File: Sys.html

package info (click to toggle)
ocaml-doc 4.11-2
links: PTS, VCS
area: non-free
in suites: bookworm, bullseye, forky, sid, trixie
size: 20,580 kB
sloc: sh: 37; makefile: 11
file content (710 lines) | stat: -rw-r--r-- 32,371 bytes
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<link rel="stylesheet" href="style.css" type="text/css">
<meta content="text/html; charset=iso-8859-1" http-equiv="Content-Type">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="Start" href="index.html">
<link rel="previous" href="StringLabels.html">
<link rel="next" href="Thread.html">
<link rel="Up" href="index.html">
<link title="Index of types" rel=Appendix href="index_types.html">
<link title="Index of extensions" rel=Appendix href="index_extensions.html">
<link title="Index of exceptions" rel=Appendix href="index_exceptions.html">
<link title="Index of values" rel=Appendix href="index_values.html">
<link title="Index of modules" rel=Appendix href="index_modules.html">
<link title="Index of module types" rel=Appendix href="index_module_types.html">
<link title="Arg" rel="Chapter" href="Arg.html">
<link title="Array" rel="Chapter" href="Array.html">
<link title="ArrayLabels" rel="Chapter" href="ArrayLabels.html">
<link title="Bigarray" rel="Chapter" href="Bigarray.html">
<link title="Bool" rel="Chapter" href="Bool.html">
<link title="Buffer" rel="Chapter" href="Buffer.html">
<link title="Bytes" rel="Chapter" href="Bytes.html">
<link title="BytesLabels" rel="Chapter" href="BytesLabels.html">
<link title="Callback" rel="Chapter" href="Callback.html">
<link title="CamlinternalFormat" rel="Chapter" href="CamlinternalFormat.html">
<link title="CamlinternalFormatBasics" rel="Chapter" href="CamlinternalFormatBasics.html">
<link title="CamlinternalLazy" rel="Chapter" href="CamlinternalLazy.html">
<link title="CamlinternalMod" rel="Chapter" href="CamlinternalMod.html">
<link title="CamlinternalOO" rel="Chapter" href="CamlinternalOO.html">
<link title="Char" rel="Chapter" href="Char.html">
<link title="Complex" rel="Chapter" href="Complex.html">
<link title="Condition" rel="Chapter" href="Condition.html">
<link title="Digest" rel="Chapter" href="Digest.html">
<link title="Dynlink" rel="Chapter" href="Dynlink.html">
<link title="Ephemeron" rel="Chapter" href="Ephemeron.html">
<link title="Event" rel="Chapter" href="Event.html">
<link title="Filename" rel="Chapter" href="Filename.html">
<link title="Float" rel="Chapter" href="Float.html">
<link title="Format" rel="Chapter" href="Format.html">
<link title="Fun" rel="Chapter" href="Fun.html">
<link title="Gc" rel="Chapter" href="Gc.html">
<link title="Genlex" rel="Chapter" href="Genlex.html">
<link title="Hashtbl" rel="Chapter" href="Hashtbl.html">
<link title="Int" rel="Chapter" href="Int.html">
<link title="Int32" rel="Chapter" href="Int32.html">
<link title="Int64" rel="Chapter" href="Int64.html">
<link title="Lazy" rel="Chapter" href="Lazy.html">
<link title="Lexing" rel="Chapter" href="Lexing.html">
<link title="List" rel="Chapter" href="List.html">
<link title="ListLabels" rel="Chapter" href="ListLabels.html">
<link title="Map" rel="Chapter" href="Map.html">
<link title="Marshal" rel="Chapter" href="Marshal.html">
<link title="MoreLabels" rel="Chapter" href="MoreLabels.html">
<link title="Mutex" rel="Chapter" href="Mutex.html">
<link title="Nativeint" rel="Chapter" href="Nativeint.html">
<link title="Obj" rel="Chapter" href="Obj.html">
<link title="Ocaml_operators" rel="Chapter" href="Ocaml_operators.html">
<link title="Oo" rel="Chapter" href="Oo.html">
<link title="Option" rel="Chapter" href="Option.html">
<link title="Parsing" rel="Chapter" href="Parsing.html">
<link title="Printexc" rel="Chapter" href="Printexc.html">
<link title="Printf" rel="Chapter" href="Printf.html">
<link title="Queue" rel="Chapter" href="Queue.html">
<link title="Random" rel="Chapter" href="Random.html">
<link title="Result" rel="Chapter" href="Result.html">
<link title="Scanf" rel="Chapter" href="Scanf.html">
<link title="Seq" rel="Chapter" href="Seq.html">
<link title="Set" rel="Chapter" href="Set.html">
<link title="Spacetime" rel="Chapter" href="Spacetime.html">
<link title="Stack" rel="Chapter" href="Stack.html">
<link title="StdLabels" rel="Chapter" href="StdLabels.html">
<link title="Stdlib" rel="Chapter" href="Stdlib.html">
<link title="Str" rel="Chapter" href="Str.html">
<link title="Stream" rel="Chapter" href="Stream.html">
<link title="String" rel="Chapter" href="String.html">
<link title="StringLabels" rel="Chapter" href="StringLabels.html">
<link title="Sys" rel="Chapter" href="Sys.html">
<link title="Thread" rel="Chapter" href="Thread.html">
<link title="ThreadUnix" rel="Chapter" href="ThreadUnix.html">
<link title="Uchar" rel="Chapter" href="Uchar.html">
<link title="Unit" rel="Chapter" href="Unit.html">
<link title="Unix" rel="Chapter" href="Unix.html">
<link title="UnixLabels" rel="Chapter" href="UnixLabels.html">
<link title="Weak" rel="Chapter" href="Weak.html"><link title="Signal handling" rel="Section" href="#1_Signalhandling">
<link title="Optimization" rel="Section" href="#1_Optimization">
<link title="Signal numbers for the standard POSIX signals." rel="Subsection" href="#2_SignalnumbersforthestandardPOSIXsignals">
<title>Sys</title>
</head>
<body>
<div class="navbar"><a class="pre" href="StringLabels.html" title="StringLabels">Previous</a>
&nbsp;<a class="up" href="index.html" title="Index">Up</a>
&nbsp;<a class="post" href="Thread.html" title="Thread">Next</a>
</div>
<h1>Module <a href="type_Sys.html">Sys</a></h1>

