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| <h2 class="chapter">1 Mathematical Functions (<samp><span class="file">math.h</span></samp>)</h2> |
| |
| <p>This chapter groups a wide variety of mathematical functions. The |
| corresponding definitions and declarations are in <samp><span class="file">math.h</span></samp>. |
| Two definitions from <samp><span class="file">math.h</span></samp> are of particular interest. |
| |
| <ol type=1 start=1> |
| <li>The representation of infinity as a <code>double</code> is defined as |
| <code>HUGE_VAL</code>; this number is returned on overflow by many functions. |
| The macro <code>HUGE_VALF</code> is a corresponding value for <code>float</code>. |
| |
| <li>The structure <code>exception</code> is used when you write customized error |
| handlers for the mathematical functions. You can customize error |
| handling for most of these functions by defining your own version of |
| <code>matherr</code>; see the section on <code>matherr</code> for details. |
| </ol> |
| |
| <p><a name="index-system-calls-1"></a><a name="index-support-subroutines-2"></a><a name="index-stubs-3"></a><a name="index-OS-stubs-4"></a>Since the error handling code calls <code>fputs</code>, the mathematical |
| subroutines require stubs or minimal implementations for the same list |
| of OS subroutines as <code>fputs</code>: <code>close</code>, <code>fstat</code>, |
| <code>isatty</code>, <code>lseek</code>, <code>read</code>, <code>sbrk</code>, <code>write</code>. |
| See <a href="../libc/syscalls.html#syscalls">System Calls</a>, |
| for a discussion and for sample minimal implementations of these support |
| subroutines. |
| |
| <p>Alternative declarations of the mathematical functions, which exploit |
| specific machine capabilities to operate faster—but generally have |
| less error checking and may reflect additional limitations on some |
| machines—are available when you include <samp><span class="file">fastmath.h</span></samp> instead of |
| <samp><span class="file">math.h</span></samp>. |
| |
| <ul class="menu"> |
| <li><a accesskey="1" href="version.html#version">version</a>: Version of library |
| <li><a accesskey="2" href="acos.html#acos">acos</a>: Arccosine |
| <li><a accesskey="3" href="acosh.html#acosh">acosh</a>: Inverse hyperbolic cosine |
| <li><a accesskey="4" href="asin.html#asin">asin</a>: Arcsine |
| <li><a accesskey="5" href="asinh.html#asinh">asinh</a>: Inverse hyperbolic sine |
| <li><a accesskey="6" href="atan.html#atan">atan</a>: Arctangent |
| <li><a accesskey="7" href="atan2.html#atan2">atan2</a>: Arctangent of y/x |
| <li><a accesskey="8" href="atanh.html#atanh">atanh</a>: Inverse hyperbolic tangent |
| <li><a accesskey="9" href="jN.html#jN">jN</a>: Bessel functions (jN, yN) |
| <li><a href="cbrt.html#cbrt">cbrt</a>: Cube root |
| <li><a href="copysign.html#copysign">copysign</a>: Sign of Y, magnitude of X |
| <li><a href="cosh.html#cosh">cosh</a>: Hyperbolic cosine |
| <li><a href="erf.html#erf">erf</a>: Error function (erf, erfc) |
| <li><a href="exp.html#exp">exp</a>: Exponential, base e |
| <li><a href="exp2.html#exp2">exp2</a>: Exponential, base 2 |
| <li><a href="expm1.html#expm1">expm1</a>: Exponential, base e, of x - 1 |
| <li><a href="fabs.html#fabs">fabs</a>: Absolute value (magnitude) |
| <li><a href="fdim.html#fdim">fdim</a>: Positive difference |
| <li><a href="floor.html#floor">floor</a>: Floor and ceiling (floor, ceil) |
| <li><a href="fma.html#fma">fma</a>: Floating multiply add |
| <li><a href="fmax.html#fmax">fmax</a>: Maximum |
| <li><a href="fmin.html#fmin">fmin</a>: Minimum |
| <li><a href="fmod.html#fmod">fmod</a>: Floating-point remainder (modulo) |
| <li><a href="fpclassify.html#fpclassify">fpclassify</a>: Floating-point classification macro |
| <li><a href="frexp.html#frexp">frexp</a>: Split floating-point number |
| <li><a href="gamma.html#gamma">gamma</a>: Logarithmic gamma function |
| <li><a href="hypot.html#hypot">hypot</a>: Distance from origin |
| <li><a href="ilogb.html#ilogb">ilogb</a>: Get exponent |
| <li><a href="infinity.html#infinity">infinity</a>: Floating infinity |
| <li><a href="isgreater.html#isgreater">isgreater</a>: Comparison macros |
| <li><a href="ldexp.html#ldexp">ldexp</a>: Scale by a power of 2 |
| <li><a href="log.html#log">log</a>: Natural logarithms |
| <li><a href="log10.html#log10">log10</a>: Base 10 logarithms |
| <li><a href="log1p.html#log1p">log1p</a>: Log of 1 + X |
| <li><a href="log2.html#log2">log2</a>: Base 2 logarithms |
| <li><a href="logb.html#logb">logb</a>: Get exponent |
| <li><a href="lrint.html#lrint">lrint</a>: Round to integer |
| <li><a href="lround.html#lround">lround</a>: Round to integer, away from zero (lround, llround) |
| <li><a href="matherr.html#matherr">matherr</a>: Modifiable math error handler |
| <li><a href="modf.html#modf">modf</a>: Split fractional and integer parts |
| <li><a href="nan.html#nan">nan</a>: Floating Not a Number |
| <li><a href="nearbyint.html#nearbyint">nearbyint</a>: Round to integer |
| <li><a href="nextafter.html#nextafter">nextafter</a>: Get next representable number |
| <li><a href="pow.html#pow">pow</a>: X to the power Y |
| <li><a href="remainder.html#remainder">remainder</a>: remainder of X divided by Y |
| <li><a href="remquo.html#remquo">remquo</a>: Remainder and part of quotient |
| <li><a href="rint.html#rint">rint</a>: Round to integer |
| <li><a href="round.html#round">round</a>: Round to integer, away from zero |
| <li><a href="scalbn.html#scalbn">scalbn</a>: Scale by a power of FLT_RADIX (2) |
| <li><a href="signbit.html#signbit">signbit</a>: Does floating-point number have negative sign? |
| <li><a href="sin.html#sin">sin</a>: Sine or cosine (sin, cos) |
| <li><a href="sinh.html#sinh">sinh</a>: Hyperbolic sine |
| <li><a href="sqrt.html#sqrt">sqrt</a>: Positive square root |
| <li><a href="tan.html#tan">tan</a>: Tangent |
| <li><a href="tanh.html#tanh">tanh</a>: Hyperbolic tangent |
| <li><a href="trunc.html#trunc">trunc</a>: Round to integer, towards zero |
| </ul> |
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