NAME
feholdexcept() — save floating-point environment
SYNOPSIS
#include <fenv.h>
int feholdexcept(fenv_t *envp);
DESCRIPTION
The
feholdexcept()
function saves the current floating-point environment in the object
pointed to by the argument
envp,
clears the exception flags, and disables all traps.
Use
feholdexcept()
with
feupdateenv()
to hide spurious exceptions.
Use it with
fesetenv()
to hide all exceptions.
The ISO/ANSI C committee has approved the
feholdexcept()
function for inclusion in the C9X draft standard.
To use this function, compile either with the default
-Ae
option or with the
-Aa
and
-D_HPUX_SOURCE
options. Make sure your program includes
<fenv.h>.
Link in the math library by specifying
-lm
on the compiler or linker command line.
For more information, see the
HP-UX Floating-Point Guide.
RETURN VALUE
The
feholdexcept()
function returns a zero value, indicating the successful disabling
of any traps.
ERRORS
No errors are defined.
EXAMPLE
Store the current floating-point environment in
holdenv,
hide spurious underflow exceptions, and continue on any exceptions
that occur until the call to
feupdateenv()
is encountered.
#include <fenv.h>
/*...*/
fenv_t holdenv;
feholdexcept(&holdenv);
/* perform operations */
if (/* test for spurious underflow */)
feclearexcept(FE_UNDERFLOW);
feupdateenv(&holdenv); /* raise accumulated exceptions */
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