Id: OTP-9057</p>
</item>
<item>
<p>
The VM could fail to set IP_TOS and SO_PRIORITY in
certain situations, either because sockets were supplied
as open file descriptors, or because SO_PRIORITY by
default was set higher than the user can explicitly set
it to. Those situations are now handled.</p>
<p>
Own Id: OTP-9069</p>
</item>
<item>
<p>
Wx on MacOS X generated complains on stderr about certain
cocoa functions not beeing called from the "Main thread".
This is now corrected.</p>
<p>
Own Id: OTP-9081</p>
</item>
<item>
<p>
Fix a couple typos in driver_entry(3) (thanks to Tuncer
Ayaz).</p>
<p>
Own Id: OTP-9085</p>
</item>
<item>
<p>
Mention that "-detached" implies "-noinput"</p>
<p>
Clarify that specifying "-noinput" is unnecessary if the
"-detached" flag is given. (thanks to Holger Wei�)</p>
<p>
Own Id: OTP-9086</p>
</item>
<item>
<p>
A potential problem (found by code inspection) when
calling a fun whose code was not loaded has been fixed.</p>
<p>
Own Id: OTP-9095</p>
</item>
<item>
<p>
The emulator could get into a state where it didn't check
for I/O.</p>
<p>
Own Id: OTP-9105 Aux Id: Seq11798 </p>
</item>
<item>
<p>
Attempting to create binaries exceeding 2Gb (using for
example <c>term_to_binary/1</c>) would crash the emulator
with an attempt to allocate huge amounts of memory.
(Thanks to Jon Meredith.)</p>
<p>
Own Id: OTP-9117</p>
</item>
<item>
<p>
Fix erlang:hibernate/3 on HiPE enabled emulator (Thanks
to Paul Guyot)</p>
<p>
Own Id: OTP-9125</p>
</item>
</list>
</section>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>From this release, the previously experimental
halfword emulator is now official. It can be enabled by
giving the <c>--enable-halfword-emulator</c> option to
the <c>configure</c> script.</p>
<p>The halfword emulator is a 64-bit application, but
uses halfwords (32-bit words) for all data in Erlang
processes, therefore using less memory and being faster
than the standard 64-bit emulator. The total size of all
BEAM code and all process data for all processes is
limited to 4Gb, but ETS tables and off-heap binaries are
only limited by the amount of available memory.</p>
<p>
Own Id: OTP-8941</p>
</item>
<item>
<p>
32-bit atomic memory operations have been introduced
internally in the run time system, and are now used where
appropriate. There were previously only atomic memory
operations of word size available. The 32-bit atomic
memory operations slightly reduce memory consumption, and
slightly improve performance on 64-bit runtime systems.</p>
<p>
Own Id: OTP-8974</p>
</item>
<item>
<p>
Performance enhancements for looking up timer-entries and
removing timers from the wheel.</p>
<p>
Own Id: OTP-8990</p>
</item>
<item>
<p>
Write accesses to ETS tables have been optimized by
reducing the amount of atomic memory operations needed
during a write access.</p>
<p>
Own Id: OTP-9000</p>
</item>
<item>
<p>
Strange C coding in the VM made the -D_FORTIFY_SOURCE
option to gcc-4.5 react badly. The code is now cleaned up
so that it's accepted by gcc-4.5.</p>
<p>
Own Id: OTP-9025</p>
</item>
<item>
<p>
The memory footprint for loaded code has been somewhat
reduced (especially in the 64-bit BEAM machine).</p>
<p>
Own Id: OTP-9030</p>
</item>
<item>
<p>
The maximum number of allowed arguments for an Erlang
function has been lowered from 256 to 255, so that the
number of arguments can now fit in a byte.</p>
<p>
Own Id: OTP-9049</p>
</item>
<item>
<p>
Dependency generation for Makefiles has been added to the
compiler and erlc. See the manual pages for
<c>compile</c> and <c>erlc</c>. (Thanks to Jean-Sebastien
Pedron.)</p>
<p>
Own Id: OTP-9065</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.8.2</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p> Fix format_man_pages so it handles all man sections
and remove warnings/errors in various man pages. </p>
<p>
Own Id: OTP-8600</p>
</item>
<item>
<p>
The <c>configure</c> command line argument <seealso
marker="doc/installation_guide:INSTALL#How-to-Build-and-Install-ErlangOTP_A-Closer-Look-at-the-individual-Steps_Configuring">--enable-ethread-pre-pentium4-compatibility</seealso>
had no effect. This option is now also automatically
enabled if required on the build machine.</p>
<p>
Own Id: OTP-8847</p>
</item>
<item>
<p>
Windows 2003 and Windows XP pre SP3 would sometimes not
start the Erlang R14B VM at all due to a bug in the cpu
topology detection. The bug affects Windows only, no
other platform is even remotely affected. The bug is now
corrected.</p>
<p>
Own Id: OTP-8876</p>
</item>
<item>
<p>
The HiPE run-time in the 64-bit emulator could do a
64-bit write to a 32-bit struct field. It happened to be
harmless on Intel/AMD processors. Corrected. (Thanks to
Mikael Pettersson.)</p>
<p>
Own Id: OTP-8877</p>
</item>
<item>
<p>
A bug in <seealso
marker="erl_driver#erl_drv_tsd_get">erl_drv_tsd_get()</seealso>
and <seealso
marker="erl_nif#enif_tsd_get">enif_tsd_get()</seealso>
could cause an emulator crash. These functions are
currently not used in OTP. That is, the crash only occur
on systems with user implemented NIF libraries, or
drivers that use one of these functions.</p>
<p>
Own Id: OTP-8889</p>
</item>
<item>
<p>
Calling <c>erlang:system_info({cpu_topology,
CpuTopologyType})</c> with another <c>CpuTopologyType</c>
element than one of the documented atoms <c>defined</c>,
<c>detected</c>, or <c>used</c> caused an emulator crash.
(Thanks to Paul Guyot)</p>
<p>
Own Id: OTP-8914</p>
</item>
<item>
<p>
The ERTS internal rwlock implementation could get into an
inconsistent state. This bug was very seldom triggered,
but could be during heavy contention. The bug was
introduced in R14B (erts-5.8.1).</p>
<p>
The bug was most likely to be triggered when using the
<c>read_concurrency</c> option on an ETS table that was
frequently accessed from multiple processes doing lots of
writes and reads. That is, in a situation where you
typically don't want to use the <c>read_concurrency</c>
option in the first place.</p>
<p>
Own Id: OTP-8925 Aux Id: OTP-8544 </p>
</item>
<item>
<p>
Tracing to port could cause an emulator crash when
unloading the trace driver.</p>
<p>
Own Id: OTP-8932</p>
</item>
<item>
<p>
Removed use of CancelIoEx on Windows that had been shown
to cause problems with some drivers.</p>
<p>
Own Id: OTP-8937</p>
</item>
<item>
<p>
The fallback implementation used when no native atomic
implementation was found did not compile. (Thanks to
Patrick Baggett, and Tuncer Ayaz)</p>
<p>
Own Id: OTP-8944</p>
</item>
<item>
<p>
Some integer values used during load balancing could
under rare circumstances wrap causing a load unbalance
between schedulers.</p>
<p>
Own Id: OTP-8950</p>
</item>
<item>
<p>
The windows VM now correctly handles appending to large
files (> 4GB).</p>
<p>
Own Id: OTP-8958</p>
</item>
<item>
<p>
Name resolving of IPv6 addresses has been implemented for
Windows versions that support it. The use of ancient
resolver flags (AI_V4MAPPED | AI_ADDRCONFIG) to the
getaddrinfo() function has been removed since e.g FreeBSD
regard mapped IPv4 addresses to be a security problem and
the semantics of the address configured flag is
uncertain.</p>
<p>
Own Id: OTP-8969</p>
</item>
</list>
</section>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>
The help texts produced by the <c>configure</c> scripts
in the top directory and in the erts directory have been
aligned and cleaned up.</p>
<p>
Own Id: OTP-8859</p>
</item>
<item>
<p>
When the runtime system had fewer schedulers than logical
processors, the system could get an unnecessarily large
amount reader groups.</p>
<p>
Own Id: OTP-8861</p>
</item>
<item>
<p>
<c>run_rel</c> has been updated to support Solaris's
/dev/ptmx device and to load the necessary STREAMS
modules so that <c>to_erl</c> can provide terminal echo
of keyboard input. (Thanks to Ryan Tilder.)</p>
<p>
Own Id: OTP-8878</p>
</item>
<item>
<p>
The Erlang VM now supports Unicode filenames. The feature
is turned on by default on systems where Unicode
filenames are mandatory (Windows and MacOSX), but can be
enabled on other systems with the '+fnu' emulator option.
Enabling the Unicode filename feature on systems where it
is not default is however considered experimental and not
to be used for production. Together with the Unicode file
name support, the concept of "raw filenames" is
introduced, which means filenames provided without
implicit unicode encoding translation. Raw filenames are
provided as binaries, not lists. For further information,
see stdlib users guide and the chapter about using
Unicode in Erlang. Also see the file module manual page.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-8887</p>
</item>
<item>
<p>Buffer overflows have been prevented in <c>erlc</c>,
<c>dialyzer</c>, <c>typer</c>, <c>run_test</c>,
<c>heart</c>, <c>escript</c>, and <c>erlexec</c>.</p>
(Thanks to Michael Santos.)
<p>
Own Id: OTP-8892</p>
</item>
<item>
<p>
The runtime system is now less eager to suspend processes
sending messages over the distribution. The default value
of the distribution buffer busy limit has also been
increased from 128 KB to 1 MB. This in order to improve
throughput.</p>
<p>
Own Id: OTP-8901</p>
</item>
<item>
<p>
The distribution buffer busy limit can now be configured
at system startup. For more information see the
documentation of the <c>erl</c> <seealso
marker="erl#+zdbbl">+zdbbl</seealso> command line flag.
(Thanks to Scott Lystig Fritchie)</p>
<p>
Own Id: OTP-8912</p>
</item>
<item>
<p>
The inet driver internal buffer stack implementation has
been rewritten in order to reduce lock contention.</p>
<p>
Own Id: OTP-8916</p>
</item>
<item>
<p>
New ETS option <c>compressed</c>, to enable a more
compact storage format at the expence of heavier table
operations. For test and evaluation, <c>erl +ec</c> can
be used to force compression on all ETS tables.</p>
<p>
Own Id: OTP-8922 Aux Id: seq11658 </p>
</item>
<item>
<p>
There is now a new function inet:getifaddrs/0 modeled
after C library function getifaddrs() on BSD and LInux
that reports existing interfaces and their addresses on
the host. This replaces the undocumented and unsupported
inet:getiflist/0 and inet:ifget/2.</p>
<p>
Own Id: OTP-8926</p>
</item>
<item>
<p>
Support for detection of CPU topology and binding of
schedulers on FreeBSD 8 have been added. (Thanks to Paul
Guyot)</p>
<p>
Own Id: OTP-8939</p>
</item>
<item>
<p>
Several bugs related to hibernate/3 and HiPE have been
corrected. (Thanks to Paul Guyot.)</p>
<p>
Own Id: OTP-8952</p>
</item>
<item>
<p>
Support for soft and hard links on Windows versions and
filesystems that support them is added.</p>
<p>
Own Id: OTP-8955</p>
</item>
<item>
<p>
The win32 virtual machine is now linked large address
aware. his allows the Erlang VM to use up to 3 gigs of
address space on Windows instead of the default of 2
gigs.</p>
<p>
Own Id: OTP-8956</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.8.1.2</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p> Fix that the documentation top index generator can
handle an Ericsson internal application group. </p>
<p>
Own Id: OTP-8875</p>
</item>
<item>
<p>In embedded mode, on_load handlers that called
<c>code:priv_dir/1</c> or other functions in <c>code</c>
would hang the system. Since the <c>crypto</c>
application now contains an on_loader handler that calls
<c>code:priv_dir/1</c>, including the <c>crypto</c>
application in the boot file would prevent the system
from starting.</p>
<p>Also extended the <c>-init_debug</c> option to print
information about on_load handlers being run to
facilitate debugging.</p>
<p>
Own Id: OTP-8902 Aux Id: seq11703 </p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.8.1.1</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
Windows 2003 and Windows XP pre SP3 would sometimes not
start the Erlang R14B VM at all due to a bug in the cpu
topology detection. The bug affects Windows only, no
other platform is even remotely affected. The bug is now
corrected.</p>
<p>
Own Id: OTP-8876</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.8.1</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
Very small floating point numbers generated errors when
converting from list to float in some versions of the VM,
this is now corrected so that i.e.
list_to_float("1.0e-324"). returns 0.0 in all versions of
Erlang.</p>
<p>
Own Id: OTP-7178</p>
</item>
<item>
<p>
Windows Vista and Windows 7 file system virtualization,
which makes "old style" windows programs execute in a
file system sandbox, was previously unintentionally
turned on for the Erlang VM. This is now corrected so
that i.e. writes to C:\Program Files\. without
administrator privileges will fail.</p>
<p>
Own Id: OTP-7405</p>
</item>
<item>
<p>
Fix faulty 64-bit integer term output from drivers. Large
64-bits integers did not generate correct bignums and
could even cause emulator crash. Only affects drivers
using ERL_DRV_INT64 or ERL_DRV_UINT64, introduced in
R13B03.</p>
<p>
Own Id: OTP-8716</p>
</item>
<item>
<p>
Fixed: inet:setopts(S, [{linger,{true,2}}]) returned
{error,einval} for SCTP sockets. The inet_drv had a bug
when checking the option size.</p>
<p>
Own Id: OTP-8726 Aux Id: seq11617 </p>
</item>
<item>
<p>Fix libm linking with --as-needed flag
<p>
When building with "--as-needed" linker flags on Linux
the build will fail. This has now been fixed.</p>
<p>
(Thanks to Christian Faulhammer)</p></p>
<p>
Own Id: OTP-8728</p>
</item>
<item>
<p>
gen_udp:connect/3 was broken for SCTP enabled builds. It
did not detect remote end errors as it should.</p>
<p>
Own Id: OTP-8729</p>
</item>
<item>
<p>Reduce the risk of integer wrapping in bin vheap size
counting.</p> <p>The vheap size series will now use the
golden ratio instead of doubling and fibonacci
sequences.</p>
<p>
Own Id: OTP-8730</p>
</item>
<item>
<p>
ETS ordered_set containing <c>[]</c> as key could cause
strange thing to happen, like an infinite hanging
<c>ets:select</c>.</p>
<p>
Own Id: OTP-8732</p>
</item>
<item>
<p>reference() has been substituted for ref() in the
documentation.</p>
<p>
Own Id: OTP-8733</p>
</item>
<item>
<p>
When a native compiled module called a not loaded
non-native compiled module that had an on_load function,
the export entries were trashed after code loading so on
the next call from the native compiled module to the
non-native compiled the emulator crashed. This bug has
now been fixed.</p>
<p>
Own Id: OTP-8736</p>
</item>
<item>
<p>
HiPE-enabled Erlang VMs running on BSD systems sometimes
generated messages like "Yikes! erts_alloc() returned
misaligned address 0x8016a512c". Fixed. (Thanks to Mikael
Pettersson.)</p>
<p>
Own Id: OTP-8769</p>
</item>
<item>
<p>
A race condition in <c>erts_poll()</c> could cause delay
of poll for I/O.</p>
<p>
Own Id: OTP-8773</p>
</item>
<item>
<p>
Removed some potential vulnerabilities from the Erlang
Port Mapper Daemon (epmd) and straightened up access
control. Also removed hazardous interfaces allowing
anyone on a machine to forcefully unregister other nodes.
This means that the ei_unregister/erl_unregister
interfaces in erl_interface is rendered not only error
prone and mystifying as before, but totally ineffective.
The old behaviour of unchecked node unregistering can be
restored if needed, see epmd documentation for details.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-8780</p>
</item>
<item>
<p> Building in a source tree without prebuilt platform
independent build results failed on the SSL examples
when: </p> <list><item> cross building. This has been
solved by not building the SSL examples during a cross
build. </item><item> building on Windows. </item></list>
<p>
Own Id: OTP-8791</p>
</item>
<item>
<p>
inet:getsockopt for SCTP sctp_default_send_param had a
bug to not initialize required feilds causing random
answers. It is now corrected.</p>
<p>
Own Id: OTP-8795 Aux Id: seq11655 </p>
</item>
<item>
<p>
The hipe_bifs:get_hrvtime/0 BIF now always returns a real
value even if the "perfctr" Linux kernel extension is not
available. It used to return a dummy value. (Thanks to
Mikael Pettersson.)</p>
<p>
Own Id: OTP-8798</p>
</item>
<item>
<p>
Calling a native-code compiled module with an
<c>on_load</c> function could cause a crash. (Thanks to
Mikael Pettersson.)</p>
<p>
Own Id: OTP-8799</p>
</item>
<item>
<p>The emulator could crash while writing a crash dump if
native-compiled modules had been loaded. (Thanks to Paul
Guyot.)</p>
<p>
Own Id: OTP-8801</p>
</item>
<item>
<p>
The garbage collector could crash if invoked from
native-compiled code after a call to a BIF. (Thanks to
Paul Guyot.)</p>
<p>
Own Id: OTP-8821</p>
</item>
<item>
<p>
A rare memory leak in binary:matches is removed</p>
<p>
Own Id: OTP-8823</p>
</item>
<item>
<p>For a socket in the HTTP packet mode, the return value
from <c>gen_tcp:recv/2,3</c> if there is an error in the
header will be <c>{ok,{http_error,String}}</c> instead of
<c>{error,{http_error,String}}</c> to be consistent with
<c>ssl:recv/2,3</c>.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-8831</p>
</item>
</list>
</section>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>
ets:select_reverse/{1,2,3} are now documented.</p>
<p>
Own Id: OTP-7863</p>
</item>
<item>
<p>
External format of integers changed to make full use of
all 32 bits of INTEGER_EXT. This is a compatible change
as old code can read full 32-bit integers but only
produce 28-bit integers as INTEGER_EXT.</p>
<p>
Own Id: OTP-8540 Aux Id: seq11534 </p>
</item>
<item>
<p>
Large parts of the <c>ethread</c> library have been
rewritten. The <c>ethread</c> library is an Erlang
runtime system internal, portable thread library used by
the runtime system itself.</p>
<p>
Most notable improvement is a reader optimized rwlock
implementation which dramatically improve the performance
of read-lock/read-unlock operations on multi processor
systems by avoiding ping-ponging of the rwlock cache
lines. The reader optimized rwlock implementation is used
by miscellaneous rwlocks in the runtime system that are
known to be read-locked frequently, and can be enabled on
ETS tables by passing the <seealso
marker="stdlib:ets#new_2_read_concurrency">{read_concurrency,
true}</seealso> option upon table creation. See the
documentation of <seealso
marker="stdlib:ets#new/2">ets:new/2</seealso> for more
information. The reader optimized rwlock implementation
can be fine tuned when starting the runtime system. For
more information, see the documentation of the <seealso
marker="erts:erl#+rg">+rg</seealso> command line argument
of <c>erl</c>.</p>
<p>
There is also a new implementation of rwlocks that is not
optimized for readers. Both implementations interleaves
readers and writers during contention as opposed to,
e.g., the NPTL (Linux) pthread rwlock implementation
which use either a reader or writer preferred strategy.
The reader/writer preferred strategy is problematic since
it starves threads doing the non-preferred operation.</p>
<p>
The new rwlock implementations in general performs better
in ERTS than common pthread implementations. However, in
some extremely heavily contended cases this is not the
case. Such heavy contention can more or less only appear
on ETS tables. This when multiple processes do very large
amounts of write locked operations simultaneously on the
same table. Such use of ETS is bad regardless of rwlock
implementation, will never scale, and is something we
strongly advise against.</p>
<p>
The new rwlock implementations depend on atomic
operations. If no native atomic implementation is found,
a fallback solution will be used. Using the fallback
implies a performance degradation. That is, it is more
important now than before to build OTP with a native
atomic implementation.</p>
<p>
The <c>ethread</c> library contains native atomic
implementations for, x86 (32 and 64 bit), powerpc (32
bit), sparc V9 (32 and 64 bit), and tilera (32 bit). On
other hardware gcc's builtin support for atomic memory
access will be used if such exists. If no such support is
found, <c>configure</c> will warn about no atomic
implementation available.</p>
<p>
The <c>ethread</c> library can now also use the
<c>libatomic_ops</c> library for atomic memory accesses.
This makes it possible for the Erlang runtime system to
utilize optimized native atomic operations on more
platforms than before. If <c>configure</c> warns about no
atomic implementation available, try using the
<c>libatomic_ops</c> library. Use the <seealso
marker="doc/installation_guide:INSTALL#How-to-Build-and-Install-ErlangOTP_A-Closer-Look-at-the-individual-Steps_Configuring">--with-libatomic_ops=PATH</seealso>
<c>configure</c> command line argument when specifying
where the <c>libatomic_ops</c> installation is located.
The <c>libatomic_ops</c> library can be downloaded from:
<url
href="http://www.hpl.hp.com/research/linux/atomic_ops/">http://www.hpl.hp.com/research/linux/atomic_ops/</url></p>
<p>
The changed API of the <c>ethread</c> library has also
caused modifications in the Erlang runtime system.
Preparations for the to come "delayed deallocation"
feature has also been done since it depends on the
<c>ethread</c> library.</p>
<p>
<em>Note</em>: When building for x86, the <c>ethread</c>
library will now use instructions that first appeared on
the pentium 4 processor. If you want the runtime system
to be compatible with older processors (back to 486) you
need to pass the <seealso
marker="doc/installation_guide:INSTALL#How-to-Build-and-Install-ErlangOTP_A-Closer-Look-at-the-individual-Steps_Configuring">--enable-ethread-pre-pentium4-compatibility</seealso>
<c>configure</c> command line argument when configuring
the system.</p>
<p>
Own Id: OTP-8544</p>
</item>
<item>
<p>
erlang:localtime_to_universaltime({{2008, 8, 1}, {0, 0,
0}},true) when TZ=UTC now behaves consistently on all
Unix platforms.</p>
<p>
The problem fixed was originally reported by Paul Guyot
on erlang-bugs mailing list:</p>
<p>
http://www.erlang.org/pipermail/erlang-bugs/2008-November/001077.html</p>
<p>
Own Id: OTP-8580</p>
</item>
<item>
<p>
Optimization reducing memory consumption by two words per
ETS object.</p>
<p>
Own Id: OTP-8737</p>
</item>
<item>
<p>
Fixes for unsupported halfword-emulator</p>
<p>
Own Id: OTP-8745</p>
</item>
<item>
<p>
NIF 64-bit integer support; <c>enif_get_int64</c>,
<c>enif_get_uint64</c>, <c>enif_make_int64</c>,
<c>enif_make_uint64</c>.</p>
<p>
Own Id: OTP-8746</p>
</item>
<item>
<p>
Alignment of trailing data in messages has been adjusted.
This in order to be able to pass data of any type as
trailing data in the future.</p>
<p>
Own Id: OTP-8754</p>
</item>
<item>
<p>
The obsolete/driver.h header file has been removed. It
has been obsolete and deprecated since R8B. Drivers that
still include obsolete/driver.h must be updated to
include erl_driver.h.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-8758</p>
</item>
<item>
<p>
Added erlang:system_info(build_type) which makes it
easier to chose drivers, NIF libraries, etc based on
build type of the runtime system.</p>
<p>
The NIF library for crypto can now be built for valgrind
and/or debug as separate NIF libraries that will be
automatically loaded if the runtime system has been built
with a matching build type.</p>
<p>
Own Id: OTP-8760</p>
</item>
<item>
<p>
Further lessened the memory requirements of ETS objects.</p>
<p>
Own Id: OTP-8762</p>
</item>
<item>
<p>The broken elib_malloc alternate memory allocator has
been removed. <c>erlang:system_info(elib_malloc)</c> will
always return <c>false</c>, and in R15,
<c>erlang:system_info(elib_malloc)</c> will fail with a
<c>badarg</c> exception.</p>
<p>
Own Id: OTP-8764</p>
</item>
<item>
<p>
Calling <c>erlang:system_info/1</c> with the new argument
<c>update_cpu_info</c> will make the runtime system
reread and update the internally stored CPU information.
For more information see the documentation of <seealso
marker="erlang#update_cpu_info">erlang:system_info(update_cpu_info)</seealso>.</p>
<p>
The CPU topology is now automatically detected on Windows
systems with less than 33 logical processors. The runtime
system will now, also on Windows, by default bind
schedulers to logical processors using the
<c>default_bind</c> bind type if the amount of schedulers
is at least equal to the amount of logical processors
configured, binding of schedulers is supported, and a CPU
topology is available at startup.</p>
<p>
Own Id: OTP-8765</p>
</item>
<item>
<p>
The SMP ERTS internal child waiter thread used on Linux
system with NPTL was unintentionally disabled during
cross compilation rewrites (OTP-8323 in R13B03). It has
now been re-enabled. Enabling it again gives a slight
performance improvement.</p>
<p>
Own Id: OTP-8774</p>
</item>
<item>
<p>
<c>epmd</c> used to generate a message to the syslog when
it started up, which could be annoying. This has been
changed to only generate the message if the debug swith
is given. (Thanks to Michael Santos.)</p>
<p>
Own Id: OTP-8775</p>
</item>
<item>
<p>
The scheduler wakeup threshold is now possible to adjust
at system boot. For more information see the <seealso
marker="erl#+swt">+swt</seealso> command line argument of
<c>erl</c>.</p>
<p>
Own Id: OTP-8811</p>
</item>
<item>
<p>
The undocumented function inet:ifget/2 has been improved
to return interface hardware address (MAC) on platforms
supporting getaddrinfo() (such as BSD unixes). Note it
still does not work on all platforms for example not
Windows nor Solaris, so the function is still
undocumented.</p>
<p>
Buffer overflow and field init bugs for inet:ifget/2 and
inet:getservbyname/2 has also been fixed.</p>
<p>
Thanks to Michael Santos.</p>
<p>
Own Id: OTP-8816</p>
</item>
<item>
<p>
Optimizations for MIPS when using gcc atomics. (Thanks to
Steve Vinoski)</p>
<p>
Own Id: OTP-8834</p>
</item>
<item>
<p>
Lock optimization in timer functionality.</p>
<p>
Own Id: OTP-8835</p>
</item>
</list>
</section>
<section><title>Known Bugs and Problems</title>
<list>
<item>
<p>Fix epmd and build environment to build on VxWorks</p>
<p>
Own Id: OTP-8838</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.8</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
Driver threads, such as async threads, using <seealso
marker="erl_driver#ErlDrvPDL">port data locks</seealso>
peeked at the port status field without proper locking
when looking up the driver queue.</p>
<p>
Own Id: OTP-8475</p>
</item>
<item>
<p>
The use of <c>mmap()</c> was unnecessarily disabled when
cross compiling.</p>
<p>
The <c>configure</c> arguments <c>--with-ssl</c>, and
<c>--with-odbc</c> refused to accept libraries outside of
<c>$erl_xcomp_sysroot</c> when cross compiling for no
good reason.</p>
<p>
The <c>configure</c> argument <c>--with-odbc</c> didn't
handle the value <c>yes</c> correct.</p>
<p>
The <c>configure</c> arguments <c>--with-odbc</c>, and
<c>--without-odbc</c> have also been added to the
configure help.</p>
<p>
(Thanks to Steve Vinoski for reporting these issues)</p>
<p>
Own Id: OTP-8484</p>
</item>
<item>
<p>
A call to the BIF <c>unregister(RegName)</c> when a port
had the name <c>RegName</c> registered in the runtime
system without SMP support caused a runtime system crash.
