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Diffstat (limited to 'lib/stdlib/doc/src/notes.xml')
| -rw-r--r-- | lib/stdlib/doc/src/notes.xml | 415 |
1 files changed, 414 insertions, 1 deletions
diff --git a/lib/stdlib/doc/src/notes.xml b/lib/stdlib/doc/src/notes.xml index c55eafc8b8..6c618bc798 100644 --- a/lib/stdlib/doc/src/notes.xml +++ b/lib/stdlib/doc/src/notes.xml @@ -30,6 +30,419 @@ </header> <p>This document describes the changes made to the STDLIB application.</p> +<section><title>STDLIB 1.17.1</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p>reference() has been substituted for ref() in the + documentation.</p> + <p> + Own Id: OTP-8733</p> + </item> + </list> + </section> + + + <section><title>Improvements and New Features</title> + <list> + <item> + <p> + The ms_transform now warns if the fun head shadows + surrounding variables (just like the warnings you would + get for an ordinary fun in the same context).</p> + <p> + Own Id: OTP-6759</p> + </item> + <item> + <p> + ets:select_reverse/{1,2,3} are now documented.</p> + <p> + Own Id: OTP-7863</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> + Some Built In Functions (BIFs) from the module erlang was + never made autoimported for backward compatibility + reasons. As local functions now override autoimports, new + autoimports is no longer a problem, why the following + BIFs are finally made autoimported: monitor/2, monitor/3, + demonitor/2, demonitor/3, error/1, error/2, + integer_to_list/2, list_to_integer/2.</p> + <p> + Own Id: OTP-8763</p> + </item> + </list> + </section> + +</section> + +<section><title>STDLIB 1.17</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p>The Erlang code preprocessor (<c>epp</c>) sent extra + messages on the form <c>{eof,Location}</c> to the client + when parsing the <c>file</c> attribute. This bug, + introduced in R11B, has been fixed.</p> + <p> + Own Id: OTP-8470</p> + </item> + <item> + <p>The abstract type 'fun' could not be printed by the + Erlang pretty printer (<c>erl_pp</c>). This bug has been + fixed.</p> + <p> + Own Id: OTP-8473</p> + </item> + <item> + <p>The function <c>erl_scan:reserved_word/1</c> no longer + returns <c>true</c> when given the word <c>spec</c>. This + bug was introduced in STDLIB-1.15.3 (R12B-3).</p> + <p> + Own Id: OTP-8567</p> + </item> + <item> + <p>The documentation of <c>lists:keysort/2</c> states + that the sort is stable.</p> + <p> + Own Id: OTP-8628 Aux Id: seq11576 </p> + </item> + <item> + <p> + The shell's line editing has been improved to more + resemble the behaviour of readline and other shells. + (Thanks to Dave Peticolas)</p> + <p> + Own Id: OTP-8635</p> + </item> + <item> + <p>The Erlang code preprocessor (<c>epp</c>) did not + correctly handle premature end-of-input when defining + macros. This bug, introduced in STDLIB 1.16, has been + fixed.</p> + <p> + Own Id: OTP-8665 Aux Id: OTP-7810 </p> + </item> + </list> + </section> + + + <section><title>Improvements and New Features</title> + <list> + <item> + <p> + The module binary from EEP31 (and EEP9) is implemented.</p> + <p> + Own Id: OTP-8217</p> + </item> + <item> + <p>The erlang pretty printer (<c>erl_pp</c>) no longer + quotes atoms in types.</p> + <p> + Own Id: OTP-8501</p> + </item> + <item> + <p>The Erlang code preprocessor (<c>epp</c>) now + considers records with no fields as typed.</p> + <p> + Own Id: OTP-8503</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>The Erlang parser no longer duplicates the singleton + type <c>undefined</c> in the type of record fields + without initial value.</p> + <p> + Own Id: OTP-8522</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>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> + Some properties of a compiled re pattern are defined to + allow for guard tests.</p> + <p> + Own Id: OTP-8577</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>The undocumented, unsupport, and deprecated function + <c>lists:flat_length/1</c> has been removed.</p> + <p> + Own Id: OTP-8584</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>Nested records can now be accessed without + parenthesis. See the Reference Manual for examples. + (Thanks to YAMASHINA Hio and Tuncer Ayaz.)</p> + <p> + Own Id: OTP-8597</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 beam_lib:cmp/2 function now compares BEAM files in + stricter way. The BEAM files will be considered different + if there are any changes except in the compilation + information ("CInf") chunk. beam_lib:cmp/2 used to ignore + differences in the debug information (significant for + Dialyzer) and other chunks that did not directly change + the run-time behavior.</p> + <p> + Own Id: OTP-8625</p> + </item> + <item> + <p> + When a gen_server, gen_fsm process, or gen_event + terminates abnormally, sometimes the text representation + of the process state can occupy many lines of the error + log, depending on the definition of the state term. A + mechanism to trim out parts of the state from the log has + been added (using a format_status/2 callback). See the + documentation.</p> + <p> + Own Id: OTP-8630</p> + </item> + <item> + <p> + Calling <c>sys:get_status()</c> for processes that have + globally registered names that were not atoms would cause + a crash. Corrected. (Thanks to Steve Vinoski.)</p> + <p> + Own Id: OTP-8656</p> + </item> + <item> + <p>The Erlang scanner has been augmented with two new + tokens: <c>..</c> and <c>...</c>.</p> + <p> + Own Id: OTP-8657</p> + </item> + <item> + <p>Expressions evaluating to integers can now be used in + types and function specifications where hitherto only + integers were allowed ("Erlang_Integer").</p> + <p> + Own Id: OTP-8664</p> + </item> + <item> + <p>The compiler optimizes record operations better.</p> + <p> + Own Id: OTP-8668</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> + 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> + The predefined builtin type tid() has been removed. + Instead, ets:tid() should be used.</p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-8687</p> + </item> + </list> + </section> + +</section> + <section><title>STDLIB 1.16.5</title> <section><title>Fixed Bugs and Malfunctions</title> @@ -50,7 +463,7 @@ <item> <p>A number of bugs concerning re and unicode are corrected:</p> - <p>re:compile no longer looses unicode option, which also + <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> |