
NAME
	  setjmp, longjmp - non-local goto
SYNTAX
	  #include <setjmp.h>
	  int setjmp (env)
	  jmp_buf env;
	  void longjmp (env, val)
	  jmp_buf env;
	  int val;
DESCRIPTION
	  These	functions are useful for dealing with errors and
	  interrupts encountered in a low-level	subroutine of a
	  program.
	  Setjmp saves its stack environment in	env (whose type,
	  jmp_buf, is defined in the <setjmp.h>	header file) for later
	  use by longjmp.  It returns the value	0.
	  Longjmp restores the environment saved by the	last call of
	  setjmp with the corresponding	env argument.  After longjmp
	  is completed,	program	execution continues as if the
	  corresponding	call of	setjmp (which must not itself have
	  returned in the interim) had just returned the value val.
	  Longjmp cannot cause setjmp to return	the value 0.  If
	  longjmp is invoked with a second argument of 0, setjmp will
	  return 1.  All accessible data had values as of the time
	  longjmp was called.
SEE ALSO
	  signal(2).
     WARNING
	  If longjmp is	called even though env was never primed	by a
	  call to setjmp, or when the last such	call was in a function
	  which	has since returned, absolute chaos is guaranteed.
				  
 
