diff options
Diffstat (limited to 'erts/doc/src/erlang.xml')
| -rw-r--r-- | erts/doc/src/erlang.xml | 667 |
1 files changed, 549 insertions, 118 deletions
diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml index 06fefa8efb..483d81cfb6 100644 --- a/erts/doc/src/erlang.xml +++ b/erts/doc/src/erlang.xml @@ -1,4 +1,4 @@ -<?xml version="1.0" encoding="latin1" ?> +<?xml version="1.0" encoding="utf-8" ?> <!DOCTYPE erlref SYSTEM "erlref.dtd"> <erlref> @@ -235,7 +235,7 @@ <code> 1> Bin = <<1,2,3,4,5,6,7,8,9,10>>. -2> binary_part(Bin,{byte_size(Bin), -5)). +2> binary_part(Bin,{byte_size(Bin), -5}). <<6,7,8,9,10>> </code> @@ -501,16 +501,87 @@ <name name="check_process_code" arity="2"/> <fsummary>Check if a process is executing old code for a module</fsummary> <desc> - <p>Returns <c>true</c> if the process <c><anno>Pid</anno></c> is executing - old code for <c><anno>Module</anno></c>. That is, if the current call of - the process executes old code for this module, or if the - process has references to old code for this module, or if the - process contains funs that references old code for this - module. Otherwise, it returns <c>false</c>.</p> - <pre> -> <input>check_process_code(Pid, lists).</input> -false</pre> + <p>The same as + <seealso marker="#check_process_code/3"><c>erlang:check_process_code(<anno>Pid</anno>, + <anno>Module</anno>, [])</c></seealso>.</p> + </desc> + </func> + <func> + <name name="check_process_code" arity="3"/> + <fsummary>Check if a process is executing old code for a module</fsummary> + <desc> + <p>Check if the node local process identified by <c><anno>Pid</anno></c> + is executing old code for <c><anno>Module</anno></c>.</p> + <p>Currently available <c><anno>Option</anno>s</c>:</p> + <taglist> + <tag><c>{allow_gc, boolean()}</c></tag> + <item> + Determines if garbage collection is allowed when performing + the operation. If <c>{allow_gc, false}</c> is passed, and + a garbage collection is needed in order to determine the + result of the operation, the operation will be aborted + (see information on <c><anno>CheckResult</anno></c> below). + The default is to allow garbage collection, i.e., + <c>{allow_gc, true}</c>. + </item> + <tag><c>{async, RequestId}</c></tag> + <item> + The <c>check_process_code/3</c> function will return + the value <c>async</c> immediately after the request + has been sent. When the request has been processed, the + process that called this function will be passed a + message on the form:<br/> + <c>{check_process_code, <anno>RequestId</anno>, <anno>CheckResult</anno>}</c>. + </item> + </taglist> + <p>If <c><anno>Pid</anno></c> equals <c>self()</c>, and + no <c>async</c> option has been passed, the operation will + be performed at once. In all other cases a request for + the operation will be sent to the process identified by + <c><anno>Pid</anno></c>, and will be handled when + appropriate. If no <c>async</c> option has been passed, + the caller will block until <c><anno>CheckResult</anno></c> + is available and can be returned.</p> + <p><c><anno>CheckResult</anno></c> informs about the result of + the request:</p> + <taglist> + <tag><c>true</c></tag> + <item> + The process identified by <c><anno>Pid</anno></c> is + executing old code for <c><anno>Module</anno></c>. + That is, the current call of the process executes old + code for this module, or the process has references + to old code for this module, or the process contains + funs that references old code for this module. + </item> + <tag><c>false</c></tag> + <item> + The process identified by <c><anno>Pid</anno></c> is + not executing old code for <c><anno>Module</anno></c>. + </item> + <tag><c>aborted</c></tag> + <item> + The operation was aborted since the process needed to + be garbage collected in order to determine the result + of the operation, and the operation was requested + by passing the <c>{allow_gc, false}</c> option.</item> + </taglist> <p>See also <seealso marker="kernel:code">code(3)</seealso>.</p> + <p>Failures:</p> + <taglist> + <tag><c>badarg</c></tag> + <item> + If <c><anno>Pid</anno></c> is not a node local process identifier. + </item> + <tag><c>badarg</c></tag> + <item> + If <c><anno>Module</anno></c> is not an atom. + </item> + <tag><c>badarg</c></tag> + <item> + If <c><anno>OptionList</anno></c> is not a valid list of options. + </item> + </taglist> </desc> </func> <func> @@ -816,7 +887,7 @@ false</pre> <fsummary>Print a term on standard output</fsummary> <desc> <p>Prints a text representation of <c><anno>Term</anno></c> on the standard - output.</p> + output. On OSE the term is printed to the ramlog.</p> <warning> <p>This BIF is intended for debugging only.</p> </warning> @@ -1197,20 +1268,74 @@ true that the spontaneous garbage collection will occur too late or not at all. Improper use may seriously degrade system performance.</p> - <p>Compatibility note: In versions of OTP prior to R7, - the garbage collection took place at the next context switch, - not immediately. To force a context switch after a call to - <c>erlang:garbage_collect()</c>, it was sufficient to make - any function call.