getcontext, setcontext -- get and set user thread context
Standard C Library (libc, -lc)
setcontext(const ucontext_t *ucp);
The getcontext() function saves the current thread's execution context in
the structure pointed to by ucp. This saved context may then later be
restored by calling setcontext().
The setcontext() function makes a previously saved thread context the
current thread context, i.e., the current context is lost and
setcontext() does not return. Instead, execution continues in the context
specified by ucp, which must have been previously initialized by a
call to setcontext(), makecontext(3), or by being passed as an argument
to a signal handler (see sigaction(2)).
If ucp was initialized by getcontext(), then execution continues as if
the original getcontext() call had just returned (again).
If ucp was initialized by makecontext(3), execution continues with the
invocation of the function specified to makecontext(3). When that function
returns, ucp->uc_link determines what happens next: if ucp->uc_link
is NULL, the process exits; otherwise, setcontext(ucp->uc_link) is
If ucp was initialized by the invocation of a signal handler, execution
continues at the point the thread was interrupted by the signal.
If successful, getcontext() returns zero and setcontext() does not
return; otherwise -1 is returned.
No errors are defined for getcontext() or setcontext().
sigaction(2), sigaltstack(2), makecontext(3), ucontext(3)
FreeBSD 5.2.1 September 10, 2002 FreeBSD 5.2.1 [ Back ]