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<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="exp.html" title="c/numeric/math/exp"><span class="t-lines"><span>exp</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="exp2.html" title="c/numeric/math/exp2"><span class="t-lines"><span>exp2</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="expm1.html" title="c/numeric/math/expm1"><span class="t-lines"><span>expm1</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="log.html" title="c/numeric/math/log"><span class="t-lines"><span>log</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="log10.html" title="c/numeric/math/log10"><span class="t-lines"><span>log10</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="log1p.html" title="c/numeric/math/log1p"><span class="t-lines"><span>log1p</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="log2.html" title="c/numeric/math/log2"><span class="t-lines"><span>log2</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Power functions</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="sqrt.html" title="c/numeric/math/sqrt"><span class="t-lines"><span>sqrt</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="cbrt.html" title="c/numeric/math/cbrt"><span class="t-lines"><span>cbrt</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="hypot.html" title="c/numeric/math/hypot"><span class="t-lines"><span>hypot</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="pow.html" title="c/numeric/math/pow"><span class="t-lines"><span>pow</span></span></a></div></div></td></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Trigonometric and hyperbolic functions</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="sin.html" title="c/numeric/math/sin"><span class="t-lines"><span>sin</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="cos.html" title="c/numeric/math/cos"><span class="t-lines"><span>cos</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="tan.html" title="c/numeric/math/tan"><span class="t-lines"><span>tan</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="asin.html" title="c/numeric/math/asin"><span class="t-lines"><span>asin</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><strong class="selflink"><span class="t-lines"><span>acos</span></span></strong></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="atan.html" title="c/numeric/math/atan"><span class="t-lines"><span>atan</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="atan2.html" title="c/numeric/math/atan2"><span class="t-lines"><span>atan2</span></span></a></div></div></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="sinh.html" title="c/numeric/math/sinh"><span class="t-lines"><span>sinh</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="cosh.html" title="c/numeric/math/cosh"><span class="t-lines"><span>cosh</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="tanh.html" title="c/numeric/math/tanh"><span class="t-lines"><span>tanh</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="asinh.html" title="c/numeric/math/asinh"><span class="t-lines"><span>asinh</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="acosh.html" title="c/numeric/math/acosh"><span class="t-lines"><span>acosh</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="atanh.html" title="c/numeric/math/atanh"><span class="t-lines"><span>atanh</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Error and gamma functions</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="erf.html" title="c/numeric/math/erf"><span class="t-lines"><span>erf</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="erfc.html" title="c/numeric/math/erfc"><span class="t-lines"><span>erfc</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="lgamma.html" title="c/numeric/math/lgamma"><span class="t-lines"><span>lgamma</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="tgamma.html" title="c/numeric/math/tgamma"><span class="t-lines"><span>tgamma</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Nearest integer floating point operations</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="ceil.html" title="c/numeric/math/ceil"><span class="t-lines"><span>ceil</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="floor.html" title="c/numeric/math/floor"><span class="t-lines"><span>floor</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="round.html" title="c/numeric/math/round"><span class="t-lines"><span>round</span><span>lround</span><span>llround</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></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="trunc.html" title="c/numeric/math/trunc"><span class="t-lines"><span>trunc</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="nearbyint.html" title="c/numeric/math/nearbyint"><span class="t-lines"><span>nearbyint</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="rint.html" title="c/numeric/math/rint"><span class="t-lines"><span>rint</span><span>lrint</span><span>llrint</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></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Floating