manual: Clarify undefined behavior of feenableexcept (BZ 31019)

Explain undefined behavior of feenableexcept in a special case.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This commit is contained in:
Bruno Haible 2023-11-01 02:10:11 +01:00 committed by Adhemerval Zanella
parent 787282dede
commit e55599e028

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@ -1176,6 +1176,12 @@ enabled, the status of the other exceptions is not changed.
The function returns the previous enabled exceptions in case the
operation was successful, @code{-1} otherwise.
Note: Enabling traps for an exception for which the exception flag is
currently already set (@pxref{Status bit operations}) has unspecified
consequences: it may or may not trigger a trap immediately.
@c It triggers a trap immediately on powerpc*, at the next floating-
@c instruction on i386, and not at all on the other CPUs.
@end deftypefun
@deftypefun int fedisableexcept (int @var{excepts})