NAME
feraiseexcept —
raise floating-point exception
SYNOPSIS
#include
<fenv.h>
int feraiseexcept(int excepts);
DESCRIPTION
[CX] 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.1-2024 defers to the ISO C standard.
The feraiseexcept () function
shall attempt to raise the supported floating-point exceptions represented
by the excepts argument. The order in which these
floating-point exceptions are raised is unspecified,
[MX] except that if
the excepts argument represents IEC 60559 valid coincident
floating-point exceptions for atomic operations (namely overflow and
inexact, or underflow and inexact), then overflow or underflow shall be
raised before inexact. Whether the feraiseexcept ()
function additionally raises the inexact floating-point exception whenever
it raises the overflow or underflow floating-point exception is
implementation-defined.
RETURN VALUE
If the argument is zero or if all the specified exceptions were
successfully raised, feraiseexcept () shall return
zero. Otherwise, it shall return a non-zero value.
ERRORS
No errors are defined.
EXAMPLES
None.
APPLICATION USAGE
The effect is intended to be similar to that of floating-point exceptions raised by arithmetic operations. Hence, enabled traps for floating-point exceptions raised by this function are taken.
RATIONALE
Raising overflow or underflow is allowed to also raise inexact because on some architectures the only practical way to raise an exception is to execute an instruction that has the exception as a side-effect. The function is not restricted to accept only valid coincident expressions for atomic operations, so the function can be used to raise exceptions accrued over several operations.
FUTURE DIRECTIONS
None.
SEE ALSO
feclearexcept(3), fegetexceptflag(3), fetestexcept(3)
XBD <fenv.h>
CHANGE HISTORY
First released in Issue 6. Derived from the ISO/IEC 9899:1999 (“ISO C99”) standard.
ISO/IEC 9899:1999 (“ISO C99”) standard, Technical Corrigendum 1 is incorporated.
Issue 7
POSIX.1-2008, Technical Corrigendum 2, XSH/TC2-2008/0111 [543] is applied.