point manipulation functions</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="ldexp.html" title="c/numeric/math/ldexp"><span class="t-lines"><span>ldexp</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="scalbn.html" title="c/numeric/math/scalbn"><span class="t-lines"><span>scalbn</span><span>scalbln</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></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="ilogb.html" title="c/numeric/math/ilogb"><span class="t-lines"><span>ilogb</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="logb.html" title="c/numeric/math/logb"><span class="t-lines"><span>logb</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="frexp.html" title="c/numeric/math/frexp"><span class="t-lines"><span>frexp</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="modf.html" title="c/numeric/math/modf"><span class="t-lines"><span>modf</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="nextafter.html" title="c/numeric/math/nextafter"><span class="t-lines"><span>nextafter</span><span>nexttoward</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></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="copysign.html" title="c/numeric/math/copysign"><span class="t-lines"><span>copysign</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Classification</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="fpclassify.html" title="c/numeric/math/fpclassify"><span class="t-lines"><span>fpclassify</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="isfinite.html" title="c/numeric/math/isfinite"><span class="t-lines"><span>isfinite</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="isinf.html" title="c/numeric/math/isinf"><span class="t-lines"><span>isinf</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="isnan.html" title="c/numeric/math/isnan"><span class="t-lines"><span>isnan</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="isnormal.html" title="c/numeric/math/isnormal"><span class="t-lines"><span>isnormal</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="signbit.html" title="c/numeric/math/signbit"><span class="t-lines"><span>signbit</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="isgreater.html" title="c/numeric/math/isgreater"><span class="t-lines"><span>isgreater</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="isgreaterequal.html" title="c/numeric/math/isgreaterequal"><span class="t-lines"><span>isgreaterequal</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="isless.html" title="c/numeric/math/isless"><span class="t-lines"><span>isless</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="islessequal.html" title="c/numeric/math/islessequal"><span class="t-lines"><span>islessequal</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="islessgreater.html" title="c/numeric/math/islessgreater"><span class="t-lines"><span>islessgreater</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="isunordered.html" title="c/numeric/math/isunordered"><span class="t-lines"><span>isunordered</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
</table></div></td></tr>
<tr class="t-nv-h1"><td colspan="5"> Types</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="div.html" title="c/numeric/math/div"><span class="t-lines"><span>div_t</span><span>ldiv_t</span><span>lldiv_t</span><span>imaxdiv_t</span></span></a></div><div><span class="t-lines"><span></span><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></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="float_t.html" title="c/numeric/math/float t"><span class="t-lines"><span>float_t</span><span>double_t</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></div></div></td></tr>
</table></div></td></tr>
<tr class="t-nv-h1"><td colspan="5"> Macro constants</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="HUGE_VAL.html" title="c/numeric/math/HUGE VAL"><span class="t-lines"><span>HUGE_VALF</span><span>HUGE_VAL</span><span>HUGE_VALL</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span><span></span><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="fma.html" title="c/numeric/math/fma"><span class="t-lines"><span>FP_FAST_FMAF</span><span>FP_FAST_FMA</span><span>FP_FAST_FMAL</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></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="math_errhandling.html" title="c/numeric/math/math errhandling"><span class="t-lines"><span>math_errhandling</span><span>MATH_ERRNO</span><span>MATH_ERRNOEXCEPT</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></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="INFINITY.html" title="c/numeric/math/INFINITY"><span class="t-lines"><span>INFINITY</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="NAN.html" title="c/numeric/math/NAN"><span class="t-lines"><span>NAN</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="ilogb.html" title="c/numeric/math/ilogb"><span class="t-lines"><span>FP_ILOGB0</span><span>FP_ILOGBNAN</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></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="FP_categories.html" title="c/numeric/math/FP categories"><span class="t-lines"><span>FP_NORMAL</span><span>FP_SUBNORMAL</span><span>FP_ZERO</span><span>FP_INFINITE</span><span>FP_NAN</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><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></tr>
