UCONTEXT(2) BSD System Calls Manual UCONTEXT(2)NAMEucontext — 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 con‐
text; 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 struc‐
ture 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 specifi‐
cation.
BSD April 29, 2010 BSD
