The Open Group Base Specifications Issue 7
IEEE Std 1003.1-2008, 2016 Edition
Copyright © 2001-2016 The IEEE and The Open Group

#### NAME

> feupdateenv - update floating-point environment

#### SYNOPSIS

> ``#include <fenv.h>
> int feupdateenv(const fenv_t *`envp`);
> ``

#### DESCRIPTION

> [CX] The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1-2008 defers to the ISO C standard.

> The feupdateenv() 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, and then attempt to raise the saved floating-point exceptions. The argument envp shall point to an object set by a call to feholdexcept() or fegetenv(), or equal a floating-point environment macro.

#### RETURN VALUE

> The feupdateenv() function shall return a zero value if and only if all the required actions were successfully carried out.

#### ERRORS

> No errors are defined.

The following sections are informative.

#### EXAMPLES

> The following example shows sample code to hide spurious underflow floating-point exceptions:

>     #include <fenv.h>
>     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;
>     }

#### APPLICATION USAGE

> None.

#### RATIONALE

> None.

#### FUTURE DIRECTIONS

> None.

#### SEE ALSO

> fegetenv, feholdexcept

> XBD <fenv.h>

#### CHANGE HISTORY

> First released in Issue 6. Derived from the ISO/IEC 9899:1999 standard.

> ISO/IEC 9899:1999 standard, Technical Corrigendum 1 is incorporated.

End of informative text.

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