getcontext(3) BSD Library Functions Manual getcontext(3)
NAME
getcontext, setcontext -- get and set user thread context
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <ucontext.h>
int
getcontext(ucontext_t *ucp);
int
setcontext(const ucontext_t *ucp);
DESCRIPTION
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 con-
text specified by ucp, which must have been previously initialized by a
call to getcontext(), 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 func-
tion returns, ucp->uc_link determines what happens next: if ucp->uc_link
is NULL, the process exits; otherwise, setcontext(ucp->uc_link) is
implicitly invoked.
If ucp was initialized by the invocation of a signal handler, execution
continues at the point the thread was interrupted by the signal.
RETURN VALUES
If successful, getcontext() returns zero and setcontext() does not
return; otherwise -1 is returned.
ERRORS
No errors are defined for getcontext() or setcontext().
SEE ALSO
sigaction(2), sigaltstack(2), makecontext(3), ucontext(3)
BSD September 10, 2002 BSD
Mac OS X 10.8 - Generated Mon Aug 27 18:44:31 CDT 2012