devdocs/c/numeric%2Ffenv%2Ffeexceptflag.html


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    <h1 id="firstHeading" class="firstHeading">fegetexceptflag, fesetexceptflag</h1>            <table class="t-dcl-begin"> <tr class="t-dsc-header"> <th> Defined in header <code>&lt;fenv.h&gt;</code> </th> <th> </th> <th> </th> </tr> <tr class="t-dcl t-since-c99"> <td> <pre data-language="c">int fegetexceptflag( fexcept_t* flagp, int excepts );</pre>
</td> <td> (1) </td> <td> <span class="t-mark-rev t-since-c99">(since C99)</span> </td> </tr> <tr class="t-dcl t-since-c99"> <td> <pre data-language="c">int fesetexceptflag( const fexcept_t* flagp, int excepts );</pre>
</td> <td> (2) </td> <td> <span class="t-mark-rev t-since-c99">(since C99)</span> </td> </tr>  </table> <p>1) Attempts to obtain the full contents of the floating-point exception flags that are listed in the bitmask argument <code>excepts</code>, which is a bitwise OR of the <a href="fe_exceptions" title="c/numeric/fenv/FE exceptions">floating-point exception macros</a>.</p>
<p>2) Attempts to copy the full contents of the floating-point exception flags that are listed in <code>excepts</code> from <code>flagp</code> into the floating-point environment. Does not raise any exceptions, only modifies the flags.</p>
<p>The full contents of a floating-point exception flag is not necessarily a boolean value indicating whether the exception is raised or cleared. For example, it may be a struct which includes the boolean status and the address of the code that triggered the exception. These functions obtain all such content and obtain/store it in <code>flagp</code> in implementation-defined format.</p>
<h3 id="Parameters"> Parameters</h3> <table class="t-par-begin"> <tr class="t-par"> <td> flagp </td> <td> - </td> <td> pointer to an <code>fexcept_t</code> object where the flags will be stored or read from </td>
</tr> <tr class="t-par"> <td> excepts </td> <td> - </td> <td> bitmask listing the exception flags to get/set </td>
</tr>
</table> <h3 id="Return_value"> Return value</h3> <p><code>0</code> on success, non-zero otherwise.</p>
<h3 id="Example"> Example</h3> <div class="t-example"> <div class="c source-c"><pre data-language="c">#include &lt;stdio.h&gt;
#include &lt;fenv.h&gt;
 
#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)
{
    fexcept_t excepts;
 
    /* Setup a "current" set of exception flags. */
    feraiseexcept(FE_INVALID);
    show_fe_exceptions();
 
    /* Save current exception flags. */
    fegetexceptflag(&amp;excepts,FE_ALL_EXCEPT);
 
    /* Temporarily raise two other exceptions. */
    feclearexcept(FE_ALL_EXCEPT);
    feraiseexcept(FE_OVERFLOW | FE_INEXACT);
    show_fe_exceptions();
 
    /* Restore previous exception flags. */
    fesetexceptflag(&amp;excepts,FE_ALL_EXCEPT);
    show_fe_exceptions();
 
    return 0;
}</pre></div> <p>Output:</p>
<div class="text source-text"><pre data-language="c">current exceptions raised: FE_INVALID
current exceptions raised: FE_INEXACT FE_OVERFLOW
current exceptions raised: FE_INVALID</pre></div> </div> <h3 id="References"> References</h3>  <ul>
<li> C11 standard (ISO/IEC 9899:2011): </li>
<ul>
<li> 7.6.2.2 The fegetexceptflag function (p: 210) </li>
<li> 7.6.2.4 The fesetexceptflag function (p: 211) </li>
</ul>
<li> C99 standard (ISO/IEC 9899:1999): </li>
<ul>
<li> 7.6.2.2 The fegetexceptflag function (p: 191) </li>
<li> 7.6.2.4 The fesetexceptflag function (p: 192) </li>
</ul>
</ul>        <h3 id="See_also"> See also</h3> <table class="t-dsc-begin"> <tr class="t-dsc"> <td colspan="2"> <span><a href="https://en.cppreference.com/w/cpp/numeric/fenv/feexceptflag" title="cpp/numeric/fenv/feexceptflag">C++ documentation</a></span> for <code>fegetexceptflag, fesetexceptflag</code> </td>
</tr> </table>           <div class="_attribution">
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