</table></div></td></tr>
</table></div><div><span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:c/numeric/math/navbar_content&action=edit">[edit]</a></span></div></div></div></div><div class="t-navbar-sep"> </div></div>
<table class="t-dcl-begin"><tbody>
<tr class="t-dsc-header">
<td> <div>Defined in header <code><math.h></code>
</div></td>
<td></td>
<td></td>
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<tr class="t-dcl t-since-c99">
<td> <div><span class="mw-geshi c source-c"><span class="kw4">float</span>       acosf<span class="br0">(</span> <span class="kw4">float</span> arg <span class="br0">)</span><span class="sy4">;</span></span></div></td>
<td> (1) </td>
<td> <span class="t-mark-rev t-since-c99">(since C99)</span> </td>
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<tr class="t-dcl">
<td> <div><span class="mw-geshi c source-c"><span class="kw4">double</span>      acos<span class="br0">(</span> <span class="kw4">double</span> arg <span class="br0">)</span><span class="sy4">;</span></span></div></td>
<td> (2) </td>
<td class="t-dcl-nopad"> </td>
</tr>
<tr class="t-dcl t-since-c99">
<td> <div><span class="mw-geshi c source-c"><span class="kw4">long</span> <span class="kw4">double</span> acosl<span class="br0">(</span> <span class="kw4">long</span> <span class="kw4">double</span> arg <span class="br0">)</span><span class="sy4">;</span></span></div></td>
<td> (3) </td>
<td> <span class="t-mark-rev t-since-c99">(since C99)</span> </td>
</tr>
<tr class="t-dsc-header">
<td> <div>Defined in header <code><tgmath.h></code>
</div></td>
<td></td>
<td></td>
</tr>
<tr class="t-dcl t-since-c99">
<td> <div><span class="mw-geshi c source-c"><span class="co2">#define acos( arg )</span></span></div></td>
<td> (4) </td>
<td> <span class="t-mark-rev t-since-c99">(since C99)</span> </td>
</tr>
<tr class="t-dcl-sep"><td></td><td></td><td></td></tr>
</tbody></table>
<div class="t-li1"><span class="t-li">1-3)</span> Computes the principal value of the arc cosine of <code>arg</code>.</div>
<div class="t-li1"><span class="t-li">4)</span> Type-generic macro: If the argument has type <span class="t-c"><span class="mw-geshi c source-c"><span class="kw4">long</span> <span class="kw4">double</span></span></span>, <code>acosl</code> is called. Otherwise, if the argument has integer type or the type <span class="t-c"><span class="mw-geshi c source-c"><span class="kw4">double</span></span></span>, <code>acos</code> is called. Otherwise, <code>acosf</code> is called. If the argument is complex, then the macro invokes the corresponding complex function (<span class="t-c"><span class="mw-geshi c source-c"><a href="../complex/cacos.html"><span class="kw781">cacosf</span></a></span></span>, <span class="t-c"><span class="mw-geshi c source-c"><a href="../complex/cacos.html"><span class="kw780">cacos</span></a></span></span>, <span class="t-c"><span class="mw-geshi c source-c"><a href="../complex/cacos.html"><span class="kw782">cacosl</span></a></span></span>).</div>
<table id="toc" class="toc"><tr><td><div id="toctitle"><h2>Contents</h2></div>
<ul>
<li class="toclevel-1 tocsection-1"><a href="acos.html#Parameters"><span class="tocnumber">1</span> <span class="toctext">Parameters</span></a></li>
<li class="toclevel-1 tocsection-2"><a href="acos.html#Return_value"><span class="tocnumber">2</span> <span class="toctext">Return value</span></a></li>
<li class="toclevel-1 tocsection-3"><a href="acos.html#Error_handling"><span class="tocnumber">3</span> <span class="toctext">Error handling</span></a></li>
<li class="toclevel-1 tocsection-4"><a href="acos.html#Example"><span class="tocnumber">4</span> <span class="toctext">Example</span></a></li>
<li class="toclevel-1 tocsection-5"><a href="acos.html#References"><span class="tocnumber">5</span> <span class="toctext">References</span></a></li>
<li class="toclevel-1 tocsection-6"><a href="acos.html#See_also"><span class="tocnumber">6</span> <span class="toctext">See also</span></a></li>
</ul>
</td></tr></table>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=c/numeric/math/acos&action=edit&section=1" title="Edit section: Parameters">edit</a>]</span> <span class="mw-headline" id="Parameters">Parameters</span></h3>
<table class="t-par-begin">
<tr class="t-par">
<td> arg
</td>
<td> -
</td>
<td> floating point value
</td></tr></table>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=c/numeric/math/acos&action=edit&section=2" title="Edit section: Return value">edit</a>]</span> <span class="mw-headline" id="Return_value">Return value</span></h3>
<p>If no errors occur, the arc cosine of <code>arg</code> (<span class="texhtml" style="white-space: nowrap;">arccos(arg)</span>) in the range <span class="texhtml" style="white-space: nowrap;">[0 ; π]</span>, is returned.