</p> </desc> </func> <func> <name name="garbage_collect" arity="1"/> - <fsummary>Force an immediate garbage collection of a process</fsummary> + <fsummary>Garbage collect a process</fsummary> + <desc> + <p>The same as + <seealso marker="#garbage_collect/2"><c>garbage_collect(<anno>Pid</anno>, [])</c></seealso>.</p> + </desc> + </func> + <func> + <name name="garbage_collect" arity="2"/> + <fsummary>Garbage collect a process</fsummary> <desc> - <p>Works like <c>erlang:garbage_collect()</c> but on any - process. The same caveats apply. Returns <c>false</c> if - <c><anno>Pid</anno></c> refers to a dead process; <c>true</c> otherwise.</p> + <p>Garbage collect the node local process identified by + <c><anno>Pid</anno></c>.</p> + <p>Currently available <c><anno>Option</anno></c>s:</p> + <taglist> + <tag><c>{async, RequestId}</c></tag> + <item> + The <c>garbage_collect/2</c> function will return + the value <c>async</c> immediately after the request + has been sent. When the request has been processed, the + process that called this function will be passed a + message on the form:<br/> + <c>{garbage_collect, <anno>RequestId</anno>, <anno>GCResult</anno>}</c>. + </item> + </taglist> + <p>If <c><anno>Pid</anno></c> equals <c>self()</c>, and + no <c>async</c> option has been passed, the garbage + collection will be performed at once, i.e. the same as + calling + <seealso marker="#garbage_collect/0">garbage_collect/0</seealso>. + In all other cases a request for garbage collection will + be sent to the process identified by <c><anno>Pid</anno></c>, + and will be handled when appropriate. If no <c>async</c> + option has been passed, the caller will block until + <c><anno>GCResult</anno></c> is available and can be + returned.</p> + <p><c><anno>GCResult</anno></c> informs about the result of + the garbage collection request:</p> + <taglist> + <tag><c>true</c></tag> + <item> + The process identified by <c><anno>Pid</anno></c> has + been garbage collected. + </item> + <tag><c>false</c></tag> + <item> + No garbage collection was performed. This since the + the process identified by <c><anno>Pid</anno></c> + terminated before the request could be satisfied. + </item> + </taglist> + <p>Note that the same caveats as for + <seealso marker="#garbage_collect/0">garbage_collect/0</seealso> + apply.</p> + <p>Failures:</p> + <taglist> + <tag><c>badarg</c></tag> + <item> + If <c><anno>Pid</anno></c> is not a node local process identifier. + </item> + <tag><c>badarg</c></tag> + <item> + If <c><anno>OptionList</anno></c> is not a valid list of options. + </item> + </taglist> </desc> </func> <func> @@ -1659,6 +1784,15 @@ os_prompt% </pre> </desc> </func> <func> + <name name="is_map" arity="1"/> + <fsummary>Check whether a term is a map</fsummary> + <desc> + <p>Returns <c>true</c> if <c><anno>Term</anno></c> is a map; + otherwise returns <c>false</c>.</p> + <p>Allowed in guard tests.</p> + </desc> + </func> + <func> <name name="is_number" arity="1"/> <fsummary>Check whether a term is a number</fsummary> <desc> @@ -2095,6 +2229,17 @@ os_prompt% </pre> </desc> </func> <func> + <name name="map_size" arity="1"/> + <fsummary>Return the size of a map</fsummary> + <desc> + <p>Returns an integer which is the number of key-value pairs in <c><anno>Map</anno></c>.</p> + <pre> +> <input>map_size(#{a=>1, b=>2, c=>3}).</input> +3</pre> + <p>Allowed in guard tests.</p> + </desc> + </func> + <func> <name name="max" arity="2"/> <fsummary>Return the largest of two term</fsummary> <desc> @@ -2467,7 +2612,7 @@ os_prompt% </pre> fails, a <c>nodedown</c> message is delivered.</p> <p>Nodes connected through hidden connections can be monitored as any other node.</p> - <p>Failure: <c>badarg</c>if the local node is not alive.</p> + <p>Failure: <c>badarg</c> if the local node is not alive.</p> </desc> </func> <func> @@ -2613,7 +2758,28 @@ os_prompt% </pre> <desc> <p>Returns a port identifier as the result of opening a new Erlang port. A port can be seen as an external Erlang - process. <c><anno>PortName</anno></c> is one of the following:</p> + process. + </p> + <p>The name of the executable as well as the arguments + given in <c>cd</c>, <c>env</c>, <c>args</c> and <c>arg0</c> is subject to + Unicode file name translation if the system is running + in Unicode file name mode. To avoid + translation or force i.e. UTF-8, supply the executable + and/or arguments as a binary in the correct + encoding. See the <seealso + marker="kernel:file">file</seealso> module, the + <seealso marker="kernel:file#native_name_encoding/0"> + file:native_name_encoding/0</seealso> function and the + <seealso marker="stdlib:unicode_usage">stdlib users guide + </seealso> for details.</p> + + <note><p>The characters in the name (if given as a list) + can only be > 255 if the Erlang VM is started in + Unicode file name translation mode, otherwise the name + of the executable is limited to the ISO-latin-1 + character set.</p></note> + + <p><c><anno>PortName</anno></c> is one of the following:</p> <taglist> <tag><c>{spawn, <anno>Command</anno>}</c></tag> <item> @@ -2668,25 +2834,6 @@ os_prompt% </pre> executed, the appropriate command interpreter will implicitly be invoked, but there will still be no command argument expansion or implicit PATH search.