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<title>FE_DIVBYZERO, FE_INEXACT, FE_INVALID, FE_OVERFLOW, FE_UNDERFLOW, FE_ALL_EXCEPT</title>
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<h1 id="firstHeading" class="firstHeading"><small>FE_DIVBYZERO, FE_INEXACT, FE_INVALID, FE_OVERFLOW, FE_UNDERFLOW, FE_ALL_EXCEPT</small></h1>
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<div id="contentSub"><span class="subpages">&lt; <a href="c.html">c</a>&lrm; | <a href="c-numeric.html">numeric</a>&lrm; | <a href="c-numeric-fenv.html">fenv</a></span></div>
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<div>&#23450;&#20041;&#20110;&#22836;&#25991;&#20214; <code>&lt;fenv.h&gt;</code></div>
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<div><span class="mw-geshi c source-c"><span class="co2">#define FE_DIVBYZERO &nbsp; &nbsp;/*implementation defined power of 2*/</span></span></div>
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<td><span class="t-mark-rev t-since-c99">(C99 &#36215;)</span></td>
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<div><span class="mw-geshi c source-c"><span class="co2">#define FE_INEXACT &nbsp; &nbsp; &nbsp;/*implementation defined power of 2*/</span></span></div>
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<td><span class="t-mark-rev t-since-c99">(C99 &#36215;)</span></td>
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<div><span class="mw-geshi c source-c"><span class="co2">#define FE_INVALID &nbsp; &nbsp; &nbsp;/*implementation defined power of 2*/</span></span></div>
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<td><span class="t-mark-rev t-since-c99">(C99 &#36215;)</span></td>
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<div><span class="mw-geshi c source-c"><span class="co2">#define FE_OVERFLOW &nbsp; &nbsp; /*implementation defined power of 2*/</span></span></div>
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<td><span class="t-mark-rev t-since-c99">(C99 &#36215;)</span></td>
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<div><span class="mw-geshi c source-c"><span class="co2">#define FE_UNDERFLOW &nbsp; &nbsp;/*implementation defined power of 2*/</span></span></div>
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<td><span class="t-mark-rev t-since-c99">(C99 &#36215;)</span></td>
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<div><span class="mw-geshi c source-c"><span class="co2">#define FE_ALL_EXCEPT &nbsp;FE_DIVBYZERO | FE_INEXACT | \<br /></span></span>
<p><span class="mw-geshi c source-c">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;FE_INVALID | FE_OVERFLOW | &nbsp;\<br /></span></p>
<span class="mw-geshi c source-c">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;FE_UNDERFLOW</span></div>
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<td><span class="t-mark-rev t-since-c99">(C99 &#36215;)</span></td>
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<p>&#25152;&#26377;&#36825;&#20123;&#23439;&#24120;&#37327;&#65288;&#38500;&#20102; <span class="t-lc"><strong class="selflink">FE_ALL_EXCEPT</strong></span> &#65289;&#37117;&#23637;&#24320;&#25104;&#20540;&#20026; 2 &#30340;&#30456;&#24322;&#27425;&#24130;&#25972;&#25968;&#24120;&#37327;&#34920;&#36798;&#24335;&#65292;&#21807;&#19968;&#22320;&#37492;&#21035;&#25152;&#26377;&#21463;&#25903;&#25345;&#28014;&#28857;&#24322;&#24120;&#12290;&#27599;&#20010;&#23439;&#20165;&#33509;&#21463;&#25903;&#25345;&#25165;&#24471;&#21040;&#23450;&#20041;&#12290;</p>