<pre><span id="MODULESys"><span class="keyword">module</span> Sys</span>: <code class="code"><span class="keyword">sig</span></code> <a href="Sys.html">..</a> <code class="code"><span class="keyword">end</span></code></pre><div class="info module top">
<div class="info-desc">
<p>System interface.</p>

<p>Every function in this module raises <code class="code"><span class="constructor">Sys_error</span></code> with an
  informative message when the underlying system call signal
  an error.</p>
</div>
</div>
<hr width="100%">

<pre><span id="VALargv"><span class="keyword">val</span> argv</span> : <code class="type">string array</code></pre><div class="info ">
<div class="info-desc">
<p>The command line arguments given to the process.
   The first element is the command name used to invoke the program.
   The following elements are the command-line arguments
   given to the program.</p>
</div>
</div>

<pre><span id="VALexecutable_name"><span class="keyword">val</span> executable_name</span> : <code class="type">string</code></pre><div class="info ">
<div class="info-desc">
<p>The name of the file containing the executable currently running.
    This name may be absolute or relative to the current directory, depending
    on the platform and whether the program was compiled to bytecode or a native
    executable.</p>
</div>
</div>

<pre><span id="VALfile_exists"><span class="keyword">val</span> file_exists</span> : <code class="type">string -> bool</code></pre><div class="info ">
<div class="info-desc">
<p>Test if a file with the given name exists.</p>
</div>
</div>

<pre><span id="VALis_directory"><span class="keyword">val</span> is_directory</span> : <code class="type">string -> bool</code></pre><div class="info ">
<div class="info-desc">
<p>Returns <code class="code"><span class="keyword">true</span></code> if the given name refers to a directory,
    <code class="code"><span class="keyword">false</span></code> if it refers to another kind of file.</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 3.10.0</li>
<li><b>Raises</b> <code>Sys_error</code> if no file exists with the given name.</li>
</ul>
</div>

<pre><span id="VALremove"><span class="keyword">val</span> remove</span> : <code class="type">string -> unit</code></pre><div class="info ">
<div class="info-desc">
<p>Remove the given file name from the file system.</p>
</div>
</div>

