share/doc/gcc-linaro-aarch64-none-elf/html/newlib/libc.html/Signals.html - manifest_repos/gnu_toolchain - Git at Google

 <html lang="en">
 <head>
 <title>Signals - Untitled</title>
 <meta http-equiv="Content-Type" content="text/html">
 <meta name="description" content="Untitled">
 <meta name="generator" content="makeinfo 4.13">
 <link title="Top" rel="start" href="index.html#Top">
 <link rel="prev" href="Wchar-strings.html#Wchar-strings" title="Wchar strings">
 <link rel="next" href="Timefns.html#Timefns" title="Timefns">
 <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
 <meta http-equiv="Content-Style-Type" content="text/css">
 <style type="text/css"><!--
   pre.display { font-family:inherit }
   pre.format  { font-family:inherit }
   pre.smalldisplay { font-family:inherit; font-size:smaller }
   pre.smallformat  { font-family:inherit; font-size:smaller }
   pre.smallexample { font-size:smaller }
   pre.smalllisp    { font-size:smaller }
   span.sc    { font-variant:small-caps }
   span.roman { font-family:serif; font-weight:normal; }
   span.sansserif { font-family:sans-serif; font-weight:normal; }
 --></style>
 </head>
 <body>
 <div class="node">
 <a name="Signals"></a>
 <p>
 Next:&nbsp;<a rel="next" accesskey="n" href="Timefns.html#Timefns">Timefns</a>,
 Previous:&nbsp;<a rel="previous" accesskey="p" href="Wchar-strings.html#Wchar-strings">Wchar strings</a>,
 Up:&nbsp;<a rel="up" accesskey="u" href="index.html#Top">Top</a>
 <hr>
 </div>

 <h2 class="chapter">7 Signal Handling (<samp><span class="file">signal.h</span></samp>)</h2>

 <p>A <dfn>signal</dfn> is an event that interrupts the normal flow of control
 in your program.  Your operating environment normally defines the full
 set of signals available (see <samp><span class="file">sys/signal.h</span></samp>), as well as the
 default means of dealing with them&mdash;typically, either printing an
 error message and aborting your program, or ignoring the signal.

    <p>All systems support at least the following signals:
      <dl>
 <dt><code>SIGABRT</code><dd>Abnormal termination of a program; raised by the &lt;&lt;abort&gt;&gt; function.

      <br><dt><code>SIGFPE</code><dd>A domain error in arithmetic, such as overflow, or division by zero.

      <br><dt><code>SIGILL</code><dd>Attempt to execute as a function data that is not executable.

      <br><dt><code>SIGINT</code><dd>Interrupt; an interactive attention signal.

      <br><dt><code>SIGSEGV</code><dd>An attempt to access a memory location that is not available.

      <br><dt><code>SIGTERM</code><dd>A request that your program end execution.
 </dl>

    <p>Two functions are available for dealing with asynchronous
 signals&mdash;one to allow your program to send signals to itself (this is
 called <dfn>raising</dfn> a signal), and one to specify subroutines (called
 <dfn>handlers</dfn> to handle particular signals that you anticipate may
 occur&mdash;whether raised by your own program or the operating environment.

    <p>To support these functions, <samp><span class="file">signal.h</span></samp> defines three macros:

      <dl>
 <dt><code>SIG_DFL</code><dd>Used with the <code>signal</code> function in place of a pointer to a
 handler subroutine, to select the operating environment's default
 handling of a signal.

      <br><dt><code>SIG_IGN</code><dd>Used with the <code>signal</code> function in place of a pointer to a
 handler, to ignore a particular signal.

      <br><dt><code>SIG_ERR</code><dd>Returned by the <code>signal</code> function in place of a pointer to a
 handler, to indicate that your request to set up a handler could not
 be honored for some reason.
 </dl>

    <p><samp><span class="file">signal.h</span></samp> also defines an integral type, <code>sig_atomic_t</code>.
 This type is not used in any function declarations; it exists only to
 allow your signal handlers to declare a static storage location where
 they may store a signal value.  (Static storage is not otherwise
 reliable from signal handlers.)