</p> - - <p>The name of the executable as well as the arguments - given in <c>args</c> and <c>arg0</c> is subject to - Unicode file name translation if the system is running - in Unicode file name mode. To avoid - translation or force i.e. UTF-8, supply the executable - and/or arguments as a binary in the correct - encoding. See the <seealso - marker="kernel:file">file</seealso> module, the - <seealso marker="kernel:file#native_name_encoding/0"> - file:native_name_encoding/0</seealso> function and the - <seealso marker="stdlib:unicode_usage">stdlib users guide - </seealso> for details.</p> - - <note><p>The characters in the name (if given as a list) - can only be > 255 if the Erlang VM is started in - Unicode file name translation mode, otherwise the name - of the executable is limited to the ISO-latin-1 - character set.</p></note> <p>If the <c><anno>FileName</anno></c> cannot be run, an error exception, with the posix error code as the reason, is @@ -2762,11 +2909,7 @@ os_prompt% </pre> strings. The one exception is <c><anno>Val</anno></c> being the atom <c>false</c> (in analogy with <c>os:getenv/1</c>), which removes the environment variable. - </p> - <p>If Unicode filename encoding is in effect (see the <seealso - marker="erts:erl#file_name_encoding">erl manual - page</seealso>), the strings (both <c>Name</c> and - <c>Value</c>) may contain characters with codepoints > 255.</p> + </p> </item> <tag><c>{args, [ string() | binary() ]}</c></tag> <item> @@ -2794,21 +2937,6 @@ os_prompt% </pre> should not be given in this list. The proper executable name will automatically be used as argv[0] where applicable.</p> - <p>When the Erlang VM is running in Unicode file name - mode, the arguments can contain any Unicode characters and - will be translated into whatever is appropriate on the - underlying OS, which means UTF-8 for all platforms except - Windows, which has other (more transparent) ways of - dealing with Unicode arguments to programs. To avoid - Unicode translation of arguments, they can be supplied as - binaries in whatever encoding is deemed appropriate.</p> - - <note><p>The characters in the arguments (if given as a - list of characters) can only be > 255 if the Erlang - VM is started in Unicode file name mode, - otherwise the arguments are limited to the - ISO-latin-1 character set.</p></note> - <p>If one, for any reason, wants to explicitly set the program name in the argument vector, the <c>arg0</c> option can be used.</p> @@ -2824,9 +2952,6 @@ os_prompt% </pre> responds to this is highly system dependent and no specific effect is guaranteed.</p> - <p>The unicode file name translation rules of the - <c>args</c> option apply to this option as well.</p> - </item> <tag><c>exit_status</c></tag> @@ -2906,11 +3031,11 @@ os_prompt% </pre> <tag><marker id="open_port_parallelism"><c>{parallelism, Boolean}</c></marker></tag> <item> <p>Set scheduler hint for port parallelism. If set to <c>true</c>, - the VM will schedule port tasks when it by this can improve the + the VM will schedule port tasks when doing so will improve parallelism in the system. If set to <c>false</c>, the VM will - try to perform port tasks immediately and by this improving the - latency at the expense of parallelism. The default can be set on - system startup by passing the + try to perform port tasks immediately, improving latency at the + expense of parallelism. The default can be set on system startup + by passing the <seealso marker="erl#+spp">+spp</seealso> command line argument to <seealso marker="erl">erl(1)</seealso>. </p> @@ -3032,7 +3157,10 @@ os_prompt% </pre> (see below), being synchronous, and that the port does <em>not</em> reply with <c>{Port, closed}</c>. Any process may close a port with <c>port_close/1</c>, not only the port owner - (the connected process).</p> + (the connected process). If the calling process is linked to + port identified by <c><anno>Port</anno></c>, an exit signal due + to that link will be received by the process prior to the return + from <c>port_close/1</c>.</p> <p>For comparison: <c><anno>Port</anno> ! {self(), close}</c> fails with <c>badarg</c> if <c><anno>Port</anno></c> cannot be sent to (i.e., <c><anno>Port</anno></c> refers neither to a port nor to a process). If @@ -3041,6 +3169,7 @@ os_prompt% </pre> the port replies with <c>{Port, closed}</c> when all buffers have been flushed and the port really closes, but if the calling process is not the port owner the <em>port owner</em> fails with <c>badsig</c>.</p> + <p>Note that any process can close a port using <c><anno>Port</anno> ! {PortOwner, close}</c> just as if it itself was the port owner, but the reply always goes to the port owner.</p> @@ -3050,8 +3179,17 @@ os_prompt% </pre> implementation has been synchronous. <c>port_close/1</c> is however still fully synchronous. This due to its error behavior.</p> - <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not an open port or - the registered name of an open port.