<p>&#23439;&#24120;&#37327; <span class="t-lc"><strong class="selflink">FE_ALL_EXCEPT</strong></span> &#23637;&#24320;&#25104;&#25152;&#26377;&#20854;&#20182; <code>FE_*</code> &#30340;&#36880;&#20301;&#25110;&#65292;&#19988;&#22987;&#32456;&#26377;&#23450;&#20041;&#65292;&#33509;&#23454;&#29616;&#19981;&#25903;&#25345;&#28014;&#28857;&#24322;&#24120;&#65292;&#21017;&#20026;&#38646;&#12290;</p>
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<td>&#24120;&#37327;</td>
<td>&#23450;&#20041;</td>
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<td><code>FE_DIVBYZERO</code></td>
<td>&#20986;&#29616;&#20110;&#20043;&#21069;&#28014;&#28857;&#36816;&#31639;&#30340;&#26497;&#28857;&#38169;&#35823;</td>
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<td><code>FE_INEXACT</code></td>
<td>&#19981;&#20934;&#30830;&#32467;&#26524;&#65306;&#24517;&#39035;&#33293;&#20837;&#20197;&#23384;&#20648;&#20043;&#21069;&#28014;&#28857;&#36816;&#31639;&#30340;&#32467;&#26524;</td>
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<td><code>FE_INVALID</code></td>
<td>&#20986;&#29616;&#20110;&#20043;&#21069;&#28014;&#28857;&#36816;&#31639;&#30340;&#23450;&#20041;&#22495;&#38169;&#35823;</td>
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<td><code>FE_OVERFLOW</code></td>
<td>&#20043;&#21069;&#28014;&#28857;&#36816;&#31639;&#30340;&#32467;&#26524;&#36807;&#22823;&#32780;&#26080;&#27861;&#34920;&#31034;</td>
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<td><code>FE_UNDERFLOW</code></td>
<td>&#20043;&#21069;&#28014;&#28857;&#36816;&#31639;&#30340;&#32467;&#26524;&#20026;&#26377;&#31934;&#24230;&#25439;&#22833;&#30340;&#38750;&#27491;&#35268;&#20540;</td>
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<td><code>FE_ALL_EXCEPT</code></td>
<td>&#25152;&#26377;&#21463;&#25903;&#25345;&#28014;&#28857;&#24322;&#24120;&#30340;&#36880;&#20301;&#25110;</td>
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<p>&#23454;&#29616;&#21487;&#20110; <code>&lt;fenv.h&gt;</code> &#23450;&#20041;&#38468;&#21152;&#23439;&#24120;&#37327;&#20197;&#37492;&#21035;&#38468;&#21152;&#28014;&#28857;&#24322;&#24120;&#12290;&#25152;&#26377;&#36825;&#31181;&#24120;&#37327;&#37117;&#20197; <code>FE_</code> &#21518;&#38543;&#33267;&#23569;&#19968;&#20010;&#22823;&#20889;&#23383;&#27597;&#24320;&#22987;&#12290;</p>
<p>&#26356;&#22810;&#32454;&#33410;&#35265; <a href="c-numeric-math-math_errhandling.html"><tt>math_errhandling</tt></a> &#12290;</p>
<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">&#31034;&#20363;</span></h3>
<div class="t-example">
<div class="t-example-live-link"></div>
<div dir="ltr" class="mw-geshi" style="text-align: left;">
<div class="c source-c">
<pre class="de1"><span class="co2">#include &lt;stdio.h&gt;</span>
<span class="co2">#include &lt;math.h&gt;</span>
<span class="co2">#include &lt;float.h&gt;</span>
<span class="co2">#include &lt;fenv.h&gt;</span>
<span class="co2">#pragma STDC FENV_ACCESS ON</span>
<span class="kw4">void</span> show_fe_exceptions<span class="br0">(</span><span class="kw4">void</span><span class="br0">)</span>
<span class="br0">{</span>
<a href="c-io-fprintf.html"><span class="kw845">printf</span></a><span class="br0">(</span><span class="st0">&quot;exceptions raised:&quot;</span><span class="br0">)</span><span class="sy4">;</span>
<span class="kw1">if</span><span class="br0">(</span><a href="c-numeric-fenv-fetestexcept.html"><span class="kw719">fetestexcept</span></a><span class="br0">(</span>FE_DIVBYZERO<span class="br0">)</span><span class="br0">)</span> <a href="c-io-fprintf.html"><span class="kw845">printf</span></a><span class="br0">(</span><span class="st0">&quot; FE_DIVBYZERO&quot;</span><span class="br0">)</span><span class="sy4">;</span>