(Thanks to Per Hedeland for the bugfix and test case.)</p>
<p>
Own Id: OTP-8487</p>
</item>
<item>
<p>
The runtime system crashed if fewer logical processors
were found than reported by <c>sysconf(
SC_NPROCESSORS_CONF)</c>.</p>
<p>
Own Id: OTP-8549</p>
</item>
<item>
<p>
Fix memory management bug causing crash of non-SMP
emulator with async threads enabled. The bug did first
appear in R13B03.</p>
<p>
Own Id: OTP-8591 Aux Id: seq11554 </p>
</item>
<item>
<p>
Port locks could be prematurely destroyed.</p>
<p>
Own Id: OTP-8612</p>
</item>
<item>
<p>The <c>empd</c> program could loop and consume 100%
CPU time if an unexpected error ocurred in
<c>listen()</c> or <c>accept()</c>. Now <c>epmd</c> will
terminate if a non-recoverable error occurs. (Thanks to
Michael Santos.)</p>
<p>
Own Id: OTP-8618</p>
</item>
<item>
<p>
When kernel poll has been enabled, a livelock could in
rare circumstances occur. Problem reported by Chetan
Ahuja, fix by Mikael Pettersson.</p>
<p>
Own Id: OTP-8632</p>
</item>
<item>
<p>
Windows: Closing port of program that stalled without
reading all data could deadlock scheduler thread.</p>
<p>
Own Id: OTP-8641</p>
</item>
<item>
<p>
On some combination of Montavista Linux on Cavium Octeon
processors, some socket-related system calls returned
other numbers than -1 for errors. This caused a core dump
in inet_drv.c. Now the code works around this problem.</p>
<p>
Own Id: OTP-8654</p>
</item>
<item>
<p>
Missing memory barriers in <c>erts_poll()</c> could cause
the runtime system to hang indefinitely.</p>
<p>
Own Id: OTP-8658</p>
</item>
<item>
<p>
<c>ethr_rwmutex_tryrlock()</c> acquired and refused to
acquire a lock with inverted logic. The lock was however
never acquired in a thread unsafe manner. (Thanks to JR
Zhang for noting this issue)</p>
<p>
Own Id: OTP-8662</p>
</item>
<item>
<p>
Extreme combinations of register/unregister in a highly
parallell SMP application could crash the VM. The error
is corrected.</p>
<p>
Own Id: OTP-8663</p>
</item>
<item>
<p>
On Windows, files are now opened with FILE_SHARE_DELETE
to get closer to Unix semantics.</p>
<p>
Own Id: OTP-8667</p>
</item>
<item>
<p>
<c>erlang:system_info(multi_scheduling)</c> sometimes
erroneously returned <c>enabled</c> when it should have
returned <c>blocked</c>.</p>
<p>
Own Id: OTP-8675</p>
</item>
<item>
<p>
Fix bug causing <c>erlang:decode_packet</c> and
<c>enif_make_string</c> to generate faulty strings with
negative character values for ascii values larger than
127. (Thanks to Paul Guyot)</p>
<p>
Own Id: OTP-8685</p>
</item>
<item>
<p>
<c>open_port/2</c> with the <c>spawn</c> and
<c>spawn_executable</c> options can include an
<c>{env,Env}</c> option. In some cases unsetting
variables would not work on Unix (typically if more
variables were unset than were actually present in the
environment).</p>
<p>
Own Id: OTP-8701</p>
</item>
<item>
<p>
A user defined CPU topology set via a call to <seealso
marker="erlang#system_flag_cpu_topology">erlang:system_flag(cpu_topology,
CPUTopology)</seealso> was not properly verified, and
could in worst case cause an emulator crash. The emulator
crash could only occur when a user defined CPU topology
already existed and was redefined.</p>
<p>
Own Id: OTP-8710</p>
</item>
</list>
</section>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>
The grammar for match specifications in ERTS users guide
only described the tracing dialect of match
specifications. An informal grammar for the ETS dialect
is added.</p>
<p>
Own Id: OTP-8086 Aux Id: seq11333 </p>
</item>
<item>
<p>
The module binary from EEP31 (and EEP9) is implemented.</p>
<p>
Own Id: OTP-8217</p>
</item>
<item>
<p>
New NIF API function <c>enif_make_new_binary</c></p>
<p>
Own Id: OTP-8474</p>
</item>
<item>
<p>
The guard BIF <c>is_boolean/1</c> (introduced in R10B)
has now been included in the lists of BIFs allowed in
guards in the Reference Manual.</p>
<p>
Own Id: OTP-8477</p>
</item>
<item>
<p>
Added function <c>zip:foldl/3</c> to iterate over zip
archives.</p>
<p>
Added functions to create and extract escripts. See
<c>escript:create/2</c> and <c>escript:extract/2</c>.</p>
<p>
The undocumented function <c>escript:foldl/3</c> has been
removed. The same functionality can be achieved with the
more flexible functions <c>escript:extract/2</c> and
<c>zip:foldl/3</c>.</p>
<p>
Record fields has been annotated with type info. Source
files as been adapted to fit within 80 chars and trailing
whitespace has been removed.</p>
<p>
Own Id: OTP-8521</p>
</item>
<item>
<p>A regular expression with many levels of parenthesis
could cause a buffer overflow. That has been corrected.
(Thanks to Michael Santos.)</p>
<p>
Own Id: OTP-8539</p>
</item>
<item>
<p>
<c>erlang:decode_packet(httph_bin,..)</c> could return
corrupt header strings or even crash the VM. This has
been fixed. It only happened on 32-bit VM if the header
name was unknown and between 16 and 20 characters long.
Sockets with simular <c>packet</c> option did not suffer
from this bug.</p>
<p>
Own Id: OTP-8548</p>
</item>
<item>
<p>New NIF features:</p> <list><item> Send messages from
a NIF, or from thread created by NIF, to any local
process (<c>enif_send</c>) </item><item> Store terms
between NIF calls (<c>enif_alloc_env</c>,
<c>enif_make_copy</c>) </item><item> Create binary terms
with user defined memory management
(<c>enif_make_resource_binary</c>) </item></list> <p>And
some incompatible changes made to the API. For more
information see the warning text in <seealso
marker="erl_nif">erl_nif(3)</seealso>.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-8555</p>
</item>
<item>
<p>If the '<c>fop</c>' program (needed for building PDF
files) cannot not be found, it is now possible to build
the HTML and man pages anyway (there will also be dummy
PDF files with no real content created). (Thanks to
Tuncer Ayaz.)</p>
<p>
Own Id: OTP-8559</p>
</item>
<item>
<p>When defining macros the closing right parenthesis
before the dot is now mandatory.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-8562</p>
</item>
<item>
<p>Local and imported functions now override the
auto-imported BIFs when the names clash. The pre R14
behaviour was that auto-imported BIFs would override
local functions. To avoid that old programs change
behaviour, the following will generate an error:</p>
<list><item><p>Doing a call without explicit module name
to a local function having a name clashing with the name
of an auto-imported BIF that was present (and
auto-imported) before OTP R14A</p></item>
<item><p>Explicitly importing a function having a name
clashing with the name of an autoimported BIF that was
present (and autoimported) before OTP R14A</p></item>
<item><p>Using any form of the old compiler directive
<c>nowarn_bif_clash</c></p></item> </list> <p>If the BIF
was added or auto-imported in OTP R14A or later,
overriding it with an import or a local function will
only result in a warning,</p> <p>To resolve clashes, you
can either use the explicit module name <c>erlang</c> to
call the BIF, or you can remove the auto-import of that
specific BIF by using the new compiler directive
<c>-compile({no_auto_import,[F/A]}).</c>, which makes all
calls to the local or imported function without explicit
module name pass without warnings or errors.</p> <p>The
change makes it possible to add auto-imported BIFs
without breaking or silently changing old code in the
future. However some current code ingeniously utilizing
the old behaviour or the <c>nowarn_bif_clash</c> compiler
directive, might need changing to be accepted by the
compiler.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-8579</p>
</item>
<item>
<p>
A bug in re that could cause certain regular expression
matches never to terminate is corrected. (Thanks to
Michael Santos and Gordon Guthrie.)</p>
<p>
Own Id: OTP-8589</p>
</item>
<item>
<p>The erlang:open_port spawn and spawn_executable
directives can include an <c>{env,Env}</c> directive to
set up environment variables for the spawned process. A
bug prevented applications from using <c>{env,Env}</c> to
set an environment variable whose value ended with a
'<c>=</c>' (equal sign) character; the trailing equal
sign was mistaken as an indication that an environment
variable was to be cleared from the environment of the
spawned process. (Thanks to Steve Vinoski.)</p>
<p>
Own Id: OTP-8614</p>
</item>
<item>
<p><c>receive</c> statements that can only read out a
newly created reference are now specially optimized so
that it will execute in constant time regardless of the
number of messages in the receive queue for the process.
That optimization will benefit calls to
<c>gen_server:call()</c>. (See <c>gen:do_call/4</c> for
an example of a receive statement that will be
optimized.)</p>
<p>
Own Id: OTP-8623</p>
</item>
<item>
<p>
The functions file:advise/4 and file:datasync/1 have been
added. (Thanks to Filipe David Manana.)</p>
<p>
Own Id: OTP-8637</p>
</item>
<item>
<p>
New NIF API functions: <c>enif_make_atom_len</c>,
<c>enif_make_existing_atom_len</c>,
<c>enif_make_string_len</c>, <c>enif_get_atom_length</c>,
<c>enif_get_list_length</c>, <c>enif_is_list</c>,
<c>enif_is_tuple</c> (by Tuncer Ayaz)</p>
<p>
Own Id: OTP-8640</p>
</item>
<item>
<p>
Support for using gcc's built-in functions for atomic
memory access has been added. This functionallity will be
used if available and no other native atomic
implementation in ERTS is available.</p>
<p>
Own Id: OTP-8659</p>
</item>
<item>
<p>
The number of spinlocks used when implementing atomic
fall-backs when no native atomic implementation is
available has been increased from 16 to 1024.</p>
<p>
Own Id: OTP-8660</p>
</item>
<item>
<p>
Writer preferred pthread read/write locks has been
enabled on Linux.</p>
<p>
Own Id: OTP-8661</p>
</item>
<item>
<p>
The runtime system will by default bind schedulers to
logical processors using the <c>default_bind</c> bind
type if the amount of schedulers are at least equal to
the amount of logical processors configured, binding of
schedulers is supported, and a CPU topology is available
at startup. </p>
<p>
<em>NOTE:</em> If the Erlang runtime system is the only
operating system process that binds threads to logical
processors, this improves the performance of the runtime
system. However, if other operating system processes (as
for example another Erlang runtime system) also bind
threads to logical processors, there might be a
performance penalty instead. If this is the case you, are
are advised to unbind the schedulers using the <seealso
marker="erl#+sbt">+sbtu</seealso> command line argument,
or by invoking <seealso
marker="erlang#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type,
unbound)</seealso>.</p>
<p>
Own Id: OTP-8666</p>
</item>
<item>
<p>
The recently added BIFs erlang:min/2, erlang:max/2 and
erlang:port_command/3 are now auto-imported (as they were
originally intended to be). Due to the recent compiler
change (OTP-8579), the only impact on old code defining
it's own min/2, max/2 or port_command/3 functions will be
a warning, the local functions will still be used. The
warning can be removed by using
-compile({no_auto_import,[min/2,max/2,port_command/3]}).
in the source file.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-8669 Aux Id: OTP-8579 </p>
</item>
<item>
<p>
There is a new option 'exclusive' to file:open/2 that
uses the OS O_EXCL flag where supported to open the file
in exclusive mode.</p>
<p>
Own Id: OTP-8670</p>
</item>
<item>
<p>
Now, binary_to_term/2 is auto-imported. This will cause a
compile warning if and only if a module has got a local
function with that name.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-8671</p>
</item>
<item>
<p>
Alignment of scheduler data and run queues were adjusted.</p>
<p>
Own Id: OTP-8673</p>
</item>
<item>
<p>Call time breakpoint tracing</p> <list><item>Introduce
a <c>call_time</c> option to
<c>erlang:trace_pattern/3</c>.This option enables call
time breakpoint tracing on code that is executed by
processes with call tracing enabled. Call time tracing
stores the number of calls and the time spent of each
function with this trace pattern enabled. The information
can be retrieved with <c>erlang:trace_info/2</c></item>
<item>Add a scheduler array for BpData. To solve the
issue of multiple schedulers constantly updating the head
pointer to the bp data wheel, each scheduler now has its
own entrypoint to the wheel. This head pointer can be
updated without a locking being taken.</item></list>
<p>Teach call count tracing to use atomics</p>
<list><item>Call count previously used a global lock for
accessing and writing its counter in the breakpoint. This
is now changed to atomics instead.</item> <item>The
change will let call count tracing and cprof to scale
better when increasing the number of
schedulers.</item></list>
<p>
Own Id: OTP-8677</p>
</item>
<item>
<p><c>eprof</c> has been reimplemented with support in
the Erlang virtual machine and is now both faster (i.e.
slows down the code being measured less) and scales much
better. In measurements we saw speed-ups compared to the
old eprof ranging from 6 times (for sequential code that
only uses one scheduler/core) up to 84 times (for
parallel code that uses 8 cores).</p>
<p>Note: The API for the <c>eprof</c> has been cleaned up
and extended. See the documentation.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-8706</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.7.5.1</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
Driver threads, such as async threads, using <seealso
marker="erl_driver#ErlDrvPDL">port data locks</seealso>
peeked at the port status field without proper locking
when looking up the driver queue.</p>
<p>
Own Id: OTP-8475</p>
</item>
<item>
<p>
A call to the BIF <c>unregister(RegName)</c> when a port
had the name <c>RegName</c> registered in the runtime
system without SMP support caused a runtime system crash.
(Thanks to Per Hedeland for the bugfix and test case.)</p>
<p>
Own Id: OTP-8487</p>
</item>
<item>
<p>
Fix memory management bug causing crash of non-SMP
emulator with async threads enabled. The bug did first
appear in R13B03.</p>
<p>
Own Id: OTP-8591 Aux Id: seq11554 </p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.7.5</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
Fix <c>binary_to_term</c> crash on compressed term with
corrupt size field.</p>
<p>
Own Id: OTP-8336</p>
</item>
<item>
<p>
Processes and/or ports could get stuck on a blocked
scheduler when <c>erlang:system_flag(multi_scheduling,
block)</c> was used.</p>
<p>
Processes and/or ports could get stuck on an offline
scheduler when schedulers online were reduced using
<c>erlang:system_flag(schedulers_online,
SchedulersOnline)</c>.</p>
<p>
Own Id: OTP-8342</p>
</item>
<item>
<p>Building on Windows will now work if the paths to
<c>mc.exe</c> and <c>rc.exe</c> contain spaces. The
README.win32 file has been updated with some information
about building using Visual Studio 2008. (Thanks to
Andrew Thompson.)</p>
<p>
Own Id: OTP-8345</p>
</item>
<item>
<p>
EPMD now correctly handles the extra data field which can
be given in the ALIVE2_REQ request and retrieved in the
PORT2_RESP response. (Thanks to Klas Johansson.)</p>
<p>
Own Id: OTP-8361</p>
</item>
<item>
<p>
The configure test for reliable floating point exceptions
has been update to work on modern versions of Mac OS X.
(Thanks to Trannie Carter.)</p>
<p>
Own Id: OTP-8368</p>
</item>
<item>
<p>
ERTS makefiles used to detect the use of a gcc C compiler
by checking if CC equaled gcc. That is, the makefiles
failed to detect gcc C compilers with other command line
names than gcc. `configure' now substitute GCC into the
makefiles. If CC is a gcc C compiler, GCC will have the
value yes. (Thanks to Jean-S�bastien P�dron)</p>
<p>
Own Id: OTP-8373</p>
</item>
<item>
<p>
ETS bug causing the <c>memory</c> counter from
<c>ets:info</c> for ordered_set's to sometimes get out of
synch and absurdly high.</p>
<p>
Own Id: OTP-8377 Aux Id: seq11442 </p>
</item>
<item>
<p>
Immediately repeated multi-scheduling block/unblock
cycles using <c>erlang:system_flag(multi_scheduling,
block | unblock)</c> could deadlock the runtime system.</p>
<p>
Own Id: OTP-8386</p>
</item>
<item>
<p>A number of bugs concerning re and unicode are
corrected:</p>
<p>re:compile no longer loses unicode option, which also
fixes bug in re:split.</p>
<p>re:replace now handles unicode charlist replacement
argument</p>
<p>re:replace now handles unicode RE charlist argument
correctly</p>
<p>re:replace now handles binary unicode output correctly
when nothing is replaced.</p>
<p>Most code, testcases and error isolation done by Rory
Byrne.</p>
<p>
Own Id: OTP-8394</p>
</item>
<item>
<p>
The loading of native code was not properly atomic in the
SMP emulator, which could cause crashes. Also a per-MFA
information table for the native code has now been
protected with a lock since it turns that it could be
accessed concurrently in the SMP emulator. (Thanks to
Mikael Pettersson.)</p>
<p>
Own Id: OTP-8397</p>
</item>
<item>
<p>
Fix processes in exiting status that are about to be
scheduled, to not be allowed to garbage collect.</p>
<p>
Own Id: OTP-8420</p>
</item>
<item>
<p>Removed bogus "\011" character sequence in
documentation.</p>
<p>
Own Id: OTP-8422</p>
</item>
<item>
<p>
The resolver routines failed to look up the own node name
as hostname, if the OS native resolver was erroneously
configured, bug reported by Yogish Baliga, now fixed.</p>
<p>
The resolver routines now tries to parse the hostname as
an IP string as most OS resolvers do, unless the native
resolver is used.</p>
<p>
The DNS resolver inet_res and file resolver inet_hosts
now do not read OS configuration files until they are
needed. Since the native resolver is default, in most
cases they are never needed.</p>
<p>
The DNS resolver's automatic updating of OS configuration
file data (/etc/resolv.conf) now uses the 'domain'
keyword as default search domain if there is no 'search'
keyword.</p>
<p>
Own Id: OTP-8426 Aux Id: OTP-8381 </p>
</item>
<item>
<p>
The re module: A regular expression with an option change
at the start of a pattern that had top-level alternatives
could cause overwriting and/or a crash. (Thanks to
Michael Santos.)</p>
<p>
Own Id: OTP-8438</p>
</item>
<item>
<p>
Harmless buffer overflow by one byte in asn1 and
ram_file_drv.</p>
<p>
Own Id: OTP-8451</p>
</item>
</list>
</section>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>
Improved GC performance after BIF/NIF call when a lot of
heap fragments was created. This will mainly benefit NIFs
that return large compound terms.</p>
<p>
Own Id: OTP-8240</p>
</item>
<item>
<p>Incompatible changes in the experimental NIF
feature.</p> <list><item> Changed the NIF function
prototypes in order to allow more than 3 function
arguments. </item><item> <c>enif_get_data</c> renamed as
<c>enif_priv_data</c>. </item><item>
<c>enif_make_string</c> got a third argument for
character encoding. </item><item> The return value of
<c>erlang:load_nif/2</c> on error changed. </item></list>
<p>Read more in the documentation of <c>erl_nif</c> and
<c>erlang:load_nif/2</c></p>.
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-8304</p>
</item>
<item>
<p>Cross compilation improvements and other build system
improvements.</p>
<p>Most notable:</p> <list><item> Lots of cross
compilation improvements. The old cross compilation
support was more or less non-existing as well as broken.
Please, note that the cross compilation support should
still be considered as experimental. Also note that old
cross compilation configurations cannot be used without
modifications. For more information on cross compiling
Erlang/OTP see the <c>$ERL_TOP/INSTALL-CROSS.md</c> file.
</item><item> Support for staged install using <url
href="http://www.gnu.org/prep/standards/html_node/DESTDIR.html">DESTDIR</url>.
The old broken <c>INSTALL_PREFIX</c> has also been fixed.
For more information see the <c>$ERL_TOP/INSTALL.md</c>
file. </item><item> Documentation of the <c>release</c>
target of the top <c>Makefile</c>. For more information
see the <c>$ERL_TOP/INSTALL.md</c> file. </item><item>
<c>make install</c> now by default creates relative
symbolic links instead of absolute ones. For more
information see the <c>$ERL_TOP/INSTALL.md</c> file.
</item><item> <c>$ERL_TOP/configure --help=recursive</c>
now works and prints help for all applications with
<c>configure</c> scripts. </item><item> Doing <c>make
install</c>, or <c>make release</c> directly after
<c>make all</c> no longer triggers miscellaneous
rebuilds. </item><item> Existing bootstrap system is now
used when doing <c>make install</c>, or <c>make
release</c> without a preceding <c>make all</c>.
</item><item> The <c>crypto</c> and <c>ssl</c>
applications use the same runtime library path when
dynamically linking against <c>libssl.so</c> and
<c>libcrypto.so</c>. The runtime library search path has
also been extended. </item><item> The <c>configure</c>
scripts of <c>erl_interface</c> and <c>odbc</c> now
search for thread libraries and thread library quirks the
same way as <c>erts</c> do. </item><item> The
<c>configure</c> script of the <c>odbc</c> application
now also looks for odbc libraries in <c>lib64</c> and
<c>lib/64</c> directories when building on a 64-bit
system. </item><item> The <c>config.h.in</c> file in the
<c>erl_interface</c> application is now automatically
generated in instead of statically updated which reduces
the risk of <c>configure</c> tests without any effect.
</item></list>
<p>(Thanks to Henrik Riomar for suggestions and
testing)</p>
<p>(Thanks to Winston Smith for the AVR32-Linux cross
configuration and testing)</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-8323</p>
</item>
<item>
<p>NIF improvements:</p> <list><item> Driver API for
multi-threading made available for NIFs. </item><item>
Support for mempory managed (garbage collected) resource
objects. A way to pass "pointers" to native data
structures between C and Erlang in a safe way.
</item><item> Support for references, floats and term
comparison. </item><item> Various new functions, like
<c>enif_inspect_iolist_as_binary</c>,
<c>enif_make_sub_binary</c>, <c>enif_get_string</c>,
<c>enif_get_atom</c>, <c>enif_make_tuple_from_array</c>,
<c>enif_make_list_from_array</c>,
<c>enif_make_existing_atom</c>. </item></list>
<p>
Own Id: OTP-8335</p>
</item>
<item>
<p>
Minor alignment adjustments of scheduler specific data.</p>
<p>
Own Id: OTP-8341</p>
</item>
<item>
<p>The documentation is now possible to build in an open
source environment after a number of bugs are fixed and
some features are added in the documentation build
process. </p>
<p>- The arity calculation is updated.</p>
<p>- The module prefix used in the function names for
bif's are removed in the generated links so the links
will look like
"http://www.erlang.org/doc/man/erlang.html#append_element-2"
instead of
"http://www.erlang.org/doc/man/erlang.html#erlang:append_element-2".</p>
<p>- Enhanced the menu positioning in the html
documentation when a new page is loaded.</p>
<p>- A number of corrections in the generation of man
pages (thanks to Sergei Golovan)</p>
<p>- The legal notice is taken from the xml book file so
OTP's build process can be used for non OTP
applications.</p>
<p>
Own Id: OTP-8343</p>
</item>
<item>
<p>
There is new <c>erlang:binary_to_term/2</c> BIF that
takes an option list. The option <c>safe</c> can be used
to prevent creation of resources that are not garbage
collected (such as atoms). (Thanks to Jayson Vantuyl.)</p>
<p>
Own Id: OTP-8367</p>
</item>
<item>
<p>
The default settings for garbage collection of binaries
has been adjusted to be less aggressive than in R13B03.
It is now also possible configure the settings for binary
GC. See the documentation for <c>spawn_opt/2-5</c>,
<c>erlang:system_info/1</c>, <c>erlang:system_flag/2</c>,
<c>process_flag/2-3</c>, <c>erlang:trace/3</c>, and the
documenation for <c>erl</c> for the new command line
options <c>+hms</c> and <c>+hmbs</c>.</p>
<p>
Own Id: OTP-8370</p>
</item>
<item>
<p>
A bug causing memory corruption in re:run() has been
corrected. (Thanks to Yamashina Hio.)</p>
<p>
Own Id: OTP-8375</p>
</item>
<item>
<p>
The <c>-Werror</c> option for <c>erlc</c> and the
compiler option <c>warnings_as_errors</c> will cause
warnings to be treated as errors. (Thanks to Christopher
Faulet.)</p>
<p>
Own Id: OTP-8382</p>
</item>
<item>
<p>
Explicit top directories in archive files are now
optional.</p>
<p>
For example, if an archive (app-vsn.ez) just contains an
app-vsn/ebin/mod.beam file, the file info for the app-vsn
and app-vsn/ebin directories are faked using the file
info from the archive file as origin. The virtual
direcories can also be listed. For short, the top
directories are virtual if they does not exist.</p>
<p>
Own Id: OTP-8387</p>
</item>
<item>
<p>
An unnecessary lock operation in os:timestamp/0 has been
eliminated, making it slightly more efficient. (Thanks to
Jonas Falkevik and Tuncer Ayaz.)</p>
<p>
Own Id: OTP-8390</p>
</item>
<item>
<p>
There is a new <c>+t</c> emulator option for changing the
maximum number of atoms. (Thanks to Julien Barbot.)</p>
<p>
Own Id: OTP-8405</p>
</item>
<item>
<p>
Fixed numerous compiler warnings generated by gcc 4.4.1
and tile-cc 2.0.1.78377 when compiling the runtime
system.</p>
<p>
Own Id: OTP-8412</p>
</item>
<item>
<p>
<c>configure</c> learned the option
<c>--enable-m32-build</c> to force the building of a
32-bit run-time on systems where the default C compiler
generates 64-bit executables by default.</p>
<p>
Own Id: OTP-8415</p>
</item>
<item>
<p>
HiPE now works in the 64-bit emulator on Mac OS X.