</p> + <p>Failure:</p> + <taglist> + <tag><c>badarg</c></tag> + <item> + If <c><anno>Port</anno></c> is not an identifier of an open + port, or the registered name of an open port. If the calling + process was linked to the previously open port identified by + <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to this exception. + </item> + </taglist> </desc> </func> <func> @@ -3086,8 +3224,11 @@ os_prompt% </pre> <taglist> <tag><c>badarg</c></tag> <item> - If <c><anno>Port</anno></c> is not an open port or the registered name - of an open port. + If <c><anno>Port</anno></c> is not an identifier of an open + port, or the registered name of an open port. If the calling + process was linked to the previously open port identified by + <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to this exception. </item> <tag><c>badarg</c></tag> <item> @@ -3130,8 +3271,11 @@ os_prompt% </pre> <taglist> <tag><c>badarg</c></tag> <item> - If <c><anno>Port</anno></c> is not an open port or the registered name - of an open port. + If <c><anno>Port</anno></c> is not an identifier of an open + port, or the registered name of an open port. If the calling + process was linked to the previously open port identified by + <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to this exception. </item> <tag><c>badarg</c></tag> <item> @@ -3198,9 +3342,20 @@ os_prompt% </pre> implementation has been synchronous. <c>port_connect/2</c> is however still fully synchronous. This due to its error behavior.</p> - <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not an open port - or the registered name of an open port, or if <c>Pid</c> is - not an existing local pid.</p> + <p>Failures:</p> + <taglist> + <tag><c>badarg</c></tag> + <item> + If <c><anno>Port</anno></c> is not an identifier of an open + port, or the registered name of an open port. If the calling + process was linked to the previously open port identified by + <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to this exception. + </item> + <tag><c>badarg</c></tag> + <item>If process identified by <c>Pid</c> is not an existing + local process.</item> + </taglist> </desc> </func> <func> @@ -3236,12 +3391,33 @@ os_prompt% </pre> binary term format and sent to the port.</p> <p>Returns: a term from the driver. The meaning of the returned data also depends on the port driver.</p> - <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not an open port or - the registered name of an open port, if <c><anno>Operation</anno></c> - cannot fit in a 32-bit integer, if the port driver does not - support synchronous control operations, or if the port driver - so decides for any reason (probably something wrong with - <c><anno>Operation</anno></c> or <c><anno>Data</anno></c>).</p> + <p>Failures:</p> + <taglist> + <tag><c>badarg</c></tag> + <item> + If <c><anno>Port</anno></c> is not an identifier of an open + port, or the registered name of an open port. If the calling + process was linked to the previously open port identified by + <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to this exception. + </item> + <tag><c>badarg</c></tag> + <item> + If <c><anno>Operation</anno></c> does not fit in a + 32-bit integer. + </item> + <tag><c>badarg</c></tag> + <item> + If the port driver does not support synchronous control + operations. + </item> + <tag><c>badarg</c></tag> + <item> + If the port driver so decides for any reason (probably + something wrong with <c><anno>Operation</anno></c>, or + <c><anno>Data</anno></c>). + </item> + </taglist> </desc> </func> <func> @@ -3251,7 +3427,12 @@ os_prompt% </pre> <p>Returns a list containing tuples with information about the <c><anno>Port</anno></c>, or <c>undefined</c> if the port is not open. The order of the tuples is not defined, nor are all the - tuples mandatory.</p> + tuples mandatory. + If <c>undefined</c> is returned and the calling process + was linked to a previously open port identified by + <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/1</c>.</p> <p>Currently the result will containt information about the following <c>Item</c>s: <c>registered_name</c> (if the port has a registered name), <c>id</c>, <c>connected</c>, <c>links</c>, @@ -3269,7 +3450,11 @@ os_prompt% </pre> <p><c><anno>Pid</anno></c> is the process identifier of the process connected to the port.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3281,7 +3466,11 @@ os_prompt% </pre> <p><c><anno>Index</anno></c> is the internal index of the port. This index may be used to separate ports.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3293,7 +3482,11 @@ os_prompt% </pre> <p><c><anno>Bytes</anno></c> is the total number of bytes read from the port.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3305,7 +3498,11 @@ os_prompt% </pre> <p><c><anno>Pids</anno></c> is a list of the process identifiers of the processes that the port is linked to.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3320,7 +3517,11 @@ os_prompt% </pre> that these results are highly implementation specific and might change in the future.