signal.h.html

IEEE 1003.1-2003, Single Unix Specification v3

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<p class="tent">File size limit exceeded. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></p>
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<p>The default actions are as follows:</p>

<dl compact>
<dt>T</dt>

<dd>Abnormal termination of the process. The process is terminated with all the consequences of <a href=
"../functions/_exit.html"><i>_exit</i>()</a> except that the status made available to <a href=
"../functions/wait.html"><i>wait</i>()</a> and <a href="../functions/waitpid.html"><i>waitpid</i>()</a> indicates abnormal
termination by the specified signal.</dd>

<dt>A</dt>

<dd>Abnormal termination of the process.<br>
<sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
Additionally, implementation-defined abnormal termination actions, such as creation of a <b>core</b> file, may occur. <img src=
"../images/opt-end.gif" alt="[Option End]" border="0"></dd>

<dt>I</dt>

<dd>Ignore the signal.</dd>

<dt>S</dt>

<dd>Stop the process.</dd>

<dt>C</dt>

<dd>Continue the process, if it is stopped; otherwise, ignore the signal.</dd>
</dl>

<br>
<p><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> The
header shall provide a declaration of <b>struct sigaction</b>, including at least the following members:</p>

<pre>
<tt>void (*sa_handler)(int) </tt> Pointer to a signal-catching function or one of the macros <tt>
                        </tt> SIG_IGN or SIG_DFL. <tt>
sigset_t sa_mask        </tt> Set of signals to be blocked during execution of the signal <tt>
                        </tt> handling function. <tt>
int      sa_flags       </tt> Special flags. <tt>
void (*sa_sigaction)(int, siginfo_t *, void *)
                        </tt> Pointer to a signal-catching function. <tt>
</tt>
</pre>

<img src="../images/opt-end.gif" alt="[Option End]" border="0"> 

<p><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
The storage occupied by <i>sa_handler</i> and <i>sa_sigaction</i> may overlap, and a conforming application shall not use both
simultaneously. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></p>

<p>The following shall be declared as constants:</p>

<dl compact>
<dt>SA_NOCLDSTOP</dt>

<dd><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> Do
not generate SIGCHLD when children stop <img src="../images/opt-end.gif" alt="[Option End]" border="0"><br>
<sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> or
stopped children continue. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></dd>

<dt>SIG_BLOCK</dt>

<dd><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
The resulting set is the union of the current set and the signal set pointed to by the argument <i>set</i>. <img src=
"../images/opt-end.gif" alt="[Option End]" border="0"></dd>

<dt>SIG_UNBLOCK</dt>

<dd><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
The resulting set is the intersection of the current set and the complement of the signal set pointed to by the argument
<i>set</i>. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></dd>

<dt>SIG_SETMASK</dt>

<dd><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
The resulting set is the signal set pointed to by the argument <i>set</i>. <img src="../images/opt-end.gif" alt="[Option End]"
border="0"></dd>

<dt>SA_ONSTACK</dt>

<dd><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
Causes signal delivery to occur on an alternate stack. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></dd>

<dt>SA_RESETHAND</dt>

<dd><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
Causes signal dispositions to be set to SIG_DFL on entry to signal handlers. <img src="../images/opt-end.gif" alt="[Option End]"
border="0"></dd>

<dt>SA_RESTART</dt>

<dd><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
Causes certain functions to become restartable. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></dd>

<dt>SA_SIGINFO</dt>

<dd><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
Causes extra information to be passed to signal handlers at the time of receipt of a signal. <img src="../images/opt-end.gif" alt=
"[Option End]" border="0"></dd>

<dt>SA_NOCLDWAIT</dt>

<dd><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
Causes implementations not to create zombie processes on child death. <img src="../images/opt-end.gif" alt="[Option End]" border=
"0"></dd>

<dt>SA_NODEFER</dt>

<dd><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
Causes signal not to be automatically blocked on entry to signal handler. <img src="../images/opt-end.gif" alt="[Option End]"
border="0"></dd>

<dt>SS_ONSTACK</dt>

<dd><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
Process is executing on an alternate signal stack. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></dd>

<dt>SS_DISABLE</dt>

<dd><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
Alternate signal stack is disabled. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></dd>

