setjmp, sigsetjmp — save stack context for non-local goto
#include <setjmp.h>
int
setjmp( |
jmp_buf | env) ; |
int
sigsetjmp( |
sigjmp_buf | env, |
int | savesigs) ; |
setjmp
() and longjmp(3) are useful for
dealing with errors and interrupts encountered in a low-level
subroutine of a program. setjmp
() saves the stack
context/environment in env
for later use by longjmp(3). The stack
context will be invalidated if the function which called
setjmp
() returns.
sigsetjmp
() is similar to
setjmp
(). If savesigs
is non-zero, the set
of blocked signals is saved in env
and will be restored if a
siglongjmp(3) is later
performed with this env
.
setjmp
() and sigsetjmp
() return 0 if returning directly,
and non-zero when returning from longjmp(3) using the saved
context.
POSIX does not specify whether setjmp
() will save the signal context. (In
System V it will not. In 4.3BSD it will, and there is a
function _setjmp
that will not.) If you want to save signal masks, use
sigsetjmp
().
setjmp
() and sigsetjmp
() make programs hard to
understand and maintain. If possible an alternative should be
used.
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