PROLOG<\/a> This manual page is part of the POSIX Programmer\u2019s Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.<\/p>\n feupdateenv \u2014 update floating-point environment<\/p>\n #include int feupdateenv(const fenv_t *envp<\/i>);<\/p>\n The functionality described on this reference page is aligned with the ISO\u00a0C standard. Any conflict between the requirements described here and the ISO\u00a0C standard is unintentional. This volume of POSIX.1-2017 defers to the ISO\u00a0C standard.<\/p>\n The feupdateenv<\/i>() function shall attempt to save the currently raised floating-point exceptions in its automatic storage, attempt to install the floating-point environment represented by the object pointed to by envp<\/i>, and then attempt to raise the saved floating-point exceptions. The argument envp<\/i> shall point to an object set by a call to feholdexcept<\/i>() or fegetenv<\/i>(), or equal a floating-point environment macro.<\/p>\n The feupdateenv<\/i>() function shall return a zero value if and only if all the required actions were successfully carried out.<\/p>\n No errors are defined.<\/p>\n The following sections are informative.<\/i><\/p>\n The following example shows sample code to hide spurious underflow floating-point exceptions:<\/p>\n #include None.<\/p>\n None.<\/p>\n None.<\/p>\n fegetenv<\/i>(), feholdexcept<\/i>()<\/p>\n
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double f(double x)
{
#pragma STDC FENV_ACCESS ON
double result;
fenv_t save_env;
feholdexcept(&save_env);
\/\/ compute result
if (\/* test spurious underflow *\/)
feclearexcept(FE_UNDERFLOW);
feupdateenv(&save_env);
return result;
}<\/p>\nAPPLICATION USAGE <\/a> <\/h2>\n
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