(Thanks to Geoff Cant.)</p>
<p>
Own Id: OTP-8416</p>
</item>
<item>
<p>
Improved handling of symbolic links to escripts</p>
<p>
Own Id: OTP-8417</p>
</item>
<item>
<p>
Add lock profiling tool.</p>
<p>
The Lock profiling tool, lcnt, can make use of the
internal lock statistics when the runtime system is built
with this feature enabled.</p>
<p>
This provides a mechanism to examine potential lock
bottlenecks within the runtime itself.</p>
<p>
- Add erts_debug:lock_counters({copy_save, bool()}). This
option enables or disables statistics saving for
destroyed processes and ets-tables. Enabling this might
consume a lot of memory.</p>
<p>
- Add id-numbering for lock classes which is otherwise
undefined.</p>
<p>
Own Id: OTP-8424</p>
</item>
<item>
<p>
Removed spurious options to the emulator from escript.</p>
<p>
Own Id: OTP-8427</p>
</item>
<item>
<p>
Minor documentation fixes. Mainly anchor adjustments.</p>
<p>
Own Id: OTP-8457</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.7.4</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
An insufficient stack allocation was made when reading
CPU information on BSD operating systems. (Thanks Michael
Turner and Akira Kitada)</p>
<p>
Own Id: OTP-8207</p>
</item>
<item>
<p>
A bug when supplying an argument without a dash directly
after the program name when starting erlang could prevent
distribution to start. This is now corrected.</p>
<p>
Own Id: OTP-8209</p>
</item>
<item>
<p>
A ticker process could potentially be blocked
indefinitely trying to send a tick to a node not
responding. If this happened, the connection would not be
brought down as it should.</p>
<p>
Own Id: OTP-8218</p>
</item>
<item>
<p>
Using certain firewalls (i.e. MS IAS Client and certain
versions of COMODO) could expose an undocumented
behaviour in the Win32 socket interface causing the name
resolution calls to hang infinitely. This is now worked
around by adding possibilities for port programs under
Windows to use overlapped I/O on their standard
input/output file handles.</p>
<p>
Own Id: OTP-8230</p>
</item>
<item>
<p>
Fixed bug on ETS tables with <c>write_concurrency</c>.
The emulator could crash when doing a <c>select</c> or
<c>match</c> with a bound key without finding any object.</p>
<p>
Own Id: OTP-8242</p>
</item>
<item>
<p>The <c>information-request</c> /
<c>information-response</c>, and
<c>group-leader-change-request</c> /
<c>group-leader-changed-response</c> signal pairs
described below did not always adhere to the signal order
guarantees of Erlang's signal model in the runtime system
with SMP support. These signals could for example
sometimes pass exit signals.</p>
<p>The following BIFs behaviors can be modeled as if an
asynchronous <c>information-request</c> signal is sent to
<c>Pid</c>. If <c>Pid</c> is alive, it responds with an
asynchronous <c>information-response</c> signal;
otherwise, the runtime system responds with a
<c>no-such-process</c> signal. When the response is
received, the caller transforms it into the result of the
BIF.</p> <list> <item><c>is_process_alive(Pid)</c></item>
<item><c>erlang:process_display(Pid, Type)</c></item>
<item><c>process_info(Pid)</c></item>
<item><c>process_info(Pid, ItemSpec)</c></item> </list>
<p>When <c>Pid</c> resides on the same node as the caller
of <c>group_leader(GroupLeader, Pid)</c>, the
<c>group_leader/2</c> BIFs behavior can be modeled as if
an asynchronous <c>group-leader-change-request</c> signal
is sent to <c>Pid</c>. If <c>Pid</c> is alive, it
responds with an asynchronous
<c>group-leader-changed-response</c> signal; otherwise,
the runtime system responds with a <c>no-such-process</c>
signal. When the response is received, the caller
transforms it into the result of the BIF. The distributed
case which only consists of an asynchronous
<c>group-leader-change-request</c> signal and no response
is not effected.</p>
<p>
Own Id: OTP-8245</p>
</item>
<item>
<p>
Errors in the <c>system_profile</c> documentation has
been corrected.</p>
<p>
Own Id: OTP-8257</p>
</item>
<item>
<p>
Low watermark socket option modified high watermark
instead of low watermark in the inet_driver. (Thanks to
Feng Yu and Tuncer Ayaz)</p>
<p>
Own Id: OTP-8279</p>
</item>
<item>
<p>
A race condition could cause the runtime system with SMP
support to end up in a completely unresponsive state.</p>
<p>
Own Id: OTP-8297</p>
</item>
</list>
</section>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>
The use of <c>pthread_cond_timedwait()</c> have been
completely removed from the runtime system. This since
its behavior is unpredictable when the system clock is
suddenly changed. The previous use of it was harmless.</p>
<p>
Own Id: OTP-8193</p>
</item>
<item>
<p>
The documentation is now built with open source tools
(xsltproc and fop) that exists on most platforms. One
visible change is that the frames are removed.</p>
<p>
Own Id: OTP-8201</p>
</item>
<item>
<p>
A new garbage collecting strategy for binaries which is
more aggressive than the previous implementation.
Binaries now has a virtual binary heap tied to each
process. When binaries are created or received to a
process it will check if the heap limit has been reached
and if a reclaim should be done. This imitates the
behavior of ordinary Erlang terms. The virtual heaps are
grown and shrunk like ordinary heaps. This will lessen
the memory footprint of binaries in a system.</p>
<p>
Own Id: OTP-8202</p>
</item>
<item>
<p>
The <c>ErlDrvTermData</c> term types used by
<c>driver_output_term()</c> and <c>driver_send_term()</c>
have been extended with the term types
<c>ERL_DRV_INT64</c>, and <c>ERL_DRV_UINT64</c> for
passing 64-bit integers. Also the 64-bit integer data
types <c>ErlDrvSInt64</c> and <c>ErlDrvUInt64</c> have
been introduced.</p>
<p>
For more information see the <seealso
marker="erl_driver">erl_driver(3)</seealso>
documentation.</p>
<p>
Own Id: OTP-8205</p>
</item>
<item>
<p>
[escript] The restriction that the first line in escripts
must begin with <c>#!</c> has been removed.</p>
<p>
[escript] Some command line options to the escript
executable has now been documented. For example you can
run an escript in the debugger by just adding a command
line option.</p>
<p>
[escript] The documentation of the escript header syntax
has been clarified. For example the header is optional.
This means that it is possible to directly "execute"
<c>.erl</c>, <c>.beam</c> and<c>.zip</c> files.</p>
<p>
Own Id: OTP-8215</p>
</item>
<item>
<p>
The instruction for building OTP on Windows was outdated
and incomplete, the document is updated.</p>
<p>
Also the otp_build script required windows drives to show
up in Cygwin using the /cygdrive prefix. That requirement
is now removed.</p>
<p>
Own Id: OTP-8219</p>
</item>
<item>
<p>
A module can have native implemented functions (NIFs)
that are dynamically loaded by calling
<c>erlang:load_nif/2</c>. This is an experimental feature
that is not yet intended for production systems. It is
released with intention to get some early feedback on the
interfaces before they are carved in stone.</p>
<p>
Own Id: OTP-8220</p>
</item>
<item>
<p>
The <c>float/1</c> BIF would always force a garbage
collection. The BIFs <c>size/1</c>, <c>byte_size/1</c>,
<c>bit_size/1</c>, <c>abs/1</c>, and <c>round/1</c> would
force a garbage-collection if the result was not a
sufficiently small integer.</p>
<p>
Own Id: OTP-8221</p>
</item>
<item>
<p>
The <seealso
marker="erlang#port_command/3">erlang:port_command/3</seealso>
BIF has been added. <c>erlang:port_command/3</c> is
currently not auto imported, but it is planned to be auto
imported in OTP R14. For more information see the
<seealso marker="erlang">erlang(3)</seealso>
documentation.</p>
<p>
Own Id: OTP-8225</p>
</item>
<item>
<p>
'<c>configure --enable-darwin-64bit</c>' would fail if
Snow Leopard had been booted with the 64-bit kernel.
(Thanks to Ryan M. Graham.)</p>
<p>
Own Id: OTP-8236</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.7.3</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
On Windows, open_port({spawn,Command},Opts) could not run
executables with spaces in the path or filename,
regardless of quoting efforts. While
open_port({spawn_executable,Exec},Opts) can run any
executable, it was still impossible to use 'spawn' to do
the same thing. This is now corrected.</p>
<p>
Own Id: OTP-8055</p>
</item>
<item>
<p>
The scheduler bind type <c>processor_spread</c> spread
schedulers too much on large NUMA systems.</p>
<p>
The new scheduler bind type <c>spread</c> spreads
schedulers as much as possible, and behaves as
<c>processor_spread</c> previously did. For more
information see the documentation of the <c>+sbt</c>
command line argument in the <c>erl(1)</c> documentation,
and the documentation of
<c>erlang:system_flag(scheduler_bind_type,
SchedulerBindType)</c>.</p>
<p>
Own Id: OTP-8063</p>
</item>
<item>
<p>
Automatically detected CPU topology on Linux system could
erroneously contain logical processors with <c>-1</c> as
identifiers. This happened when
<c>sysconf(_SC_NPROCESSORS_CONF)</c> returned a value
larger than the amount of logical processors found.</p>
<p>
Own Id: OTP-8064</p>
</item>
<item>
<p>
When the minimal term [] (end of list) was sent as the
complete message to a process on another node, and
received there, it could not be decoded. This bug is now
corrected. Fortunately [] is uncommon as the complete
message in real applications but it is a serious bug
anyway.</p>
<p>
Own Id: OTP-8092</p>
</item>
<item>
<p>A bug when the floating point exception pointer was
not initialized has been corrected. It manifested itself
on CentOS 5.1 sometimes when a floating point value was
sent to a remote node. Bug reported and patch suggested
by David Reiss, confirmed by Mikael Pettersson.</p>
<p>Some build problems on IRIX was also corrected.
Problem reported by Patrick Baggett, patch by Mikael
Pettersson.</p>
<p>
Own Id: OTP-8095</p>
</item>
<item>
<p>
A terminating process could erroneously unregister a name
for another process. This could occur under the following
conditions: The name of the terminating process was
unregistered and then registered for another process
simultaneously as the process that first had the name was
terminating.</p>
<p>
Own Id: OTP-8099 Aux Id: seq11344 </p>
</item>
<item>
<p>
Running erlc in a very deep directory (with a path length
of more 256 or more characters) would cause the emulator
to crash in a call to <c>list_to_atom/1</c>. (Thanks to
Chris Newcombe.)</p>
<p>
Own Id: OTP-8124</p>
</item>
<item>
<p>
A deadlock of the runtime system could occur when
unregistering the name of a port.</p>
<p>
Own Id: OTP-8145</p>
</item>
<item>
<p>
<c>Makefile.in</c> has been updated to use the LDFLAGS
environment variable (if set). (Thanks to Davide
Pesavento.)</p>
<p>
Own Id: OTP-8157</p>
</item>
<item>
<p>
The pthread rwlock implemention on Linux could cause
starvation of writers. We, therefore, now use our own
rwlock implementation on Linux.</p>
<p>
Own Id: OTP-8158</p>
</item>
<item>
<p>
Open source Erlang builds are updated to work well on
Snow Leopard (MacOS X 10.6)</p>
<p>
Own Id: OTP-8168</p>
</item>
<item>
<p>
A call to <c>erlang:system_info(schedulers_online)</c>
could end up in an infinite loop. This happened if the
amount of schedulers was larger than one, the amount of
schedulers online was one, and someone was blocking
multi-scheduling.</p>
<p>
Own Id: OTP-8169</p>
</item>
<item>
<p>
An error in erlang:system_profile/2 could cause
timestamped messages to arrive out of order in the SMP
case. This has now been fixed.</p>
<p>
Own Id: OTP-8171</p>
</item>
<item>
<p>
<c>binary_to_atom/2</c> and
<c>binary_to_existing_atom/2</c> would leak memory if the
binary contained unaligned data.</p>
<p>
Own Id: OTP-8192</p>
</item>
<item>
<p>
The async thread pool in the runtime system without SMP
support used a memory allocator that was not thread safe
for async jobs.</p>
<p>
Own Id: OTP-8194</p>
</item>
</list>
</section>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>
Processor internal NUMA nodes are now supported in the
ERTS internal CPU topology representation. For more
information see the documentation of the <c>+sct</c>
command line argument in the <c>erl(1)</c> documentation,
and the documentation of
<c>erlang:system_info(cpu_topology)</c>.</p>
<p>
Own Id: OTP-8041</p>
</item>
<item>
<p>
Documentation for ets improved about concurrency.</p>
<p>
Own Id: OTP-8050</p>
</item>
<item>
<p>
Emulator flags in an escript were earlier inherited to
emulators started from from the emulator running the
escript. For example when an escript invoked
<c>os:cmd("erl")</c>, the new emulator were given
erroneous emulator flags. This bug has now been fixed</p>
<p>
Escript filenames may now contain dots.</p>
<p>
Own Id: OTP-8060</p>
</item>
<item>
<p>
Made some BIFs non-recursive (relational operators,hash
and phash) to limit internal stack usage.</p>
<p>
Own Id: OTP-8065</p>
</item>
<item>
<p>
Fixed Windows specific bug in erl_prim_loader. Now it
handles the root directory (e.g. c:/) better. This bug
affected the directory listing in the debugger.</p>
<p>
Own Id: OTP-8080</p>
</item>
<item>
<p>
A TCP socket with option <c>{packet,4}</c> could crash
the emulator if it received a packet header with a very
large size value (>2Gb). The same bug caused
<c>erlang:decode_packet/3</c> to return faulty values.
(Thanks to Georgos Seganos.)</p>
<p>
Own Id: OTP-8102</p>
</item>
<item>
<p>
The maximum size of the export table has been raised from
65536 to 524288 entries.</p>
<p>
Own Id: OTP-8104 Aux Id: seq11345 </p>
</item>
<item>
<p>
The file module has now a read_line/1 function similar to
the io:get_line/2, but with byte oriented semantics. The
function file:read_line/1 works for raw files as well,
but for good performance it is recommended to use it
together with the 'read_ahead' option for raw file
access.</p>
<p>
Own Id: OTP-8108</p>
</item>
<item>
<p>
Fixed bug causing emulator crash when reading a term in
external format containing a corrupt list with a negative
length.</p>
<p>
Own Id: OTP-8117</p>
</item>
<item>
<p>
New emulator flag <c>+sss</c>, to set stack size of
scheduler threads.</p>
<p>
Own Id: OTP-8119</p>
</item>
<item>
<p>
The Windows utility Erlsrv, run in interactive mode now
accepts options for registering internal service name and
description field of Windows registry database.</p>
<p>
Own Id: OTP-8132</p>
</item>
<item>
<p>
<c>erlang:demonitor(Mon, [flush])</c> has been optimized.
Previously it always searched the message queue of the
caller for a <c>'DOWN'</c> message. Current
implementation only search the message queue when
necessary. It is quite common that the search is not
necessary.</p>
<p>
A new option <c>info</c> has been added to
<c>erlang:demonitor/2</c>. For more information see the
<c>erlang(3)</c> documentation.</p>
<p>
Own Id: OTP-8143</p>
</item>
<item>
<p>
I/O tasks could unnecessarily be rescheduled. This was
harmless, but not useful work.</p>
<p>
Own Id: OTP-8148</p>
</item>
<item>
<p>
Minor improvements of <c>erlang:memory/[1,2]</c>.</p>
<p>
Own Id: OTP-8152</p>
</item>
<item>
<p>
New configuration option to enable use of shared zlib.</p>
<p>
Own Id: OTP-8155</p>
</item>
<item>
<p>
Fixed smp bug in ETS that could cause emulator crash when
table with more than 1000 objects accessed by several
processes, including calls to variants of <c>select</c>
or <c>match</c> combined with concurrent object deletion.</p>
<p>
Own Id: OTP-8166 Aux Id: seq11392 </p>
</item>
<item>
<p>
The code path interpretation is now more relaxed. The
flag -code_path_choice now defaults to relaxed instead of
strict. See the documentation of code and init for more
info.</p>
<p>
Own Id: OTP-8170</p>
</item>
<item>
<p>
Load balancing of run queues and check for I/O are
triggered more often than before in situations where
processes are scheduled often but are doing very little
work each time they execute.</p>
<p>
Own Id: OTP-8172</p>
</item>
<item>
<p>
Call tracing binary comprehensions would cause an
emulator crash. (Thanks to Paul Mineiro.)</p>
<p>
Own Id: OTP-8179</p>
</item>
<item>
<p>
<c>binary_to_term/1</c> would crash the emulator instead
of generating a <c>badarg</c> exception when given
certain invalid terms. (Thanks to Scott Lystig Fritchie.)</p>
<p>
Own Id: OTP-8180</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.7.2</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
Crash dumps should now cause less problems for the
crashdump_viewer application. (For processes where arity
was non-zero, the arguments are now longer printed - they
used to be printed in a format that was not parseable.)</p>
<p>
Own Id: OTP-7472 Aux Id: seq11019, 11292 </p>
</item>
<item>
<p>
Processes could potentially get stuck on an offline
scheduler.</p>
<p>
Own Id: OTP-7990</p>
</item>
<item>
<p>
<c>binary_to_atom/2</c> and
<c>binary_to_existing_atom/2</c> could leak memory if
they caused a <c>badarg</c> exception.</p>
<p>
Own Id: OTP-7997</p>
</item>
<item>
<p>
A process could under very rare circumstances erroneously
be resumed.</p>
<p>
Own Id: OTP-8000</p>
</item>
<item>
<p>
Load balancing between schedulers could under rare
circumstances cause an emulator crash.</p>
<p>
Own Id: OTP-8008</p>
</item>
<item>
<p>
<c>erlang:memory(processes_used)</c> always returned
<c>0</c> instead of the correct value. (Thanks to Geoff
Cant)</p>
<p>
Own Id: OTP-8022</p>
</item>
</list>
</section>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>
Major improvements of the Erlang distribution for Erlang
runtime systems with SMP support. Previously distribution
port locks were heavily contended, and all encoding and
decoding for a specific distribution channel had to be
done in sequence. Lock contention due to the distribution
is now negligible and both encoding and decoding of
Erlang messages can be done in parallel.</p>
<p>
The old atom cache protocol used by the Erlang
distribution has been dropped since it effectively
prevented all parallel encoding and decoding of messages
passed over the same distribution channel.</p>
<p>
A new atom cache protocol has been introduced which
isolates atom cache accesses and makes parallel encoding
and decoding of messages passed over the same
distribution channel possible. The new atom cache
protocol also use an atom cache size 8 times larger than
before. The new atom cache protocol is documented in the
ERTS users guide.</p>
<p>
Erlang messages received via the distribution are now
decoded by the receiving Erlang processes without holding
any distribution channel specific locks. Erlang messages
and signals sent over the distribution are as before
encoded by the sending Erlang process, but now without
holding any distribution channel specific locks during
the encoding. That is, both encoding and decoding can be
and are done in parallel regardless of distribution
channel used.</p>
<p>
The part that cannot be parallelized is the atom cache
updates. Atom cache updates are therefore now scheduled
on the distribution port. Since it is only one entity per
distribution channel doing this work there is no lock
contention due to the atom cache updates.</p>
<p>
The new runtime system does not understand the old atom
cache protocol. New and old runtime systems can however
still communicate, but no atom cache will be used.</p>
<p>
Own Id: OTP-7774</p>
</item>
<item>
<p>
Fixed a bug that caused error logging from
<c>driver_select</c> sometimes with additional symptoms
such as failing IP communications or even an emulator
crash.</p>
<p>
Own Id: OTP-7898 Aux Id: seq11304 </p>
</item>
<item>
<p>
Improved SMP concurrency for ETS tables. Several mutating
operations can now be performed truly concurrent on
different records of the same table. To support this, the
table has to be created with option
<c>write_concurrency</c>, as it is achieved at the
expense of some execution and memory overhead.
<c>ets:select</c> and <c>select_count</c> has also been
improved for all tables to not acquire exclusive table
lock during the iteration.</p>
<p>
Own Id: OTP-7922</p>
</item>
<item>
<p>
erl (that is erl.exe and dyn_erl) and erlexec has been
made more dynamic so no hard coded paths needs to added
at installation time to erl (that is erl.ini and erl).
Reltool will make use of this in a future release.</p>
<p>
Own Id: OTP-7952</p>
</item>
<item>
<p>
Added functionality to get higher resolution timestamp
from system. The erlang:now function returns a timestamp
that's not always consistent with the actual operating
system time (due to resilience against large time changes
in the operating system). The function os:timestamp/0 is
added to get a similar timestamp as the one being
returned by erlang:now, but untouched by Erlangs time
correcting and smoothing algorithms. The timestamp
returned by os:timestamp is always consistent with the
operating systems view of time, like the calendar
functions for getting wall clock time, but with higher
resolution. Example of usage can be found in the os
manual page.</p>
<p>
Own Id: OTP-7971</p>
</item>
<item>
<p>
Two new options are added to open_port - spawn_executable
which runs external executables in a controlled way, and
spawn_driver which only opens port to loaded Erlang
drivers. See the erlang manual page for details.</p>
<p>
Own Id: OTP-7995</p>
</item>
<item>
<p>
New functionality in ETS to transfer the ownership of a
table. A table can either change owner be declaring an
"heir", another process that will inherit the table if
the owner terminates. A table can also change owner by
calling a new function <c>ets:give_away</c>.</p>
<p>
Own Id: OTP-8006</p>
</item>
<item>
<p>
Updates to Tilera build environment.</p>
<p>
Own Id: OTP-8009</p>
</item>
<item>
<p>
A stack trace was unnecessarily saved during process
termination.</p>
<p>
Own Id: OTP-8014</p>
</item>
<item>
<p>
User defined CPU topology and scheduler bind type can now
be set from the command line when starting an emulator.
