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.
int sigsetjmp (sigjmp_buf state, int savesigs) ¶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 a
siglongjmp is later performed with this state.
void siglongjmp (sigjmp_buf state, int value) ¶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 the sigsetjmp call that set this state used a
nonzero savesigs flag, siglongjmp also restores the set of
blocked signals.