NAME
ucontext —
user context
SYNOPSIS
#include <ucontext.h>
DESCRIPTION
The
ucontext_t is a structure type which is used to
describe the context of a thread of control within the execution of a process.
A thread's context includes its stack, saved registers, and list of blocked
signals.
The
ucontext_t structure includes the following members:
ucontext_t *uc_link
sigset_t uc_sigmask
stack_t uc_stack
mcontext_t uc_mcontext
The
uc_link member points to the context that will be
resumed after the function specified when modifying a context using
makecontext(3) has
returned. If
uc_link is a
NULL
pointer, then the context is the main context, and the process will exit with
an exit status of 0 upon return.
The
uc_sigmask member is the set of signals that are
blocked when the context is activated. Further information can be found in
sigprocmask(2).
The
uc_stack member defines the stack used by the context.
Further information can be found in
sigaltstack(2).
The
uc_mcontext member defines the machine state
associated with the context; it may consist of general registers, floating
point registers and other machine-specific information. Its description is
beyond the scope of this manual page; portable applications should not access
this structure member.
SEE ALSO
_exit(2),
getcontext(2),
setcontext(2),
sigaltstack(2),
sigprocmask(2),
makecontext(3),
swapcontext(3)
STANDARDS
The
ucontext_t type conforms to
X/Open
System Interfaces and Headers Issue 5 (“XSH5”) and
IEEE Std 1003.1-2001 (“POSIX.1”). The
IEEE Std 1003.1-2008 (“POSIX.1”) revision
removed the
ucontext_t from the specification.