<pre><span id="VALrename"><span class="keyword">val</span> rename</span> : <code class="type">string -> string -> unit</code></pre><div class="info ">
<div class="info-desc">
<p>Rename a file.  <code class="code">rename&nbsp;oldpath&nbsp;newpath</code> renames the file
    called <code class="code">oldpath</code>, giving it <code class="code">newpath</code> as its new name,
    moving it between directories if needed.  If <code class="code">newpath</code> already
    exists, its contents will be replaced with those of <code class="code">oldpath</code>.
    Depending on the operating system, the metadata (permissions,
    owner, etc) of <code class="code">newpath</code> can either be preserved or be replaced by
    those of <code class="code">oldpath</code>.</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.06 concerning the "replace existing file" behavior</li>
</ul>
</div>

<pre><span id="VALgetenv"><span class="keyword">val</span> getenv</span> : <code class="type">string -> string</code></pre><div class="info ">
<div class="info-desc">
<p>Return the value associated to a variable in the process
   environment.</p>
</div>
<ul class="info-attributes">
<li><b>Raises</b> <code>Not_found</code> if the variable is unbound.</li>
</ul>
</div>

<pre><span id="VALgetenv_opt"><span class="keyword">val</span> getenv_opt</span> : <code class="type">string -> string option</code></pre><div class="info ">
<div class="info-desc">
<p>Return the value associated to a variable in the process
    environment or <code class="code"><span class="constructor">None</span></code> if the variable is unbound.</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.05</li>
</ul>
</div>

<pre><span id="VALcommand"><span class="keyword">val</span> command</span> : <code class="type">string -> int</code></pre><div class="info ">
<div class="info-desc">
<p>Execute the given shell command and return its exit code.</p>

<p>The argument of <a href="Sys.html#VALcommand"><code class="code"><span class="constructor">Sys</span>.command</code></a> is generally the name of a
  command followed by zero, one or several arguments, separated
  by whitespace.  The given argument is interpreted by a
  shell: either the Windows shell <code class="code">cmd.exe</code> for the Win32 ports of
  OCaml, or the POSIX shell <code class="code">sh</code> for other ports.  It can contain
  shell builtin commands such as <code class="code">echo</code>, and also special characters
  such as file redirections <code class="code">&gt;</code> and <code class="code">&lt;</code>, which will be honored by the
  shell.</p>

<p>Conversely, whitespace or special shell characters occurring in
  command names or in their arguments must be quoted or escaped
  so that the shell does not interpret them.  The quoting rules vary
  between the POSIX shell and the Windows shell.
  The <a href="Filename.html#VALquote_command"><code class="code"><span class="constructor">Filename</span>.quote_command</code></a> performs the appropriate quoting
  given a command name, a list of arguments, and optional file redirections.</p>
</div>
</div>

<pre><span id="VALtime"><span class="keyword">val</span> time</span> : <code class="type">unit -> float</code></pre><div class="info ">
<div class="info-desc">
<p>Return the processor time, in seconds, used by the program
   since the beginning of execution.</p>
</div>
</div>

<pre><span id="VALchdir"><span class="keyword">val</span> chdir</span> : <code class="type">string -> unit</code></pre><div class="info ">
<div class="info-desc">
<p>Change the current working directory of the process.</p>
</div>
</div>

<pre><span id="VALgetcwd"><span class="keyword">val</span> getcwd</span> : <code class="type">unit -> string</code></pre><div class="info ">
<div class="info-desc">
<p>Return the current working directory of the process.</p>
</div>
</div>

<pre><span id="VALreaddir"><span class="keyword">val</span> readdir</span> : <code class="type">string -> string array</code></pre><div class="info ">
<div class="info-desc">
<p>Return the names of all files present in the given directory.
   Names denoting the current directory and the parent directory
   (<code class="code"><span class="string">"."</span></code> and <code class="code"><span class="string">".."</span></code> in Unix) are not returned.  Each string in the
   result is a file name rather than a complete path.  There is no
   guarantee that the name strings in the resulting array will appear
   in any specific order; they are not, in particular, guaranteed to
   appear in alphabetical order.</p>
</div>
</div>