</p><p>If a domain error occurs, an implementation-defined value is returned (NaN where supported).
</p><p>If a range error occurs due to underflow, the correct result (after rounding) is returned.
</p>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=c/numeric/math/acos&action=edit&section=3" title="Edit section: Error handling">edit</a>]</span> <span class="mw-headline" id="Error_handling">Error handling</span></h3>
<p>Errors are reported as specified in <a href="math_errhandling.html" title="c/numeric/math/math errhandling">math_errhandling</a>.
</p><p>Domain error occurs if <code>arg</code> is outside the range <code>[-1.0; 1.0]</code>.
</p><p>If the implementation supports IEEE floating-point arithmetic (IEC 60559),
</p>
<ul><li> If the argument is <span class="texhtml" style="white-space: nowrap;">+1</span>, the value <code>+0</code> is returned.
</li><li> If <span class="texhtml" style="white-space: nowrap;">|arg| > 1</span>, a domain error occurs and NaN is returned.
</li><li> if the argument is NaN, NaN is returned
</li></ul>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=c/numeric/math/acos&action=edit&section=4" title="Edit section: Example">edit</a>]</span> <span class="mw-headline" id="Example">Example</span></h3>
<div class="t-example"><div class="t-example-live-link"><div class="coliru-btn coliru-btn-run-init">Run this code</div></div>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="c source-c"><pre class="de1"><span class="co2">#include <stdio.h></span>
<span class="co2">#include <math.h></span>
<span class="co2">#include <errno.h></span>
<span class="co2">#include <fenv.h></span>
<span class="co2">#include <string.h></span>
 
<span class="co2">#pragma STDC FENV_ACCESS ON</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="../../io/fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">"acos(-1) = %f<span class="es1">\n</span>"</span>, acos<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>
<a href="../../io/fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">"acos(0.0) = %f 2*acos(0.0) = %f<span class="es1">\n</span>"</span>, acos<span class="br0">(</span><span class="nu0">0</span><span class="br0">)</span>, <span class="nu0">2</span><span class="sy2">*</span>acos<span class="br0">(</span><span class="nu0">0</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
<a href="../../io/fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">"acos(0.5) = %f 3*acos(0.5) = %f<span class="es1">\n</span>"</span>, acos<span class="br0">(</span><span class="nu16">0.5</span><span class="br0">)</span>, <span class="nu0">3</span><span class="sy2">*</span>acos<span class="br0">(</span><span class="nu16">0.5</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
<a href="../../io/fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">"acos(1) = %f<span class="es1">\n</span>"</span>, acos<span class="br0">(</span><span class="nu0">1</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
<span class="co1">// error handling </span>
<span class="kw2">errno</span> <span class="sy1">=</span> <span class="nu0">0</span><span class="sy4">;</span> <a href="../fenv/feclearexcept.html"><span class="kw717">feclearexcept</span></a><span class="br0">(</span><a href="../fenv/FE_exceptions.html"><span class="kw728">FE_ALL_EXCEPT</span></a><span class="br0">)</span><span class="sy4">;</span>
<a href="../../io/fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">"acos(1.1) = %f<span class="es1">\n</span>"</span>, acos<span class="br0">(</span><span class="nu16">1.1</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
<span class="kw1">if</span><span class="br0">(</span><span class="kw2">errno</span> <span class="sy1">==</span> <a href="../../error/errno_macros.html"><span class="kw426">EDOM</span></a><span class="br0">)</span> <a href="../../io/perror.html"><span class="kw878">perror</span></a><span class="br0">(</span><span class="st0">" errno == EDOM"</span><span class="br0">)</span><span class="sy4">;</span>
<span class="kw1">if</span><span class="br0">(</span><a href="../fenv/fetestexcept.html"><span class="kw718">fetestexcept</span></a><span class="br0">(</span><a href="../fenv/FE_exceptions.html"><span class="kw731">FE_INVALID</span></a><span class="br0">)</span><span class="br0">)</span> <a href="../../io/puts.html"><span class="kw835">puts</span></a><span class="br0">(</span><span class="st0">" FE_INVALID raised"</span><span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<p>Possible output:
