tttk_block_while(library call)               tttk_block_while(library call)




 NAME    [Toc]    [Back]
      tttk_block_while - block while a counter is greater than zero

 SYNOPSIS    [Toc]    [Back]
      #include <Tt/tttk.h>
      Tt_status tttk_block_while(
      XtAppContext app2run,
      const int *blocked,
      int ms_timeout);

 DESCRIPTION    [Toc]    [Back]
      The tttk_block_while function is used to process asynchronous events,
      such as ToolTalk messages or window system events, while waiting for a
      condition or timeout.

      If app2run is not zero, then an event loop is run for that application
      context, by repeatedly calling XtAppProcessEvent(3) with ms_timeout
      being effected using XtAppAddTimeOut(3). If app2run is zero, then the
      file descriptor (as returned by tt_fd(3)) of the default procid is
      polled (using the poll(2) function) and tttk_Xt_input_handler(3) is
      called whenever the file descriptor is active.

      If blocked is zero, then tttk_block_while runs until ms_timeout
      occurs.  If blocked is non-zero, then the loop is run until either
      ms_timeout occurs, or *blocked is less than 1.

      If ms_timeout is zero, tttk_block_while checks once for events,
      processes the first one, and then returns.  If ms_timeout is negative,
      no timeout is in effect.

 RETURN VALUE    [Toc]    [Back]
      Upon successful completion, the tttk_block_while function returns the
      status of the operation as one of the following Tt_status values:

      TT_OK     The operation completed successfully.

      TT_DESKTOP_ETIMEDOUT
                The timeout occurred within ms_timeout milliseconds, or
                ms_timeout was zero and no input was available.

      TT_DESKTOP_EINTR
                The app2run argument was zero, and poll(2) was interrupted
                by a signal.

      TT_DESKTOP_EAGAIN
                The app2run argument was zero, and poll(2) returned EAGAIN.

      If app2run is not zero and ms_timeout is negative, then
      tttk_block_while will only return when *blocked is less than 1, with
      TT_OK being returned.




                                    - 1 -       Formatted:  January 24, 2005






 tttk_block_while(library call)               tttk_block_while(library call)




      If app2run is not zero, ms_timeout is negative, and blocked is zero,
      then tttk_block_while behaves equivalent to XtAppMainLoop(3), and will
      never return.

 APPLICATION USAGE    [Toc]    [Back]
      If app2run is zero, then only messaging events for the default procid
      will be serviced.  Events for other procids will be blocked, as will
      window system events, so that the graphical user interface of the
      application will not update itself even, for example, after expose
      events.

      On the other hand, if the application passes its Xt context in as
      app2run, then window system events will continue to be handled, as
      will message activity for all procids for which an XtAppAddInput(3)
      has been done.  Since the window system event loop is fully
      operational in this case, the application should take care to disable
      any user interface controls that the user should not operate while the
      application is waiting for tttk_block_while to return.

 SEE ALSO    [Toc]    [Back]
      Tt/tttk.h - Tttttk(5), tttk_Xt_input_handler(3); poll(2),
      XtAppPending(3), XtAppAddTimeOut(3), XtAppNextEvent(3),
      XtDispatchEvent(3).


                                    - 2 -       Formatted:  January 24, 2005