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diff --git a/devdocs/c/numeric%2Fmath%2Ffpclassify.html b/devdocs/c/numeric%2Fmath%2Ffpclassify.html new file mode 100644 index 00000000..0014938b --- /dev/null +++ b/devdocs/c/numeric%2Fmath%2Ffpclassify.html @@ -0,0 +1,52 @@ + <h1 id="firstHeading" class="firstHeading">fpclassify</h1> <table class="t-dcl-begin"> <tr class="t-dsc-header"> <th> Defined in header <code><math.h></code> </th> <th> </th> <th> </th> </tr> <tr class="t-dcl t-since-c99"> <td> <pre data-language="c">#define fpclassify(arg) /* implementation defined */</pre> +</td> <td class="t-dcl-nopad"> </td> <td> <span class="t-mark-rev t-since-c99">(since C99)</span> </td> </tr> </table> <p>Categorizes floating point value <code>arg</code> into the following categories: zero, subnormal, normal, infinite, NAN, or implementation-defined category. The macro returns an integral value.</p> +<p><code><a href="../../types/limits/flt_eval_method" title="c/types/limits/FLT EVAL METHOD">FLT_EVAL_METHOD</a></code> is ignored: even if the argument is evaluated with more range and precision than its type, it is first converted to its semantic type, and the classification is based on that: a normal long double value might become subnormal when converted to double and zero when converted to float.</p> +<h3 id="Parameters"> Parameters</h3> <table class="t-par-begin"> <tr class="t-par"> <td> arg </td> <td> - </td> <td> floating point value </td> +</tr> +</table> <h3 id="Return_value"> Return value</h3> <p>One of <code><a href="fp_categories" title="c/numeric/math/FP categories">FP_INFINITE</a></code>, <code><a href="fp_categories" title="c/numeric/math/FP categories">FP_NAN</a></code>, <code><a href="fp_categories" title="c/numeric/math/FP categories">FP_NORMAL</a></code>, <code><a href="fp_categories" title="c/numeric/math/FP categories">FP_SUBNORMAL</a></code>, <code><a href="fp_categories" title="c/numeric/math/FP categories">FP_ZERO</a></code> or implementation-defined type, specifying the category of <code>arg</code>.</p> +<h3 id="Example"> Example</h3> <div class="t-example"> <div class="c source-c"><pre data-language="c">#include <stdio.h> +#include <math.h> +#include <float.h> + +const char *show_classification(double x) { + switch(fpclassify(x)) { + case FP_INFINITE: return "Inf"; + case FP_NAN: return "NaN"; + case FP_NORMAL: return "normal"; + case FP_SUBNORMAL: return "subnormal"; + case FP_ZERO: return "zero"; + default: return "unknown"; + } +} +int main(void) +{ + printf("1.0/0.0 is %s\n", show_classification(1/0.0)); + printf("0.0/0.0 is %s\n", show_classification(0.0/0.0)); + printf("DBL_MIN/2 is %s\n", show_classification(DBL_MIN/2)); + printf("-0.0 is %s\n", show_classification(-0.0)); + printf("1.0 is %s\n", show_classification(1.0)); +}</pre></div> <p>Output:</p> +<div class="text source-text"><pre data-language="c">1.0/0.0 is Inf +0.0/0.0 is NaN +DBL_MIN/2 is subnormal +-0.0 is zero +1.0 is normal</pre></div> </div> <h3 id="References"> References</h3> <ul> +<li> C11 standard (ISO/IEC 9899:2011): </li> +<ul><li> 7.12.3.1 The fpclassify macro (p: 235) </li></ul> +<li> C99 standard (ISO/IEC 9899:1999): </li> +<ul><li> 7.12.3.1 The fpclassify macro (p: 216) </li></ul> +</ul> <h3 id="See_also"> See also</h3> <table class="t-dsc-begin"> <tr class="t-dsc"> <td> <div><a href="isfinite" 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> </td> <td> checks if the given number has finite value <br> <span class="t-mark">(function macro)</span> </td> +</tr> <tr class="t-dsc"> <td> <div><a href="isinf" 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> </td> <td> checks if the given number is infinite <br> <span class="t-mark">(function macro)</span> </td> +</tr> <tr class="t-dsc"> <td> <div><a href="isnan" 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> </td> <td> checks if the given number is NaN <br> <span class="t-mark">(function macro)</span> </td> +</tr> <tr class="t-dsc"> <td> <div><a href="isnormal" 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> </td> <td> checks if the given number is normal <br> <span class="t-mark">(function macro)</span> </td> +</tr> <tr class="t-dsc"> <td colspan="2"> <span><a href="https://en.cppreference.com/w/cpp/numeric/math/fpclassify" title="cpp/numeric/math/fpclassify">C++ documentation</a></span> for <code>fpclassify</code> </td> +</tr> </table> <div class="_attribution"> + <p class="_attribution-p"> + © cppreference.com<br>Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.<br> + <a href="https://en.cppreference.com/w/c/numeric/math/fpclassify" class="_attribution-link">https://en.cppreference.com/w/c/numeric/math/fpclassify</a> + </p> +</div> |