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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta name="generator" content="HTML Tidy, see www.w3.org"><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 --><!-- Copyright (c) 2001-2004 IEEE and The Open Group, All Rights Reserved --><title>sigsetjmp</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="sigsetjmp"></a> <a name="tag_03_697"></a><!-- sigsetjmp --> <!--header start--><center><font size="2">The Open Group Base Specifications Issue 6<br>IEEE Std 1003.1, 2004 Edition<br>Copyright © 2001-2004 The IEEE and The Open Group, All Rights reserved.</font></center><!--header end--><hr size="2" noshade><h4><a name="tag_03_697_01"></a>NAME</h4><blockquote>sigsetjmp - set jump point for a non-local goto</blockquote><h4><a name="tag_03_697_02"></a>SYNOPSIS</h4><blockquote class="synopsis"><div class="box"><code><tt><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> #include <<a href="../basedefs/setjmp.h.html">setjmp.h</a>><br><br> int sigsetjmp(sigjmp_buf</tt> <i>env</i><tt>, int</tt> <i>savemask</i><tt>); <img src="../images/opt-end.gif" alt="[Option End]"border="0"></tt></code></div><tt><br></tt></blockquote><h4><a name="tag_03_697_03"></a>DESCRIPTION</h4><blockquote><p>The <i>sigsetjmp</i>() function shall be equivalent to the <a href="../functions/setjmp.html"><i>setjmp</i>()</a> function,except as follows:</p><ul><li><p>References to <a href="../functions/setjmp.html"><i>setjmp</i>()</a> are equivalent to <i>sigsetjmp</i>().</p></li><li><p>References to <a href="../functions/longjmp.html"><i>longjmp</i>()</a> are equivalent to <a href="../functions/siglongjmp.html"><i>siglongjmp</i>()</a>.</p></li><li><p>If the value of the <i>savemask</i> argument is not 0, <i>sigsetjmp</i>() shall also save the current signal mask of the callingthread as part of the calling environment.</p></li></ul></blockquote><h4><a name="tag_03_697_04"></a>RETURN VALUE</h4><blockquote><p>If the return is from a successful direct invocation, <i>sigsetjmp</i>() shall return 0. If the return is from a call to <ahref="../functions/siglongjmp.html"><i>siglongjmp</i>()</a>, <i>sigsetjmp</i>() shall return a non-zero value.</p></blockquote><h4><a name="tag_03_697_05"></a>ERRORS</h4><blockquote><p>No errors are defined.</p></blockquote><hr><div class="box"><em>The following sections are informative.</em></div><h4><a name="tag_03_697_06"></a>EXAMPLES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_697_07"></a>APPLICATION USAGE</h4><blockquote><p>The distinction between <a href="../functions/setjmp.html"><i>setjmp</i>()</a>/ <a href="../functions/longjmp.html"><i>longjmp</i>()</a> and <i>sigsetjmp</i>()/ <a href="../functions/siglongjmp.html"><i>siglongjmp</i>()</a> is only significant for programs which use <a href="../functions/sigaction.html"><i>sigaction</i>()</a>, <a href="../functions/sigprocmask.html"><i>sigprocmask</i>()</a>, or <a href="../functions/sigsuspend.html"><i>sigsuspend</i>()</a>.</p><p>Note that since this function is defined in terms of <a href="../functions/setjmp.html"><i>setjmp</i>()</a>, if <i>savemask</i>is zero, it is unspecified whether the signal mask is saved.</p></blockquote><h4><a name="tag_03_697_08"></a>RATIONALE</h4><blockquote><p>The ISO C standard specifies various restrictions on the usage of the <a href="../functions/setjmp.html"><i>setjmp</i>()</a> macro in order to permit implementors to recognize the name in the compiler and notimplement an actual function. These same restrictions apply to the <i>sigsetjmp</i>() macro.</p><p>There are processors that cannot easily support these calls, but this was not considered a sufficient reason to excludethem.</p><p>4.2 BSD, 4.3 BSD, and XSI-conformant systems provide functions named <a href="../functions/_setjmp.html"><i>_setjmp</i>()</a>and <a href="../functions/_longjmp.html"><i>_longjmp</i>()</a> that, together with <a href="../functions/setjmp.html"><i>setjmp</i>()</a> and <a href="../functions/longjmp.html"><i>longjmp</i>()</a>, provide the samefunctionality as <i>sigsetjmp</i>() and <a href="../functions/siglongjmp.html"><i>siglongjmp</i>()</a>. On those systems, <a href="../functions/setjmp.html"><i>setjmp</i>()</a> and <a href="../functions/longjmp.html"><i>longjmp</i>()</a> save and restore signalmasks, while <a href="../functions/_setjmp.html"><i>_setjmp</i>()</a> and <a href="../functions/_longjmp.html"><i>_longjmp</i>()</a> do not. On System V Release 3 and in corresponding issues of the SVID, <a href="../functions/setjmp.html"><i>setjmp</i>()</a> and <a href="../functions/longjmp.html"><i>longjmp</i>()</a> are explicitly definednot to save and restore signal masks. In order to permit existing practice in both cases, the relation of <a href="../functions/setjmp.html"><i>setjmp</i>()</a> and <a href="../functions/longjmp.html"><i>longjmp</i>()</a> to signal masks is notspecified, and a new set of functions is defined instead.</p><p>The <a href="../functions/longjmp.html"><i>longjmp</i>()</a> and <a href="../functions/siglongjmp.html"><i>siglongjmp</i>()</a>functions operate as in the previous issue provided the matching <a href="../functions/setjmp.html"><i>setjmp</i>()</a> or<i>sigsetjmp</i>() has been performed in the same thread. Non-local jumps into contexts saved by other threads would be at best aquestionable practice and were not considered worthy of standardization.</p></blockquote><h4><a name="tag_03_697_09"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_697_10"></a>SEE ALSO</h4><blockquote><p><a href="siglongjmp.html"><i>siglongjmp</i>()</a>, <a href="signal.html"><i>signal</i>()</a>, <a href="sigprocmask.html"><i>sigprocmask</i>()</a>, <a href="sigsuspend.html"><i>sigsuspend</i>()</a>, the Base Definitions volume ofIEEE Std 1003.1-2001, <a href="../basedefs/setjmp.h.html"><i><setjmp.h></i></a></p></blockquote><h4><a name="tag_03_697_11"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 3. Included for alignment with the POSIX.1-1988 standard.</p></blockquote><h4><a name="tag_03_697_12"></a>Issue 5</h4><blockquote><p>The DESCRIPTION is updated for alignment with the POSIX Threads Extension.</p></blockquote><h4><a name="tag_03_697_13"></a>Issue 6</h4><blockquote><p>The DESCRIPTION is reworded in terms of <a href="../functions/setjmp.html"><i>setjmp</i>()</a>.</p><p>The SYNOPSIS is marked CX since the presence of this function in the <a href="../basedefs/setjmp.h.html"><i><setjmp.h></i></a> header is an extension over the ISO C standard.</p></blockquote><div class="box"><em>End of informative text.</em></div><hr size="2" noshade><center><font size="2"><!--footer start-->UNIX ® is a registered Trademark of The Open Group.<br>POSIX ® is a registered Trademark of The IEEE.<br>[ <a href="../mindex.html">Main Index</a> | <a href="../basedefs/contents.html">XBD</a> | <a href="../utilities/contents.html">XCU</a> | <a href="../functions/contents.html">XSH</a> | <a href="../xrat/contents.html">XRAT</a>]</font></center><!--footer end--><hr size="2" noshade></body></html>?? 快捷鍵說明
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