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3334,7 +3535,11 @@ os_prompt% </pre> that the port itself might have allocated memory which is not included in <c><anno>Bytes</anno></c>.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3346,7 +3551,11 @@ os_prompt% </pre> <p><c><anno>Monitors</anno></c> represent processes that this port is monitoring.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3358,7 +3567,11 @@ os_prompt% </pre> <p><c><anno>Name</anno></c> is the command name set by <seealso marker="#open_port/2">open_port/2</seealso>.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3373,7 +3586,11 @@ os_prompt% </pre> Command}, Options)</seealso>. If the port is not the result of spawning an OS process, the value is <c>undefined</c>.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3389,7 +3606,11 @@ os_prompt% </pre> or <c><anno>Port</anno> ! {Owner, {command, Data}</c>. </p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3412,7 +3633,11 @@ os_prompt% </pre> in bytes, queued by the port using the ERTS driver queue implementation.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3424,7 +3649,11 @@ os_prompt% </pre> <p><c><anno>RegisteredName</anno></c> is the registered name of the port. If the port has no registered name, <c>[]</c> is returned.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -4477,6 +4706,7 @@ true</pre> </func> <func> <name name="spawn_opt" arity="2"/> + <type name="priority_level" /> <fsummary>Create a new process with a fun as entry point</fsummary> <desc> <p>Returns the pid of a new process started by the application @@ -4490,6 +4720,7 @@ true</pre> </func> <func> <name name="spawn_opt" arity="3"/> + <type name="priority_level" /> <fsummary>Create a new process with a fun as entry point on a given node</fsummary> <desc> <p>Returns the pid of a new process started by the application @@ -4501,6 +4732,7 @@ true</pre> </func> <func> <name name="spawn_opt" arity="4"/> + <type name="priority_level" /> <fsummary>Create a new process with a function as entry point</fsummary> <desc> <p>Works exactly like @@ -4602,6 +4834,7 @@ true</pre> </func> <func> <name name="spawn_opt" arity="5"/> + <type name="priority_level" /> <fsummary>Create a new process with a function as entry point on a given node</fsummary> <desc> <p>Returns the pid of a new process started by the application @@ -4609,6 +4842,8 @@ true</pre> <c><anno>Node</anno></c> does not exist, a useless pid is returned. Otherwise works like <seealso marker="#spawn_opt/4">spawn_opt/4</seealso>.</p> + <note><p>The <c>monitor</c> option is currently not supported by + <c>spawn_opt/5</c>.</p></note> </desc> </func> <func> @@ -4723,8 +4958,8 @@ true</pre> <name name="statistics" arity="1" clause_i="6"/> <fsummary>Information about the run-queue</fsummary> <desc> - <p>Returns the length of the run queue, that is, the number - of processes that are ready to run.</p> + <p>Returns the total length of the run queues, that is, the number + of processes that are ready to run on all available run queues.</p> </desc> </func> <func> @@ -4733,7 +4968,7 @@ true</pre> <desc> <p>Note that the run-time is the sum of the run-time for all threads in the Erlang run-time system and may therefore be greater - than the wall-clock time.</p> + than the wall-clock time. The time is returned in milliseconds.</p> <pre> > <input>statistics(runtime).</input> {1690,1620} @@ -4981,6 +5216,34 @@ ok </func> <func> <name name="system_flag" arity="2" clause_i="3"/> + <fsummary>Set system flag dirty CPU schedulers online</fsummary> + <desc> + <p><marker id="system_flag_dirty_cpu_schedulers_online"></marker> + Sets the amount of dirty CPU schedulers online. Valid range is + <![CDATA[1 <= DirtyCPUSchedulersOnline <= N]]> where <c>N</c> is the + lesser of the return values of <c>erlang:system_info(dirty_cpu_schedulers)</c> and + <c>erlang:system_info(schedulers_online)</c>. + </p> + <p>Returns the old value of the flag.</p> + <p>Note that the number of dirty CPU schedulers online may change if the number of + schedulers online changes. For example, if there are 12 schedulers and all are + online, and 6 dirty CPU schedulers, all online as well, and <c>system_flag/2</c> + is used to set the number of schedulers online to 6, then the number of dirty + CPU schedulers online is automatically decreased by half as well, down to 3. + Similarly, the number of dirty CPU schedulers online increases proportionally + to increases in the number of schedulers online.</p> + <p><em>Note that the dirty schedulers functionality is experimental</em>, and + that you have to enable support for dirty schedulers when building OTP in order + to try out the functionality.