For more information see the documentation of the
<c>+sct</c>, and the <c>+sbt</c> emulator flags in the
<c>erl(1)</c> documentation.</p>
<p>
The CPU topologies returned from
<c>erlang:system_info/1</c> and
<c>erlang:system_flag/2</c> now always contain the
<c>processor</c> level, also when not strictly necessary.</p>
<p>
Own Id: OTP-8030</p>
</item>
<item>
<p>
Various fixes in ETS: <c>ets:first</c> could return a
deleted key in a fixated table. <c>ets:lookup</c> could
return objects out of order if a deleted object was
re-inserted into a fixed bag. <c>ets:delete_object</c>
could fail to delete duplicate objects in a
duplicate_bag.</p>
<p>
Own Id: OTP-8040</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.7.1</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
Fixed a bug on Windows that could make
<c>gen_tcp:send</c> hang trying to send an iolist of more
than 16 binaries.</p>
<p>
Own Id: OTP-7816</p>
</item>
<item>
<p>
The runtime system could under rare circumstances crash
during load balancing.</p>
<p>
Own Id: OTP-7908 Aux Id: otp-7500 </p>
</item>
<item>
<p>
<c>run_erl</c> uses fallback if Unix98 pseudo-terminal is
not present on host.</p>
<p>
Own Id: OTP-7916 Aux Id: seq11249 </p>
</item>
<item>
<p>
A message buffer memory leak in the runtime system
without smp support has been fixed.</p>
<p>
Own Id: OTP-7941</p>
</item>
<item>
<p>Attempting to append a binary of 16Mb or greater to
another binary using the bit syntax would cause a
<c>system_limit</c> exception. There was also several
cases when constructing binaries when a <c>badarg</c>
exception was generated when it should have been
<c>system_limit</c>.</p>
<p>
Own Id: OTP-7942</p>
</item>
<item>
<p>
The runtime system with SMP support failed to terminate
the caller of <c>link(RemotePid)</c> properly, if
<c>RemotePid</c> was the pid of a process on an
unreachable node. The calling process was in this case
marked as exiting, but never terminated.</p>
<p>
Own Id: OTP-7946</p>
</item>
</list>
</section>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>
Rudimentary support for cross compiling is added to the
source release. The support is still in its infancy and
has only been used to cross compile on Linux for a
different cpu architecture and a different Linux version,
but should be extendible to support other platforms as
well. The cross configuration files with examples are
placed in $ERL_TOP/xcomp/. View README.xcomp and run
$ERL_TOP/otp_build -help for further information.</p>
<p>
Own Id: OTP-7854</p>
</item>
<item>
<p>The escape sequence <c>\{</c> which was given a new
interpretation in R13A has retained its old meaning (the
ASCII code for <c>{</c>), which means that codes greater
than 255 have to be stated using hexadecimal characters
(for example, <c>\x{AAA}</c>). The escape sequence
<c>\xH</c> where H is a hexadecimal character followed by
something else but a hexadecimal character is no longer
valid (incompatibility with R13A). Character codes less
than 256 can be stated using two hexadecimal characters
(for example, <c>\x0D</c>).</p>
<p>
Own Id: OTP-7891 Aux Id: OTP-7855 </p>
</item>
<item>
<p>The <c>term_to_binary/1</c> BIF used to be implemented
with recursive C code, which could cause the Erlang
emulator to terminate because of a stack overflow.</p>
<p>Also fixed some minor issues in
<c>term_to_binary/1</c> and <c>binary_to_term/1</c>
pointed out by Matthew Dempsky.</p>
<p>
Own Id: OTP-7894</p>
</item>
<item>
<p>
Several glitches and performance issues in the Unicode
and I/O-system implementation of R13A have been
corrected.</p>
<p>
Own Id: OTP-7896 Aux Id: OTP-7648 OTP-7887 </p>
</item>
<item>
<p>
Minor documentation improvements of the
<c>scheduler_bind_type</c> argument of
<c>erlang:system_flag/2</c>, and the
<c>scheduler_bind_type</c>, and the
<c>scheduler_bindings</c> arguments of
<c>erlang:system_info/1</c>.</p>
<p>
Own Id: OTP-7901 Aux Id: OTP-7777 </p>
</item>
<item>
<p>
There is a new BIF <c>erlang:make_tuple/3</c>.</p>
<p>
Own Id: OTP-7913</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.7</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p><em>OpenSource:</em></p>
<p>FreeBSD leap-seconds are handled according to patch
submitted by OpenSource user Kenji Rikitake. No test case
covers this functionality (unsupported platform).</p>
<p>
Own Id: OTP-7609</p>
</item>
<item>
<p>
A corrected bug in <c>ets</c> for <c>bag</c> and
<c>duplicate_bag</c>. A <c>delete/2</c> or
<c>lookup_element/3</c> could miss objects in a fixed
table if one or more objects with the same key had
already been deleted.</p>
<p>
Own Id: OTP-7665</p>
</item>
<item>
<p>
A new driver call-back <c>stop_select</c> is introduced
to allow drivers to de-select and then close a file
descriptor in a safe way in a SMP emulator. The old way
was not strictly according to posix standard and could in
some rare cases lead to unexpected behavior. A new flag
<c>ERL_DRV_USE</c> can be passed to
<c>driver_select()</c> to tell it that the descriptor
should be closed. <c>stop_select</c> is then called when
it is safe to do so. Old drivers will however still work
as before.</p>
<p>
Own Id: OTP-7670</p>
</item>
<item>
<p>
A bug fixed for TCP sockets with option
<c>{packet,http}</c>. An HTTP request with an absolute
URI was returned with a corrupt path string. This bug did
only exist in R12B-4 and R12B-5.</p>
<p>
Own Id: OTP-7682 Aux Id: OTP-7647 </p>
</item>
<item>
<p>
run_erl did in some cases fail to extract control
sequences from to_erl (like: winsize=X,Y) and did instead
send them to be interpreted by the erlang shell.</p>
<p>
Own Id: OTP-7688</p>
</item>
<item>
<p>
A bug in the installer on Windows not updating file
associations properly is now corrected.</p>
<p>
Own Id: OTP-7746</p>
</item>
<item>
<p>More space than necessary could be allocated in
binaries when appending to a binary (also in a binary
comprehension) and the data appended did not consist of
wholes bytes (e.g. 13 bits).</p>
<p>
Own Id: OTP-7747</p>
</item>
<item>
<p>
The gen_sctp option sctp_peer_addr_params,
#sctp_paddrparams{address={IP,Port} was erroneously
decoded in the inet driver. This bug has now been
corrected.</p>
<p>
Own Id: OTP-7755</p>
</item>
<item>
<p>
Outstanding async driver jobs leaked memory if the
issuing port died before the async jobs completed.</p>
<p>
Own Id: OTP-7784</p>
</item>
<item>
<p>A bug in the dynamic library loading affecting, among
others, OpenSolaris is now corrected. (Thanks to Paul
Fisher.)</p>
<p>
Own Id: OTP-7796</p>
</item>
<item>
<p>
run_erl compile errors fixed for FreeBSD</p>
<p>
Own Id: OTP-7817</p>
</item>
<item>
<p>
A bug in the inet driver for SCTP on Solaris showing for
e.g gen_sctp:abort/1 and gen_sctp:eof/1 has been
corrected. Patch suggestion by Simon Cornish.</p>
<p>
Own Id: OTP-7866</p>
</item>
</list>
</section>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>
The order of objects visited in select for ordered_set is
now documented.</p>
<p>
Own Id: OTP-7339</p>
</item>
<item>
<p>
The runtime system with SMP support now uses multiple,
scheduler specific run queues, instead of one globally
shared run queue.</p>
<p>
The lock protecting the shared run queue was heavily
contended, and the shared run queue also caused Erlang
processes to randomly migrate between schedulers with
negative cache effects as a result.</p>
<p>
With the current scheduler specific run queue solution,
lock contention due to run queue protection has been
reduced, and Erlang processes are only migrated when
needed to balance the load between the schedulers. The
reduced amount of migration also reduce lock contention
on locks protecting the scheduler specific instances of
the erts internal memory allocators.</p>
<p>
The scheduler specific run queues are also a necessity
for a lot of future planned NUMA (Non-Uniform Memory
Access) specific optimizations.</p>
<p>
Own Id: OTP-7500</p>
</item>
<item>
<p>Support for Unicode is implemented as described in
EEP10. Formatting and reading of unicode data both from
terminals and files is supported by the io and io_lib
modules. Files can be opened in modes with automatic
translation to and from different unicode formats. The
module 'unicode' contains functions for conversion
between external and internal unicode formats and the re
module has support for unicode data. There is also
language syntax for specifying string and character data
beyond the ISO-latin-1 range.</p>
<p>The interactive shell will support input and output of
unicode characters when the terminal and operating system
supports it.</p>
<p>Please see the EEP and the io/io_lib manual pages as
well as the stdlib users guide for details.</p>
<p><em>I/O-protocol incompatibilities:</em></p>
<p>The io_protocol between io_Server and client is
updated to handle protocol data in unicode formats. The
updated protocol is now documented. The specification
resides in the stdlib <em>users manual</em>, which is a
new part of the manual.</p>
<p><em>io module incompatibilities:</em></p>
<p>The io:put_chars, io:get_chars and io:get_line all
handle and return unicode data. In the case where
binaries can be provided (as to io:put_chars), they shall
be encoded in UTF-8. When binaries are returned (as by
io:get_line/get_chars when the io_server is set in
<em>binary mode</em>) the returned data is also
<em>always</em> encoded as UTF-8. The file module however
still returns byte-oriented data, why file:read can be
used instead of io:get_chars to read binary data in
ISO-latin-1.</p>
<p><em>io_lib module incompatibilities:</em></p>
<p>io_lib:format can, given new format directives (i.e
"~ts" and "~tc"), return lists containing integers larger
than 255. </p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-7648 Aux Id: OTP-7580 OTP-7514 OTP-7494
OTP-7443 OTP-7181 EEP10 EEP11 </p>
</item>
<item>
<p>
The format of the string returned by
<c>erlang:system_info(system_version)</c> (as well as the
first message when Erlang is started) has changed. The
string now contains the both the OTP version number as
well as the erts version number.</p>
<p>
Own Id: OTP-7649</p>
</item>
<item>
<p>
Message passing has been further optimized for parallel
execution. Serial message passing is slightly more
expensive than before, but parallel send to a common
receiver is much cheaper.</p>
<p>
Own Id: OTP-7659</p>
</item>
<item>
<p>
Lock contention on the atom table lock when decoding
Erlang terms on the external format has been drastically
reduced.</p>
<p>
Own Id: OTP-7660</p>
</item>
<item>
<p>
The undocumented, unsupported, and deprecated guard BIF
<c>is_constant/1</c> has been removed.</p>
<p>
*** INCOMPATIBILITY with R12B ***</p>
<p>
Own Id: OTP-7673</p>
</item>
<item>
<p>
The Erlang process lock implementation has been improved
by Mat Hostetter at Tilera Corporation.</p>
<p>
Own Id: OTP-7692</p>
</item>
<item>
<p>
A <c>{nodedown, Node}</c> message passed by the
<c>net_kernel:monitor_nodes/X</c> functionality is now
guaranteed to be sent after <c>Node</c> has been removed
from the result returned by <c>erlang:nodes/Y</c>.</p>
<p>
Own Id: OTP-7725</p>
</item>
<item>
<p>The short-circuit operators <c>andalso</c> and
<c>orelse</c> no longer guarantees that their second
argument is either <c>true</c> or <c>false</c>. As a
consequence, <c>andalso</c>/<c>orelse</c> are now
tail-recursive.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-7748</p>
</item>
<item>
<p>
A new BIF, <c>lists:keyfind/3</c>, has been added. It
works like <c>lists:keysearch/3</c> except that it does
not wrap the returned tuple in a <c>value</c> tuple in
case of success. (Thanks to James Hague for suggesting
this function.)</p>
<p>
Own Id: OTP-7752</p>
</item>
<item>
<p>
Optimization for drivers by creating small binaries
direct on process heap.</p>
<p>
Own Id: OTP-7762</p>
</item>
<item>
<p><c>I bsl N</c> could cause the Erlang virtual machine
to run of memory instead generating a <c>system_limit</c>
if N was absurdly huge. (Thanks to Daniel Hedlund.)</p>
<p>There would always be a garbage collection when
evaluating <c>I bsl N</c> or <c>I bsr N</c> if <c>I</c>
was a bignum.</p>
<p>If <c>I</c> is an integer and <c>N</c> a bignum, <c>I
bsl N</c> will now cause the correct <c>system_limit</c>
exception instead of <c>bad_arith</c> as in earlier
releases.</p>
<p>If <c>I</c> is an integer and <c>N</c> a bignum, <c>I
bsr N</c> will return either 0 or -1 depending on the
sign of <c>I</c> instead of causing a <c>bad_arith</c>
exception as in earlier releases.</p>
<p>
Own Id: OTP-7764</p>
</item>
<item>
<p>
Scheduler threads can now be bound to logical processors
on newer Linux and Solaris systems. More systems will be
supported in the future.</p>
<p>
In some cases performance has increased drastically when
binding schedulers. Schedulers are not bound by default,
though. This since it might cause a performance
degradation if multiple programs have bound to
processors, e.g. multiple Erlang runtime systems. For
more information see the documentation of
<c>erlang:system_flag/2</c>.</p>
<p>
In order to bind scheduler threads the CPU topology need
to be known. On some newer Linux and Solaris systems the
runtime system automatically detects the CPU topology. If
the emulator isn't able to automatically detect the CPU
topology, the CPU topology can be defined. For more
information see the documentation of
<c>erlang:system_flag/2</c>.</p>
<p>
Own Id: OTP-7777</p>
</item>
<item>
<p>The compiler will refuse to a compile file where the
module name in the file differs from the output file
name.</p>
<p>When compiling using <c>erlc</c>, the current working
directory will no be included in the code path (unless
explicitly added using "-pa .").</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-7793</p>
</item>
<item>
<p>
The BIFs <c>atom_to_binary/2</c>,
<c>binary_to_atom/2</c>, and
<c>binary_to_existing_atom/2</c> have been added.</p>
<p>
Own Id: OTP-7804</p>
</item>
<item>
<p>
The amount of schedulers online can now be changed during
operation. The amount of schedulers online defaults to
the same amount as available logical processors. For more
information see the documentation of
<c>erlang:system_flag/2</c> and <c>erl</c>.</p>
<p>
Own Id: OTP-7811</p>
</item>
<item>
<p>The deprecated functions <c>erlang:fault/1</c>,
<c>erlang:fault/2</c>, and <c>file:rawopen/2</c> have
been removed.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-7812</p>
</item>
<item>
<p>
Erts internal dynamically allocated process and port
specific data for rarely used data. This is used to
reduce memory usage of processes and ports that do not
use specific functionality. More functionality will be
moved to process and port specific data in future
releases.</p>
<p>
Own Id: OTP-7818</p>
</item>
<item>
<p>
New packet type <c>http_bin</c> for gen_tcp sockets and
<c>erlang:decode_packet</c>. It works like <c>http</c>
except that strings are returned as binaries instead of
lists.</p>
<p>
Own Id: OTP-7821</p>
</item>
<item>
<p>
The obsolete wd_keeper program for embedded Solaris
systems has been removed.</p>
<p>
Own Id: OTP-7822</p>
</item>
<item>
<p>
Nodes belonging to different independent clusters can now
co-exist on the same host with the help of a new
environment variable setting ERL_EPMD_PORT.</p>
<p>
Own Id: OTP-7826</p>
</item>
<item>
<p>There are new functions <c>erlang:min/2</c> and
<c>erlang:max/2</c> to calculate the minimum and maximum
of two terms, respectively. Note that the functions are
not auto-imported, so they need to be imported explicitly
or the <c>erlang</c> prefix must be used when calling
them.</p>
<p>
Own Id: OTP-7841</p>
</item>
<item>
<p>The copyright notices have been updated.</p>
<p>
Own Id: OTP-7851</p>
</item>
<item>
<p>Enhanced build environment for cross compilation to
Tilera Tile architecture.</p>
<p>Support for native ethread atomics on Tilera
Tile64/TilePro (Thanks to Tilera Corporation).</p>
<p>
Own Id: OTP-7852</p>
</item>
<item>
<p>The escape sequences <c>\x</c> and <c>\{</c> have been
assigned new interpretations (they used to return the
ASCII code for <c>x</c> and <c>{</c> respectively). One
or more octal characters inside curly brackets after a
leading backslash is from now on an alternative to the
existing syntax <c>\NNN</c>, but can also be used for
codes greater than 255. In a similar fashion, one or more
hexadecimal characters can be put inside curly brackets
after a leading <c>\x</c>. Furthermore, the escape
sequences <c>\xH</c> and <c>\xHH</c>, where N is a
hexadecimal character, can be used for codes less than
256.</p>
<p>NOTE: These new escape sequences are still considered
experimental and may be changed in the R13B release.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-7855</p>
</item>
<item>
<p>
The PCRE library's exported function names are now
prefixed with erts_ in the erlang emulator to avoid
clashes with dynamically loaded drivers.</p>
<p>
Own Id: OTP-7861</p>
</item>
<item>
<p>
A runtime system with SMP support will now be built by
default on most platforms if a usable posix thread
library or native windows threads are found.</p>
<p>
For more information see the top README file.</p>
<p>
Own Id: OTP-7872</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.6.5.1</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
A corrected bug in <c>ets</c> for <c>bag</c> and
<c>duplicate_bag</c>. A <c>delete/2</c> or
<c>lookup_element/3</c> could miss objects in a fixed
table if one or more objects with the same key had
already been deleted.</p>
<p>
Own Id: OTP-7665</p>
</item>
<item>
<p>
A bug fixed for TCP sockets with option
<c>{packet,http}</c>. An HTTP request with an absolute
URI was returned with a corrupt path string. This bug did
only exist in R12B-4 and R12B-5.</p>
<p>
Own Id: OTP-7682 Aux Id: OTP-7647 </p>
</item>
<item>
<p>
Calling <c>gen_tcp:send()</c> from several processes on
socket with option <c>send_timeout</c> could lead to much
longer timeout than specified. The solution is a new
socket option <c>{send_timeout_close,true}</c> that will
do automatic close on timeout. Subsequent calls to send
will then immediately fail due to the closed connection.</p>
<p>
Own Id: OTP-7731 Aux Id: seq11161 </p>
</item>
<item>
<p>
A process being garbage collected via the
<c>garbage_collect/1</c> BIF or the
<c>check_process_code/2</c> BIF didn't handle message
receive and resume correctly during the garbage collect.
When this occurred, the process returned to the state it
had before the garbage collect instead of entering the
new state.</p>
<p>
Own Id: OTP-7738</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.6.5</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
A bug in inet_drv concerning gen_tcp:connect has been
corrected. A connect towards a non-open port through open
firewalls could sometimes erroneously be successful. Any
subsequent operation would fail, though.</p>
<p>
Own Id: OTP-6542</p>
</item>
<item>
<p>
Floating point arithmetics in drivers could cause a
runtime system crash and/or unexpected results on runtime
systems with floating point exceptions enabled. Floating
point exceptions are disabled unless explicitly enabled
or if hipe is enabled.</p>
<p>
Own Id: OTP-7237</p>
</item>
<item>
<p>
A bug when many sockets got signalled simultaneously
causing the emulator to panic with the message
"Inconsistent, why isnt io reported?" is now corrected.</p>
<p>
Own Id: OTP-7420</p>
</item>
<item>
<p>
Starting erl with option "-detached" now disconnects
correctly from terminal session on Unix.</p>
<p>
Own Id: OTP-7461</p>
</item>
<item>
<p>
Mended gdb etp-commands for ETS access.</p>
<p>
Own Id: OTP-7538</p>
</item>
<item>
<p>
<c>erlang:decode_packet/3</c> allows white space between
HTTP header tag and colon according to RFC2616.</p>
<p>
Own Id: OTP-7543</p>
</item>
<item>
<p>
An emulator compiled for SCTP now starts even if the
dynamic libraries are not present. The SCTP driver is
then of course not loaded.</p>
<p>
Own Id: OTP-7551</p>
</item>
<item>
<p>To build on Mac OS X, 10.3.0 or later is now required
because of fixes for two problems:</p>
<p>There would be a resource leak when <c>erl_ddl</c>
attempted to unload a driver. This problem has been
corrected by using <c>dlopen()</c> (which works on all
modern Unix-like platforms) instead of the Mac OS X
specific API calls.</p>
<p>Signal handling in the run-time system for HiPE has
been updated to work on later versions of Mac OS X than
10.2.x. Therefore, <c>--enable-hipe</c> now works on Mac
OS X with Intel CPUs.</p>
<p>Thanks to Geoff Cant for the patches.</p>
<p>
Own Id: OTP-7562</p>
</item>
<item>
<p>Corrected some information about the protocol between
EPMD and Erlang nodes. (Thanks to Michael Regen.)</p>
<p>
Own Id: OTP-7594</p>
</item>
<item>
<p>
When using
<c>erlang:system_monitor(Pid,{long_gc,Time})</c>, and the
GC time exceeded 1 second, it sometimes erroneously
showed up as about 4300 seconds. (This bug was corrected
in R9C, but re-introduced in R12B.) (Thanks to Chris
Newcombe.)</p>
<p>
Own Id: OTP-7622 Aux Id: OTP-4903, seq8379 </p>
</item>
</list>
</section>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>
The driver entry of a dynamically loaded driver is now
copied when loaded which enables some internal
optimizations. Note that drivers that modify the driver
entry during execution will not work anymore. Such a
miss-use of the driver interface is however not
supported.</p>
<p>
Own Id: OTP-6900</p>
</item>
<item>
<p>
The split function is now added to the re library.
Exceptions and errors from both run, replace and split
are made more consistent.</p>
<p>
Own Id: OTP-7514 Aux Id: OTP-7494 </p>
</item>
<item>
<p>
Fixed harmless compiler warnings when building the
emulator and minor build changes in order to avoid
unnecessary rebuilds.</p>
<p>
Own Id: OTP-7530</p>
</item>
<item>
<p>
There is now experimental support for loading of code
from archive files. See the documentation of <c>code</c>,
<c>init</c>, <c>erl_prim_loader </c> and <c>escript</c>
for more info.</p>
<p>
The error handling of <c>escripts</c> has been improved.</p>
<p>
An <c>escript</c> may now set explicit arguments to the
emulator, such as <c>-smp enabled</c>.</p>
<p>
An <c>escript</c> may now contain a precompiled beam
file.</p>
<p>
An <c>escript</c> may now contain an archive file
containing one or more applications (experimental).</p>
<p>
The internal module <c>code_aux</c> has been removed.</p>
<p>
Own Id: OTP-7548 Aux Id: otp-6622 </p>
</item>
<item>
<p>
The reallocation functionality part of the ERTS internal
memory allocators, now consider current block in
combination with surrounding free blocks as an
alternative location for a reallocation.</p>
<p>
Own Id: OTP-7555</p>
</item>
<item>
<p>There could remain false references from a process to
a module that has been called earlier, so that the
process would be killed if the module was reloaded.
(Thanks to Richard Carlsson.)</p>
<p>Also, the fix for this bug also made it possible to
make stack backtraces (as returned from
<c>erlang:get_stacktrace/0</c> and other functions) more
correct in that the immediate caller is always included
in the stack backtrace (it could sometimes be
missing).</p>
<p>
Own Id: OTP-7559</p>
</item>
<item>
<p>
Improved locking in IO-handling for better smp
performance.</p>
<p>
Own Id: OTP-7560</p>
</item>
<item>
<p>
Improved BIF rescheduling functionality.</p>
<p>
Own Id: OTP-7587</p>
</item>
<item>
<p>
Loading a module compiled with Erlang/OTP R9C and calling
<c>module_info/0</c> in the module would crash the
emulator. The emulator now refuses to load any module
compiled with R9C or earlier. (Note: only trivial modules
compiled with R10B or earlier could be loaded anyway.)
(Thanks to Martin Kjellin.)</p>
<p>
Own Id: OTP-7590</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.6.4.2</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
A process calling one of the following BIFs could under
very rare conditions deadlock in the runtime system with
SMP support: <c>check_process_code/2</c>,
<c>garbage_collect/1</c>, <c>process_info/[1,2]</c>,
<c>system_flag/2</c>, and
<c>erlang:suspend_process/[1,2]</c>.</p>
<p>
Own Id: OTP-7582</p>
</item>
<item>
<p>
A couple of statistics variables were not managed in a
thread safe manner in the runtime system with SMP
support.</p>
<p>
Own Id: OTP-7583</p>
</item>
<item>
<p>
An extremely rare race condition when terminating a
process could potentially cause a runtime system crash.</p>
<p>
Own Id: OTP-7584</p>
</item>
<item>
<p>
Under certain conditions and when using run_erl/to_erl,
the terminal Erlang driver (ttsl_drv) could crash the
emulator by doing a division by zero due to incorrect
handling of terminals reporting a zero width. For
terminals reporting zero width, the driver now fallbacks
to a default width of 80 and a default height of 24
(vt100), as a fallback behaviour. This fixes the crashes
and also makes output on "dumb" terminals much more
readable.</p>
<p>
Own Id: OTP-7592 Aux Id: seq11073 </p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.6.4.1</title>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>
A new <c>erts_alloc</c> parameter
<c>+M<S>rmbcmt</c> (relative multiblock carrier
move threshold) has been added. It determines when to
force a moving realloc in a multiblock carrier when a
block is shrunk. For more information see the
<c>erts_alloc(3)</c> documentation.</p>
<p>
Own Id: OTP-7540</p>
</item>
<item>
<p>The new option <c>+d</c> can be given to <c>erl</c> to
suppress the crash dump generation if an internal error
is detected. As a result, a more useful core dump is
produced.</p>
<p>
Own Id: OTP-7578 Aux Id: seq11052 </p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.6.4</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
Double backslashes in format string passed to the erts
internal printf implementation produced erroneous
results. No such format strings were passed to the erts
internal printf implementation, i.e., the bug was
therefore completely harmless. (Thanks to Perry Smith.)</p>
<p>
Own Id: OTP-7408</p>
</item>
<item>
<p>
Large files are now handled on Windows, where the
filesystem supports it.</p>
<p>
Own Id: OTP-7410</p>
</item>
<item>
<p>
Bug fixed for <c>{packet,http}</c> when space follows
http headers.</p>
<p>
Own Id: OTP-7458</p>
</item>
<item>
<p>
The trace option <c>running</c> could cause an emulator
crash if the current function couldn't be determined.</p>
<p>
Own Id: OTP-7484</p>
</item>
<item>
<p>
Using 16#ffffFFFF as a timeout value in receive...after
would often cause a timeout almost at once due to an
32-bit integer overflow. (Thanks to Serge Aleynikov and
Matthias Lang.)</p>
<p>
Own Id: OTP-7493</p>
</item>
<item>
<p>
For the process that an escript runs in, the
<c>trap_exit</c> process flag is now <c>false</c> instead
of <c>true</c> (as in previous releases). Scripts that
depend on the previous (counter-intuitive) behaviour
might not work. (Thanks to Bengt Kleberg.)</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-7517</p>
</item>
<item>
<p>
A bug in the <c>string:to_integer/1</c> builtin made the
emulator unstable. This is now corrected. (Thanks to Lev
Walkin.)</p>
<p>
Own Id: OTP-7526</p>
</item>
</list>
</section>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>Performance for ETS intensive applications should now
be better in the SMP emulator. Also, ETS table
identifiers (as returned by <c>ets:new/2</c>) are now
spread out in wider range than before (using 28 bits in a
32-bit emulator) to make sure that the table identifier
for a deleted table will not be quickly re-used.</p>
<p>NOTE: Table identifiers can now be negative integers.
Programs that (incorrectly) assume that table identifiers
can only be positive integers might stop to work. (The
type of a table identifier is intentionally not
documented, and may change in a future release.)</p>
<p>
Own Id: OTP-7348</p>
</item>
<item>
<p>
New BIF <c>erlang:decode_packet/3</c> that extracts a
protocol packet from a binary. Similar to the socket
option <c>{packet, Type}</c>. Also documented the socket
packet type <c>http</c> and made it official.
<em>NOTE</em>: The tuple format for <c>http</c> packets
sent from an active socket has been changed in an
incompatible way.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-7404</p>
</item>
<item>
<p>
The source code for the documentation for some
applications (erts, kernel, stdlib, and several others)
are now included in the source tar ball. There is
currently no Makefile support for building HTML files
from the source (such support will be included in a
future release).</p>
<p>
Own Id: OTP-7406</p>
</item>
<item>
<p>
A lot of frequently accessed memory counters (erts
internal) have been removed. This since they hurt
performance on the runtime system with SMP support. As a
result <c>erlang:memory/[0,1]</c> will only deliver a
result if all <c>erts_alloc(3)</c> allocators are enabled
(default). The result delivered when all
<c>erts_alloc(3)</c> allocators are enabled are both more
accurate and less accurate than before. More memory than
before are included in the result, but the different
parts that are summed are not gathered atomically. A call
to <c>erlang:memory/[0,1]</c> is much cheaper for the
system than before. This since the information isn't
gathered atomically anymore which was very expensive.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-7468</p>
</item>
<item>
<p>
Pre-allocators used for, for example, timers, and
messages have been rewritten to be scheduler specific.
That is, different schedulers will now allocate from
different pools which reduces lock contention.</p>
<p>
Own Id: OTP-7470</p>
</item>
<item>
<p>
On Mac OS X, file:sync/1 now guarantees that all
filesystem buffers are written to the disk by using the
fcntl() with F_FULLFSYNC option. Previously, file:sync/1
called fsync(), which only guaranteed that the data had
been transferred to the disk drive. (Thanks to Jan
Lehnardt.)</p>
<p>
Own Id: OTP-7471</p>
</item>
<item>
<p>
Termination of a process that takes a long time can now
be preempted, i.e., the terminating process will be
rescheduled for later continuation of termination so that
other processes can execute. Termination of a process
that owns many and/or large ets tables typically takes a
long time.</p>
<p>
Own Id: OTP-7477</p>
</item>
<item>
<p>
A new trace option <c>exiting</c> has been added. The
<c>exiting</c> trace is similar to the <c>running</c>
trace, but for exiting processes. For more information
see the erlang(3) documentation.</p>
<p>
The <c>erlang:trace/3</c> bif now doesn't block other
scheduler threads if only one tracee is specified in the
call to <c>erlang:trace/3</c>.</p>
<p>
Own Id: OTP-7481</p>
</item>
<item>
<p>
The re module is extended with repetitive matches (global
option) and replacement function.</p>
<p>
Own Id: OTP-7494 Aux Id: OTP-7181 </p>
</item>
<item>
<p>
In the section about binary construction, the reference
manual now mentions what happens when an integer value
does not fit into an integer segment of size N (namely,
that the N least significant bits will be put into into
the binary and that the most significant bits will be
silently discarded). (Thanks to Edwin Fine.)</p>
<p>
Own Id: OTP-7506</p>
</item>
<item>
<p>
Setting the <c>{active,once}</c> for a socket (using
inets:setopts/2) is now specially optimized (because the
<c>{active,once}</c> option is typically used much more
frequently than other options).</p>
<p>
Own Id: OTP-7520</p>
</item>
</list>
</section>
<section><title>Known Bugs and Problems</title>
<list>
<item>
<p>
Floating point arithmetics in drivers can cause a runtime
system crash and/or unexpected results on runtime systems
with floating point exceptions enabled. Floating point
exceptions are disabled unless explicitly enabled or if
hipe is enabled.</p>
<p>
Own Id: OTP-7237</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.6.3.3</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
Binary construction with an integer field of size 0 at
the end of the constructed binary (and the size given in
a variable), would cause a write of one byte outside the
memory reserved for the binary, which in turn could cause
an emulator crash.</p>
<p>
Own Id: OTP-7422</p>
</item>
<item>
<p>
A race condition in the dynamic driver implementation
could cause an emulator crash. (Thanks to Paul Fisher)</p>
<p>
Own Id: OTP-7464</p>
</item>
<item>
<p>
Calls to <c>erlang:system_info(allocated_areas)</c> could
cause the runtime system with SMP support to crash.</p>
<p>
Own Id: OTP-7474</p>
</item>
<item>
<p>
The <c>env</c> option to <c>open_port()</c> could cause
the runtime system with SMP support to crash.</p>
<p>
Own Id: OTP-7475</p>
</item>
</list>
</section>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>
Operations that needed to block other threads in the
runtime system with SMP support unnecessarily waited for
async threads to block. Most important the
<c>erlang:memory/[0,1]</c> bif, code loading, and the
<c>erlang:trace/3</c> bif.</p>
<p>
Own Id: OTP-7480</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.6.3.2</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
Calls to <c>erlang:memory/[0,1]</c> could cause the
runtime system with SMP support to crash.</p>
<p>
Own Id: OTP-7415</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.6.3.1</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
Doing local call trace on bit syntax matching code that
has been optimized with delayed sub-binary creation could
crash the emulator.</p>
<p>
Own Id: OTP-7399 Aux Id: seq10978 </p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.6.3</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
Only one to_erl process at a time is allowed to connect
to the same run_erl pipe. Prevents buggy behaviour when
IO from several to_erl's get interleaved.</p>
<p>
Own Id: OTP-5107</p>
</item>
<item>
<p>
IPv6 name resolving has now been fixed to use
getaddrinfo() patch (thoroughly reworked) courtesy of Love
H�rnquist-�strand submitted by Fredrik Thulin. It also
can use gethostname2() patch (also reworked) courtesy of
Mikael Magnusson for debian submitted by Sergei Golovan.</p>
<p>
Own Id: OTP-5382</p>
</item>
<item>
<p>
Improved error handling in run_erl</p>
<p>
Own Id: OTP-7252</p>
</item>
<item>
<p>A permanent fix for the deadlock issue temporarily
fixed by OTP-7260.</p> <taglist><tag>OTP-7260</tag><item>
The runtime system with SMP support could under rare
circumstances deadlock when a distribution channel was
taken down while multiple simultaneous operations were
performed on it. </item></taglist>
<p>
Own Id: OTP-7267 Aux Id: OTP-7260 </p>
</item>
<item>
<p>
./configure has been improved to find 64-bit OpenSSL
libraries.</p>
<p>
Own Id: OTP-7270</p>
</item>
<item>
<p>
A terminating process could under very rare circumstances
trigger a bug which could crash the runtime system with
SMP support.</p>
<p>
Own Id: OTP-7272</p>
</item>
<item>
<p>
SCTP_ADDR_CONFIRMED events are now handled by gen_sctp.</p>
<p>
Own Id: OTP-7276</p>
</item>
<item>
<p>
binary_to_term/1 would crash the emulator if the binary
data contained an external fun with non-atom module
and/or function. Corrected to generate a badarg
exception.</p>
<p>
Own Id: OTP-7281</p>
</item>
<item>
<p>
On Mac OS 10.5 (Leopard), sending to socket which the
other end closes could cause the emulator to consume 100%
CPU time. (Thanks to Matthias Radestock.)</p>
<p>
Own Id: OTP-7289</p>
</item>
<item>
<p>
The vanilla driver used on Windows could crash the
emulator and sometimes produced corrupt files. The
vanilla driver is the driver that is used when one only
pass a filename as first argument to <c>open_port/2</c>.
