feholdexcept

feholdexcept

Install a non-trapping floating point environment

Portability: C99

SYNOPSIS
DESCRIPTION
RETURN VALUE
CAUTIONS
RELATED FUNCTIONS
SEE ALSO

SYNOPSIS

   #include <fenv.h>

   int feholdexcept(fenv_t *envp);

DESCRIPTION

feholdexcept is used to save the current floating-point environment and establish a new environment in which no floating-point exceptions are indicated, and in which trapping is not enabled. The existing floating-point environment is stored in the location addressed by the ENVP argument. The floating-point environment includes the exception bits, the rounding mode, and the definition of the exceptions for which trapping is enabled.

RETURN VALUE

feholdexcept returns zero if it was successful, or a non-zero value if it was unable to establish a non-trapping environment.

CAUTIONS

feholdexcept returns -1 when called from a function whose default floating-point format is hexadecimal, that is, one compiled without the bfp option.

A program which calls feholdexcept must use the standard FENV_ACCESS pragma in an enclosing scope, or the effects are unpredictable.

RELATED FUNCTIONS

fegetenv, fesetenv, feupdateenv

SEE ALSO

"Mathematical Functions" in Chapter 2, "Function Categories"

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