redhat man page for setjmp

SETJMP(3)							 Library functions							 SETJMP(3)

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);

DESCRIPTION
       setjmp()  and  longjmp()  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().  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 sig-
       longjmp() is later performed with this env.

RETURN VALUE
       setjmp() and sigsetjmp() return 0 if returning directly, and non-zero when returning from longjmp() using the saved context.

CONFORMING TO
       POSIX, ISO 9899 (C99)

NOTES
       POSIX does not specify whether setjmp will save the signal context. (In SYSV it will not. In BSD4.3  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)

								    1997-03-02								 SETJMP(3)