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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"><html><head><!-- Copyright 1997 The Open Group, All Rights Reserved --><title>sigqueue</title></head><body bgcolor=white><center><font size=2>The Single UNIX ® Specification, Version 2<br>Copyright © 1997 The Open Group</font></center><hr size=2 noshade><h4><a name = "tag_000_008_702"> </a>NAME</h4><blockquote>sigqueue - queue a signal to a process(<b>REALTIME</b>)</blockquote><h4><a name = "tag_000_008_703"> </a>SYNOPSIS</h4><blockquote><pre><code>#include <<a href="systypes.h.html">sys/types.h</a>>#include <<a href="signal.h.html">signal.h</a>>int sigqueue(pid_t <i>pid</i>, int <i>signo</i>, const union sigval <i>value</i>);</code></pre></blockquote><h4><a name = "tag_000_008_704"> </a>DESCRIPTION</h4><blockquote>The<i>sigqueue()</i>function causes the signal specified by<i>signo</i>to be sent with the value specified by<i>value</i>to the process specified by<i>pid.</i>If<i>signo</i>is zero (the null signal), error checking is performedbut no signal is actually sent.The null signal can be used to check the validity of<i>pid</i>.<p>The conditions required for a process to have permission to queue a signalto another process are the same as for the<i><a href="kill.html">kill()</a></i>function.<p>The<i>sigqueue()</i>function returns immediately.If SA_SIGINFO is set for<i>signo</i>and if the resources were available to queue the signal,the signal is queued and sent to the receiving process.If SA_SIGINFO is not set for<i>signo</i>,then<i>signo</i>is sent at least once to the receiving process;it is unspecified whether<i>value</i>will be sent to the receiving process as a result of this call.<p>If the value of<i>pid</i>causes<i>signo</i>to be generated for the sending process,and if<i>signo</i>is not blocked for the calling thread and if no other thread has<i>signo</i>unblocked or is waiting in a<i><a href="sigwait.html">sigwait()</a></i>function for<i>signo</i>,either<i>signo</i>or at least the pending, unblocked signalwill be delivered to the calling thread before the<i>sigqueue()</i>function returns.Should any of multiple pending signals in the range SIGRTMIN toSIGRTMAX be selected for delivery, it will be the lowest numbered one.The selection order between realtime and non-realtime signals, orbetween multiple pending non-realtime signals, is unspecified.</blockquote><h4><a name = "tag_000_008_705"> </a>RETURN VALUE</h4><blockquote>Upon successful completion,the specified signal will have been queued, and the<i>sigqueue()</i>function returns a value of zero.Otherwise, the function returns a value of -1 and sets<i>errno</i>to indicate the error.</blockquote><h4><a name = "tag_000_008_706"> </a>ERRORS</h4><blockquote>The <i>sigqueue()</i>function will fail if:<dl compact><dt>[EAGAIN]<dd>No resources available to queue the signal.The process has already queued SIGQUEUE_MAXsignals that are still pending at the receiver(s),or a system-wide resource limit has been exceeded.<dt>[EINVAL]<dd>The value of the<i>signo</i>argument is an invalid or unsupported signal number.<dt>[ENOSYS]<dd>The function<i>sigqueue()</i>is not supported by this implementation.<dt>[EPERM]<dd>The process does not have the appropriate privilegeto send the signal to the receiving process.<dt>[ESRCH]<dd>The process<i>pid</i>does not exist.</dl></blockquote><h4><a name = "tag_000_008_707"> </a>EXAMPLES</h4><blockquote>None.</blockquote><h4><a name = "tag_000_008_708"> </a>APPLICATION USAGE</h4><blockquote>None.</blockquote><h4><a name = "tag_000_008_709"> </a>FUTURE DIRECTIONS</h4><blockquote>None.</blockquote><h4><a name = "tag_000_008_710"> </a>SEE ALSO</h4><blockquote><i><a href="signal.h.html"><signal.h></a></i>.</blockquote><h4>DERIVATION</h4><blockquote>Derived from the POSIX Realtime Extension (1003.1b-1993/1003.1i-1995) and the POSIX Threads Extension (1003.1c-1995)</blockquote><hr size=2 noshade><center><font size=2>UNIX ® is a registered Trademark of The Open Group.<br>Copyright © 1997 The Open Group<br> [ <a href="../index.html">Main Index</a> | <a href="../xshix.html">XSH</a> | <a href="../xcuix.html">XCU</a> | <a href="../xbdix.html">XBD</a> | <a href="../cursesix.html">XCURSES</a> | <a href="../xnsix.html">XNS</a> ]</font></center><hr size=2 noshade></body></html>⌨️ 快捷键说明
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