</p> + <p>For more information see + <seealso marker="#system_info_dirty_cpu_schedulers">erlang:system_info(dirty_cpu_schedulers)</seealso> + and + <seealso marker="#system_info_dirty_cpu_schedulers_online">erlang:system_info(dirty_cpu_schedulers_online)</seealso>. + </p> + </desc> + </func> + <func> + <name name="system_flag" arity="2" clause_i="4"/> <fsummary>Set system flag fullsweep_after</fsummary> <desc> <p><c><anno>Number</anno></c> is a non-negative integer which indicates @@ -4998,7 +5261,7 @@ ok </desc> </func> <func> - <name name="system_flag" arity="2" clause_i="4"/> + <name name="system_flag" arity="2" clause_i="5"/> <fsummary>Set system flag min_heap_size</fsummary> <desc> <p>Sets the default minimum heap size for processes. The @@ -5013,7 +5276,7 @@ ok </desc> </func> <func> - <name name="system_flag" arity="2" clause_i="5"/> + <name name="system_flag" arity="2" clause_i="6"/> <fsummary>Set system flag min_bin_vheap_size</fsummary> <desc> <p>Sets the default minimum binary virtual heap size for processes. The @@ -5028,7 +5291,7 @@ ok </desc> </func> <func> - <name name="system_flag" arity="2" clause_i="6"/> + <name name="system_flag" arity="2" clause_i="7"/> <fsummary>Set system flag multi_scheduling</fsummary> <desc> <p><marker id="system_flag_multi_scheduling"></marker> @@ -5066,7 +5329,7 @@ ok </desc> </func> <func> - <name name="system_flag" arity="2" clause_i="7"/> + <name name="system_flag" arity="2" clause_i="8"/> <type name="scheduler_bind_type"/> <fsummary>Set system flag scheduler_bind_type</fsummary> <desc> @@ -5186,7 +5449,7 @@ ok </desc> </func> <func> - <name name="system_flag" arity="2" clause_i="8"/> + <name name="system_flag" arity="2" clause_i="9"/> <fsummary>Set system flag scheduler_wall_time</fsummary> <desc><p><marker id="system_flag_scheduler_wall_time"></marker> Turns on/off scheduler wall time measurements. </p> @@ -5196,7 +5459,7 @@ ok </desc> </func> <func> - <name name="system_flag" arity="2" clause_i="9"/> + <name name="system_flag" arity="2" clause_i="10"/> <fsummary>Set system flag schedulers_online</fsummary> <desc> <p><marker id="system_flag_schedulers_online"></marker> @@ -5204,6 +5467,15 @@ ok <![CDATA[1 <= SchedulersOnline <= erlang:system_info(schedulers)]]>. </p> <p>Returns the old value of the flag.</p> + <p>Note that if the emulator was built with support for <seealso + marker="#system_flag_dirty_cpu_schedulers_online">dirty schedulers</seealso>, + changing the number of schedulers online can also change the number of dirty + CPU schedulers online. For example, if there are 12 schedulers and all are + online, and 6 dirty CPU schedulers, all online as well, and <c>system_flag/2</c> + is used to set the number of schedulers online to 6, then the number of dirty + CPU schedulers online is automatically decreased by half as well, down to 3. + Similarly, the number of dirty CPU schedulers online increases proportionally + to increases in the number of schedulers online.</p> <p>For more information see, <seealso marker="#system_info_schedulers">erlang:system_info(schedulers)</seealso>, and @@ -5212,7 +5484,7 @@ ok </desc> </func> <func> - <name name="system_flag" arity="2" clause_i="10"/> + <name name="system_flag" arity="2" clause_i="11"/> <fsummary>Set system flag trace_control_word</fsummary> <desc> <p>Sets the value of the node's trace control word to @@ -5312,7 +5584,11 @@ ok As of erts version 5.6.1 the return value is a list of <c>{instance, InstanceNo, InstanceInfo}</c> tuples where <c>InstanceInfo</c> contains information about - a specific instance of the allocator. + a specific instance of the allocator. As of erts version + 5.10.4 the returned list when calling + <c>erlang:system_info({allocator, mseg_alloc})</c> also + include an <c>{erts_mmap, _}</c> tuple as one element + in the list. If <c><anno>Alloc</anno></c> is not a recognized allocator, <c>undefined</c> is returned. If <c><anno>Alloc</anno></c> is disabled, <c>false</c> is returned.</p> @@ -5496,6 +5772,10 @@ ok <name name="system_info" arity="1" clause_i="49"/> <name name="system_info" arity="1" clause_i="50"/> <name name="system_info" arity="1" clause_i="51"/> + <name name="system_info" arity="1" clause_i="52"/> + <name name="system_info" arity="1" clause_i="53"/> + <name name="system_info" arity="1" clause_i="54"/> + <name name="system_info" arity="1" clause_i="55"/> <fsummary>Information about the system</fsummary> <desc> <p>Returns various information about the current system @@ -5565,6 +5845,72 @@ ok compiled; otherwise, <c>false</c>. </p> </item> + <tag><marker id="system_info_dirty_cpu_schedulers"><c>dirty_cpu_schedulers</c></marker></tag> + <item> + <p>Returns the number of dirty CPU scheduler threads used by + the emulator. Dirty CPU schedulers execute CPU-bound + native functions such as NIFs, linked-in driver code, and BIFs + that cannot be managed cleanly by the emulator's normal schedulers. + </p> + <p>The number of dirty CPU scheduler threads is determined at emulator + boot time and cannot be changed after that. The number of dirty CPU + scheduler threads online can however be changed at any time. The number of + dirty CPU schedulers can be set on startup by passing + the <seealso marker="erts:erl#+SDcpu">+SDcpu</seealso> or + <seealso marker="erts:erl#+SDPcpu">+SDPcpu</seealso> command line flags, + see <seealso marker="erts:erl#+SDcpu">erl(1)</seealso>. + </p> + <p><em>Note that the dirty schedulers functionality is experimental</em>, and + that you have to enable support for dirty schedulers when building OTP in + order to try out the functionality.