Name
setjmp, sigsetjmp — save stack context for non-local goto
Synopsis
#include <setjmp.h>
int
setjmp( |
jmp_buf | env); |
int
sigsetjmp( |
sigjmp_buf | env, |
| int | savesigs); |
![[Note]](../stylesheet/note.png) |
Note | ||
|---|---|---|---|
|
DESCRIPTION
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 nonzero, the set of
blocked signals is saved in env and will be restored if a
siglongjmp(3) is later
performed with this env.
RETURN VALUE
setjmp() and sigsetjmp() return 0 if returning directly,
and nonzero when returning from longjmp(3) using the saved
context.
NOTES
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.