<em>NOTE</em>: This use of <c>open_port/2</c> is
<em>obsolete</em>, and the documentation of this use has
previously been removed. The functionality is only
present for backward compatibility reasons and
<em>will</em> eventually be removed.</p>
<p>
Own Id: OTP-7301</p>
</item>
<item>
<p>
Faulty matching in binaries larger than 512Mb on 64bit
machines fixed.(On 32bit, the size limit for binaries is
still 512Mb). Thanks to Edwin Fine and Per Gustafsson for
finding fault and fix.</p>
<p>
Own Id: OTP-7309</p>
</item>
<item>
<p>
crypto:start() on Windows caused emulator to hang on
error popup window if openssl DLL was not found. Windows
error popups now suppressed.</p>
<p>
Own Id: OTP-7325</p>
</item>
<item>
<p>
Configuration option <c>without-termcap</c> can be used to
disable the use of termcap libraries for terminal cursor
control in the shell.</p>
<p>
Own Id: OTP-7338</p>
</item>
<item>
<p>
to_erl reports its terminal window size to run_erl in
order to get output formatted accordingly</p>
<p>
Own Id: OTP-7342</p>
</item>
<item>
<p>
On Solaris, the <c>compressed</c> option for file
operations did not work if the file descriptor happened
to be greater than 255 (a problem with fopen() and
friends in Solaris itself).</p>
<p>
Own Id: OTP-7343 Aux Id: seq10949 </p>
</item>
<item>
<p>
A race condition in the runtime system with SMP support
causing an erroneous removal of a newly created ets table
has been fixed.</p>
<p>
The race occurred when a process removed a table during
termination simultaneously as another process removed the
same table via <c>ets:delete/1</c> and a third process
created a table that accidentaly got the same internal
table index as the table being removed.</p>
<p>
Own Id: OTP-7349</p>
</item>
<item>
<p>
<c>zlib:inflate</c> failed when the size of the inflated
data was an exact multiple of the internal buffer size
(4000 bytes by default).</p>
<p>
Own Id: OTP-7359</p>
</item>
<item>
<p>
If the total number of allowed atoms is exceeded, there
will now be a controlled termination of the emulator with
a crash dump file. The emulator used to simply crash.
(Thanks Howard Yeh and Thomas Lindgren.)</p>
<p>
Own Id: OTP-7372</p>
</item>
<item>
<p>
The break handler in werl on Windows could cause the
emulator to hang or crash, that is now corrected.</p>
<p>
Own Id: OTP-7394 Aux Id: seq10969 </p>
</item>
<item>
<p>
The configure script now tests for an serious
optimization bug in gcc-4.3.0. If the bug is present, the
configure script will abort (if this happens, the only
way to build Erlang/OTP is to change to another version
of gcc). (Thanks to Mikael Pettersson.)</p>
<p>
Own Id: OTP-7397</p>
</item>
</list>
</section>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>
On Unix, the emulator now notices when the width of the
terminal has changed. (Thanks to Matthew Dempsky and
Patrick Mahoney.)</p>
<p>
Own Id: OTP-7290</p>
</item>
<item>
<p>
There is a new function <c>init:stop/1</c> which can be
used to shutdown the system cleanly AND generate a
non-zero exit status or crash dump. (Thanks to Magnus
Froberg.)</p>
<p>
Own Id: OTP-7308</p>
</item>
<item>
<p>
process_info(Pid, garbage_collection) now returns more
information</p>
<p>
Own Id: OTP-7311</p>
</item>
<item>
<p>
The <c>hide</c> option for <c>open_port/2</c> is now
documented. (Thanks to Richard Carlsson.)</p>
<p>
Own Id: OTP-7358</p>
</item>
</list>
</section>
<section><title>Known Bugs and Problems</title>
<list>
<item>
<p>
Floating point arithmetics in drivers can cause a runtime
system crash on runtime systems with floating point
exceptions enabled. Floating point exceptions are
disabled unless explicitly enabled or if hipe is enabled.</p>
<p>
Own Id: OTP-7237</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.6.2</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
The maximum length of an atom of 255 characters is now
strictly enforced. <c>binary_to_term/1</c> will now fail
with a badarg if an encoded term contains an atom longer
than 255 characters. Atoms created by drivers will now be
truncated to 255 characters if necessary. (Thanks to
Matthew Dempsky.)</p>
<p>
Own Id: OTP-7147</p>
</item>
<item>
<p>
A bug in "bignum handling" on some 64bit architectures
could cause rem and div operations on large numbers to
hang indefinitely. Rem operations involving the smallest
negative number representable in 28 bits or 60 bits could
also cause access violation and emulator crash. Both
errors are corrected.</p>
<p>
Own Id: OTP-7177</p>
</item>
<item>
<p>
When doing the initial garbage collection after waking a
hibernated process, a fullsweep garbage collection was
unnecessarily triggered.</p>
<p>
Own Id: OTP-7212</p>
</item>
<item>
<p>The beta testing module <c>gen_sctp</c> now supports
active mode as stated in the documentation. Active mode
is still rather untested, and there are some issues about
what should be the right semantics for
<c>gen_sctp:connect/5</c>. In particular: should it be
blocking or non-blocking or choosable. There is a high
probability it will change semantics in a (near) future
patch.</p> <p>Try it, give comments and send in bug
reports!</p>
<p>
Own Id: OTP-7225</p>
</item>
<item>
<p>
Invalid arguments to <c>ets:update_counter/3</c> were not
handled correctly. A tuple position (<c>Pos</c>) less
than 1 caused the element directly following the key to
be updated (as if no position at all had been specified).
All invalid values for <c>Pos</c> will now fail with
<c>badarg</c>.</p>
<p>
Own Id: OTP-7226</p>
</item>
<item>
<p>
The runtime system with SMP support could under rare
circumstances deadlock when a distribution channel was
taken down while multiple simultaneous operations were
performed on it.</p>
<p>
Own Id: OTP-7260</p>
</item>
</list>
</section>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>
More checksum/hash algorithms from the zlib library are
now available as built in functions (like md5 hashes has
been for a long time).</p>
<p>
Own Id: OTP-7128</p>
</item>
<item>
<p>
Minor improvements in the garbage collector.</p>
<p>
Own Id: OTP-7139 Aux Id: OTP-7132 </p>
</item>
<item>
<p>
The switch "-detached" to the windows werl program now
can create an erlang virtual machine without any main
window and without a temporary console showing.</p>
<p>
Own Id: OTP-7142</p>
</item>
<item>
<p><c>erlang:system_info/1</c> now accepts the
<c>logical_processors</c>, and <c>debug_compiled</c>
arguments. For more info see the, <c>erlang(3)</c>
documentation.</p> <p>The scale factor returned by
<c>test_server:timetrap_scale_factor/0</c> is now also
effected if the emulator uses a larger amount of
scheduler threads than the amount of logical processors
on the system. </p>
<p>
Own Id: OTP-7175</p>
</item>
<item>
<p>
A new BIF ets:update_element/3. To update individual
elements within an ets-tuple, without having to read,
update and write back the entire tuple.</p>
<p>
Own Id: OTP-7200</p>
</item>
<item>
<p>
A process executing the <c>processes/0</c> BIF can now be
preempted by other processes during its execution. This
in order to disturb the rest of the system as little as
possible. The returned result is, of course, still a
consistent snapshot of existing processes at a time
during the call to <c>processes/0</c>.</p>
<p>
The documentation of the <c>processes/0</c> BIF and the
<c>is_process_alive/1</c> BIF have been updated in order
to clarify the difference between an existing process and
a process that is alive.</p>
<p>
Own Id: OTP-7213</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.6.1.1</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
Not enough parameters were passed when sending an error
report in erl_check_io.c (Thanks to Matthew Dempsky).</p>
<p>
Own Id: OTP-7176</p>
</item>
<item>
<p>
In rare circumstances, complex binary matching code could
cause the emulator to crash or not match when it should.
(Thanks to Rory Byrne.)</p>
<p>
Own Id: OTP-7198</p>
</item>
</list>
</section>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>The <c>{allocator_sizes, Alloc}</c> and
<c>alloc_util_allocators</c> arguments are now accepted
by <c>erlang:system_info/1</c>. For more information see
the <c>erlang(3)</c> documentation.</p>
<p>
Own Id: OTP-7167</p>
</item>
<item>
<p>
The finishing reallocation of the heap block when
hibernating a process is now always moving the heap block
since it drastically reduces memory fragmentation when
hibernating large amounts of processes.</p>
<p>
Own Id: OTP-7187</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.6.1</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
The SMP emulator on sparc64 erroneously used the sparc32
atomic and the sparc32 spinlock implementations which
caused it to crash.</p>
<p>
Own Id: OTP-7006</p>
</item>
<item>
<p>
Call tracing the new guard BIFs <c>byte_size</c>,
<c>bit_size</c>, or <c>tuple_size</c> and the loading a
module that uses one of those functions, could cause the
emulator to terminate.</p>
<p>
Own Id: OTP-7008</p>
</item>
<item>
<p>
configuring --enable-darwin-universal or
--enable-darwin-64bit on MacOSX could result in a non
optimized emulator. Top level configure script now
corrected.</p>
<p>
Own Id: OTP-7014</p>
</item>
<item>
<p>
configuring --with-gd did not produce correct include
flags for percept.</p>
<p>
Own Id: OTP-7015</p>
</item>
<item>
<p>
Environment variables weren't handled in thread safe
manner in the runtime system with SMP support on Windows.</p>
<p>
<c>erl_drv_putenv()</c>, and <c>erl_drv_getenv()</c> has
been introduced for use in drivers. Do <em>not</em> use
putenv(), or getenv() directly in drivers. For more
information see the <c>erl_driver</c> documentation.</p>
<p>
Own Id: OTP-7035</p>
</item>
<item>
<p>
HIPE: Corrected the choice of interface to the send/3 and
setnode/3 BIFs for native-compiled code. Using the
incorrect interface could, in unusual circumstances, lead
to random runtime errors.</p>
<p>
Own Id: OTP-7067</p>
</item>
<item>
<p>
Garbage collections could become extremely slow when
there were many keys in the process dictionary. (Thanks
to Fredrik Svahn.)</p>
<p>
Own Id: OTP-7068</p>
</item>
<item>
<p>
The duplicate documentation directory in the windows
installation is removed.</p>
<p>
Own Id: OTP-7070</p>
</item>
<item>
<p>Documentation bugfixes and clarifications.</p> (Thanks
to Joern ([email protected]), Matthias Lang, and Richard
Carlsson.)
<p>
Own Id: OTP-7079</p>
</item>
<item>
<p>
The runtime system with SMP support <em>not</em> using
the native atomic integer implementation part of OTP
could deadlock when run on a system with more than one
logical processor. That is, only the runtime system with
SMP support on <em>other</em> hardware platforms than
x86, x86_64, sparc32, and powerpc32 were effected by this
bug.</p>
<p>
Own Id: OTP-7080</p>
</item>
<item>
<p>
The break handling code (run when Ctrl-C is hit) could
could potentially deadlock the runtime system with SMP
support.</p>
<p>
Own Id: OTP-7104</p>
</item>
<item>
<p>
The sctp driver has been updated to work against newer
lksctp packages e.g 1.0.7 that uses the API spelling
change adaption -> adaptation. Older lksctp (1.0.6) still
work. The erlang API in gen_sctp.erl and inet_sctp.hrl
now spells 'adaptation' regardless of the underlying C
API.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-7120</p>
</item>
<item>
<p>A bug in <c>erlang:phash2/1</c> on 64-bit platforms
has been fixed. (Thanks to Scott Lystig Fritchie.)</p>
<p>
Own Id: OTP-7127</p>
</item>
<item>
<p>
The emulator could under rare circumstances crash while
garbage collecting.</p>
<p>
Own Id: OTP-7132</p>
</item>
</list>
</section>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>The documentation has been updated so as to reflect
the last updates of the Erlang shell as well as the minor
modifications of the control sequence <c>p</c> of the
<c>io_lib</c> module.</p> <p>Superfluous empty lines have
been removed from code examples and from Erlang shell
examples.</p>
<p>
Own Id: OTP-6944 Aux Id: OTP-6554, OTP-6911 </p>
</item>
<item>
<p>
Bit syntax construction with a small integer in a
non-byte aligned field wider than the CPU's word size
could cause garbage bits in the beginning of the field.</p>
<p>
Own Id: OTP-7085</p>
</item>
<item>
<p>
All Windows versions older than Windows 2000 are now
<em>not supported</em> by the Erlang runtime system. This
since there was a need for usage of features introduced
in Windows 2000.</p>
<p>
Own Id: OTP-7086</p>
</item>
<item>
<p>Memory management improvements especially for the
runtime system with SMP support:</p> <list> <item> The
runtime system with SMP support can now use multiple,
thread specific instances of most memory allocators. This
improves performance since it reduces lock contention in
the memory allocators. It may however increase memory
usage for some applications. The runtime system with SMP
support will by default enable this feature on most
allocators. The amount of instances used can be
configured. </item> <item> <c>driver_alloc()</c>,
<c>driver_realloc()</c>, and <c>driver_free()</c> now use
their own erts specific memory allocator instead of the
default <c>malloc()</c> implementation on the system.
</item> <item> The default configuration of some
allocators have been changed to fit applications that use
much memory better. </item> <item> Some new
<c>erts_alloc</c> configuration parameters have been
added. </item> <item> <c>erts_alloc_config</c> has been
modified to be able to create configurations suitable for
multiple instances of allocators. </item> <item> The
returned value from <c>erlang:system_info({allocator,
Alloc})</c> has been changed. This since an allocator may
now run in multiple instances. </item> </list> <p>If you
for some reason want the memory allocators to be
configured as before, you can pass the <c>+Mea r11b</c>
command-line argument to <c>erl</c>.</p> <p>For more
information see the <c>erts_alloc(3)</c>, the
<c>erts_alloc_config(3)</c>, and the <c>erlang(3)</c>
documentation.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-7100</p>
</item>
<item>
<p>
On Unix, denormalized floating point numbers could not be
created using <c>list_to_float/1</c> or
<c>binary_to_term/1</c>. (Thanks to Matthew Dempsky.)</p>
<p>
Own Id: OTP-7122</p>
</item>
<item>
<p>
Native atomic integers and spin-locks are now also
available for the runtime system with SMP support on
sparc64.</p>
<p>
Own Id: OTP-7130</p>
</item>
<item>
<p>
FP exceptions support for sparc64 userspace on Linux has
been added. Note that FP exception support is now turned
off by default, so to actually enable it you need to do
'<c>./configure --enable-fp-exceptions</c>'.</p>
<p>
Own Id: OTP-7131</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.6</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
A bug for raw files when reading 0 bytes returning 'eof'
instead of empty data has been corrected.</p>
<p>
Own Id: OTP-6291 Aux Id: OTP-6967 </p>
</item>
<item>
<p>
All exported functions in gzio.c have now been renamed to
avoid conflict with drivers that are indirectly linked
with an external zlib library.</p>
<p>
Own Id: OTP-6816 Aux Id: OTP-6591 </p>
</item>
<item>
<p>
On the 64-bit Erlang emulator, bit syntax construction
with integers containing more than 60 bits ("big
numbers") into fields with more than 60 bits could
produce incorrect results.</p>
<p>
Own Id: OTP-6833</p>
</item>
<item>
<p>
When the runtime system failed to allocate memory for
binaries, it could dead lock while writing the
<c>erl_crash.dump</c>.</p>
<p>
Own Id: OTP-6848</p>
</item>
<item>
<p>
The runtime system with SMP support could deadlock if a
process called the <c>erlang:suspend_process(Pid)</c> BIF
or the <c>erlang:garbage_collect(Pid)</c> BIF while the
process identified by <c>Pid</c> was currently running
and the process calling the BIFs was terminated during
the call to the BIFs.</p>
<p>
Processes suspending each other via the
<c>erlang:suspend_process/1</c> BIF or garbage collecting
each other via the <c>erlang:garbage_collect/1</c> BIF
could deadlock each other when the runtime system with
SMP support was used.</p>
<p>
Own Id: OTP-6920</p>
</item>
<item>
<p>
<c>dbg</c> could leave traced processes in a suspended
state if the tracer process was killed with exit reason
<c>kill</c>.</p>
<p>
<c>erlang:suspend_process/2</c> has been introduced which
accepts an option list as second argument. For more
information see the <c>erlang(3)</c> documentation.</p>
<p>
Processes suspended via
<c>erlang:suspend_process/[1,2]</c> will now be
automatically resumed if the process that called
<c>erlang:suspend_process/[1,2]</c> terminates.</p>
<p>
Processes could previously be suspended by one process
and resumed by another unless someone was tracing the
suspendee. This is <em>not</em> possible anymore. The
process resuming a process <em>has</em> to be the one
that suspended it.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-6946</p>
</item>
<item>
<p>file:write_file/3, file:write/2 and file:read/2 could
crash (contrary to documentation) for odd enough file
system problems, e.g write to full file system. This bug
has now been corrected.</p> <p>In this process the file
module has been rewritten to produce better error codes.
Posix error codes now originate from the OS file system
calls or are generated only for very similar causes (for
example 'enomem' is generated if a memory allocation
fails, and 'einval' is generated if the file handle in
Erlang is a file handle but currently invalid).</p>
<p>More Erlang-ish error codes are now generated. For
example <c>{error,badarg}</c> is now returned from
<c>file:close/1</c> if the argument is not of a file
handle type. See file(3).</p> <p>The possibility to write
a single byte using <c>file:write/2</c> instead of a list
or binary of one byte, contradictory to the
documentation, has been removed.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-6967 Aux Id: OTP-6597 OTP-6291 </p>
</item>
<item>
<p>
Monitor messages produced by the system monitor
functionality, and garbage collect trace messages could
contain erroneous heap and/or stack sizes when the actual
heaps and/or stacks were huge.</p>
<p>
As of erts version 5.6 the <c>large_heap</c> option to
<c>erlang:system_monitor/[1,2]</c> has been modified. The
monitor message is sent if the sum of the sizes of all
memory blocks allocated for all heap generations is equal
to or larger than the specified size. Previously the
monitor message was sent if the memory block allocated
for the youngest generation was equal to or larger than
the specified size.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-6974 Aux Id: seq10796 </p>
</item>
<item>
<p>
<c>inet:getopts/2</c> returned random values on Windows
Vista.</p>
<p>
Own Id: OTP-7003</p>
</item>
</list>
</section>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>
The emulator internal process lock implementation has
been rewritten and optimized. A slight risk of starvation
existed in the previous implementation. This risk has
also been eliminated in the new implementation.</p>
<p>
Own Id: OTP-6500</p>
</item>
<item>
<p>
Bitstrings (bit-level) binaries and binary comprehensions
are now part of the language. See the Reference Manual.</p>
<p>
Own Id: OTP-6558</p>
</item>
<item>
<p>
The windows version of erlang now has SMP support. The
SMP emulator is run by default on machines which shows
more than one virtual or physical processor.</p>
<p>
Own Id: OTP-6560 Aux Id: OTP-6925 </p>
</item>
<item>
<p>
The details of the compressed term format has been
documented in erl_ext_dist.txt. (Thanks to Daniel
Goertzen.)</p>
<p>
Own Id: OTP-6755</p>
</item>
<item>
<p>
The runtime system with SMP support is now started by
default if more than one logical processor are detected.
For more information, see the <c>erl(3)</c>
documentation.</p>
<p>
Own Id: OTP-6756</p>
</item>
<item>
<p>
The external format for Erlang terms and the distribution
protocol are now documented in ERTS User's Guide.</p>
<p>
Own Id: OTP-6779</p>
</item>
<item>
<p>
New BIF's erlang:system_profile/1 and
erlang:system_profile/2. These BIF's controls concurrency
profiling options for processes, ports and schedulers.</p>
<p>
Own Id: OTP-6783 Aux Id: OTP-6285 </p>
</item>
<item>
<p>
The <c>ErlDrvTermData</c> term types used by
<c>driver_output_term()</c> and <c>driver_send_term()</c>
have been extended with the term types
<c>ERL_DRV_BUF2BINARY</c>, <c>ERL_DRV_EXT2TERM</c>, and
<c>ERL_DRV_UINT</c>. <c>ERL_DRV_BUF2BINARY</c> is used
for passing and creating a binary,
<c>ERL_DRV_EXT2TERM</c> is used for passing terms encoded
with the external term format, and <c>ERL_DRV_UINT</c> is
used for passing unsigned integers.</p>
<p>
Also the data types <c>ErlDrvUInt</c> and
<c>ErlDrvSInt</c> have been added which makes it more
obvious how arguments to term types are interpreted with
regards to width and signedness.</p>
<p>
The incorrect data types <c>ErlDriverTerm</c>,
<c>ErlDriverBinary</c>, and <c>ErlDriverPort</c> in the
<c>erl_driver(3)</c> documentation have been replaced
with the correct data types <c>ErlDrvTermData</c>,
<c>ErlDrvBinary</c>, and <c>ErlDrvPort</c>.</p>
<p>
For more information see the <c>erl_driver(3)</c>
documentation.</p>
<p>
Own Id: OTP-6823</p>
</item>
<item>
<p>
Miscellaneous improvements of the erts internal thread
library.</p>
<p>
It now support optimized atomic operations and spin-locks
on windows.</p>
<p>
Fall-backs based on mutexes and/or spin-locks for missing
optimized atomic operations, spin-locks, or rwlocks has
been implemented. This makes it possible to compile the
runtime system with SMP support on a lot more platforms.</p>
<p>
Default stack size on OpenBSD has been increased to 256
kilo-words.</p>
<p>
Own Id: OTP-6831 Aux Id: OTP-6560 </p>
</item>
<item>
<p>Many bit syntax operations, both construction and
matching, are faster. For further information, see the
Efficiency Guide.</p>
<p>
Own Id: OTP-6838</p>
</item>
<item>
<p>Literal lists, tuples, and binaries are no longer
constructed at run-time as they used to be, but are
stored in a per-module constant pool. Literals that are
used more than once are stored only once.</p>
<p>This is not a change to the language, only in the
details of its implementation. Therefore, the
implications of this change is described in the
Efficiency Guide.</p>
<p>Example 1: In the expression <c>element(BitNum-1,
{1,2,4,8,16,32,64,128})</c>, the tuple used to be
constructed every time the expression was executed, which
could be detrimental to performance in two ways if the
expression was executed in a loop: the time to build the
tuple itself and the time spent in garbage collections
because the heap filled up with garbage faster.</p>
<p>Example 2: Literal strings, such as <c>"abc"</c>, used
to be stored in the compiled code compactly as a byte
string and expanded to a list at run-time. Now all
strings will be stored expanded to lists (such as
<c>[$a,$b,$c]</c>) in the constant pool. That means that
the string will be faster to use at run-time, but that it
will require more space even when not used. If space is
an issue, you might want to use binary literals (that is,
<c><<"abc">></c>) instead of string literals for
infrequently used long strings (such as error
messages).</p>
<p>
Own Id: OTP-6850</p>
</item>
<item>
<p>The Erlang driver API has been extended with a
portable POSIX thread like API for multi-threading. The
Erlang driver thread API provides:</p> <list>
<item>Threads</item> <item>Mutexes</item> <item>Condition
variables</item> <item>Read/Write locks</item>
<item>Thread specific data</item> </list> <p>For more
information see the <c>erl_driver(3)</c>
documentation.</p>
<p>
Own Id: OTP-6857</p>
</item>
<item>
<p>
Recursive calls now usually consume less stack than in
R11B. See the Efficiency Guide.</p>
<p>
Own Id: OTP-6862 Aux Id: seq10746 </p>
</item>
<item>
<p>
The deprecated BIFs <c>erlang:old_binary_to_term/1</c>
and <c>erlang:info/1</c> have been removed.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-6876</p>
</item>
<item>
<p>
Calls to driver call-backs triggered by external events
are now scheduled and interleaved with execution of
Erlang processes also on the runtime system without SMP
support.</p>
<p>
Own Id: OTP-6878</p>
</item>
<item>
<p>
Faster arithmetic of integers of more than 27 bits signed
(or 60 bits signed on an 64-bit CPU), and also faster
integer multiplication. (Thanks to Tony Rogvall.)</p>
<p>
Own Id: OTP-6891</p>
</item>
<item>
<p>Significant improvements of the <c>process_info</c>
BIFs:</p> <list> <item> <c>process_info/2</c> can now be
called with a list of items as second argument in order
to atomically retrieve information about multiple items.
</item> <item> <c>process_info/[1,2]</c> has been
optimized in the runtime system with SMP support. The
whole scheduler could previously be blocked for a
significant period of time in <c>process_info/[1,2]</c>
waiting for a lock on the process being inspected. The
Erlang process calling <c>process_info/[1,2]</c> can
still be blocked for a significant period of time waiting
for the lock, but the scheduler will now be able to run
other processes while the process calling
<c>process_info/[1,2]</c> waits for the lock. </item>
<item> <c>process_info/2</c> now accept a few more items
than before. </item> <item> The documentation of
<c>process_info/[1,2]</c> has been improved. </item>
</list> <p>For more information see the <c>erlang(3)</c>
documentation.</p>
<p>
Own Id: OTP-6899</p>
</item>
<item>
<p>
<c>open_port({}, [])</c> could crash the emulator.
