In BSD Unix systems, setjmp
and longjmp
also save and
restore the set of blocked signals; see Blocking Signals. However,
the POSIX.1 standard requires setjmp
and longjmp
not to
change the set of blocked signals, and provides an additional pair of
functions (sigsetjmp
and siglongjmp
) to get the BSD
behavior.
The behavior of setjmp
and longjmp
in the GNU C Library is
controlled by feature test macros; see Feature Test Macros. The
default in the GNU C Library is the POSIX.1 behavior rather than the BSD
behavior.
The facilities in this section are declared in the header file setjmp.h.
This is similar to
jmp_buf
, except that it can also store state information about the set of blocked signals.
Preliminary: | MT-Safe | AS-Unsafe lock/hurd | AC-Unsafe lock/hurd | See POSIX Safety Concepts.
This is similar to
setjmp
. If savesigs is nonzero, the set of blocked signals is saved in state and will be restored if asiglongjmp
is later performed with this state.
Preliminary: | MT-Safe | AS-Unsafe plugin corrupt lock/hurd | AC-Unsafe corrupt lock/hurd | See POSIX Safety Concepts.
This is similar to
longjmp
except for the type of its state argument. If thesigsetjmp
call that set this state used a nonzero savesigs flag,siglongjmp
also restores the set of blocked signals.