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	 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)