FEENABLEEXCEPT(3) BSD Library Functions Manual FEENABLEEXCEPT(3)
feenableexcept, fedisableexcept, fegetexcept -- floating-point exception masking
Math Library (libm, -lm)
#pragma STDC FENV_ACCESS ON
The feenableexcept() and fedisableexcept() functions unmask and mask (respectively) excep-
tions specified in excepts. The fegetexcept() function returns the current exception mask.
All exceptions are masked by default.
Floating-point operations that produce unmasked exceptions will trap, and a SIGFPE will be
delivered to the process. By installing a signal handler for SIGFPE, applications can take
appropriate action immediately without testing the exception flags after every operation.
Note that the trap may not be immediate, but it should occur before the next floating-point
instruction is executed.
For all of these functions, the possible types of exceptions include those described in
fenv(3). Some architectures may define other types of floating-point exceptions.
The feenableexcept(), fedisableexcept(), and fegetexcept() functions return a bitmap of the
exceptions that were unmasked prior to the call.
sigaction(2), feclearexcept(3), feholdexcept(3), fenv(3), feupdateenv(3)
Functions in the standard library may trigger exceptions multiple times as a result of
intermediate computations; however, they generally do not trigger spurious exceptions.
No interface is provided to permit exceptions to be handled in nontrivial ways. There is no
uniform way for an exception handler to access information about the exception-causing
instruction, or to determine whether that instruction should be reexecuted after returning
from the handler.
BSD March 16, 2005 BSD