<dt>MINSIGSTKSZ</dt>

<dd><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
Minimum stack size for a signal handler. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></dd>

<dt>SIGSTKSZ</dt>

<dd><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
Default size in bytes for the alternate signal stack. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></dd>
</dl>

<p><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
The <b>ucontext_t</b> structure shall be defined through <b>typedef</b> as described in <a href=
"../basedefs/ucontext.h.html"><i>&lt;ucontext.h&gt;</i></a>.</p>

<p>The <b>mcontext_t</b> type shall be defined through <b>typedef</b> as described in <a href=
"../basedefs/ucontext.h.html"><i>&lt;ucontext.h&gt;</i></a>.</p>

<p>The <i>&lt;signal.h&gt;</i> header shall define the <b>stack_t</b> type as a structure that includes at least the following
members:</p>

<pre>
<tt>void     *ss_sp      </tt> Stack base or pointer. <tt>
size_t    ss_size    </tt> Stack size. <tt>
int       ss_flags   </tt> Flags. <tt>
</tt>
</pre>

<p>The <i>&lt;signal.h&gt;</i> header shall define the <b>sigstack</b> structure that includes at least the following members:</p>

<pre>
<tt>int       ss_onstack </tt> Non-zero when signal stack is in use. <tt>
void     *ss_sp      </tt> Signal stack pointer. <tt>
</tt>
</pre>

<img src="../images/opt-end.gif" alt="[Option End]" border="0"> 

<p><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> The
<i>&lt;signal.h&gt;</i> header shall define the <b>siginfo_t</b> type as a structure that includes at least the following members:
<img src="../images/opt-end.gif" alt="[Option End]" border="0"></p>

<pre>
<tt><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup><img src="../images/opt-start.gif" alt="[Option Start]" border="0">
int           si_signo </tt> Signal number. <tt>
<img src="../images/opt-end.gif" alt="[Option End]" border="0">
<sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup><img src="../images/opt-start.gif" alt="[Option Start]" border="0">
int           si_errno </tt> If non-zero, an <i>errno</i> value associated with <tt>
                       </tt> this signal, as defined in <b>&lt;errno.h&gt;.</b> <tt>
<img src="../images/opt-end.gif" alt="[Option End]" border="0">
<sup>[<a href="javascript:open_code('CX')">CX</a>]</sup><img src="../images/opt-start.gif" alt="[Option Start]" border="0">
int           si_code  </tt> Signal code. <tt>
<img src="../images/opt-end.gif" alt="[Option End]" border="0">
<sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup><img src="../images/opt-start.gif" alt="[Option Start]" border="0">
pid_t         si_pid   </tt> Sending process ID. <tt>
uid_t         si_uid   </tt> Real user ID of sending process. <tt>
void         *si_addr  </tt> Address of faulting instruction. <tt>
int           si_status</tt> Exit value or signal. <tt>
long          si_band  </tt> Band event for SIGPOLL. <tt>
<img src="../images/opt-end.gif" alt="[Option End]" border="0">
<sup>[<a href="javascript:open_code('RTS')">RTS</a>]</sup><img src="../images/opt-start.gif" alt="[Option Start]" border="0">
union sigval  si_value </tt> Signal value. <tt>
<img src="../images/opt-end.gif" alt="[Option End]" border="0">
</tt>
</pre>

<p>The macros specified in the <b>Code</b> column of the following table are defined for use as values of <i>si_code</i> that are
<sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
&nbsp;signal-specific or <img src="../images/opt-end.gif" alt="[Option End]" border="0"> non-signal-specific reasons why the signal
was generated.</p>

<hr>
<center>
<table border="1" cellpadding="3" align="center">
<tr valign="top">
<th align="center">
<p class="tent"><b>Signal</b></p>
</th>
<th align="center">
<p class="tent"><b>Code</b></p>
</th>
<th align="center">
<p class="tent"><b>Reason</b></p>
</th>
</tr>

