ucontext(5)                                                     ucontext(5)


   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 at least the following members:

               ucontextt  uclink
               sigsett    ucsigmask
               stackt     ucstack
               mcontextt  ucmcontext

         uclink is a pointer to the context that to be resumed when this
         context returns.  If uclink is equal to 0, then this context is the
         main context, and the process exits when this context returns.

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

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

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

   SEE ALSO
         getcontext(2), sigaction(2), sigprocmask(2), sigaltstack(2),
         makecontext(3C).




















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