NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | CONFORMING TO | NOTES | SEE ALSO | COLOPHON
SETJMP(3) Linux Programmer's Manual SETJMP(3)
setjmp, sigsetjmp - save stack context for non-local goto
#include <setjmp.h>
int setjmp(jmp_buf env);
int sigsetjmp(sigjmp_buf env, int savesigs);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
setjmp(): see NOTES.
sigsetjmp(): _POSIX_C_SOURCE >= 1 || _XOPEN_SOURCE || _POSIX_C_SOURCE
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, and only if, savesigs is non-zero,
the process's current signal mask 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) or siglongjmp(3) using the saved context.
C89, C99, and POSIX.1-2001 specify setjmp(). POSIX.1-2001 specifies
sigsetjmp().
POSIX does not specify whether setjmp() will save the signal mask. In System
V it will not. In 4.3BSD it will, and there is a function _setjmp that will
not. By default, Linux/glibc follows the System V behavior, but the BSD
behavior is provided if the _BSD_SOURCE feature test macro is defined and none
of _POSIX_SOURCE, _POSIX_C_SOURCE, _XOPEN_SOURCE, _XOPEN_SOURCE_EXTENDED,
_GNU_SOURCE, or _SVID_SOURCE is defined.
If you want to portably save and restore signal masks, use sigsetjmp() and
siglongjmp().
setjmp() and sigsetjmp() make programs hard to understand and maintain. If
possible an alternative should be used.
longjmp(3), siglongjmp(3)
This page is part of release 3.23 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can be found
at http://www.kernel.org/doc/man-pages/.
2009-06-26 SETJMP(3)