<pre><span id="VALinteractive"><span class="keyword">val</span> interactive</span> : <code class="type">bool <a href="Stdlib.html#TYPEref">ref</a></code></pre><div class="info ">
<div class="info-desc">
<p>This reference is initially set to <code class="code"><span class="keyword">false</span></code> in standalone
   programs and to <code class="code"><span class="keyword">true</span></code> if the code is being executed under
   the interactive toplevel system <code class="code">ocaml</code>.</p>
</div>
</div>

<pre><span id="VALos_type"><span class="keyword">val</span> os_type</span> : <code class="type">string</code></pre><div class="info ">
<div class="info-desc">
<p>Operating system currently executing the OCaml program. One of</p>
<ul>
<li> <code class="code"><span class="string">"Unix"</span></code> (for all Unix versions, including Linux and Mac OS X),</li>
<li> <code class="code"><span class="string">"Win32"</span></code> (for MS-Windows, OCaml compiled with MSVC++ or Mingw),</li>
<li> <code class="code"><span class="string">"Cygwin"</span></code> (for MS-Windows, OCaml compiled with Cygwin).</li>
</ul>
</div>
</div>

<pre><code><span id="TYPEbackend_type"><span class="keyword">type</span> <code class="type"></code>backend_type</span> = </code></pre><table class="typetable">
<tr>
<td align="left" valign="top" >
<code><span class="keyword">|</span></code></td>
<td align="left" valign="top" >
<code><span id="TYPEELTbackend_type.Native"><span class="constructor">Native</span></span></code></td>

</tr>
<tr>
<td align="left" valign="top" >
<code><span class="keyword">|</span></code></td>
<td align="left" valign="top" >
<code><span id="TYPEELTbackend_type.Bytecode"><span class="constructor">Bytecode</span></span></code></td>

</tr>
<tr>
<td align="left" valign="top" >
<code><span class="keyword">|</span></code></td>
<td align="left" valign="top" >
<code><span id="TYPEELTbackend_type.Other"><span class="constructor">Other</span></span> <span class="keyword">of</span> <code class="type">string</code></code></td>

</tr></table>

<div class="info ">
<div class="info-desc">
<p>Currently, the official distribution only supports <code class="code"><span class="constructor">Native</span></code> and
    <code class="code"><span class="constructor">Bytecode</span></code>, but it can be other backends with alternative
    compilers, for example, javascript.</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.04.0</li>
</ul>
</div>


<pre><span id="VALbackend_type"><span class="keyword">val</span> backend_type</span> : <code class="type"><a href="Sys.html#TYPEbackend_type">backend_type</a></code></pre><div class="info ">
<div class="info-desc">
<p>Backend type  currently executing the OCaml program.</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.04.0</li>
</ul>
</div>

<pre><span id="VALunix"><span class="keyword">val</span> unix</span> : <code class="type">bool</code></pre><div class="info ">
<div class="info-desc">
<p>True if <code class="code"><span class="constructor">Sys</span>.os_type&nbsp;=&nbsp;<span class="string">"Unix"</span></code>.</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.01.0</li>
</ul>
</div>

<pre><span id="VALwin32"><span class="keyword">val</span> win32</span> : <code class="type">bool</code></pre><div class="info ">
<div class="info-desc">
<p>True if <code class="code"><span class="constructor">Sys</span>.os_type&nbsp;=&nbsp;<span class="string">"Win32"</span></code>.</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.01.0</li>
</ul>
</div>

<pre><span id="VALcygwin"><span class="keyword">val</span> cygwin</span> : <code class="type">bool</code></pre><div class="info ">
<div class="info-desc">
<p>True if <code class="code"><span class="constructor">Sys</span>.os_type&nbsp;=&nbsp;<span class="string">"Cygwin"</span></code>.</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.01.0</li>
</ul>
</div>

<pre><span id="VALword_size"><span class="keyword">val</span> word_size</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Size of one word on the machine currently executing the OCaml
    program, in bits: 32 or 64.</p>
</div>
</div>

<pre><span id="VALint_size"><span class="keyword">val</span> int_size</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Size of <code class="code">int</code>, in bits. It is 31 (resp. 63) when using OCaml on a
    32-bit (resp. 64-bit) platform. It may differ for other implementations,
    e.g. it can be 32 bits when compiling to JavaScript.</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.03.0</li>
</ul>
</div>

