138 lines
4.5 KiB
HTML
138 lines
4.5 KiB
HTML
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<!-- Copyright (c) 2001 The Open Group, All Rights Reserved -->
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<title>feupdateenv</title>
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<basefont size="3"> <a name="feupdateenv"></a> <a name="tag_03_159"></a><!-- feupdateenv -->
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<!--header start-->
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<center><font size="2">The Open Group Base Specifications Issue 6<br>
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IEEE Std 1003.1-2001<br>
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Copyright © 2001 The IEEE and The Open Group, All Rights reserved.</font></center>
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<!--header end-->
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<hr size="2" noshade>
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<h4><a name="tag_03_159_01"></a>NAME</h4>
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<blockquote>feupdateenv - update floating-point environment</blockquote>
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<h4><a name="tag_03_159_02"></a>SYNOPSIS</h4>
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<blockquote class="synopsis">
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<p><code><tt>#include <<a href="../basedefs/fenv.h.html">fenv.h</a>><br>
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<br>
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int feupdateenv(const fenv_t *</tt><i>envp</i><tt>);<br>
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</tt></code></p>
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</blockquote>
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<h4><a name="tag_03_159_03"></a>DESCRIPTION</h4>
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<blockquote>
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<div class="box"><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]"
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border="0"> The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the
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requirements described here and the ISO C standard is unintentional. This volume of IEEE Std 1003.1-2001 defers to
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the ISO C standard. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></div>
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<p>The <i>feupdateenv</i>() function shall attempt to save the currently raised floating-point exceptions in its automatic storage,
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attempt to install the floating-point environment represented by the object pointed to by <i>envp</i>, and then attempt to raise
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the saved floating-point exceptions. The argument <i>envp</i> shall point to an object set by a call to <a href=
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"../functions/feholdexcept.html"><i>feholdexcept</i>()</a> or <a href="../functions/fegetenv.html"><i>fegetenv</i>()</a>, or equal
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a floating-point environment macro.</p>
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</blockquote>
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<h4><a name="tag_03_159_04"></a>RETURN VALUE</h4>
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<blockquote>
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<p>The <i>feupdateenv</i>() function shall return a zero value if and only if all the required actions were successfully carried
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out.</p>
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</blockquote>
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<h4><a name="tag_03_159_05"></a>ERRORS</h4>
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<blockquote>
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<p>No errors are defined.</p>
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</blockquote>
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<hr>
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<div class="box"><em>The following sections are informative.</em></div>
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<h4><a name="tag_03_159_06"></a>EXAMPLES</h4>
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<blockquote>
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<p>The following example shows sample code to hide spurious underflow floating-point exceptions:</p>
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<pre>
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<tt>#include <fenv.h>
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double f(double x)
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{
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# pragma STDC FENV_ACCESS ON
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double result;
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fenv_t save_env;
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feholdexcept(&save_env);
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// compute result
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if (/* test spurious underflow */)
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feclearexcept(FE_UNDERFLOW);
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feupdateenv(&save_env);
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return result;
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}
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</tt>
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</pre>
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</blockquote>
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<h4><a name="tag_03_159_07"></a>APPLICATION USAGE</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_159_08"></a>RATIONALE</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_159_09"></a>FUTURE DIRECTIONS</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_159_10"></a>SEE ALSO</h4>
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<blockquote>
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<p><a href="fegetenv.html"><i>fegetenv</i>()</a> , <a href="feholdexcept.html"><i>feholdexcept</i>()</a> , the Base Definitions
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volume of IEEE Std 1003.1-2001, <a href="../basedefs/fenv.h.html"><i><fenv.h></i></a></p>
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</blockquote>
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<h4><a name="tag_03_159_11"></a>CHANGE HISTORY</h4>
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<blockquote>
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<p>First released in Issue 6. Derived from the ISO/IEC 9899:1999 standard.</p>
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<p>ISO/IEC 9899:1999 standard, Technical Corrigendum No. 1 is incorporated.</p>
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</blockquote>
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<div class="box"><em>End of informative text.</em></div>
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POSIX ® is a registered Trademark of The IEEE.<br>
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