fegetenv(3) BSD Library Functions Manual fegetenv(3)
NAME
fegetenv, feholdexcept, fesetenv, feupdateenv -- functions providing
access to the floating-point environment.
SYNOPSIS
#include <fenv.h>
int
fegetenv(fenv_t *envp);
int
feholdexcept(fenvt_t *envp);
int
fesetenv(fenv_t *envp);
int
feupdateenv(fenv_t *envp);
DESCRIPTION
These functions provide the means to manage the entire floating-point
environment--including both status flags and control modes--as a single
entity.
The fegetenv() function attempts to store the current floating-point
environment in the object pointed to by envp. It returns zero if the
environment was successfully stored, and a nonzero value otherwise.
The feholdexcept() function saves the current floating-point environment
in the object pointed to by envp, clears the floating-point status flags,
and then installs a "non-stop" mode, if available, under which no traps
are taken for floating-point exceptions (as is the case in default
IEEE-754 floating-point execution). It returns zero if and only if such
a mode was successfully installed.
The fesetenv() function attempts to establish the floating-point environ-
ment represented by the object pointed to by envp. This object shall
have been set by a call to fegetenv() or feholdexcept(), or be equal to a
floating-point environment macro defined in <fenv.h>. Note that this
function merely installs the floating-point status flags represented by
its argument, and does not raise the corresponding floating-point excep-
tions. It returns zero if and only if the environment pointed to by envp
was successfully installed.
The feupdateenv() function attempts to save the currently raised float-
ing-point flags, install the floating-point environment represented by
*envp, and then raise the floating-point exceptions corresponding to the
saved flags. The object pointed to by envp shall have been set by a call
to fegetenv() or feholdexcept(), or be equal to a floating-point environ-
ment macro defined in <fenv.h>. It returns zero if and only if all of
the specified actions were successfully carried out.
SEE ALSO
fenv(3), feclearexcept(3), fegetexceptflag(3), fegetround(3),
feraiseexcept(3), fesetexceptflag(3), fesetround(3), feraiseexcept(3)
STANDARDS
These functions conform to ISO/IEC 9899:TC3.
BSD May 9, 2011 BSD
Mac OS X 10.8 - Generated Mon Aug 27 16:42:47 CDT 2012