<pre><span id="VALbig_endian"><span class="keyword">val</span> big_endian</span> : <code class="type">bool</code></pre><div class="info ">
<div class="info-desc">
<p>Whether the machine currently executing the Caml program is big-endian.</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.00.0</li>
</ul>
</div>

<pre><span id="VALmax_string_length"><span class="keyword">val</span> max_string_length</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Maximum length of strings and byte sequences.</p>
</div>
</div>

<pre><span id="VALmax_array_length"><span class="keyword">val</span> max_array_length</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Maximum length of a normal array (i.e. any array whose elements are
    not of type <code class="code">float</code>). The maximum length of a <code class="code">float&nbsp;array</code>
    is <code class="code">max_floatarray_length</code> if OCaml was configured with
    <code class="code">--enable-flat-float-array</code> and <code class="code">max_array_length</code> if configured
    with <code class="code">--disable-flat-float-array</code>.</p>
</div>
</div>

<pre><span id="VALmax_floatarray_length"><span class="keyword">val</span> max_floatarray_length</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Maximum length of a floatarray. This is also the maximum length of
    a <code class="code">float&nbsp;array</code> when OCaml is configured with
    <code class="code">--enable-flat-float-array</code>.</p>
</div>
</div>

<pre><span id="VALruntime_variant"><span class="keyword">val</span> runtime_variant</span> : <code class="type">unit -> string</code></pre><div class="info ">
<div class="info-desc">
<p>Return the name of the runtime variant the program is running on.
    This is normally the argument given to <code class="code">-runtime-variant</code> at compile
    time, but for byte-code it can be changed after compilation.</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.03.0</li>
</ul>
</div>

<pre><span id="VALruntime_parameters"><span class="keyword">val</span> runtime_parameters</span> : <code class="type">unit -> string</code></pre><div class="info ">
<div class="info-desc">
<p>Return the value of the runtime parameters, in the same format
    as the contents of the <code class="code"><span class="constructor">OCAMLRUNPARAM</span></code> environment variable.</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.03.0</li>
</ul>
</div>
<h2 id="1_Signalhandling">Signal handling</h2>
<pre><code><span id="TYPEsignal_behavior"><span class="keyword">type</span> <code class="type"></code>signal_behavior</span> = </code></pre><table class="typetable">
<tr>
<td align="left" valign="top" >
<code><span class="keyword">|</span></code></td>
<td align="left" valign="top" >
<code><span id="TYPEELTsignal_behavior.Signal_default"><span class="constructor">Signal_default</span></span></code></td>

</tr>
<tr>
<td align="left" valign="top" >
<code><span class="keyword">|</span></code></td>
<td align="left" valign="top" >
<code><span id="TYPEELTsignal_behavior.Signal_ignore"><span class="constructor">Signal_ignore</span></span></code></td>

</tr>
<tr>
<td align="left" valign="top" >
<code><span class="keyword">|</span></code></td>
<td align="left" valign="top" >
<code><span id="TYPEELTsignal_behavior.Signal_handle"><span class="constructor">Signal_handle</span></span> <span class="keyword">of</span> <code class="type">(int -> unit)</code></code></td>

</tr></table>

<div class="info ">
<div class="info-desc">
<p>What to do when receiving a signal:</p>
<ul>
<li><code class="code"><span class="constructor">Signal_default</span></code>: take the default behavior
     (usually: abort the program)</li>
<li><code class="code"><span class="constructor">Signal_ignore</span></code>: ignore the signal</li>
<li><code class="code"><span class="constructor">Signal_handle</span>&nbsp;f</code>: call function <code class="code">f</code>, giving it the signal
   number as argument.</li>
</ul>
</div>
</div>


<pre><span id="VALsignal"><span class="keyword">val</span> signal</span> : <code class="type">int -> <a href="Sys.html#TYPEsignal_behavior">signal_behavior</a> -> <a href="Sys.html#TYPEsignal_behavior">signal_behavior</a></code></pre><div class="info ">
<div class="info-desc">
<p>Set the behavior of the system on receipt of a given signal.  The
   first argument is the signal number.  Return the behavior
   previously associated with the signal. If the signal number is
   invalid (or not available on your system), an <code class="code"><span class="constructor">Invalid_argument</span></code>
   exception is raised.</p>
</div>
</div>

