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diff --git a/devdocs/c/numeric%2Ffenv%2Ffetestexcept.html b/devdocs/c/numeric%2Ffenv%2Ffetestexcept.html new file mode 100644 index 00000000..6e100461 --- /dev/null +++ b/devdocs/c/numeric%2Ffenv%2Ffetestexcept.html @@ -0,0 +1,60 @@ + <h1 id="firstHeading" class="firstHeading">fetestexcept</h1> <table class="t-dcl-begin"> <tr class="t-dsc-header"> <th> Defined in header <code><fenv.h></code> </th> <th> </th> <th> </th> </tr> <tr class="t-dcl t-since-c99"> <td> <pre data-language="c">int fetestexcept( int excepts );</pre> +</td> <td class="t-dcl-nopad"> </td> <td> <span class="t-mark-rev t-since-c99">(since C99)</span> </td> </tr> </table> <p>Determines which of the specified subset of the floating-point exceptions are currently set. The argument <code>excepts</code> is a bitwise OR of the <a href="fe_exceptions" title="c/numeric/fenv/FE exceptions">floating-point exception macros</a>.</p> +<h3 id="Parameters"> Parameters</h3> <table class="t-par-begin"> <tr class="t-par"> <td> excepts </td> <td> - </td> <td> bitmask listing the exception flags to test </td> +</tr> +</table> <h3 id="Return_value"> Return value</h3> <p>Bitwise OR of the floating-point exception macros that are both included in <code>excepts</code> and correspond to floating-point exceptions currently set.</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 <fenv.h> +#include <float.h> + +#pragma STDC FENV_ACCESS ON + +void show_fe_exceptions(void) +{ + printf("current exceptions raised: "); + if(fetestexcept(FE_DIVBYZERO)) printf(" FE_DIVBYZERO"); + if(fetestexcept(FE_INEXACT)) printf(" FE_INEXACT"); + if(fetestexcept(FE_INVALID)) printf(" FE_INVALID"); + if(fetestexcept(FE_OVERFLOW)) printf(" FE_OVERFLOW"); + if(fetestexcept(FE_UNDERFLOW)) printf(" FE_UNDERFLOW"); + if(fetestexcept(FE_ALL_EXCEPT)==0) printf(" none"); + printf("\n"); +} + +int main(void) +{ + /* Show default set of exception flags. */ + show_fe_exceptions(); + + /* Perform some computations which raise exceptions. */ + printf("1.0/0.0 = %f\n", 1.0/0.0); /* FE_DIVBYZERO */ + printf("1.0/10.0 = %f\n", 1.0/10.0); /* FE_INEXACT */ + printf("sqrt(-1) = %f\n", sqrt(-1)); /* FE_INVALID */ + printf("DBL_MAX*2.0 = %f\n", DBL_MAX*2.0); /* FE_INEXACT FE_OVERFLOW */ + printf("nextafter(DBL_MIN/pow(2.0,52),0.0) = %.1f\n", + nextafter(DBL_MIN/pow(2.0,52),0.0)); /* FE_INEXACT FE_UNDERFLOW */ + show_fe_exceptions(); + + return 0; +}</pre></div> <p>Output:</p> +<div class="text source-text"><pre data-language="c">current exceptions raised: none +1.0/0.0 = inf +1.0/10.0 = 0.100000 +sqrt(-1) = -nan +DBL_MAX*2.0 = inf +nextafter(DBL_MIN/pow(2.0,52),0.0) = 0.0 +current exceptions raised: FE_DIVBYZERO FE_INEXACT FE_INVALID FE_OVERFLOW FE_UNDERFLOW</pre></div> </div> <h3 id="References"> References</h3> <ul> +<li> C11 standard (ISO/IEC 9899:2011): </li> +<ul><li> 7.6.2.5 The fetestexcept function (p: 211-212) </li></ul> +<li> C99 standard (ISO/IEC 9899:1999): </li> +<ul><li> 7.6.2.5 The fetestexcept function (p: 192-193) </li></ul> +</ul> <h3 id="See_also"> See also</h3> <table class="t-dsc-begin"> <tr class="t-dsc"> <td> <div><a href="feclearexcept" title="c/numeric/fenv/feclearexcept"> <span class="t-lines"><span>feclearexcept</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> clears the specified floating-point status flags <br> <span class="t-mark">(function)</span> </td> +</tr> <tr class="t-dsc"> <td colspan="2"> <span><a href="https://en.cppreference.com/w/cpp/numeric/fenv/fetestexcept" title="cpp/numeric/fenv/fetestexcept">C++ documentation</a></span> for <code>fetestexcept</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/fenv/fetestexcept" class="_attribution-link">https://en.cppreference.com/w/c/numeric/fenv/fetestexcept</a> + </p> +</div> |