(Thanks to Matthew Dempsky.)</p>
<p>
Own Id: OTP-6901</p>
</item>
<item>
<p>Two new guard BIFs have been introduced as a
recommended replacement for <c>size/1</c>. (The
<c>size/1</c> BIF will be removed no earlier than in
R14B.) The BIFs are <c>tuple_size/1</c> to calculate the
size of a tuple and <c>byte_size/1</c> to calculate the
number of bytes needed for the contents of the binary or
bitstring (rounded up to the nearest number of bytes if
necessary).</p>
<p>There is also a new <c>bit_size/1</c> BIF that returns
the exact number of bits that a binary or bitstring
contains.</p>
<p>
Own Id: OTP-6902</p>
</item>
<item>
<p>The <c>ets:fixtable/2</c> function, which has been
deprecated for several releases, has been removed.</p>
<p>The <c>ets:info/1</c> function has been reimplemented
as a BIF, which guarantees that information returned is
consistent.</p>
<p>The <c>ets:info/2</c> function now fails with reason
<c>badarg</c> if the second argument is invalid.
(Dialyzer can be used to find buggy code where the second
argument is misspelled.)</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-6906</p>
</item>
<item>
<p>
As the linux kernel may generate a minor fault when
tracing with CPU timestamps, and there exists no patch to
the Linux kernel that fixes the problem, cpu timestamps
are disabled on Linux for now.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-6922</p>
</item>
<item>
<p>The functions io:columns/0, io:columns/1, io:rows/0
and io:rows/1 are added to allow the user to get
information about the terminal geometry. The shell takes
some advantage of this when formatting output. For
regular files and other io-devices where height and width
are not applicable, the functions return
{error,enotsup}.</p>
<p>Potential incompatibility: If one has written a custom
io-handler, the handler has to either return an error or
take care of io-requests regarding terminal height and
width. Usually that is no problem as io-handlers, as a
rule of thumb, should give an error reply when receiving
unknown io-requests, instead of crashing.</p>
<p>
*** POTENTIAL INCOMPATIBILITY ***</p>
<p>
Own Id: OTP-6933</p>
</item>
<item>
<p>
<c>driver_caller()</c> can now also be used from the
<c>start</c> callback of a driver.</p>
<p>
Own Id: OTP-6951</p>
</item>
<item>
<p>
The emulator can now be compiled for 64bit intel, as well
as a 32bit universal binary on darwin/MacOSX 10.4 and
10.5.</p>
<p>
Own Id: OTP-6961</p>
</item>
<item>
<p>
If <c>open_port</c> fails because all available ports are
already in use, it will now throw a <c>system_limit</c>
exception instead of an <c>enfile</c> exception.
(<c>enfile</c> might still be thrown if the operating
system would return ENFILE.)</p>
<p>
Own Id: OTP-6968</p>
</item>
<item>
<p>
The <c>spawn_monitor/1</c> and <c>spawn_monitor/3</c> BIFs
are now auto-imported (i.e. they no longer need an
<c>erlang:</c> prefix).</p>
<p>
Own Id: OTP-6975</p>
</item>
<item>
<p>
On Windows, the werl window now handles resize, so that
the whole window can be utilized. Text selection is also
updated to be line oriented instead of rectangle oriented
as in earlier versions.</p>
<p>
Own Id: OTP-6994 Aux Id: OTP-6933 </p>
</item>
<item>
<p>
Kqueue support (kernel-poll) has been enabled on FreeBSD.
The problem with kqueue not detecting writes on a pipe on
FreeBSD was actually not a kqueue issue, but a writev on
pipes issue. Neither poll(), nor select() detected the
write when the bug hit. NetBSD and DragonFlyBSD probably
have or have had the same bug. This bug should have been
fixed in FreeBSD 6.3 and FreeBSD 7.0 thanks to
Jean-Sebastien Pedron.</p>
<p>
Own Id: OTP-7001</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.5.5.5</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
Hanging writes on temporarily unavailable NFS
filesystems could cause the execution of (not file
related) erlang code to get blocked even though I/O
threads were used. This is now corrected.</p>
<p>
Own Id: OTP-6907 Aux Id: seq10771 </p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.5.5.4</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
Data passed to a driver via <c>erlang:port_call</c> could
be corrupted when the runtime system with SMP support was
used. (Thanks to YAMASHINA Hio.)</p>
<p>
Own Id: OTP-6879</p>
</item>
<item>
<p>
In the SMP emulator, if several processes called
ets:update_counter/3 (even for different tables) when the
counter values exceeded 27 bits, the counter values could
be corrupted or the emulator could crash.</p>
<p>
Own Id: OTP-6880 Aux Id: seq10760 </p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.5.5.3</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>Creating a named table using <c>ets:new/2</c> or
renaming a named table using <c>ets:rename/2</c> could in
rare circumstances succeed, meaning that there would be
two or more tables with the same name. Now such call will
fail with a <c>badarg</c> exception as it is supposed to
do.</p>
<p><c>ets:delete/1</c> used on a named table now removes
the name immediately so that a new table with the same
name can be created.</p>
<p>Turning on call trace on the internal BIF that
implements <c>ets:delete/1</c> would crash the
emulator.</p>
<p>SMP emulator only: Using <c>ets:rename/2</c> on a
table that <c>ets:safe_fixtable/2</c> has been used on
could cause an emulator crash or undefined behaviour
because of a missing lock.</p>
<p>
Own Id: OTP-6872 Aux Id: seq10756, seq10757 </p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.5.5.2</title>
<section><title>Known Bugs and Problems</title>
<list>
<item>
<p>
ets:select/3 on ordered_set and with a chunksize a
multiple of 1000 gave all elements instead of just 1000.
Also ets:slot/2 on ordered set could give unexpected
results on SMP emulator. Both problems are corrected.</p>
<p>
Own Id: OTP-6842</p>
</item>
</list>
</section>
</section>
<section><title>Erts 5.5.5.1</title>
<section><title>Fixed Bugs and Malfunctions</title>
<list>
<item>
<p>
All exported functions in gzio.c have now been renamed to
avoid conflict with drivers that are indirectly linked
with an external zlib library.</p>
<p>
Own Id: OTP-6816 Aux Id: OTP-6591 </p>
</item>
<item>
<p>
Calling binary_to_term/1 with certain invalid binaries
would crash the emulator.</p>
<p>
Own Id: OTP-6817</p>
</item>
</list>
</section>
<section><title>Improvements and New Features</title>
<list>
<item>
<p>
Restored speed of bit-syntax matching of 32 bits
integers.</p>
<p>
Own Id: OTP-6789 Aux Id: seq10688 </p>
</item>
</list>
</section>
</section>
<section>
<title>Erts 5.5.5</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>The functions in gzio.c have been renamed to avoid
conflict with drivers that indirectly linked with an
external zlib library.</p>
<p>Own Id: OTP-6591</p>
</item>
<item>
<p>The emulator without SMP support dumped core if an
async-thread finished a job after the emulator had begun
writing an <c><![CDATA[erl_crash.dump]]></c>. </p>
<p>Own Id: OTP-6685</p>
</item>
<item>
<p>In bit syntax matching, integer fields with greater
size than 16Mb would fail to match. (Thanks to Bertil
Karlsson and Francesco Pierfederici.)</p>
<p>Matching out a 32-bit integer not aligned on a byte
boundary from a binary could cause an heap overflow (and
subsequent termination of the emulator).</p>
<p>A module that contained bit syntax construction with a
literal field size greater than 16Mb would fail to
load.</p>
<p>Several other similar bugs having to do with huge
field sizes were eliminated.</p>
<p>Attempting to construct a binary longer than 536870911
bytes will now fail with a <c><![CDATA[system_limit]]></c> exception
(rather than fail in mysterious ways or construct an
binary with incorrect contents). Similarily, attempting
to match a binary longer than 536870911 bytes will now
fail (instead of producing an incorrect result). This
limitation has been documented in the Efficiency Guide.
(The limit is in the 32-bit emulator; use the 64-bit
emulator if you need to handle larger binaries than
536870911.)</p>
<p>Own Id: OTP-6686</p>
</item>
<item>
<p>Bugs in rem and div of very large numbers are corrected.</p>
<p>Own Id: OTP-6692</p>
</item>
<item>
<p><c><![CDATA[erlang:system_info({allocator, Alloc})]]></c> didn't
allocate enough heap when a bignum was part of the result
which could cause an emulator crash.</p>
<p>Own Id: OTP-6693</p>
</item>
<item>
<p>It was previously not possible to pass
<c><![CDATA[erts_alloc]]></c> the same configuration via the
command-line, as used by default. </p>
<p>A <c><![CDATA[+M*]]></c> command-line argument that configure a
size of some sort can now be passed a value that equals
the size of the address space. The value used, in this
case, will be <c><![CDATA["the size of the address space" - 1]]></c>.</p>
<p>Own Id: OTP-6699</p>
</item>
<item>
<p><c><![CDATA[SysIOVec* driver_peekq(ErlDrvPort port, int *vlen)]]></c> did not update <c><![CDATA[*vlen]]></c> if <c><![CDATA[port]]></c> was
invalid. <c><![CDATA[*vlen]]></c> is now set to <c><![CDATA[-1]]></c> if the
<c><![CDATA[port]]></c> is invalid.</p>
<p>The <c><![CDATA[efile]]></c> driver
expects <c><![CDATA[*vlen]]></c> to be updated also when the
<c><![CDATA[port]]></c> is invalid. This situation occurs seldom, but
when the runtime system has async-threads enabled and
ports are killed it can. When it occurred the runtime
system crashed.</p>
<p>Own Id: OTP-6729</p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>For scripts written using <c><![CDATA[escript]]></c>, there is a new
function <c><![CDATA[escript:script_name/0]]></c>, which can be used
to retrieve the pathame of the script. The documentation
has been clarified regarding pre-defined macros such as
?MODULE and the module name.</p>
<p>Own Id: OTP-6593</p>
</item>
<item>
<p>The section Guards in the chapter The Abstract Format
of the ERTS User's Guide has been updated.</p>
<p>Own Id: OTP-6600</p>
</item>
<item>
<p>Corrected protocol layer flue for socket options
SO_LINGER, SO_SNDBUF and SO_RCVBUF, for SCTP.</p>
<p>Own Id: OTP-6625 Aux Id: OTP-6336 </p>
</item>
<item>
<p>The behaviour of the inet option {active,once} on peer
close is improved and documented.</p>
<p>Own Id: OTP-6681</p>
</item>
<item>
<p>The inet option send_timeout for connection oriented
sockets is added to allow for timeouts in communicating
send requests to the underlying TCP stack.</p>
<p>Own Id: OTP-6684 Aux Id: seq10637 OTP-6681 </p>
</item>
<item>
<p>The command line flag <c><![CDATA[-args_file FileName]]></c>, and
the environment variables <c><![CDATA[ERL_AFLAGS]]></c>, and
<c><![CDATA[ERL_ZFLAGS]]></c> for the <c><![CDATA[erl]]></c> command have been
added. For more information see the <c><![CDATA[erl(1)]]></c>
documentation.</p>
<p>Own Id: OTP-6697</p>
</item>
<item>
<p>The <c><![CDATA[is_constant/1]]></c> type test has been deprecated.
<c><![CDATA[is_constant/1]]></c> is improperly named and almost
entirely undocumented.</p>
<p>Own Id: OTP-6731</p>
</item>
</list>
</section>
</section>
<section>
<title>Erts 5.5.4.3</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p><c><![CDATA[process_flag(trap_exit, Bad)]]></c> where <c><![CDATA[Bad]]></c>
was a term not equal to <c><![CDATA[true]]></c> or <c><![CDATA[false]]></c>,
didn't fail with <c><![CDATA[badarg]]></c> as it should; instead, the
failure was silently ignored. This bug was introduced in
<c><![CDATA[erts-5.5.2]]></c>.</p>
<p>Own Id: OTP-6627 Aux Id: OTP-6160 </p>
</item>
<item>
<p>The minimum and default stack size for async-threads has
been increased to 16 kilowords. This since the previous
minimum and default stack size of 8 kilowords proved to
be too small (introduced in <c><![CDATA[erts-5.5.4.2]]></c>).</p>
<p>Own Id: OTP-6628 Aux Id: OTP-6580, Seq10633 </p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>process_flag/2 accepts the new flag <c><![CDATA[sensitive]]></c>.</p>
<p>Own Id: OTP-6592 Aux Id: seq10555 </p>
</item>
</list>
</section>
</section>
<section>
<title>Erts 5.5.4.2</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>When a port steals control over a file descriptor from
another port, the stealing port tests if the other port
is alive. This in order to be able to give an accurate
error message. In the runtime system with SMP support,
this test was done without appropriate locks held. This
could in worst case lead to an erroneous error message;
therefore, this bug is to be considered harmless.</p>
<p>Own Id: OTP-6602</p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>The default stack size for threads in the async-thread
pool has been shrunk to 8 kilowords, i.e., 32 KB on
32-bit architectures. This small default size has been
chosen since the amount of async-threads might be quite
large. The default stack size is enough for drivers
delivered with Erlang/OTP, but might not be sufficiently
large for other dynamically linked in drivers that use
the <c><![CDATA[driver_async()]]></c> functionality. A suggested
stack size for threads in the async-thread pool can be
configured via the <c><![CDATA[+a]]></c> command line argument of
<c><![CDATA[erl(1)]]></c>.</p>
<p>*** POTENTIAL INCOMPATIBILITY ***</p>
<p>Own Id: OTP-6580</p>
</item>
</list>
</section>
</section>
<section>
<title>Erts 5.5.4.1</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>Setting the time on the system while using heart on a
linux machine where the emulator was built with
clock_gettime support (default from Linux 2.6/erts-5.5.4
and upwards), could make the heart command fire. This was
due to bug in the heart executable which is now
corrected.</p>
<p>Own Id: OTP-6598 Aux Id: seq10614 </p>
</item>
</list>
</section>
</section>
<section>
<title>Erts 5.5.4</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>Corrected misspelling of '<c><![CDATA[-pz]]></c>' in the help text
for <c><![CDATA[erlc]]></c>. (Thanks to Ulf Wiger.)</p>
<p>Own Id: OTP-6433</p>
</item>
<item>
<p>The MD5 calculation of a BEAM file done by
<c><![CDATA[code:module_md5/1]]></c>, <c><![CDATA[beam_lib:md5/1]]></c>, and by
the compiler for the default value of the <c><![CDATA[vsn]]></c>
attribute have all been changed so that its result will
be the same on all platforms; modules containing funs
could get different MD5s on different platforms.</p>
<p>Own Id: OTP-6459</p>
</item>
<item>
<p>The emulator could dump core while writing an
<c><![CDATA[erl_crash.dump]]></c> file if there were funs with a
large terms in its environment. Since there is no way to
inspect a fun's environment in the crashdump_viewer
application anyway, a variables in the environment are
now set to [] before dumping the fun. (Thanks to
Jean-Sebastien Pedron.)</p>
<p>Own Id: OTP-6504</p>
</item>
<item>
<p><c><![CDATA[{Port, {exit_status, S}}]]></c> messages from ports
opened with the <c><![CDATA[exit_status]]></c> option could under
rare circumstances be delayed. This bug was present on
Erlang runtime systems without SMP support on all unix
operating systems other than SunOS.</p>
<p>Own Id: OTP-6528</p>
</item>
<item>
<p>A bug in linuxthreads could cause the emulator to dump
core when dlerror() was called before the first call to
dlopen(). As a workaround the emulator always makes a
call to dlopen() on initialization when linuxthreads is
used as thread library.</p>
<p>Own Id: OTP-6530</p>
</item>
<item>
<p>file:sync/1 did not do anything on Windows. Now it calls
the system function for flushing buffers
(FlushFileBuffers()). (Thanks to Matthew Sackman.)</p>
<p>Own Id: OTP-6531</p>
</item>
<item>
<p><c><![CDATA[open_port/2]]></c> could on the runtime system with SMP
support fail with the wrong exit reason when a port
couldn't be created. When this happened the exit reason
was typically <c><![CDATA[eintr]]></c>, or <c><![CDATA[ebusy]]></c> instead of
<c><![CDATA[eagain]]></c>.</p>
<p>Own Id: OTP-6536</p>
</item>
<item>
<p>The file driver (efile_drv) did not flush data written
using the option 'delayed_write' after the set timeout
time, rather at the next file operation. This bug has now
been corrected.</p>
<p>Own Id: OTP-6538</p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>An interface towards the SCTP Socket API Extensions
has been implemented.It is an Open Source patch courtesy
of Serge Aleynikov and Leonid Timochouk. The Erlang code
parts has been adapted by the OTP team, changing the
Erlang API somewhat.</p>
<p>The Erlang interface consists of the module
<c><![CDATA[gen_sctp]]></c> and an include file
<c><![CDATA[-include_lib("kernel/include/inet_sctp.hrl").]]></c> for
option record definitions. The <c><![CDATA[gen_sctp]]></c> module is
documented.</p>
<p>The delivered Open Source patch, before the OTP team
rewrites, was written according to
http://tools.ietf.org/html/draft-ietf-tsvwg-sctpsocket-13
and was claimed to work fine, tested on Linux Fedora Core
5.0 (kernel 2.6.15-2054 or later) and on Solaris 10 and
11. The OTP team rewrites used the same standard document
but might have accidentally broken some functionality. If
so it will soon be patched to working state. The tricky
parts in C and the general design has essentially not
changed. During the rewrites the code was hand tested on
SuSE Linux Enterprise Server 10, and briefly on Solaris
10. Feedbach on code and docs is very much
appreciated.</p>
<p>The SCTP interface is in beta state. It has only been
hand tested and has no automatic test suites in OPT
meaning everything is most certainly not tested. Socket
active mode is broken. IPv6 is not tested. The
documentation has been reworked due to the API changes,
but has not been proofread after this.</p>
<p>Thank you from the OTP team to Serge Aleynikov and
Leonid Timochouk for a valuable contribution. We hope we
have not messed it up too much.</p>
<p>Own Id: OTP-6336</p>
</item>
<item>
<p>A <c><![CDATA[{minor_version,Version}]]></c> option is now recognized
by <c><![CDATA[term_to_binary/2]]></c>. {minor_version,1} will cause
floats to be encoded in an exact and more space-efficient
way compared to the previous encoding.</p>
<p>Own Id: OTP-6434</p>
</item>
<item>
<p>There is a new <c><![CDATA[escript]]></c> program that can be used
for writing scripts in Erlang. Erlang scripts don't need
to be compiled and any arguments can be passed to them
without risk that they are interpreted by the Erlang
system.</p>
<p>Own Id: OTP-6505</p>
</item>
<item>
<p>Setting and getting socket options in a "raw" fashion is
now allowed. Using this feature will inevitably produce
non portable code, but will allow setting ang getting
arbitrary uncommon options on TCP stacks that do have
them.</p>
<p>Own Id: OTP-6519</p>
</item>
<item>
<p>Miscellaneous signal handling improvements on the Erlang
runtime system with SMP support.</p>
<p>The fallback implementation of spin locks and atomic
operations are now implemented using pthread spin locks
when pthread spin locks are found on the system.</p>
<p>The Erlang runtime system with SMP support can now run on
Linux systems that has Linuxthreads instead of NPTL
(Native POSIX Thread Library). Note that the SMP support
hasn't been as thoroughly tested with Linuxthreads as
with NPTL. A runtime system with SMP support will
therefore not be built by default on Linux when NPTL
isn't found. In order to force a build of the runtime
system with SMP support, pass <c><![CDATA[--enable-smp-support]]></c>
to <c><![CDATA[configure]]></c> when building OTP.</p>
<p>Own Id: OTP-6525</p>
</item>
</list>
</section>
</section>
<section>
<title>Erts 5.5.3.1</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p><c><![CDATA[erlang:system_flag(multi_scheduling, block)]]></c> could
cause the emulator with SMP support to deadlock.</p>
<p>Own Id: OTP-6431 Aux Id: OTP-6403 </p>
</item>
<item>
<p>The runtime system with SMP support failed to call the
driver timeout callback of ports in state closing. This
could cause ports to fail flushing their I/O queues.</p>
<p>Own Id: OTP-6432</p>
</item>
<item>
<p>The <c><![CDATA[{Port, closed}]]></c> message from a closed port
could arrive at the port owner before <c><![CDATA[Port]]></c> had
been removed from the result of <c><![CDATA[erlang:ports/0]]></c> in
the runtime system with SMP support.</p>
<p>Own Id: OTP-6437</p>
</item>
<item>
<p>The async id of async jobs created via
<c><![CDATA[driver_async]]></c> wasn't created in a thread safe
manner in the runtime system with SMP support. This could
in worst case cause <c><![CDATA[driver_async_cancel()]]></c> to
cancel another async job than intended.</p>
<p>Own Id: OTP-6438</p>
</item>
<item>
<p>Under rare circumstances a terminating connection between
two nodes could cause an instantaneous reconnect between
the two nodes to fail on the runtime system with SMP
support.</p>
<p>Own Id: OTP-6447</p>
</item>
<item>
<p>In the documentation of the driver entry field
<c><![CDATA[extended_marker]]></c> of erts version 5.5.3
(<c><![CDATA[driver_entry(3)]]></c>), the following is stated: "The
following fields are ignored if this field is equal to
<c><![CDATA[0]]></c>". This is a documentation bug and has been
changed to: "If this field is equal to <c><![CDATA[0]]></c>, all the
fields following this field also <em>have</em> to be
<c><![CDATA[0]]></c>, or <c><![CDATA[NULL]]></c> in case it is a pointer field".</p>
<p>The runtime check for detection of old incompatible
drivers made when loading drivers has been improved. The
emulator can, however, not make sure that a driver that
doesn't use the extended driver interface isn't
incompatible. Therefore, when loading a driver that
doesn't use the extended driver interface, there is a
risk that it will be loaded also when the driver is
incompatible. When the driver use the extended driver
interface, the emulator can verify that it isn't of an
incompatible driver version. You are therefore advised to
use the extended driver interface.</p>
<p>For more information see the <c><![CDATA[erl_driver(3)]]></c> and
<c><![CDATA[driver_entry(3)]]></c> documentation.</p>
<p>Own Id: OTP-6452 Aux Id: OTP-6330 </p>
</item>
<item>
<p>When terminating ports on the runtime system with SMP
support, removal of links to processes was done without
locking the link lock on processes. This could cause an
emulator crash.</p>
<p>Own Id: OTP-6475</p>
</item>
<item>
<p>The emulator with SMP support could crash when a port
flushed its I/O queue by calling <c><![CDATA[driver_async()]]></c>
from the timeout driver callback.</p>
<p>Own Id: OTP-6479</p>
</item>
<item>
<p>Large exit reasons could under rare circumstances cause
the runtime system with SMP support to crash.</p>
<p>Own Id: OTP-6521</p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>Faster system calls for keeping the time accurate are
used on newer Linux kernels, which can result in a
significant speed-up of the emulator on those systems.</p>
<p>Own Id: OTP-6430</p>
</item>
<item>
<p>Added number of async threads and number of scheduler
threads to the system information that can be retrieved
via <c><![CDATA[driver_system_info()]]></c>. For more information see
the <c><![CDATA[erl_driver(3)]]></c> documentation.</p>
<p>Own Id: OTP-6440</p>
</item>
<item>
<p>When <c><![CDATA[SIGUSR1]]></c> is received by the runtime system
with SMP support, the <c><![CDATA[erl_crash.dump]]></c> is now
written by a special thread, instead of as before
directly from the signal handler.</p>
<p>Own Id: OTP-6465</p>
</item>
<item>
<p>term_to_binary/2 with compression is now faster.</p>
<p></p>
<p>term_to_binary/2 now accepts the option
'<c><![CDATA[{compressed,Level}]]></c>' for specifying the
compression level. <c><![CDATA[Level]]></c> must be in the range 0
(no compression) through 9 (highest compression level).
Default is 6.</p>
<p>Future compatibility bugfix: binary_to_term/1 did not
handle the <c><![CDATA[Uniq]]></c> and <c><![CDATA[Index]]></c> fields
correctly.</p>
<p>Own Id: OTP-6494</p>
</item>
<item>
<p>Removed unnecessary reallocation when initializing
kernel-poll set.</p>
<p>Own Id: OTP-6516</p>
</item>
</list>
</section>
</section>
<section>
<title>Erts 5.5.3</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>Node and fun table entries could under rare circumstances
be deallocated multiple times on the emulator with SMP
support.</p>
<p>Own Id: OTP-6369</p>
</item>
<item>
<p>epoll_wait() can repeat entries for the same file
descriptor in the result array. This could cause the
ready_input, ready_output, or event callbacks of a driver
to unintentionally be called multiple times. We have only
noted repeated entries when an error condition has
occurred on the file descriptor. In this case, the
repeated entries should normally not be a problem for the
driver since it should detect the error and de-select the
file descriptor. Therefore this bug should be considered
harmless. The emulator now coalesce repeated entries into
one.</p>
<p>You are only affected by this bug if you are using
erts-5.5.2.* and the kernel-poll feature on linux.</p>
<p>Own Id: OTP-6376 Aux Id: OTP-6222 </p>
</item>
<item>
<p>If a process that was waiting in gen_tcp:accept/1 was
killed, calling gen_tcp:accept/1 again on the same listen
socket would fail with '<c><![CDATA[{error,einval}]]></c>'.</p>
<p>Own Id: OTP-6381 Aux Id: seq10535 </p>
</item>
<item>
<p>The emulator failed to start on Solaris 10 when
kernel-poll support was enabled and the maximum number of
filedescriptors configured was less than or equal to 256.</p>
<p>Own Id: OTP-6384 Aux Id: OTP-6222 </p>
</item>
<item>
<p>The R10B compiler could generate unsafe
<c><![CDATA[bs_save/bs_restore]]></c> instructions that could cause
memory corruption. (The R11B compiler does not have that
problem.) The erlang emulator will now refuse to load
R10B-compiled modules that contain such unsafe
<c><![CDATA[bs_save/bs_restore]]></c> instructions. In addition, the
beam_validator module in the compiler will also reject
such instructions (in case it is used to validate R10B
code). (Thanks to Matthew Reilly.)</p>
<p>Own Id: OTP-6386</p>
</item>
<item>
<p>Process and port timers could fail to work properly on
the runtime system with SMP support. Many thanks to
Dmitriy Kargapolov and Serge Aleynikov who tracked down
this bug.</p>
<p>Own Id: OTP-6387</p>
</item>
<item>
<p>Bit syntax code compiled by an R10B compiler that matched
out a floating point number would not properly check that
the floating point number was valid; if the float was,
for instance, NaN the emulator could crash.</p>
<p>Own Id: OTP-6395</p>
</item>
<item>
<p>statistics(runtime) on Windows used to return the elapsed
system time for the process, instead of the user time.
