SETJMP(3) SETJMP(3)
NAME
setjmp, longjmp, notejmp - non-local goto
SYNOPSIS
#include <u.h>
#include <libc.h>
int setjmp(jmp_buf env)
void longjmp(jmp_buf env, int val)
void notejmp(void *uregs, jmp_buf env, int val)
DESCRIPTION
These routines are useful for dealing with errors and inter-
rupts encountered in a low-level subroutine of a program.
Setjmp saves its stack environment in env for later use by
longjmp. It returns value 0.
Longjmp restores the environment saved by the last call of
setjmp. It then causes execution to continue as if the call
of setjmp had just returned with value val. The invoker of
setjmp must not itself have returned in the interim. All
accessible data have values as of the time longjmp was
called.
Notejmp is the same as longjmp except that it is to be
called from within a note handler (see notify(3)). The uregs
argument should be the first argument passed to the note
handler.
Setjmp and longjmp can also be used to switch stacks.
SOURCE
/usr/local/plan9/src/lib9/jmp.c
SEE ALSO
notify(3)
BUGS
Notejmp cannot recover from an address trap or bus error
(page fault) on the 680x0 architectures.
To avoid name conflicts with the underlying system, setjmp,
longjmp, notejmp, and jmp_buf are preprocessor macros
defined as p9setjmp, p9longjmp, p9notejmp, and p9jmp_buf;
see intro(3).
P9setjmp is implemented as a preprocessor macro that calls
Page 1 Plan 9 (printed 12/22/24)
SETJMP(3) SETJMP(3)
sigsetjmp (see Unix's setjmp(3)).
Page 2 Plan 9 (printed 12/22/24)