</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="text source-text"><pre class="de1">acos(-1) = 3.141593
acos(0.0) = 1.570796 2*acos(0.0) = 3.141593
acos(0.5) = 1.047198 3*acos(0.5) = 3.141593
acos(1) = 0.000000
acos(1.1) = nan
errno == EDOM: Numerical argument out of domain
FE_INVALID raised</pre></div></div>
</div>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=c/numeric/math/acos&action=edit&section=5" title="Edit section: References">edit</a>]</span> <span class="mw-headline" id="References">References</span></h3>
<div class="t-ref-std-11">
<ul><li> C11 standard (ISO/IEC 9899:2011):
</li></ul>
<dl><dd><ul><li> 7.12.4.1 The acos functions (p: 238)
</li></ul>
</dd></dl>
<dl><dd><ul><li> 7.25 Type-generic math <tgmath.h> (p: 373-375)
</li></ul>
</dd></dl>
<dl><dd><ul><li> F.10.1.1 The acos functions (p: 518)
</li></ul>
</dd></dl>
<div class="t-ref-std-c99">
<ul><li> C99 standard (ISO/IEC 9899:1999):
</li></ul>
<dl><dd><ul><li> 7.12.4.1 The acos functions (p: 218)
</li></ul>
</dd></dl>
<dl><dd><ul><li> 7.22 Type-generic math <tgmath.h> (p: 335-337)
</li></ul>
</dd></dl>
<dl><dd><ul><li> F.9.1.1 The acos functions (p: 455)
</li></ul>
</dd></dl>
<div class="t-ref-std-c89">
<ul><li> C89/C90 standard (ISO/IEC 9899:1990):
</li></ul>
<dl><dd><ul><li> 4.5.2.1 The acos function
</li></ul>
</dd></dl>
</div>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=c/numeric/math/acos&action=edit&section=6" title="Edit section: See also">edit</a>]</span> <span class="mw-headline" id="See_also">See also</span></h3>
<table class="t-dsc-begin">
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="asin.html" title="c/numeric/math/asin"> <span class="t-lines"><span>asin</span><span>asinf</span><span>asinl</span></span></a></div><div><span class="t-lines"><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> computes arc sine (<span class="texhtml" style="white-space: nowrap;">arcsin(x)</span>) <br /> <span class="t-mark">(function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:c/numeric/math/dsc_asin&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="atan.html" title="c/numeric/math/atan"> <span class="t-lines"><span>atan</span><span>atanf</span><span>atanl</span></span></a></div><div><span class="t-lines"><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> computes arc tangent (<span class="texhtml" style="white-space: nowrap;">arctan(x)</span>) <br /> <span class="t-mark">(function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:c/numeric/math/dsc_atan&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="atan2.html" title="c/numeric/math/atan2"> <span class="t-lines"><span>atan2</span><span>atan2f</span><span>atan2l</span></span></a></div><div><span class="t-lines"><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> computes arc tangent, using signs to determine quadrants <br /> <span class="t-mark">(function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:c/numeric/math/dsc_atan2&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="cos.html" title="c/numeric/math/cos"> <span class="t-lines"><span>cos</span><span>cosf</span><span>cosl</span></span></a></div><div><span class="t-lines"><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> computes cosine (<span class="texhtml" style="white-space: nowrap;">cos(x)</span>) <br /> <span class="t-mark">(function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:c/numeric/math/dsc_cos&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="../complex/cacos.html" title="c/numeric/complex/cacos"> <span class="t-lines"><span>cacos</span><span>cacosf</span><span>cacosl</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> computes the complex arc cosine <br /> <span class="t-mark">(function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:c/numeric/complex/dsc_cacos&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td colspan="2"> <div class="t-dsc-see"><span><a href="../../../cpp/numeric/math/acos.html" title="cpp/numeric/math/acos">C++ documentation</a></span> for <span class="t-dsc-see-tt"><span>acos</span></span></div>
</td></tr>
</table></div>
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