<span class="kw1">if</span><span class="br0">(</span><a href="c-numeric-fenv-fetestexcept.html"><span class="kw719">fetestexcept</span></a><span class="br0">(</span>FE_INEXACT<span class="br0">)</span><span class="br0">)</span> <a href="c-io-fprintf.html"><span class="kw845">printf</span></a><span class="br0">(</span><span class="st0">&quot; FE_INEXACT&quot;</span><span class="br0">)</span><span class="sy4">;</span>
<span class="kw1">if</span><span class="br0">(</span><a href="c-numeric-fenv-fetestexcept.html"><span class="kw719">fetestexcept</span></a><span class="br0">(</span>FE_INVALID<span class="br0">)</span><span class="br0">)</span> <a href="c-io-fprintf.html"><span class="kw845">printf</span></a><span class="br0">(</span><span class="st0">&quot; FE_INVALID&quot;</span><span class="br0">)</span><span class="sy4">;</span>
<span class="kw1">if</span><span class="br0">(</span><a href="c-numeric-fenv-fetestexcept.html"><span class="kw719">fetestexcept</span></a><span class="br0">(</span>FE_OVERFLOW<span class="br0">)</span><span class="br0">)</span> <a href="c-io-fprintf.html"><span class="kw845">printf</span></a><span class="br0">(</span><span class="st0">&quot; FE_OVERFLOW&quot;</span><span class="br0">)</span><span class="sy4">;</span>
<span class="kw1">if</span><span class="br0">(</span><a href="c-numeric-fenv-fetestexcept.html"><span class="kw719">fetestexcept</span></a><span class="br0">(</span>FE_UNDERFLOW<span class="br0">)</span><span class="br0">)</span> <a href="c-io-fprintf.html"><span class="kw845">printf</span></a><span class="br0">(</span><span class="st0">&quot; FE_UNDERFLOW&quot;</span><span class="br0">)</span><span class="sy4">;</span>
<a href="c-numeric-fenv-feclearexcept.html"><span class="kw718">feclearexcept</span></a><span class="br0">(</span>FE_ALL_EXCEPT<span class="br0">)</span><span class="sy4">;</span>
<a href="c-io-fprintf.html"><span class="kw845">printf</span></a><span class="br0">(</span><span class="st0">&quot;<span class="es1">\n</span>&quot;</span><span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="kw4">void</span><span class="br0">)</span>
<span class="br0">{</span>
<a href="c-io-fprintf.html"><span class="kw845">printf</span></a><span class="br0">(</span><span class="st0">&quot;MATH_ERREXCEPT is %s<span class="es1">\n</span>&quot;</span>,
math_errhandling <span class="sy3">&amp;</span> MATH_ERREXCEPT <span class="sy4">?</span> <span class="st0">&quot;set&quot;</span> <span class="sy4">:</span> <span class="st0">&quot;not set&quot;</span><span class="br0">)</span><span class="sy4">;</span>
<a href="c-io-fprintf.html"><span class="kw845">printf</span></a><span class="br0">(</span><span class="st0">&quot;0.0/0.0 = %f<span class="es1">\n</span>&quot;</span>, <span class="nu16">0.0</span><span class="sy2">/</span><span class="nu16">0.0</span><span class="br0">)</span><span class="sy4">;</span>
show_fe_exceptions<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
<a href="c-io-fprintf.html"><span class="kw845">printf</span></a><span class="br0">(</span><span class="st0">&quot;1.0/0.0 = %f<span class="es1">\n</span>&quot;</span>, <span class="nu16">1.0</span><span class="sy2">/</span><span class="nu16">0.0</span><span class="br0">)</span><span class="sy4">;</span>
show_fe_exceptions<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
<a href="c-io-fprintf.html"><span class="kw845">printf</span></a><span class="br0">(</span><span class="st0">&quot;1.0/10.0 = %f<span class="es1">\n</span>&quot;</span>, <span class="nu16">1.0</span><span class="sy2">/</span><span class="nu16">10.0</span><span class="br0">)</span><span class="sy4">;</span>