Corrected. (Thanks to Robert Virding.)</p>
<p>Own Id: OTP-6407</p>
</item>
<item>
<p>A loadable driver (loaded by erl_ddll) which used
driver_async() would cause the emulator to crash. (Thanks
to Dmitriy Kargapolov.)</p>
<p>Own Id: OTP-6410</p>
</item>
<item>
<p>Under rare circumstances the emulator on unix platforms
could fail to terminate the Erlang port corresponding to
a port program opened with the <c><![CDATA[exit_status]]></c> option.</p>
<p>Own Id: OTP-6411</p>
</item>
<item>
<p>A link removed via <c><![CDATA[unlink/1]]></c> could under rare
circumstances transfer exit signals for a short period of
time after the call to <c><![CDATA[unlink/1]]></c> had returned when
the runtime system with SMP support was used.</p>
<p>Own Id: OTP-6425 Aux Id: OTP-6160 </p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>In the runtime system with SMP support, ports are now
being scheduled on the scheduler threads interleaved with
processes instead of being run in a separate I/O thread.</p>
<p>Own Id: OTP-6262</p>
</item>
<item>
<p>More interfaces are added in erl_ddll, to support
different usage scenarios.</p>
<p>Own Id: OTP-6307 Aux Id: OTP-6234 </p>
</item>
<item>
<p>In the runtime system with SMP support, the global
I/O lock has been replaced with a more fine grained port
locking scheme. Port locking is either done on driver
level, i.e., all ports executing the same driver share a
lock, or on port level, i.e., each port has its own lock.
Currently the inet driver, the efile driver, and the
spawn driver use port level locking and all other
statically linked in drivers use driver level locking. By
default dynamically linked in drivers will use locking on
driver level. For more information on how to enable port
level locking see the <c><![CDATA[erl_driver(3)]]></c> and the
<c><![CDATA[driver_entry(3)]]></c> man pages. </p>
<p>As of erts
version 5.5.3 the driver interface has been extended. The
extended interface introduce version management, the
possibility to pass capability flags to the runtime
system at driver initialization, and some new driver API
functions. For example, the <c><![CDATA[driver_system_info()]]></c>
function which can be used to determine if the driver is
run in a runtime system with SMP support or not. The
extended interface doesn't have to be used, <em>but</em>
dynamically linked in driver <em>have</em> to be
recompiled. For information see the <c><![CDATA[erl_driver(3)]]></c>
and the <c><![CDATA[driver_entry(3)]]></c> man pages. </p>
<p><em>NOTE:</em> Dynamically linked in drivers
<em>have</em> to be recompiled. </p>
<p>*** POTENTIAL INCOMPATIBILITY ***</p>
<p>Own Id: OTP-6330 Aux Id: OTP-6262 </p>
</item>
<item>
<p>A test and debug feature which modifies the timing of the
runtime system has been added. For more information, see
documentation of the <c><![CDATA[+T<Level>]]></c> command line
argument of <c><![CDATA[erl(1)]]></c>.</p>
<p>Own Id: OTP-6382</p>
</item>
<item>
<p>The version of zlib (http://zlib.net) linked into
run-time system has been updated to version 1.2.3.</p>
<p>Own Id: OTP-6394</p>
</item>
<item>
<p>The <c><![CDATA[erlc]]></c> program now passes on the <c><![CDATA[-smp]]></c>
and <c><![CDATA[-hybrid]]></c> options to the Erlang emulator it
starts. This is mainly useful for compiling native code,
because native code must be compiled with same type of
run-time system as in which it will be run.</p>
<p>If the <c><![CDATA[-s]]></c> option is given, <c><![CDATA[erlc]]></c> now
prints a warning that it is deprecated and that it will
be removed in R12B.</p>
<p>Own Id: OTP-6398</p>
</item>
<item>
<p>The <c><![CDATA[schedulers]]></c> option of
<c><![CDATA[erlang:system_flag/2]]></c> has been removed, i.e., the
number of scheduler threads cannot be changed after
emulator boot time any more.</p>
<p>A <c><![CDATA[multi_scheduling]]></c> option has been added to
<c><![CDATA[erlang:system_flag/2]]></c>. This option can be used for
blocking and unblocking multi-scheduling. For more
information see the <c><![CDATA[erlang(3)]]></c> documentation.</p>
<p>Own Id: OTP-6403</p>
</item>
<item>
<p>A port program that had been started with the
<c><![CDATA[exit_status]]></c> option and closed one of the pipes
used for communication with the emulator caused the
emulator to continuously poll for termination of the port
program. This only became a problem when the emulator
didn't have other things to do and the port program
closed a pipe much earlier than it terminated. When the
emulator had other things to do, such as running Erlang
processes, the emulator polled for termination in between
scheduling of processes.</p>
<p>Now the emulator doesn't poll for termination of the port
program at all; instead, it waits for the child signal
from the terminated port program to arrive and then
schedules the Erlang port for termination.</p>
<p>The termination of any port programs have also been
optimized. Previously the termination of any port program
did always cause a scan of a table of the size equal to
maximum number of file descriptors. If the maximum number
of file descriptors was large, this scan could be quite
expensive. Now the search have been reduced to the set of
ports started with the <c><![CDATA[exit_status]]></c> option.</p>
<p>Note, all of the above only applies to Erlang emulators
on Unix platforms.</p>
<p>Own Id: OTP-6412 Aux Id: seq10194 </p>
</item>
<item>
<p>* BEAM: added support for floating-point exceptions on
FreeBSD (32-bit x86)</p>
<p>* SMP: made locking procedures work even when native
lock operations aren't implemented</p>
<p>* SMP: improved timing accuracy in the timer thread
(if enabled)</p>
<p>Own Id: OTP-6424</p>
</item>
</list>
</section>
</section>
<section>
<title>Erts 5.5.2.2</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>A bug in the kernel poll implementation could cause the
emulator to omit polling for events on file descriptors.
The bug was only present when using the kernel poll
implementation based on epoll or kqueue. This bug was
introduced in erts-5.5.2.</p>
<p>Own Id: OTP-6344 Aux Id: OTP-6222 </p>
</item>
</list>
</section>
</section>
<section>
<title>Erts 5.5.2.1</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>The run_erl program now acquires its pseudo-ttys using
openpty(3), so that it will work on newer Linux
distributions that don't have the traditional pseudo-tty
devices in the file system. On platforms that don't have
openpty(3), run_erl will still search for pseudo-tty
devices in the file system.</p>
<p>The run_erl program will now wait using waitpid(3) to
prevent the program it spawned to become defunct. run_erl
will also terminate after a delay of 5 seconds (to allow
any pending output to be written to the log file) if the
spawned program terminates even if some child of it still
holds stdin and/or stdout open.</p>
<p>Own Id: OTP-6225 Aux Id: seq10500 </p>
</item>
<item>
<p>A bug in ordered_set ETS datatyp caused ets:select (and
match) to return faulty results when the table contained
process id's from another node.</p>
<p>Own Id: OTP-6338</p>
</item>
</list>
</section>
</section>
<section>
<title>Erts 5.5.2</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>erlc: A typo in the help text for '-pa path' was
corrected.</p>
<p>Own Id: OTP-6218</p>
</item>
<item>
<p>Failure in port command/control driver callbacks could
crash the non-SMP emulator. This bug was introduced in
the 5.5 version of erts.</p>
<p>Own Id: OTP-6224</p>
</item>
<item>
<p>Erroneous "<c><![CDATA[Input driver gone away without deselecting!]]></c>" error reports could sometimes occur
when a driver instance terminated in the ready_output()
callback of the driver. This bug was only present in
emulators that used poll(). Note, that this bug was
harmless, the only effect it had was the erroneous error
report.</p>
<p>Own Id: OTP-6229 Aux Id: OTP-3993, Seq5266, Seq7247,
OTP-4307 </p>
</item>
<item>
<p>The emulator could cause a type assertion failure while
writing an erl_crash.dump, causing the erl_crash.dump to
be terminated and a core dump generated.</p>
<p>Own Id: OTP-6235 Aux Id: seq10444 </p>
</item>
<item>
<p>The registered name of a process is now the last
observable resource removed before links and monitors are
triggered when a process terminates.</p>
<p>Previously ets tables were removed after the registered
name. This could cause problems on the runtime system
with SMP support for code that expected that ets tables
owned by a specific process had been removed if the name
of the process had been removed.</p>
<p>Own Id: OTP-6237</p>
</item>
<item>
<p>Failure to fork() a new (os) process could cause the
emulator to deadlock. This bug affect all emulators with
SMP support, and emulators with async thread support on
SunOS.</p>
<p>Own Id: OTP-6241 Aux Id: OTP-3906 </p>
</item>
<item>
<p>Fprof traces could become truncated for the SMP emulator.
This bug has now been corrected.</p>
<p>Own Id: OTP-6246</p>
</item>
<item>
<p>The undocumented functions inet:getiflist/0,1
inet:ifget/2,3 and inet:getif/1 were completely broken on
Windows. That has been fixed.</p>
<p>Own Id: OTP-6255</p>
</item>
<item>
<p>Behavior in case of disappeared nodes when using the
dist_auto_connect once got changed in R11B-1. The
timeouts regarding normal distributed operations is now
reverted to the old (pre R11B-1).</p>
<p>Own Id: OTP-6258 Aux Id: OTP-6200, seq10449 </p>
</item>
<item>
<p>The bsl and bsr operators could cause the emulator to
crash if given invalid arguments. (Thanks to datacompboy
and Per Gustafsson.)</p>
<p>Own Id: OTP-6259</p>
</item>
<item>
<p>driver_cancel_timer() could under certain circumstances
fail to cancel the timer on the runtime system with SMP
support.</p>
<p>Own Id: OTP-6261</p>
</item>
<item>
<p>A call to erlang:system_info(info) could deadlock the
runtime system with SMP support.</p>
<p>Own Id: OTP-6268</p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>Exit signals are now truly asynchronous in the runtime
system with SMP support. This simplifies locking in bifs
a lot, and makes process termination cheaper.</p>
<p>Own Id: OTP-6160</p>
</item>
<item>
<p>When tracing on the runtime system with SMP support it
can be difficult to know when a trace has been delivered
to the tracer. A new built in function
<c><![CDATA[erlang:trace_delivered/1]]></c> has been introduced in
order to make it easier to know when the trace has been
delivered. See the erlang(3) man page for more
information.</p>
<p>Own Id: OTP-6205 Aux Id: OTP-6269 </p>
</item>
<item>
<p>Kernel poll support can now be combined with SMP support.
Currently the following kernel poll versions exist:
<c><![CDATA[/dev/poll]]></c>, <c><![CDATA[epoll]]></c>, and <c><![CDATA[kqueue]]></c>. Linux
<c><![CDATA[kpoll]]></c> has been replaced with <c><![CDATA[epoll]]></c>. Some
time in the future there will also be a kernel poll
version using Solaris event ports.</p>
<p>The "check io" implementation for unix has been
completely rewritten. The current kernel poll
implementation reduce the amount of system calls needed
compared to the old kernel poll implementation.</p>
<p>When <c><![CDATA[epoll]]></c> or <c><![CDATA[kqueue]]></c> is used either
<c><![CDATA[poll]]></c> or <c><![CDATA[select]]></c> is used as fallback.
Previously only <c><![CDATA[poll]]></c> could be used as fallback.
Since <c><![CDATA[select]]></c> now can be used as fallback, kernel
poll support is now also available on newer MacOSX. Note
however, when <c><![CDATA[select]]></c> is used as fallback, the
maximum number of file descriptors is limited to
<c><![CDATA[FD_SETSIZE]]></c>. </p>
<p>Kernel poll support is now enabled by default if
<c><![CDATA[/dev/poll]]></c>, <c><![CDATA[epoll]]></c>, or <c><![CDATA[kqueue]]></c> is found
when building OTP, i.e. you do not have to pass the
<c><![CDATA[--enable-kernel-poll]]></c> argument to <c><![CDATA[configure]]></c>.
As before, kernel poll is disabled by default in the
runtime system. In order to enable it, pass the
<c><![CDATA[+Ktrue]]></c> command line argument to <c><![CDATA[erl]]></c>.</p>
<p>Note: <c><![CDATA[configure]]></c> will refuse to enable kernel poll
support on FreeBSD since <c><![CDATA[kqueue]]></c> have problems with
(at least) pipes on all version of FreeBSD that we have
tested.</p>
<p>Own Id: OTP-6222 Aux Id: seq10380 </p>
</item>
<item>
<p>The <c><![CDATA[erl_ddll]]></c> module and the code in the emulator
have been completely rewritten; several bugs were fixed.</p>
<p>Own Id: OTP-6234</p>
</item>
<item>
<p>The SMP emulator now avoids locking for the following
operations (thus making them as fast as in the UP
emulator): <c><![CDATA[atom_to_list/1]]></c>, atom comparison, atom
hashing, <c><![CDATA[erlang:apply/3]]></c>.</p>
<p>Own Id: OTP-6252</p>
</item>
<item>
<p>There are new BIFs <c><![CDATA[erlang:spawn_monitor/1,3]]></c>,
and the new option <c><![CDATA[monitor]]></c> for
<c><![CDATA[spawn_opt/2,3,4,5]]></c>.</p>
<p>The <c><![CDATA[observer_backend]]></c> module has been updated to
handle the new BIFs.</p>
<p>Own Id: OTP-6281</p>
</item>
</list>
</section>
</section>
<section>
<title>Erts 5.5.1.1</title>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>There is now an option read_packets for UDP sockets that
sets the maximum number of UDP packets that will be read
for each invocation of the socket driver.</p>
<p>Own Id: OTP-6249 Aux Id: seq10452 </p>
</item>
</list>
</section>
</section>
<section>
<title>Erts 5.5.1</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>Complex pattern matching of strings would fail in the 64
bits emulator because of a bug in the loader. (Thanks to
Igor Goryachev.)</p>
<p>Own Id: OTP-6142</p>
</item>
<item>
<p><c><![CDATA[-134217728 div 134217728]]></c> and <c><![CDATA[-134217728 rem 134217728]]></c> would be calculated incorrectly.
<c><![CDATA[abs(-2147483648)]]></c> could in unlucky circumstances
cause a heap overflow, as could size(Binary) when size of
the binary was larger than 128Mb.</p>
<p>Own Id: OTP-6154</p>
</item>
<item>
<p>erlang:display/1 displayed erroneous values for negative
integers.</p>
<p>Big integers (both positive and negative) were previously
displayed in hexadecimal form while small integers were
displayed in decimal form. All integers are now displayed
in decimal form.</p>
<p>NOTE: erlang:display/1 should only be used for debugging.</p>
<p>Own Id: OTP-6156</p>
</item>
<item>
<p>A call to erlang:trace/3 with erroneous flags caused the
SMP emulator to deadlock instead of exiting the calling
process with badarg.</p>
<p>Own Id: OTP-6175</p>
</item>
<item>
<p>A bug causing the emulator to hang when exiting a process
that is exception traced has been fixed.</p>
<p>Own Id: OTP-6180</p>
</item>
<item>
<p>ets:rename/1 could deadlock, or crash the SMP emulator
when the table wasn't a named table.</p>
<p>ets:next/2, and ets:prev/2 could return erroneous results
on the SMP emulator.</p>
<p>Own Id: OTP-6198 Aux Id: seq10392, seq10415 </p>
</item>
<item>
<p>A memory allocation bug could cause the SMP emulator to
crash when a process had executed a <c><![CDATA[receive after]]></c>
with a larger timeout than 10 minutes.</p>
<p>Own Id: OTP-6199</p>
</item>
<item>
<p>The runtime system with SMP support did not slowly adjust
its view of time when the system time suddenly changed.</p>
<p>Timeouts could sometimes timeout too early on the runtime
system with SMP support.</p>
<p>Own Id: OTP-6202</p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>The smp runtime system now automatically detects the
number of logical processors on MacOSX (darwin) and
OpenBSD.</p>
<p>The smp runtime system is now built by default on MacOSX
(darwin) on x86.</p>
<p>Own Id: OTP-6119</p>
</item>
<item>
<p>The <c><![CDATA[-smp]]></c> command line argument now take the
following options: <c><![CDATA[enable]]></c>, <c><![CDATA[auto]]></c>, or
<c><![CDATA[disable]]></c>.</p>
<p>Especially the <c><![CDATA[-smpauto]]></c> argument is useful since
it starts the Erlang runtime system with SMP support if
it is available and more than one logical processor are
detected; otherwise, it starts the Erlang runtime system
without SMP support. For more information see the
<c><![CDATA[erl(1)]]></c> man page.</p>
<p>Own Id: OTP-6126</p>
</item>
<item>
<p>Increased the reduction cost for sending messages in the
SMP emulator so it behaves more like the non-SMP
emulator.</p>
<p>Own Id: OTP-6196</p>
</item>
<item>
<p>A port running a dynamically linked-in driver that exits
due to the driver being unloaded now exits with exit
reason <c><![CDATA[driver_unloaded]]></c>. Previously the port exited
with exit reason <c><![CDATA[-1]]></c>.</p>
<p>*** POTENTIAL INCOMPATIBILITY ***</p>
<p>Own Id: OTP-6204</p>
</item>
<item>
<p>Changed name of the <c><![CDATA[erlang:system_info/1]]></c> argument
<c><![CDATA[scheduler]]></c> to <c><![CDATA[scheduler_id]]></c>. This since the
<c><![CDATA[scheduler]]></c> argument so easily could be mixed up
with the <c><![CDATA[schedulers]]></c> argument (both returning
integers).</p>
<p>*** POTENTIAL INCOMPATIBILITY ***</p>
<p>Own Id: OTP-6208</p>
</item>
<item>
<p>The changes below were made by Mikael Pettersson, HiPE.</p>
<p>HiPE runtime system:</p>
<p>Reduce overheads in the HiPE runtime system's BIF glue
code.</p>
<p>Fix bug when exceptions are thrown from BEAM to HiPE.</p>
<p>Support SPARC on Linux.</p>
<p>Support x86 on FreeBSD.</p>
<p>Floating-point exceptions:</p>
<p>Reduce overheads in checking results of floating-point
operations.</p>
<p>Minor bug fix in SSE2 floating-point exception
handling.</p>
<p>Support SSE2 floating-point exceptions on 32-bit x86
machines.</p>
<p>Make FP exceptions work in the SMP runtime system on
FreeBSD/x86.</p>
<p>Support floating-point exceptions on SPARCs running
Linux.</p>
<p>Runtime system:</p>
<p>Minor scheduler optimisation in the non-SMP runtime
system.</p>
<p>Substantial reduction of I/O thread overheads in the
SMP runtime system if the separate timer thread is used.
(In R11B-1, the separate timer thread is not used.)</p>
<p>Own Id: OTP-6211</p>
</item>
</list>
</section>
</section>
<section>
<title>ERTS 5.5</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>Previously <c><![CDATA[unlink/1]]></c> and <c><![CDATA[erlang:demonitor/2]]></c>
behaved completely asynchronous. This had one undesirable
effect, though. You could never know when you were
guaranteed <em>not</em> to be affected by a link that you
had unlinked or a monitor that you had demonitored.</p>
<p>The new behavior of <c><![CDATA[unlink/1]]></c> and
<c><![CDATA[erlang:demonitor/2]]></c> can be viewed as two operations
performed atomically. Asynchronously send an unlink
signal or a demonitor signal, and ignore any future
results of the link or monitor.</p>
<p><em>NOTE</em>: This change can cause some obscure code
to fail which previously did not. For example, the
following code might hang:</p>
<code type="none"><![CDATA[
Mon = erlang:monitor(process, Pid),
%% ...
exit(Pid, bang),
erlang:demonitor(Mon),
receive
{'DOWN', Mon , process, Pid, _} -> ok
%% We were previously guaranteed to get a down message
%% (since we exited the process ourself), so we could
%% in this case leave out:
%% after 0 -> ok
end,
]]></code>
<p>*** POTENTIAL INCOMPATIBILITY ***</p>
<p>Own Id: OTP-5772</p>
</item>
<item>
<p>Two bugs fixed: If the environment variable <c><![CDATA[ERL_FLAGS]]></c>
was set, its contents would be appended to the end of the
command line even if the command line had an <c><![CDATA[-extra]]></c>
options. Changed to place the options from <c><![CDATA[ERL_FLAGS]]></c>
just before <c><![CDATA[-extra]]></c>. Also, the <c><![CDATA[-smp]]></c> and
<c><![CDATA[-hybrid]]></c> flags no longer have any effect if placed
after <c><![CDATA[-extra]]></c>.</p>
<p>Own Id: OTP-6054</p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>The documentation for writing drivers in the ERTS User's
Guide has been expanded and updated.</p>
<p>Own Id: OTP-5192</p>
</item>
<item>
<p>The <c><![CDATA[andalso]]></c> and <c><![CDATA[orelse]]></c> operators are
now allowed to be used in guards. That also applies to
match specifications.</p>
<p>Own Id: OTP-5894 Aux Id: OTP-5149 </p>
</item>
<item>
<p>There is a new trace match spec function
<c><![CDATA[{exception_trace}]]></c> and a corresponding trace
message <c><![CDATA[exception_from]]></c> that can be used to trace
on any exit from a function, both normal function return
and exception return. See the documentation for
details.</p>
<p>The <c><![CDATA[return_to]]></c> trace message is now also
generated when the execution returns to a function due to
catching an exception.</p>
<p>Own Id: OTP-5956</p>
</item>
<item>
<p>Erlang runtime system with SMP (symmetric multi processing)
support.</p>
<p>The runtime system with SMP support is in this release
focused on stability and there are a number of steps
with optimizations to follow before it will take
full advantage of multi processor systems.
The released system is however truly multi threaded
and you will notice increased performance
for many applications already.
We recommend that you evaluate your application on
the SMP version of the runtime system and wait for some
more optimizations before you use it in a real product.
You will then discover if there are any problems in
your application that needs to be fixed in order for
it to work properly in a multi threaded environment.
More optimized versions of the runtime system
with SMP support will be included in the R11B
maintenance releases.</p>
<p>The SMP enabled runtime system will be started if
the <c><![CDATA[-smp]]></c> command line argument is passed to
the <c><![CDATA[erl]]></c> command. In order to make use of more than
one processor core, multiple scheduler threads are used. By
default, the number of scheduler threads will equal
the number of processor cores. The number of scheduler
threads can be set with the <c><![CDATA[+S]]></c> command line argument.
For more information see the <c><![CDATA[erl(1)]]></c> man page.</p>
<p>A runtime system with SMP support is by default built on
the following platforms if posix threads, and a gcc
compiler of at least version 2.95 is found:</p>
<list type="bulleted">
<item>
<p>Linux with at least kernel version 2.6 and the Native
POSIX Thread Library on x86, x86_64, and 32-bits
PowerPC.</p>
</item>
<item>
<p>Solaris of at least version 8 on 32-bits SPARC-V9.</p>
</item>
<item>
<p>MacOSX of at least version 10.4 (Darwin 8.0) on
32-bits PowerPC.</p>
</item>
</list>
<p>The runtime system with SMP support is known <em>not</em>
to build on:</p>
<list type="bulleted">
<item>
<p>Windows.</p>
</item>
<item>
<p>Linux with kernel versions less than 2.4, or without
the Native POSIX Thread Library.</p>
</item>
<item>
<p>Other hardware platforms than x86, x86_64, 32-bits
SPARC-V9 and 32-bits PowerPC.</p>
</item>
</list>
<p>Windows will be supported in a future release.</p>
<p>The runtime system with SMP support might build on other
operating systems in combination with supported hardware.
In order to force a build of a runtime system with SMP
support, pass the <c><![CDATA[--enable-smp-support]]></c> command line
argument to configure. Note, however, that it is not enough
that it builds. The underlying thread library and operating
system has to provide SMP support as well. If the thread
library does not distribute scheduler threads over multiple
processor cores then the runtime system will only seemingly
provide SMP support. If the runtime system is not built by
default on a specific platform, we have <em>not</em> tested
it on that platform.</p>
<p><em>NOTE</em>: The design of SMP support for drivers is
ongoing. There will probably be incompatible driver
changes (only affecting drivers run on the runtime system
with SMP support) released as patches for R11B.</p>
<p><em>Potential incompatibility</em>: Previously, specific
driver call-backs were always called from the same thread.
This is <em>not</em> true in the runtime system with SMP
support. Calls to call-backs will be made from different
threads, e.g., two consecutive calls to exactly the same
call-back can be made from two different threads. This
will in <em>most</em> cases not be a problem. All calls
to call-backs are synchronized, i.e., only one call-back
will be called at a time.</p>
<p>In the future the default behavior will <em>probably</em>
be the following: Calls to call-backs will, as now, be
made from different threads. Calls to call-backs in the
same driver <em>instance</em> will be synchronized. It
will probably be possible to configure so that all calls
to call-backs in all driver instances of a specific
driver type will be synchronized. It may be possible to
configure so that all calls to call-backs of a driver
instance or a of a specific driver type will be made from
the same thread.</p>
<p>Parallelism in the Erlang code executed is a necessity
for the Erlang runtime system to be able to take
advantage of multi-core or multi-processor hardware.
There need to be at least as many Erlang processes
runnable as processor cores for the Erlang runtime system
to be able to take advantage of all processor cores.</p>
<p>An Erlang runtime system with SMP support with only one
Erlang process runnable all the time will almost always be
slower than the same Erlang runtime system without SMP
support. This is due to thread synchronization overhead.</p>
<p>Known major bottleneck in the Erlang runtime system:</p>
<list type="bulleted">
<item>
<p>Currently the I/O system uses one "big lock", i.e. only
one thread can do I/O at a time (with the exception of
async threads and threads created by users own linked-in
drivers). This is high on the list of things to
optimize. Note, code that does not do I/O can be executed
at the same time as one thread does I/O.</p>
</item>
</list>
<p>Some pitfalls which might cause Erlang programs that work on
the non-SMP runtime system to fail on the SMP runtime
system:</p>
<list type="bulleted">
<item>
<p>A newly spawned process will often begin executing
immediately. Code that expects that the parent process
will be able to execute for a while before the child
process begins executing is likely to fail.</p>
</item>
<item>
<p>High priority processes could previously provide
mutual exclusion (bad programming style) by preventing
normal and low priority processes from being run. High
priority processes cannot be used this way to provide
mutual exclusion.</p>
</item>
<item>
<p><c><![CDATA[erlang:yield()]]></c> could be used to provide some
kind of temporary mutual exclusion (also bad programming
style). <c><![CDATA[erlang:yield()]]></c> cannot be used to provide
any kind of mutual exclusion.</p>
</item>
<item>
<p>Obscure pitfall, only if a process being traced also
sends normal messages to the tracer:<br></br>
The order between trace messages and normal
messages is undefined. I.e. the order between normal
messages sent from a tracee to a tracer and the trace
messages generated from the same tracee to the same
tracer is undefined. The internal order of normal
messages and the internal order of trace messages will,
of course, be preserved as before.</p>
</item>
</list>
<p>The kernel poll feature is currently not supported by
the runtime system with SMP support. It will probably be
supported in a future release.</p>
<p>*** POTENTIAL INCOMPATIBILITY ***</p>
<p>Own Id: OTP-6006 Aux Id: OTP-6095 </p>
</item>
<item>
<p>Linked-in driver modifications.</p>
<list type="bulleted">
<item>
<p>Linked-in drivers must be recompiled.</p>
</item>
<item>
<p>The <c><![CDATA[refc]]></c> field in the <c><![CDATA[ErlDrvBinary]]></c> type
has been removed. The reference count can be accessed
via API functions. For more information see
the <c><![CDATA[erl_driver(1)]]></c> man page.</p>
</item>
</list>
<p>*** POTENTIAL INCOMPATIBILITY ***</p>
<p>Own Id: OTP-6095 Aux Id: OTP-6006 </p>
</item>
</list>
</section>
</section>
<section>
<title>ERTS 5.4.13</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>Large files (more than 2 GBytes) are now handled on
Solaris 8.</p>
<p>Own Id: OTP-5849 Aux Id: seq10157 </p>
</item>
<item>
<p>A failing bit syntax construction could fail with the
PREVIOUS exception reason that had occurred in the process
(instead of with <c><![CDATA[badarg]]></c>).</p>
<p>Own Id: OTP-5911</p>
</item>
<item>
<p>When building OTP, the Kernel application was built in
both the primary and secondary bootstrap steps, which
would cause problems if OTP including its bootstrap is
checked into a version control system (such as CVS).
