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UCONTEXT(2) NetBSD System Calls Manual UCONTEXT(2)
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Maintained for NetBSD
by Kimmo Suominen.
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ucontext -- user context
ucontext_t is a structure type which is used to describe the context of a
thread of control within the execution of a process.
ucontext_t includes the following members:
ucontext_t * uc_link
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
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-
_exit(2), getcontext(2), setcontext(2), sigaltstack(2), sigprocmask(2),
The ucontext_t type conforms to X/Open System Interfaces and Headers
Issue 5 (``XSH5'').
The makecontext() and swapcontext() functions first appeared in AT&T
System V.4 UNIX.
NetBSD 5.0 June 13, 2001 NetBSD 5.0