Name
setjmp, sigsetjmp — save stack context for nonlocal goto
Synopsis
#include <setjmp.h>
int setjmp( |
jmp_buf env); |
int sigsetjmp( |
sigjmp_buf env, |
int savesigs); |
![[Note]](../stylesheet/note.png) |
Note | ||||
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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, and only if,
savesigs is nonzero,
the process's current signal mask 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) or siglongjmp(3) using the
saved context.
NOTES
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.
COLOPHON
This page is part of release 3.24 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/.
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Written by Michael Haardt, Fri Nov 25 14:51:42 MET 1994 This is free documentation; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The GNU General Public License's references to "object code" and "executables" are to be interpreted as the output of any document formatting or typesetting system, including intermediate and printed output. This manual is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this manual; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA. Added sigsetjmp, Sun Mar 2 22:03:05 EST 1997, jrvvanzandt.mv.com Modifications, Sun Feb 26 14:39:45 1995, faithcs.unc.edu " |