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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>fegetround</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="fegetround"></a> <a name="tag_03_150"></a><!-- fegetround --> <!--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_150_01"></a>NAME</h4><blockquote>fegetround, fesetround - get and set current rounding direction</blockquote><h4><a name="tag_03_150_02"></a>SYNOPSIS</h4><blockquote class="synopsis"><p><code><tt>#include <<a href="../basedefs/fenv.h.html">fenv.h</a>><br><br> int fegetround(void);<br> int fesetround(int</tt> <i>round</i><tt>);<br></tt></code></p></blockquote><h4><a name="tag_03_150_03"></a>DESCRIPTION</h4><blockquote><div class="box"><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]"border="0"> The functionality described on this reference page is aligned with the ISO C standard. Any conflict between therequirements described here and the ISO C standard is unintentional. This volume of IEEE Std 1003.1-2001 defers tothe ISO C standard. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></div><p>The <i>fegetround</i>() function shall get the current rounding direction.</p><p>The <i>fesetround</i>() function shall establish the rounding direction represented by its argument <i>round</i>. If theargument is not equal to the value of a rounding direction macro, the rounding direction is not changed.</p></blockquote><h4><a name="tag_03_150_04"></a>RETURN VALUE</h4><blockquote><p>The <i>fegetround</i>() function shall return the value of the rounding direction macro representing the current roundingdirection or a negative value if there is no such rounding direction macro or the current rounding direction is notdeterminable.</p><p>The <i>fesetround</i>() function shall return a zero value if and only if the requested rounding direction was established.</p></blockquote><h4><a name="tag_03_150_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_150_06"></a>EXAMPLES</h4><blockquote><p>The following example saves, sets, and restores the rounding direction, reporting an error and aborting if setting the roundingdirection fails:</p><pre><tt>#include <fenv.h>#include <assert.h>void f(int round_dir){ #pragma STDC FENV_ACCESS ON int save_round; int setround_ok; save_round = fegetround(); setround_ok = fesetround(round_dir); assert(setround_ok == 0); /* ... */ fesetround(save_round); /* ... */}</tt></pre></blockquote><h4><a name="tag_03_150_07"></a>APPLICATION USAGE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_150_08"></a>RATIONALE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_150_09"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_150_10"></a>SEE ALSO</h4><blockquote><p>The Base Definitions volume of IEEE Std 1003.1-2001, <a href="../basedefs/fenv.h.html"><i><fenv.h></i></a></p></blockquote><h4><a name="tag_03_150_11"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 6. Derived from the ISO/IEC 9899:1999 standard.</p><p>ISO/IEC 9899:1999 standard, Technical Corrigendum 1 is incorporated.</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>⌨️ 快捷键说明
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