<tr valign="top">
<td align="left">
<p class="tent"><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]"
border="0"> SIGILL</p>
</td>
<td align="left">
<p class="tent">ILL_ILLOPC</p>
</td>
<td align="left">
<p class="tent">Illegal opcode.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">&nbsp;</p>
</td>
<td align="left">
<p class="tent">ILL_ILLOPN</p>
</td>
<td align="left">
<p class="tent">Illegal operand.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">&nbsp;</p>
</td>
<td align="left">
<p class="tent">ILL_ILLADR</p>
</td>
<td align="left">
<p class="tent">Illegal addressing mode.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">&nbsp;</p>
</td>
<td align="left">
<p class="tent">ILL_ILLTRP</p>
</td>
<td align="left">
<p class="tent">Illegal trap.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">&nbsp;</p>
</td>
<td align="left">
<p class="tent">ILL_PRVOPC</p>
</td>
<td align="left">
<p class="tent">Privileged opcode.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">&nbsp;</p>
</td>
<td align="left">
<p class="tent">ILL_PRVREG</p>
</td>
<td align="left">
<p class="tent">Privileged register.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">&nbsp;</p>
</td>
<td align="left">
<p class="tent">ILL_COPROC</p>
</td>
<td align="left">
<p class="tent">Coprocessor error.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">&nbsp;</p>
</td>
<td align="left">
<p class="tent">ILL_BADSTK</p>
</td>
<td align="left">
<p class="tent">Internal stack error.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">SIGFPE</p>
</td>
<td align="left">
<p class="tent">FPE_INTDIV</p>
</td>
<td align="left">
<p class="tent">Integer divide by zero.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">&nbsp;</p>
</td>
<td align="left">
<p class="tent">FPE_INTOVF</p>
</td>
<td align="left">
<p class="tent">Integer overflow.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">&nbsp;</p>
</td>
<td align="left">
<p class="tent">FPE_FLTDIV</p>
</td>
<td align="left">
<p class="tent">Floating-point divide by zero.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">&nbsp;</p>
</td>
<td align="left">
<p class="tent">FPE_FLTOVF</p>
</td>
<td align="left">
<p class="tent">Floating-point overflow.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">&nbsp;</p>
</td>
<td align="left">
<p class="tent">FPE_FLTUND</p>
</td>
<td align="left">
<p class="tent">Floating-point underflow.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">&nbsp;</p>
</td>
<td align="left">
<p class="tent">FPE_FLTRES</p>
</td>
<td align="left">
<p class="tent">Floating-point inexact result.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">&nbsp;</p>
</td>
<td align="left">
<p class="tent">FPE_FLTINV</p>
</td>
<td align="left">
<p class="tent">Invalid floating-point operation.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">&nbsp;</p>
</td>
<td align="left">
<p class="tent">FPE_FLTSUB</p>
</td>
<td align="left">
<p class="tent">Subscript out of range.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">SIGSEGV</p>
</td>
<td align="left">
<p class="tent">SEGV_MAPERR</p>
</td>
<td align="left">
<p class="tent">Address not mapped to object.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">&nbsp;</p>
</td>
<td align="left">
<p class="tent">SEGV_ACCERR</p>
</td>
<td align="left">
<p class="tent">Invalid permissions for mapped object.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">SIGBUS</p>
</td>
<td align="left">
<p class="tent">BUS_ADRALN</p>
</td>
<td align="left">
<p class="tent">Invalid address alignment.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">&nbsp;</p>
</td>
<td align="left">
<p class="tent">BUS_ADRERR</p>
</td>
<td align="left">
<p class="tent">Nonexistent physical address.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">&nbsp;</p>
</td>
<td align="left">
<p class="tent">BUS_OBJERR</p>
</td>
<td align="left">
<p class="tent">Object-specific hardware error.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">SIGTRAP</p>
</td>
<td align="left">
<p class="tent">TRAP_BRKPT</p>
</td>
<td align="left">
<p class="tent">Process breakpoint.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">&nbsp;</p>
</td>
<td align="left">
<p class="tent">TRAP_TRACE</p>
</td>
<td align="left">
<p class="tent">Process trace trap.</p>
</td>
</tr>

<tr valign="top">
<td align="left">
<p class="tent">SIGCHLD</p>
</td>
<td align="left">
<p class="tent">CLD_EXITED</p>
</td>
<td align="left">
<p class="tent">Child has exited.</p>
</td>
</tr>

<tr valign="top">