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FEENABLEEXCEPT(3)	    Library Functions Manual	     FEENABLEEXCEPT(3)

NAME
       feenableexcept,	fedisableexcept,  fegetexcept -- floating-point	excep-
       tion masking

LIBRARY
       Math Library (libm, -lm)

SYNOPSIS
       #include	<fenv.h>
       #pragma STDC FENV_ACCESS	ON

       int
       feenableexcept(int excepts);

       int
       fedisableexcept(int excepts);

       int
       fegetexcept(void);

DESCRIPTION
       The feenableexcept() and	fedisableexcept() functions  unmask  and  mask
       (respectively)  exceptions  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  immedi-
       ately  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.

RETURN VALUES
       The feenableexcept(), fedisableexcept(),	 and  fegetexcept()  functions
       return a	bitmap of the exceptions that were unmasked prior to the call.

SEE ALSO
       sigaction(2),	  feclearexcept(3),	 feholdexcept(3),     fenv(3),
       feupdateenv(3)

BUGS
       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 nontriv-
       ial  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.

FreeBSD	15.0			March 16, 2005		     FEENABLEEXCEPT(3)

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