<pre><span id="VALset_signal"><span class="keyword">val</span> set_signal</span> : <code class="type">int -> <a href="Sys.html#TYPEsignal_behavior">signal_behavior</a> -> unit</code></pre><div class="info ">
<div class="info-desc">
<p>Same as <a href="Sys.html#VALsignal"><code class="code"><span class="constructor">Sys</span>.signal</code></a> but return value is ignored.</p>
</div>
</div>
<h3 id="2_SignalnumbersforthestandardPOSIXsignals">Signal numbers for the standard POSIX signals.</h3>
<pre><span id="VALsigabrt"><span class="keyword">val</span> sigabrt</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Abnormal termination</p>
</div>
</div>

<pre><span id="VALsigalrm"><span class="keyword">val</span> sigalrm</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Timeout</p>
</div>
</div>

<pre><span id="VALsigfpe"><span class="keyword">val</span> sigfpe</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Arithmetic exception</p>
</div>
</div>

<pre><span id="VALsighup"><span class="keyword">val</span> sighup</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Hangup on controlling terminal</p>
</div>
</div>

<pre><span id="VALsigill"><span class="keyword">val</span> sigill</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Invalid hardware instruction</p>
</div>
</div>

<pre><span id="VALsigint"><span class="keyword">val</span> sigint</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Interactive interrupt (ctrl-C)</p>
</div>
</div>

<pre><span id="VALsigkill"><span class="keyword">val</span> sigkill</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Termination (cannot be ignored)</p>
</div>
</div>

<pre><span id="VALsigpipe"><span class="keyword">val</span> sigpipe</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Broken pipe</p>
</div>
</div>

<pre><span id="VALsigquit"><span class="keyword">val</span> sigquit</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Interactive termination</p>
</div>
</div>

<pre><span id="VALsigsegv"><span class="keyword">val</span> sigsegv</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Invalid memory reference</p>
</div>
</div>

<pre><span id="VALsigterm"><span class="keyword">val</span> sigterm</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Termination</p>
</div>
</div>

<pre><span id="VALsigusr1"><span class="keyword">val</span> sigusr1</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Application-defined signal 1</p>
</div>
</div>

<pre><span id="VALsigusr2"><span class="keyword">val</span> sigusr2</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Application-defined signal 2</p>
</div>
</div>

<pre><span id="VALsigchld"><span class="keyword">val</span> sigchld</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Child process terminated</p>
</div>
</div>

<pre><span id="VALsigcont"><span class="keyword">val</span> sigcont</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Continue</p>
</div>
</div>

<pre><span id="VALsigstop"><span class="keyword">val</span> sigstop</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Stop</p>
</div>
</div>

<pre><span id="VALsigtstp"><span class="keyword">val</span> sigtstp</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Interactive stop</p>
</div>
</div>

<pre><span id="VALsigttin"><span class="keyword">val</span> sigttin</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Terminal read from background process</p>
</div>
</div>

<pre><span id="VALsigttou"><span class="keyword">val</span> sigttou</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Terminal write from background process</p>
</div>
</div>

<pre><span id="VALsigvtalrm"><span class="keyword">val</span> sigvtalrm</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Timeout in virtual time</p>
</div>
</div>

<pre><span id="VALsigprof"><span class="keyword">val</span> sigprof</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Profiling interrupt</p>
</div>
</div>

<pre><span id="VALsigbus"><span class="keyword">val</span> sigbus</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Bus error</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.03</li>
</ul>
</div>

<pre><span id="VALsigpoll"><span class="keyword">val</span> sigpoll</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Pollable event</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.03</li>
</ul>
</div>

<pre><span id="VALsigsys"><span class="keyword">val</span> sigsys</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Bad argument to routine</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.03</li>
</ul>
</div>

<pre><span id="VALsigtrap"><span class="keyword">val</span> sigtrap</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Trace/breakpoint trap</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.03</li>
</ul>
</div>

<pre><span id="VALsigurg"><span class="keyword">val</span> sigurg</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Urgent condition on socket</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.03</li>
</ul>
</div>

