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LONGJMP(3)		       Library functions		    LONGJMP(3)

NAME
       longjmp, siglongjmp - non-local jump to a saved stack context

SYNOPSIS
       #include <setjmp.h>

       void longjmp(jmp_buf env, int val);
       void siglongjmp(sigjmp_buf env, int val);

DESCRIPTION
       longjmp()  and  setjmp()	 are useful for dealing with errors and inter-
       rupts encountered in a low-level subroutine of  a  program.   longjmp()
       restores	 the  environment  saved by the last call of setjmp() with the
       corresponding env argument.  After longjmp() is completed, program exe-
       cution  continues  as  if  the  corresponding call of setjmp() had just
       returned the value val.	longjmp() cannot cause 0 to be	returned.   If
       longjmp	is  invoked  with  a  second argument of 0, 1 will be returned
       instead.

       siglongjmp() is similar to longjmp() except for the  type  of  its  env
       argument.   If  the  sigsetjmp() call that set this env used a non-zero
       savesigs flag, siglongjmp() also restores the set of blocked signals.

RETURN VALUE
       These functions never return.

CONFORMING TO
       POSIX.1-2001.

NOTES
       POSIX does not specify whether longjmp() will restore the  signal  con-
       text.   If you want to save and restore signal masks, use siglongjmp().

       longjmp() and siglongjmp() make programs hard to understand  and	 main-
       tain.  If possible an alternative should be used.

SEE ALSO
       setjmp(3), sigsetjmp(3)

				  1997-03-02			    LONGJMP(3)