(Thanks to Sebastian Strollo.)</p>
<p>Own Id: OTP-5921</p>
</item>
<item>
<p><c><![CDATA[binary_to_term(<<131,109,255,255,255,255)]]></c> and
similar expressions used to crash the emulator instead of
causing a <c><![CDATA[badarg]]></c> exception. (Thanks to Matthias
Lang.)</p>
<p>Own Id: OTP-5933</p>
</item>
<item>
<p><c><![CDATA[erlang:hibernate/3]]></c> could sometimes crash the emulator
when no heap was needed.</p>
<p>Own Id: OTP-5940</p>
</item>
<item>
<p>Execution of match specs could under rare circumstances
cause the emulator to dump core.</p>
<p>Execution of match specs could cause memory leaks in the
hybrid emulator.</p>
<p>Own Id: OTP-5955</p>
</item>
<item>
<p>A bug in <c><![CDATA[erlang:trace_info/2]]></c> when getting info for a
function in a deleted module resulting in an emulator
crash, has been corrected.</p>
<p>Own Id: OTP-5957</p>
</item>
<item>
<p>Different (and old) <c><![CDATA[config.guess]]></c> files in the
ERTS and Erl_Interface applications would cause build
problems on the new Intel-based iMacs.
(Thanks to Sebastion Strollo.)</p>
<p>Own Id: OTP-5967</p>
</item>
<item>
<p>pthread header and library mismatch on Linux systems (at
least some SuSE and Debian) with both NPTL and
Linuxthreads libraries installed.</p>
<p>Own Id: OTP-5981</p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>The driver_set_timer did not change the previous timeout
if called a second time. Now it works as specified,
changing the timeout.</p>
<p>Own Id: OTP-5942</p>
</item>
<item>
<p>The undocumented <c><![CDATA[{packet,http}]]></c> option (for the
<c><![CDATA[gen_tcp]]></c> module) did not not work correctly when
there were multiple continuation lines. (Thanks to Per
Hedeland.)</p>
<p>Own Id: OTP-5945</p>
</item>
<item>
<p>The setuid_socket_wrap program was corrected to work for
C compilers that treat the <c><![CDATA[char]]></c> type as unsigned.
(Thanks to Magnus Henoch.)</p>
<p>Own Id: OTP-5946</p>
</item>
</list>
</section>
</section>
<section>
<title>ERTS 5.4.12</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>Fixed a minor build problem on Windows.</p>
<p>Own Id: OTP-5819 Aux Id: OTP-5382 OTP-5540 OTP-5577 </p>
</item>
<item>
<p>The <c><![CDATA[delay_send]]></c> option for <c><![CDATA[gen_tcp]]></c> was
broken on Windows.</p>
<p>Own Id: OTP-5822</p>
</item>
<item>
<p>If there were user-defined variables in the boot
script, and their values were not provided using the
<c><![CDATA[-boot_var]]></c> option, the emulator would refuse to
start with a confusing error message. Corrected to show a
clear, understandable message.</p>
<p>The <c><![CDATA[prim_file]]></c> module was modified to not depend
on the <c><![CDATA[lists]]></c> module, to make it possible to start
the emulator using a user-defined loader. (Thanks to
Martin Bjorklund.)</p>
<p>Own Id: OTP-5828 Aux Id: seq10151 </p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>The HiPE compiler identifies more leaf functions,
giving slightly faster code.</p>
<p>Corrected problems in HiPE's coalescing register
allocating that would cause it to fail when compiling
very large functions (e.g. some of parse modules in the
Megaco application).</p>
<p>Own Id: OTP-5853</p>
</item>
</list>
</section>
</section>
<section>
<title>ERTS 5.4.11</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>Timers could sometimes timeout too early. This bug has
now been fixed.</p>
<p>Automatic cancellation of timers created by
<c><![CDATA[erlang:send_after(Time,pid(),Msg)]]></c> and
<c><![CDATA[erlang:start_timer(Time,pid(),Msg)]]></c> has been
introduced. Timers created with the receiver specified by a
pid, will automatically be cancelled when the receiver
exits. For more information see the <c><![CDATA[erlang(3)]]></c> man
page.</p>
<p>In order to be able to maintain a larger amount of timers
without increasing the maintenance cost, the internal
timer wheel and bif timer table have been enlarged.</p>
<p>Also a number of minor bif timer optimizations have been
implemented.</p>
<p>Own Id: OTP-5795 Aux Id: OTP-5090, seq8913, seq10139,
OTP-5782 </p>
</item>
<item>
<p><c><![CDATA[erlang:monitor(process,Pid)]]></c> hanged if <c><![CDATA[Pid]]></c>
referred to a process on a non-existing node with the same
nodename as the nodename of node on which the call was made.
This bug has now been fixed.</p>
<p>Own Id: OTP-5827</p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>By setting Unix environment variables, the priority for
the emulator can be lowered when it is writing crash
dumps and the time allowed for finishing writing a crash
dump can be set to a certain number of seconds. See the
documentation for <c><![CDATA[erl]]></c> in the ERTS application.
(Also, a few other previously undocumented environment
variables are now documented.)</p>
<p>Own Id: OTP-5818</p>
</item>
<item>
<p>Documentation improvements:</p>
<p>- documentation for <c><![CDATA[erlang:link/1]]></c> corrected</p>
<p>- command line flag <c><![CDATA[-code_path_cache]]></c> added</p>
<p>- <c><![CDATA[erl]]></c> command line flags clarifications</p>
<p>- <c><![CDATA[net_kernel(3)]]></c> clarifications</p>
<p>Own Id: OTP-5847</p>
</item>
</list>
</section>
</section>
<section>
<title>ERTS 5.4.10</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>-D_GNU_SOURCE is now always passed on the compile command
line on linux. This in order to ensure that all included
system headers see _GNU_SOURCE defined.</p>
<p>_GNU_SOURCE is now also defined on linux in configure
when looking for features.</p>
<p>Some minor (harmless) configure bugs were also fixed.</p>
<p>Own Id: OTP-5749</p>
</item>
<item>
<p>Some compiler warnings and Dialyzer warnings were
eliminated in the Tools application.</p>
<p>When tracing to a port (which <c><![CDATA[fprof]]></c> does),
there could be fake schedule out/schedule in messages
sent for a process that had exited.</p>
<p>Own Id: OTP-5757</p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>The BIFs <c><![CDATA[iolist_size/1]]></c> and <c><![CDATA[iolist_to_binary/1]]></c>
has been added.</p>
<p>The BIF <c><![CDATA[list_to_existing_atom/1]]></c> has been added.</p>
<p>Minor bug fix: The exception reason could be changed
to <c><![CDATA[error]]></c> inside nested try/catch constructs if the
<c><![CDATA[erlang:raise/3]]></c> BIF was called with an empty
stacktrace. (Calling <c><![CDATA[erlang:raise/3]]></c> with an empty
stacktrace is NOT recommended.)</p>
<p>Minor bugfix: On Windows, <c><![CDATA[file:open/2]]></c> will now
return the documented error reason <c><![CDATA[{error,eisdir}]]></c>
if the filename refers to a directory (it used to return
<c><![CDATA[{error,eacces}]]></c>).</p>
<p>The message in the documentation for
<c><![CDATA[erlang:system_monitor/2]]></c>, description of
<c><![CDATA[busy_dist_port]]></c>, was corrected.</p>
<p>Own Id: OTP-5709 Aux Id: seq10100 </p>
</item>
<item>
<p>The previously undocumented and UNSUPPORTED <c><![CDATA[zlib]]></c>
module has been updated in an incompatible way and many
bugs have been corrected. It is now also documented.</p>
<p>*** POTENTIAL INCOMPATIBILITY ***</p>
<p>Own Id: OTP-5715</p>
</item>
<item>
<p>New socket options <c><![CDATA[priority]]></c> and <c><![CDATA[tos]]></c> for
platforms that support them (currently only Linux).</p>
<p>Own Id: OTP-5756</p>
</item>
<item>
<p>Only the emulator is now linked with termcap library in
order to decrease library dependencies for other otp
programs.</p>
<p>Own Id: OTP-5758</p>
</item>
</list>
</section>
</section>
<section>
<title>ERTS 5.4.9.2</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>The native resolver has gotten an control API for
extended debugging and soft restart. It is:
<c><![CDATA[inet_gethost_native:control(Control)]]></c><br></br><c><![CDATA[Control = {debug_level,Level} | soft_restart]]></c><br></br><c><![CDATA[Level = integer() in the range 0-4]]></c>.</p>
<p>Own Id: OTP-5751 Aux Id: EABln25013 </p>
</item>
</list>
</section>
</section>
<section>
<title>ERTS 5.4.9.1</title>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>On VxWorks, epmd did not handle file descriptors with
higher numbers than 63. Also, if epmd should get a file
descriptor with a number >= FD_SETSIZE, it will close a
the file descriptor and write a message to the log
(instead of mysteriously fail); the Erlang node that
tried to register will fail with a duplicate_name error
(unfortunately, epmd has no way to indicate to the Erlang
node why the register attempt failed).</p>
<p>Own Id: OTP-5716 Aux Id: seq10070 </p>
</item>
</list>
</section>
</section>
<section>
<title>ERTS 5.4.9</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>Timezone data is now initialized better. (was a problem
at least on NetBSD 2.0.2) Thanks to Rich Neswold.</p>
<p>Own Id: OTP-5621</p>
</item>
<item>
<p>The hybrid-heap emulator ('erl -hybrid') is much more
stable. We have corrected all known bugs that caused it
to dump core while running our test suites.</p>
<p>Own Id: OTP-5634</p>
</item>
<item>
<p>Fixed rare memory leaks in <c><![CDATA[erlang:demonitor/1]]></c> when
distributed monitors were removed.</p>
<p>Own Id: OTP-5692</p>
</item>
<item>
<p>Processes were sometimes unnecessarily garbage collected
when terminating. These unnecessary garbage collections
have now been eliminated.</p>
<p>Own Id: OTP-5693</p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>The <c><![CDATA[c:i/0]]></c> function will now run in a paged mode if
there are more than 100 processes in the system. (Thanks
to Ulf Wiger.)</p>
<p><c><![CDATA[erlang:system_info(process_count)]]></c> has
been optimized and does now return exactly the same value
as <c><![CDATA[length(processes())]]></c>. Previously
<c><![CDATA[erlang:system_info(process_count)]]></c> did not include
exiting processes which are included in
<c><![CDATA[length(processes())]]></c>.</p>
<p>The <c><![CDATA[+P]]></c> flag for <c><![CDATA[erl]]></c>, which sets the maximum
number of processes allowed to exist at the same, no longer
accepts values higher than 134217727. (You will still
probably run out of memory before you'll be able to reach
that limit.)</p>
<p>Own Id: OTP-5645 Aux Id: seq9984 </p>
</item>
<item>
<p>The term-building driver functions
<c><![CDATA[driver_output_term()]]></c> and <c><![CDATA[driver_send_term()]]></c>
have been updated:</p>
<p>The ERL_DRV_FLOAT type has been added.</p>
<p>For the ERL_DRV_BINARY type, the length and offset are
now validated against the length of the driver binary.</p>
<p>The ERL_DRV_PID type is now implemented (it was
documented, but not implemented).</p>
<p>Own Id: OTP-5674</p>
</item>
</list>
</section>
</section>
<section>
<title>ERTS 5.4.8</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p><c><![CDATA[ets:delete/1]]></c> now allows other Erlang process to run
when a large table is being deleted.</p>
<p>Own Id: OTP-5572</p>
</item>
<item>
<p>A bug regarding tcp sockets which results in hanging
<c><![CDATA[gen_tcp:send/2]]></c> has been corrected. To encounter
this bug you needed one process that read from a socket,
one that wrote more date than the reader read out so the
sender got suspended, and then the reader closed the
socket. (Reported and diagnosed by Alexey Shchepin.)</p>
<p>Corrected a bug in the (undocumented and unsupported)
option <c><![CDATA[{packet,http}]]></c> for <c><![CDATA[gen_tcp.]]></c>
(Thanks to Claes Wikstrom and Luke Gorrie.)</p>
<p>Updated the documentation regarding the second argument to
<c><![CDATA[gen_tcp:recv/2]]></c>, the <c><![CDATA[Length]]></c> to receive.</p>
<p>Own Id: OTP-5582 Aux Id: seq9839 </p>
</item>
<item>
<p>Erlang/OTP will now build on Mac OS X 10.4 "Tiger" (the
problem was that 10.4 has a partially implemented poll()
function that can't handle devices). Also, on Mac OS X
10.3 "Panther", Erlang/OTP will now use select() instead
of poll() (because poll() on Mac OS X 10.3 is implemented
using select()).</p>
<p>Own Id: OTP-5595</p>
</item>
<item>
<p>A bug in the file driver when opening a file in
compressed mode, and the returned allocated pointer from
the compressing library was in very high memory (>= 2GB),
causing e.g. <c><![CDATA[file:read/2]]></c> to return
<c><![CDATA[{error,ebadf}]]></c>, has been corrected.</p>
<p>Own Id: OTP-5618</p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>The new fun <c><![CDATA[M:F/A]]></c> construct creates a fun that
refers to the latest version of <c><![CDATA[M:F/A.]]></c> This syntax is
meant to replace tuple funs <c><![CDATA[{M,F}]]></c> which have many
problems.</p>
<p>The new type test <c><![CDATA[is_function(Fun,A)]]></c> (which may be
used in guards) test whether <c><![CDATA[Fun]]></c> is a fun that can be
applied with <c><![CDATA[A]]></c> arguments. (Currently, <c><![CDATA[Fun]]></c>
can also be a tuple fun.)</p>
<p>Own Id: OTP-5584</p>
</item>
<item>
<p>In the HiPE application, there's a new experimental
register allocator (optimistic coalescing), and the
linear scan register allocator is now also available on
ppc. Plus lots of cleanups.</p>
<p>Minor hybrid heap corrections.</p>
<p>The maximum size of a heap used to be artificially
limited so that the size of a heap would fit in 28 bits;
that limitation could cause the emulator to terminate in
a garbage collection even if there still was available
memory. Now the largest heap size for a 32 bit CPU is
1,699,221,830 bytes. (Thanks to Jesper Wilhelmsson.)</p>
<p>Also removed the undocumented <c><![CDATA[+H]]></c> emulator option.</p>
<p>Own Id: OTP-5596</p>
</item>
</list>
</section>
</section>
<section>
<title>ERTS 5.4.7</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p><c><![CDATA[to_erl]]></c> could close unexpectedly on Linux systems.
Also, output from the emulator could be lost. Corrected.</p>
<p>Own Id: OTP-5561</p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>The <c><![CDATA[cpu_timestamp]]></c> option for <c><![CDATA[erlang:trace/3]]></c>
is now also supported on Linux.</p>
<p>Own Id: OTP-5532 Aux Id: seq9813 </p>
</item>
<item>
<p>The last known <c><![CDATA[werl]]></c> window size/position is now saved
correctly when <c><![CDATA[werl]]></c> is stopped with the window
minimized. A problem with the placement not being saved if
the emulator is halted or stopped from the JCL menu has also
been fixed.</p>
<p>Own Id: OTP-5544 Aux Id: OTP-5522 </p>
</item>
</list>
</section>
</section>
<section>
<title>ERTS 5.4.6</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>Some math libraries do not always throw floating-point
exceptions on errors. In order to be able to use these
libraries, floating-point errors are now more thoroughly
checked.</p>
<p>Misc floating-point fixes for Linux and MacOSX.</p>
<p>Own Id: OTP-5467</p>
</item>
<item>
<p>An internal buffer was sometimes not cleared which caused
garbage to appear in error messages sent to the error
logger.</p>
<p><c><![CDATA[errno]]></c> was sometimes clobbered which caused erroneous
error reports about <c><![CDATA[poll()]]></c> errors.</p>
<p>Only emulators on unix platforms were affected by these
bugs.</p>
<p>Own Id: OTP-5492</p>
</item>
<item>
<p>The ethread library now works on OpenBSD.</p>
<p>Own Id: OTP-5515</p>
</item>
<item>
<p>Corrected a bug in the (undocumented and unsupported)
option <c><![CDATA[{packet,http}]]></c> for <c><![CDATA[gen_tcp]]></c>.
(Thanks to Claes Wikstrom and Luke Gorrie.)</p>
<p>Own Id: OTP-5519</p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p><c><![CDATA[binary_to_term/1]]></c> could cause the emulator to crash
when given invalid pids or funs.</p>
<p>Own Id: OTP-5484 Aux Id: seq9801 </p>
</item>
<item>
<p>Some more stability problems were fixed in the
hybrid-heap emulator.</p>
<p>Own Id: OTP-5489</p>
</item>
<item>
<p>After <c><![CDATA[werl]]></c> was closed with the window minimized, it
was not possible to restart <c><![CDATA[werl]]></c> with an open
window. A temporary solution has so far been implemented
that restores the initial window settings every time
<c><![CDATA[werl]]></c> is started.</p>
<p>Own Id: OTP-5522</p>
</item>
</list>
</section>
</section>
<section>
<title>ERTS 5.4.5</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>If a process had node links (created by
<c><![CDATA[monitor_node/2]]></c>), executing
<c><![CDATA[process_info(Pid,memory)]]></c> for that process would
crash the emulator.</p>
<p>Own Id: OTP-5420</p>
</item>
<item>
<p>Minor corrections to the help text printed by <c><![CDATA[erlc -help]]></c>. The documentation for <c><![CDATA[erlc]]></c> was also
slightly updated.</p>
<p>Own Id: OTP-5428</p>
</item>
<item>
<p>32-bit words were used for offsets in the garbage
collector. This caused the emulator to crash on 64-bit
machines when heaps were moved more than 4 GB during
garbage collection.</p>
<p>Own Id: OTP-5430</p>
</item>
<item>
<p><c><![CDATA[is_boolean(42.5)]]></c> failed to load if optimization was
explicitly turned off.</p>
<p>Own Id: OTP-5448</p>
</item>
<item>
<p>If there was a call to <c><![CDATA[Module:foo/X]]></c> from any loaded
module, the returned by <c><![CDATA[M:module_info(exports)]]></c> would
always include <c><![CDATA[{foo,X}]]></c> (even though
<c><![CDATA[Module:foo/X]]></c> if was not defined).</p>
<p>Own Id: OTP-5450 Aux Id: seq9722 </p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>The <c><![CDATA[c]]></c> option for the <c><![CDATA[+B]]></c> flag has been
introduced which makes it possible to use Ctrl-C
(Ctrl-Break on Windows) to interrupt the shell process
rather than to invoke the emulator break handler. All new
<c><![CDATA[+B]]></c> options are also supported on Windows
(<c><![CDATA[werl]]></c>) as of now. Furthermore, Ctrl-C on Windows has
now been reserved for copying text (what Ctrl-Ins was used
for previously). Ctrl-Break should be used for break
handling. Lastly, the documentation of the system flags has
been updated.</p>
<p>Own Id: OTP-5388</p>
</item>
</list>
</section>
</section>
<section>
<title>ERTS 5.4.4</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>The function <c><![CDATA[erlang:float/1]]></c> can now be used in
match specifications and is recognized by
<c><![CDATA[dbg:fun2ms/1]]></c> and <c><![CDATA[ets:fun2ms/1]]></c>. This
addition is part of the work to "harmonize" match
specification guards with Erlang guards.</p>
<p>Own Id: OTP-5297 Aux Id: OTP-4927 </p>
</item>
<item>
<p>The <c><![CDATA[register/2]]></c> BIF would return <c><![CDATA[true]]></c> even if
the second argument was not a pid for living process.
Corrected to cause an exception.</p>
<p>Own Id: OTP-5324 Aux Id: seq9698 </p>
</item>
<item>
<p>In the 'bag' type of ets tables, elements having the same
key were supposed to be order in insertion order. The
would be wrong if a rehash occurred.</p>
<p>Own Id: OTP-5340 Aux Id: seq9704 </p>
</item>
<item>
<p>Linked in drivers in the Crypto and Asn1 applications
are now compiled with the <c><![CDATA[-D_THREAD_SAFE]]></c> and
<c><![CDATA[-D_REENTRANT]]></c> switches on unix when the emulator has
thread support enabled.</p>
<p>Linked in drivers on MacOSX are not compiled with the
undocumented <c><![CDATA[-lbundle1.o]]></c> switch anymore. Thanks to
Sean Hinde who sent us a patch.</p>
<p>Linked in driver in Crypto, and port programs in SSL, now
compiles on OSF1.</p>
<p>Minor makefile improvements in Runtime_Tools.</p>
<p>Own Id: OTP-5346</p>
</item>
<item>
<p>Fixed a bug in the hybrid heap in distributed send
operations.</p>
<p>Own Id: OTP-5361</p>
</item>
<item>
<p>A BIF <c><![CDATA[erlang:raise/3]]></c> has been added. See the manual
for details. It is intended for internal system programming
only, advanced error handling.</p>
<p>Own Id: OTP-5376 Aux Id: OTP-5257 </p>
</item>
<item>
<p>Mikael Pettersson (HiPE) corrected a few bugs in the
emulator that caused problems when compiled with the
experimental gcc-4.0.0.</p>
<p>Own Id: OTP-5386</p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>Minor update of the internal documentation of
the <c><![CDATA[epmd]]></c> protocol.</p>
<p>The listen port of <c><![CDATA[epmd]]></c> has now been registered at
IANA:
<url href="http://www.iana.org/assignments/port-numbers">http://www.iana.org/assignments/port-numbers</url>.</p>
<p>Own Id: OTP-5234</p>
</item>
<item>
<p><c><![CDATA[run_erl.c]]></c> now works on Mac OS X and FreeBSD.</p>
<p>Own Id: OTP-5384</p>
</item>
<item>
<p>A few bugs were corrected in the HiPE application.</p>
<p>Own Id: OTP-5385</p>
</item>
</list>
</section>
</section>
<section>
<title>ERTS 5.4.3</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>Font and color preferences for <c><![CDATA[werl.exe]]></c> now can be
saved even after the first time you run <c><![CDATA[werl.exe]]></c>.
The window position and size is also saved. Patch from
James Hague who did all the hard work.</p>
<p>Own Id: OTP-5250</p>
</item>
<item>
<p>OTP archive libraries, e.g. the <c><![CDATA[erl_interface]]></c>
library, on MacOSX could not be used without first
rerunning <c><![CDATA[ranlib]]></c> on them. This bug has now been
fixed.</p>
<p>Own Id: OTP-5274</p>
</item>
<item>
<p>Bugs in <c><![CDATA[erlang:hash/2]]></c> and <c><![CDATA[erlang:phash/2]]></c> on
64-bit platforms have been fixed.</p>
<p>Own Id: OTP-5292</p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>Corrected a crash in the 64-bits emulator.</p>
<p>Corrected a problem in the hybrid heap emulator.</p>
<p>In the chapter about the abstract format in the ERTS User's
Guide, updated the last section about how the abstract
format is stored in BEAM files.</p>
<p>Own Id: OTP-5262</p>
</item>
<item>
<p>The maximum number of concurrent threads in the internal
ethread thread package has been limited to 2048.</p>
<p>Own Id: OTP-5280</p>
</item>
</list>
</section>
</section>
<section>
<title>ERTS 5.4.2.1</title>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>If Erlang/OTP was installed in a short directory name,
such as <c><![CDATA[C:\Program\erl5.4.2]]></c>, the emulator would not
start.</p>
<p>Own Id: OTP-5254</p>
</item>
</list>
</section>
</section>
<section>
<title>ERTS 5.4.2</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>If one used <c><![CDATA[select/3]]></c> and <c><![CDATA[select/1]]></c> on a
non-fixed ETS table and deleted objects simultaneously,
the emulator could crash. Note that the result of such
simultaneous operations on tables that are not in a fixed
state is still undefined, but the emulator crash is,
needless to say, fixed.</p>
<p>Own Id: OTP-5209 Aux Id: seq9198 </p>
</item>
<item>
<p>Arithmetic with big numbers could crash the emulator.</p>
<p>The HiPE native code compiler and run-time code in the
emulator has been updated. (Note: Native code is still
not supported.)</p>
<p>Eliminated a few bugs that could crash the hybrid emulator
(which is not supported).</p>
<p>Own Id: OTP-5233 Aux Id: seq9587 </p>
</item>
</list>
</section>
</section>
<section>
<title>ERTS 5.4.1</title>
<section>
<title>Fixed Bugs and Malfunctions</title>
<list type="bulleted">
<item>
<p>The ethread library was unnecessarily rebuilt multiple
times during the build process, also a debug version of
the library was build during the install phase. These
unnecessary builds have now been removed. Note, the
content of the installed Erlang/OTP system is not
effected at all by this change.</p>
<p>Own Id: OTP-5203</p>
</item>
<item>
<p>The emulator could fail to clear the memory segment
cache. This could potentially cause memory allocation to
unnecessarily fail when memory usage was close to its
maximum. This bug has now been fixed.</p>
<p>Own Id: OTP-5211</p>
</item>
<item>
<p>std_alloc (std short for standard) was sometimes called
def_alloc (def short for default). std_alloc is now
everywhere referred to as std_alloc.</p>
<p>Own Id: OTP-5216</p>
</item>
<item>
<p>A documentation bug has been corrected in
the <c><![CDATA[erts_alloc(3)]]></c> documentation. It was stated that
some of the memory allocators present were by default
disabled. This is true for Erlang/OTP R9C, but is not true
for Erlang/OTP R10B. In R10B all memory allocators present
are enabled by default.</p>
<p>Own Id: OTP-5217</p>
</item>
</list>
</section>
<section>
<title>Improvements and New Features</title>
<list type="bulleted">
<item>
<p>The emulator now close all open files and sockets
immediately after receiving an USR1 signal. This causes
the emulator to unregister at <c><![CDATA[epmd]]></c> as early as
possible.</p>
<p>Own Id: OTP-5221 Aux Id: OTP-4985, seq9514 </p>
</item>
<item>
<p>Try/catch support in the emulator slightly updated.</p>
<p>Own Id: OTP-5229</p>
</item>
</list>
</section>
</section>
</chapter>
