NAME

ucontext − user context

SYNOPSIS

#include <ucontext.h>

DESCRIPTION

The ucontext structure defines the context of a thread of control within an executing process. 

This structure includes the following members:

sigset_t    uc_sigmask
stack_t     uc_stack
mcontext_t  uc_mcontext

uc_sigmask defines the set of signals that are blocked when this context is active [see sigprocmask(2)]. 

uc_stack defines the stack used by this context [see sigaltstack(2)]. 

uc_mcontext contains the saved set of machine registers and any implementation specific context data.  Portable applications should not modify or access uc_mcontext. 

The ucontext structure, type ucontext_t is available to signal handlers when the SA_SIGINFO is used during the call to sigaction(2) that defines the handler. 

SEE ALSO

sigaction(2), sigprocmask(2), sigaltstack(2), signal(5). 

WARNINGS

Attempts to modify the context from within a signal handler are likely to cause unpredictable and undesirable results. 

CX/UX Programmer’s Reference Manual