NAME
feupdateenv - update floating-point environment
SYNOPSIS
#include <fenv.h>
int feupdateenv(const fenv_t *envp);
DESCRIPTION
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() , the Base Definitions volume of
IEEE Std 1003.1-2001, <fenv.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online
at http://www.opengroup.org/unix/online.html .