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] Note
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
sigsetjmp():
_POSIX_C_SOURCE || _XOPEN_SOURCE

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.

CONFORMING TO

C89, C99, and POSIX.1-2001 specify setjmp(). POSIX.1-2001 specifies sigsetjmp().

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.

SEE ALSO

longjmp(3), siglongjmp(3)

COLOPHON

This page is part of release 2.79 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/.


  Written by Michael Haardt, Fri Nov 25 14:51:42 MET 1994

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Added sigsetjmp, Sun Mar  2 22:03:05 EST 1997, jrvvanzandt.mv.com
Modifications, Sun Feb 26 14:39:45 1995, faithcs.unc.edu
"