show_fe_exceptions<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
<a href="c-io-fprintf.html"><span class="kw845">printf</span></a><span class="br0">(</span><span class="st0">&quot;sqrt(-1) = %f<span class="es1">\n</span>&quot;</span>, <a href="c-numeric-math-sqrt.html"><span class="kw665">sqrt</span></a><span class="br0">(</span><span class="sy2">-</span><span class="nu0">1</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
show_fe_exceptions<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
<a href="c-io-fprintf.html"><span class="kw845">printf</span></a><span class="br0">(</span><span class="st0">&quot;DBL_MAX*2.0 = %f<span class="es1">\n</span>&quot;</span>, <a href="c-types-limits.html"><span class="kw378">DBL_MAX</span></a><span class="sy2">*</span><span class="nu16">2.0</span><span class="br0">)</span><span class="sy4">;</span>
show_fe_exceptions<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
<a href="c-io-fprintf.html"><span class="kw845">printf</span></a><span class="br0">(</span><span class="st0">&quot;nextafter(DBL_MIN/pow(2.0,52),0.0) = %.1f<span class="es1">\n</span>&quot;</span>,
<a href="c-numeric-math-nexttoward.html"><span class="kw701">nextafter</span></a><span class="br0">(</span><a href="c-types-limits.html"><span class="kw375">DBL_MIN</span></a><span class="sy2">/</span><a href="c-numeric-math-pow.html"><span class="kw668">pow</span></a><span class="br0">(</span><span class="nu16">2.0</span>,<span class="nu0">52</span><span class="br0">)</span>,<span class="nu16">0.0</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
show_fe_exceptions<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div>
</div>
<p>&#21487;&#33021;&#30340;&#36755;&#20986;&#65306;</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;">
<div class="text source-text">
<pre class="de1">MATH_ERREXCEPT is set
0.0/0.0 = nan
exceptions raised: FE_INVALID
1.0/0.0 = inf
exceptions raised: FE_DIVBYZERO
1.0/10.0 = 0.100000
exceptions raised: FE_INEXACT
sqrt(-1) = -nan
exceptions raised: FE_INVALID
DBL_MAX*2.0 = inf
exceptions raised: FE_INEXACT FE_OVERFLOW
nextafter(DBL_MIN/pow(2.0,52),0.0) = 0.0
exceptions raised: FE_INEXACT FE_UNDERFLOW</pre></div>
</div>
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<h3><span class="mw-headline" id=".E5.BC.95.E7.94.A8">&#24341;&#29992;</span></h3>
<div class="t-ref-std-11">
<ul>
<li>C11 &#26631;&#20934;&#65288;ISO/IEC 9899:2011&#65289;&#65306;</li>
</ul>
<dl>
<dd>
<ul>
<li>7.6/6 Floating-point environment &lt;fenv.h&gt; (p: 207)</li>
</ul>
</dd>
</dl>
<div class="t-ref-std-c99">
<ul>
<li>C99 &#26631;&#20934;&#65288;ISO/IEC 9899:1999&#65289;&#65306;</li>
</ul>
<dl>
<dd>
<ul>
<li>7.6/5 Floating-point environment &lt;fenv.h&gt; (p: 188)</li>
</ul>
</dd>
</dl>
</div>
<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">&#21442;&#38405;</span></h3>
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<td>
<div class="t-dsc-member-div">
<div><a href="c-numeric-math-math_errhandling.html"><span class="t-lines"><span>math_errhandling</span><span>MATH_ERRNO</span><span>MATH_ERREXCEPT</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span><span><span class="t-mark-rev t-since-c99">(C99)</span></span><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div>
</div>
</td>
<td>&#23450;&#20041;&#29992;&#20110;&#24120;&#29992;&#25968;&#23398;&#20989;&#25968;&#30340;&#38169;&#35823;&#22788;&#29702;&#26426;&#21046;<br />
<span class="t-mark">(&#23439;&#24120;&#37327;)</span></td>
</tr>
</table>
</div>
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<div class="visualClear"></div>
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