 <ul class="menu">
 <li><a accesskey="1" href="psignal.html#psignal">psignal</a>:  Print a signal message to standard error
 <li><a accesskey="2" href="raise.html#raise">raise</a>:    Send a signal
 <li><a accesskey="3" href="signal.html#signal">signal</a>:   Specify handler subroutine for a signal
 </ul>

    </body></html>
	<html lang="en">
	<head>
	<title>Signals - Untitled</title>
	<meta http-equiv="Content-Type" content="text/html">
	<meta name="description" content="Untitled">
	<meta name="generator" content="makeinfo 4.13">
	<link title="Top" rel="start" href="index.html#Top">
	<link rel="prev" href="Wchar-strings.html#Wchar-strings" title="Wchar strings">
	<link rel="next" href="Timefns.html#Timefns" title="Timefns">
	<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
	<meta http-equiv="Content-Style-Type" content="text/css">
	<style type="text/css"><!--
	pre.display { font-family:inherit }
	pre.format { font-family:inherit }
	pre.smalldisplay { font-family:inherit; font-size:smaller }
	pre.smallformat { font-family:inherit; font-size:smaller }
	pre.smallexample { font-size:smaller }
	pre.smalllisp { font-size:smaller }
	span.sc { font-variant:small-caps }
	span.roman { font-family:serif; font-weight:normal; }
	span.sansserif { font-family:sans-serif; font-weight:normal; }
	--></style>
	</head>
	<body>
	<div class="node">
	<a name="Signals"></a>
	<p>
	Next: <a rel="next" accesskey="n" href="Timefns.html#Timefns">Timefns</a>,
	Previous: <a rel="previous" accesskey="p" href="Wchar-strings.html#Wchar-strings">Wchar strings</a>,
	Up: <a rel="up" accesskey="u" href="index.html#Top">Top</a>
	<hr>
	</div>

	<h2 class="chapter">7 Signal Handling (<samp><span class="file">signal.h</span></samp>)</h2>

	<p>A <dfn>signal</dfn> is an event that interrupts the normal flow of control
	in your program. Your operating environment normally defines the full
	set of signals available (see <samp><span class="file">sys/signal.h</span></samp>), as well as the
	default means of dealing with them—typically, either printing an
	error message and aborting your program, or ignoring the signal.

	<p>All systems support at least the following signals:
	<dl>
	<dt><code>SIGABRT</code><dd>Abnormal termination of a program; raised by the <<abort>> function.

	<br><dt><code>SIGFPE</code><dd>A domain error in arithmetic, such as overflow, or division by zero.

	<br><dt><code>SIGILL</code><dd>Attempt to execute as a function data that is not executable.

	<br><dt><code>SIGINT</code><dd>Interrupt; an interactive attention signal.

	<br><dt><code>SIGSEGV</code><dd>An attempt to access a memory location that is not available.

	<br><dt><code>SIGTERM</code><dd>A request that your program end execution.
	</dl>

	<p>Two functions are available for dealing with asynchronous
	signals—one to allow your program to send signals to itself (this is
	called <dfn>raising</dfn> a signal), and one to specify subroutines (called
	<dfn>handlers</dfn> to handle particular signals that you anticipate may
	occur—whether raised by your own program or the operating environment.

	<p>To support these functions, <samp><span class="file">signal.h</span></samp> defines three macros:

	<dl>
	<dt><code>SIG_DFL</code><dd>Used with the <code>signal</code> function in place of a pointer to a
	handler subroutine, to select the operating environment's default
	handling of a signal.

	<br><dt><code>SIG_IGN</code><dd>Used with the <code>signal</code> function in place of a pointer to a
	handler, to ignore a particular signal.

	<br><dt><code>SIG_ERR</code><dd>Returned by the <code>signal</code> function in place of a pointer to a
	handler, to indicate that your request to set up a handler could not
	be honored for some reason.
	</dl>

	<p><samp><span class="file">signal.h</span></samp> also defines an integral type, <code>sig_atomic_t</code>.
	This type is not used in any function declarations; it exists only to
	allow your signal handlers to declare a static storage location where
	they may store a signal value. (Static storage is not otherwise
	reliable from signal handlers.)

	<ul class="menu">
	<li><a accesskey="1" href="psignal.html#psignal">psignal</a>: Print a signal message to standard error
	<li><a accesskey="2" href="raise.html#raise">raise</a>: Send a signal
	<li><a accesskey="3" href="signal.html#signal">signal</a>: Specify handler subroutine for a signal
	</ul>

	</body></html>