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SETJMP(3)                  Linux Programmer's Manual                 SETJMP(3)



NAME
       setjmp, sigsetjmp - save stack context for non-local goto

SYNOPSIS
       #include <&lt;setjmp.h>&gt;

       int setjmp(jmp_buf env);

       int sigsetjmp(sigjmp_buf env, int savesigs);

   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 inter-
       rupts 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  sig-
       longjmp(3) is later performed with this env.

RETURN VALUE
       setjmp()  and  sigsetjmp() return 0 if returning directly, and non-zero
       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 3.05 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/.



                                  2007-07-26                         SETJMP(3)