точечная среда (point environment)
Пролог (Prolog)
This manual page is part of the POSIX Programmer's 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.
Имя (Name)
feupdateenv — update floating-point environment
Синопсис (Synopsis)
#include <fenv.h>
int feupdateenv(const fenv_t *envp);
Описание (Description)
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.1‐2017 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.
Возвращаемое значение (Return value)
The feupdateenv() function shall return a zero value if and only
if all the required actions were successfully carried out.
Ошибки (Error)
No errors are defined.
The following sections are informative.
Примеры (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;
}
Использование в приложениях (Application usage)
None.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
fegetenv(3p), feholdexcept(3p)
The Base Definitions volume of POSIX.1‐2017, fenv.h(0p)