<pre><span id="VALsigxcpu"><span class="keyword">val</span> sigxcpu</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>Timeout in cpu time</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.03</li>
</ul>
</div>

<pre><span id="VALsigxfsz"><span class="keyword">val</span> sigxfsz</span> : <code class="type">int</code></pre><div class="info ">
<div class="info-desc">
<p>File size limit exceeded</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.03</li>
</ul>
</div>

<pre><span id="EXCEPTIONBreak"><span class="keyword">exception</span> Break</span></pre>
<div class="info ">
<div class="info-desc">
<p>Exception raised on interactive interrupt if <a href="Sys.html#VALcatch_break"><code class="code"><span class="constructor">Sys</span>.catch_break</code></a>
   is on.</p>
</div>
</div>

<pre><span id="VALcatch_break"><span class="keyword">val</span> catch_break</span> : <code class="type">bool -> unit</code></pre><div class="info ">
<div class="info-desc">
<p><code class="code">catch_break</code> governs whether interactive interrupt (ctrl-C)
   terminates the program or raises the <code class="code"><span class="constructor">Break</span></code> exception.
   Call <code class="code">catch_break&nbsp;<span class="keyword">true</span></code> to enable raising <code class="code"><span class="constructor">Break</span></code>,
   and <code class="code">catch_break&nbsp;<span class="keyword">false</span></code> to let the system
   terminate the program on user interrupt.</p>
</div>
</div>

<pre><span id="VALocaml_version"><span class="keyword">val</span> ocaml_version</span> : <code class="type">string</code></pre><div class="info ">
<div class="info-desc">
<p><code class="code">ocaml_version</code> is the version of OCaml.
    It is a string of the form
      <code class="code"><span class="string">"major.minor[.patchlevel][(+|~)additional-info]"</span></code>,
    where <code class="code">major</code>, <code class="code">minor</code>, and <code class="code">patchlevel</code> are integers, and
    <code class="code">additional-info</code> is an arbitrary string.
    The <code class="code">[.patchlevel]</code> part is absent for versions anterior to 3.08.0.
    The <code class="code">[(+|~)additional-info]</code> part may be absent.</p>
</div>
</div>

<pre><span id="VALenable_runtime_warnings"><span class="keyword">val</span> enable_runtime_warnings</span> : <code class="type">bool -> unit</code></pre><div class="info ">
<div class="info-desc">
<p>Control whether the OCaml runtime system can emit warnings
    on stderr.  Currently, the only supported warning is triggered
    when a channel created by <code class="code">open_*</code> functions is finalized without
    being closed.  Runtime warnings are disabled by default.</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.03.0</li>
</ul>
</div>

<pre><span id="VALruntime_warnings_enabled"><span class="keyword">val</span> runtime_warnings_enabled</span> : <code class="type">unit -> bool</code></pre><div class="info ">
<div class="info-desc">
<p>Return whether runtime warnings are currently enabled.</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.03.0</li>
</ul>
</div>
<h2 id="1_Optimization">Optimization</h2>
<pre><span id="VALopaque_identity"><span class="keyword">val</span> opaque_identity</span> : <code class="type">'a -> 'a</code></pre><div class="info ">
<div class="info-desc">
<p>For the purposes of optimization, <code class="code">opaque_identity</code> behaves like an
    unknown (and thus possibly side-effecting) function.</p>

<p>At runtime, <code class="code">opaque_identity</code> disappears altogether.</p>

<p>A typical use of this function is to prevent pure computations from being
    optimized away in benchmarking loops.  For example:</p>
<pre class="codepre"><code class="code">      <span class="keyword">for</span> _round = 1 <span class="keyword">to</span> 100_000 <span class="keyword">do</span>
        ignore (<span class="constructor">Sys</span>.opaque_identity (my_pure_computation ()))
      <span class="keyword">done</span>
    </code></pre></div>
<ul class="info-attributes">
<li><b>Since</b> 4.03.0</li>
</ul>
</div>

<pre><span id="MODULEImmediate64"><span class="keyword">module</span> <a href="Sys.Immediate64.html">Immediate64</a></span>: <code class="code"><span class="keyword">sig</span></code> <a href="Sys.Immediate64.html">..</a> <code class="code"><span class="keyword">end</span></code></pre></body></html>