int
getcontext(
ucontext_t *ucp
)
int
setcontext(
const ucontext_t *ucp
)
)
function initializes the object pointed to by
ucp
to the current user context of the calling thread.
The user context defines a thread's execution environment and includes
the contents of its machine registers,
its signal mask,
and its current execution stack.
The
setcontext()
function restores the user context defined in the object pointed to by
ucp
as most recently initialized by a previous call to either
getcontext()
or
makecontext(3).
If successful, execution of the program resumes as defined in the
ucp
argument, and
setcontext()
will not return.
If
ucp
was initialized by the
getcontext()
function, program execution continues as if the corresponding invocation of
getcontext(
)
had just returned (successfully).
If
ucp
was initialized by the
makecontext(3)
function, program execution continues with the function (and function
arguments) passed to
makecontext(3).
)
returns 0 and
setcontext(
)
does not return.
Otherwise a value of -1 is returned and
errno
is set to indicate the error.
)
and
setcontext(
)
functions will fail if:
EFAULT
]
ucp
argument points to an invalid address.
The
setcontext()
function will fail if:
EINVAL
]
ucp
are invalid.
)
and
setcontext(
)
functions conform to
X/Open System Interfaces and Headers Issue 5 (``XSH5'') .
The
errno
indications are an extension to the standard.
)
and
setcontext(
)
functions first appeared in
AT&T
System V.4 UNIX
.