DragonFly On-Line Manual Pages
FEENABLEEXCEPT(3) DragonFly Library Functions Manual FEENABLEEXCEPT(3)
feenableexcept, fedisableexcept, fegetexcept -- floating-point exception
Math Library (libm, -lm)
#pragma STDC FENV_ACCESS ON
The feenableexcept() and fedisableexcept() functions unmask and mask
(respectively) exceptions specified in excepts. The fegetexcept() func-
tion returns the current exception mask. All exceptions are masked by
Floating-point operations that produce unmasked exceptions will trap, and
a SIGFPE will be delivered to the process. By installing a signal han-
dler 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
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 infor-
mation about the exception-causing instruction, or to determine whether
that instruction should be reexecuted after returning from the handler.
DragonFly 3.9 March 16, 2005 DragonFly 3.9