</p> + <p>See also <seealso marker="#system_flag_dirty_cpu_schedulers_online">erlang:system_flag(dirty_cpu_schedulers_online, DirtyCPUSchedulersOnline)</seealso>, + <seealso marker="#system_info_dirty_cpu_schedulers_online">erlang:system_info(dirty_cpu_schedulers_online)</seealso>, + <seealso marker="#system_info_dirty_io_schedulers">erlang:system_info(dirty_io_schedulers)</seealso>, + <seealso marker="#system_info_schedulers">erlang:system_info(schedulers)</seealso>, + <seealso marker="#system_info_schedulers_online">erlang:system_info(schedulers_online)</seealso>, and + <seealso marker="#system_flag_schedulers_online">erlang:system_flag(schedulers_online, SchedulersOnline)</seealso>.</p> + </item> + <tag><marker id="system_info_dirty_cpu_schedulers_online"><c>dirty_cpu_schedulers_online</c></marker></tag> + <item> + <p>Returns the number of dirty CPU schedulers online. The return value + satisfies the following relationship: + <c><![CDATA[1 <= DirtyCPUSchedulersOnline <= N]]></c>, where <c>N</c> is + the lesser of the return values of <c>erlang:system_info(dirty_cpu_schedulers)</c> and + <c>erlang:system_info(schedulers_online)</c>. + </p> + <p>The number of dirty CPU schedulers online can be set on startup by passing + the <seealso marker="erts:erl#+SDcpu">+SDcpu</seealso> command line flag, see + <seealso marker="erts:erl#+SDcpu">erl(1)</seealso>. + </p> + <p><em>Note that the dirty schedulers functionality is experimental</em>, and + that you have to enable support for dirty schedulers when building OTP in + order to try out the functionality.</p> + <p>For more information, see + <seealso marker="#system_info_dirty_cpu_schedulers">erlang:system_info(dirty_cpu_schedulers)</seealso>, + <seealso marker="#system_info_dirty_io_schedulers">erlang:system_info(dirty_io_schedulers)</seealso>, + <seealso marker="#system_info_schedulers_online">erlang:system_info(schedulers_online)</seealso>, and + <seealso marker="#system_flag_dirty_cpu_schedulers_online">erlang:system_flag(dirty_cpu_schedulers_online, DirtyCPUSchedulersOnline)</seealso>. + </p> + </item> + <tag><marker id="system_info_dirty_io_schedulers"><c>dirty_io_schedulers</c></marker></tag> + <item> + <p>Returns the number of dirty I/O schedulers as an integer. Dirty I/O schedulers + execute I/O-bound native functions such as NIFs and linked-in driver code that + cannot be managed cleanly by the emulator's normal schedulers. + </p> + <p>This value can be set on startup by passing + the <seealso marker="erts:erl#+SDio">+SDio</seealso> command line flag, see + <seealso marker="erts:erl#+SDio">erl(1)</seealso>. + </p> + <p><em>Note that the dirty schedulers functionality is experimental</em>, and + that you have to enable support for dirty schedulers when building OTP in + order to try out the functionality.</p> + <p>For more information, see + <seealso marker="#system_info_dirty_cpu_schedulers">erlang:system_info(dirty_cpu_schedulers)</seealso>, + <seealso marker="#system_info_dirty_cpu_schedulers_online">erlang:system_info(dirty_cpu_schedulers_online)</seealso>, and + <seealso marker="#system_flag_dirty_cpu_schedulers_online">erlang:system_flag(dirty_cpu_schedulers_online, DirtyCPUSchedulersOnline)</seealso>. + </p> + </item> <tag><c>dist</c></tag> <item> <p>Returns a binary containing a string of distribution @@ -5572,6 +5918,13 @@ ok information see the <seealso marker="erts:crash_dump">"How to interpret the Erlang crash dumps"</seealso> chapter in the ERTS User's Guide.</p> </item> + <tag><marker id="system_info_dist_buf_busy_limit"><c>dist_buf_busy_limit</c></marker></tag> + <item> + <p>Returns the value of the distribution buffer busy limit + in bytes. This limit can be set on startup by passing the + <seealso marker="erts:erl#+zdbbl">+zdbbl</seealso> command line + flag to <c>erl</c>.</p> + </item> <tag><c>dist_ctrl</c></tag> <item> <p>Returns a list of tuples @@ -5618,12 +5971,24 @@ ok The return value will always be <c>false</c> since the elib_malloc allocator has been removed.</p> </item> - <tag><marker id="system_info_dist_buf_busy_limit"><c>dist_buf_busy_limit</c></marker></tag> + <tag><marker id="system_info_eager_check_io"><c>eager_check_io</c></marker></tag> <item> - <p>Returns the value of the distribution buffer busy limit - in bytes. This limit can be set on startup by passing the - <seealso marker="erts:erl#+zdbbl">+zdbbl</seealso> command line - flag to <c>erl</c>.</p> + <p> + Returns the value of the <c>erl</c> + <seealso marker="erl#+secio">+secio</seealso> command line + flag which is either <c>true</c> or <c>false</c>. See the + documentation of the command line flag for information about + the different values. + </p> + </item> + <tag><c>ets_limit</c></tag> + <item> + <p>Returns the maximum number of ETS tables allowed. This limit + can be increased on startup by passing the <seealso + marker="erts:erl#+e">+e</seealso> command line flag to + <c>erl</c> or by setting the environment variable + <c>ERL_MAX_ETS_TABLES</c> before starting the Erlang runtime + system.