Manual Pages for UNIX Operating System command usage for man getcontext

System Calls                                        getcontext(2)



NAME
     getcontext, setcontext - get and set current user context

SYNOPSIS
     #include 

     int getcontext(ucontext_t *ucp);


     int setcontext(const ucontext_t *ucp);


DESCRIPTION
     The getcontext() function initializes the structure  pointed
     to  by  ucp  to the current user context of the calling pro-
     cess.  The ucontext_t type that ucp points  to  defines  the
     user  context  and includes the contents of the calling pro-
     cess' machine registers, the signal mask,  and  the  current
     execution stack.


     The setcontext() function restores the user context  pointed
     to  by  ucp.   A  successful  call  to setcontext() does not
     return; program execution resumes at the point specified  by
     the  ucp  argument  passed to setcontext(). The ucp argument
     should be created either by a prior call to getcontext(), or
     by  being  passed as an argument to a signal handler. If the
     ucp argument was created with getcontext(),  program  execu-
     tion  continues as if the corresponding call of getcontext()
     had just returned.  If the ucp  argument  was  created  with
     makecontext(3C),  program execution continues with the func-
     tion passed to makecontext(3C). When that function  returns,
     the  process  continues  as  if after a call to setcontext()
     with the ucp argument that was input to makecontext(3C).  If
     the  ucp  argument  was  passed to a signal handler, program
     execution continues with the program  instruction  following
     the  instruction  interrupted by the signal.  If the uc_link
     member of the ucontext_t structure pointed  to  by  the  ucp
     argument  is  equal to 0, then this context is the main con-
     text, and the process will exit when this  context  returns.
     The  effects  of  passing  a  ucp argument obtained from any
     other source are unspecified.

RETURN VALUES
     On successful completion, setcontext() does not  return  and
     getcontext() returns 0. Otherwise, -1 is returned.

ERRORS
     No errors are defined.

USAGE




SunOS 5.11           Last change: 5 Feb 2001                    1






System Calls                                        getcontext(2)



     Portable  applications  should  not  modify  or  access  the
     uc_mcontext  member  of  ucontext_t.  A portable application
     cannot assume that context includes any process-wide  static
     data,  possibly including errno. Users manipulating contexts
     should take care to handle these explicitly when required.

ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|


SEE ALSO
     sigaction(2),        sigaltstack(2),         sigprocmask(2),
     bsd_signal(3C),  makecontext(3C),  ucontext.h(3HEAD), attri-
     butes(5), standards(5)
































SunOS 5.11           Last change: 5 Feb 2001                    2