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 inter-
       rupts 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  siglongjmp()
       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)