</p> </item> <tag><c>fullsweep_after</c></tag> <item> @@ -5779,9 +6144,24 @@ ok <seealso marker="#system_info_multi_scheduling">erlang:system_info(multi_scheduling)</seealso>, and <seealso marker="#system_info_schedulers">erlang:system_info(schedulers)</seealso>.</p> </item> + <tag><c>nif_version</c></tag> + <item> + <p>Returns a string containing the erlang NIF version + used by the runtime system. It will be on the form "<major ver>.<minor ver>".</p> + </item> <tag><marker id="system_info_otp_release"><c>otp_release</c></marker></tag> <item> - <p>Returns a string containing the OTP release number.</p> + <p>Returns a string containing the OTP release number of the + OTP release that the currently executing ERTS application is + part of.</p> + <p>As of OTP release 17, the OTP release number corresponds to + the major OTP version number. There is no + <c>erlang:system_info()</c> argument giving the exact OTP + version. This since the exact OTP version in the general case + is hard to determine. For more information see + <seealso marker="doc/system_principles:versions">the + documentation of versions in the system principles + guide</seealso>.</p> </item> <tag><marker id="system_info_port_parallelism"><c>port_parallelism</c></marker></tag> <item><p>Returns the default port parallelism scheduling hint used. @@ -5931,6 +6311,13 @@ ok (<seealso marker="erts:erl_driver#driver_async">driver_async()</seealso>) as an integer.</p> </item> + <tag><marker id="system_info_tolerant_timeofday"><c>tolerant_timeofday</c></marker></tag> + <item> + <p>Returns whether compensation for sudden changes of system + time is <c>enabled</c> or <c>disabled</c>.</p> + <p>See also <seealso marker="erts:erl#+c">+c</seealso> + command line flag.</p> + </item> <tag><c>trace_control_word</c></tag> <item> <p>Returns the value of the node's trace control word. @@ -6054,6 +6441,49 @@ ok notice. </p> </item> + <tag><c>{long_schedule, Time}</c></tag> + <item> + <p>If a process or port in the system runs uninterrupted + for at least <c>Time</c> wall clock milliseconds, a + message <c>{monitor, PidOrPort, long_schedule, Info}</c> + is sent to <c>MonitorPid</c>. <c>PidOrPort</c> is the + process or port that was running and <c>Info</c> is a + list of two-element tuples describing the event. In case + of a <c>pid()</c>, the tuples <c>{timeout, Millis}</c>, + <c>{in, Location}</c> and <c>{out, Location}</c> will be + present, where <c>Location</c> is either an MFA + (<c>{Module, Function, Arity}</c>) describing the + function where the process was scheduled in/out, or the + atom <c>undefined</c>. In case of a <c>port()</c>, the + tuples <c>{timeout, Millis}</c> and <c>{port_op,Op}</c> + will be present. <c>Op</c> will be one of <c>proc_sig</c>, + <c>timeout</c>, <c>input</c>, <c>output</c>, + <c>event</c> or <c>dist_cmd</c>, depending on which + driver callback was executing. <c>proc_sig</c> is an + internal operation and should never appear, while the + others represent the corresponding driver callbacks + <c>timeout</c>, <c>ready_input</c>, <c>ready_output</c>, + <c>event</c> and finally <c>outputv</c> (when the port + is used by distribution). The <c>Millis</c> value in + the <c>timeout</c> tuple will tell you the actual + uninterrupted execution time of the process or port, + which will always be <c>>=</c> the <c>Time</c> value + supplied when starting the trace. New tuples may be + added to the <c>Info</c> list in the future, and the + order of the tuples in the list may be changed at any + time without prior notice. + </p> + <p>This can be used to detect problems with NIF's or + drivers that take too long to execute. Generally, 1 ms + is considered a good maximum time for a driver callback + or a NIF. However, a time sharing system should usually + consider everything below 100 ms as "possible" and + fairly "normal". Schedule times above that might however + indicate swapping or a NIF/driver that is + misbehaving. Misbehaving NIF's and drivers could cause + bad resource utilization and bad overall performance of + the system.</p> + </item> <tag><c>{large_heap, Size}</c></tag> <item> <p>If a garbage collection in the system results in @@ -6204,11 +6634,12 @@ ok some details of the encoding. This option was introduced in R11B-4. Currently, the allowed values for <c><anno>Version</anno></c> are <c>0</c> and <c>1</c>.</p> - <p><c>{minor_version, 1}</c> forces any floats in the term to be encoded + <p><c>{minor_version, 1}</c> is since 17.0 the default, it forces any floats in + the term to be encoded in a more space-efficient and exact way (namely in the 64-bit IEEE format, rather than converted to a textual representation). <c>binary_to_term/1</c> - in R11B-4 and later is able decode the new representation.</p> - <p><c>{minor_version, 0}</c> is currently the default, meaning that floats + in R11B-4 and later is able decode this representation.</p> + <p><c>{minor_version, 0}</c> meaning that floats will be encoded using a textual representation; this option is useful if you want to ensure that releases prior to R11B-4 can decode resulting binary.</p> |