XAddConnectionWatch(3X11)

     NAME
          XAddConnectionWatch, XRemoveConnectionWatch,
          XProcessInternalConnection, XInternalConnectionNumbers -
          handle Xlib internal connections

     SYNTAX
          typedef void (*XConnectionWatchProc)(display, client_data,
          fd, opening, watch_data)
                Display *display;
                XPointer client_data;
                int fd;
                Bool opening;
                XPointer *watch_data;

          Status XAddConnectionWatch(display, procedure, client_data)
                Display *display;
                XWatchProc procedure;
                XPointer client_data;

          Status XRemoveConnectionWatch(display, procedure,
          client_data)
                Display *display;
                XWatchProc procedure;
                XPointer client_data;

          void XProcessInternalConnection(display, fd)
                Display *display;
                int fd;

          void XProcessInternalConnection(display, fd)
                Display *display;
                int fd;

          Status XInternalConnectionNumbers(display, fd_return,
          count_return)
                Display *display;
                int **fd_return;
                int *count_return;

     ARGUMENTS
          client_data
                    Specifies the additional client data.

          count_return
                    Returns the number of file descriptors.

          display   Specifies the connection to the X server.

          fd        Specifies the file descriptor.

          fd_return Returns the file descriptors.
          procedure Specifies the procedure to be called.

     DESCRIPTION
          The XAddConnectionWatch function registers a procedure to be
          called each time Xlib opens or closes an internal connection
          for the specified display.  The procedure is passed the
          display, the specified client_data, the file descriptor for
          the connection, a Boolean indicating whether the connection
          is being opened or closed, and a pointer to a location for
          private watch data.  If opening is True, the procedure can
          store a pointer to private data in the location pointed to
          by watch_data; when the procedure is later called for this
          same connection and opening is False, the location pointed
          to by watch_data will hold this same private data pointer.

          This function can be called at any time after a display is
          opened.  If internal connections already exist, the
          registered procedure will immediately be called for each of
          them, before XAddConnectionWatch returns.
          XAddConnectionWatch returns a nonzero status if the
          procedure is successfully registered; otherwise, it returns
          zero.

          The registered procedure should not call any Xlib functions.
          If the procedure directly or indirectly causes the state of
          internal connections or watch procedures to change, the
          result is not defined.  If Xlib has been initialized for
          threads, the procedure is called with the display locked and
          the result of a call by the procedure to any Xlib function
          that locks the display is not defined unless the executing
          thread has externally locked the display using XLockDisplay.

          The XRemoveConnectionWatch function removes a previously
          registered connection watch procedure.  The client_data must
          match the client_data used when the procedure was initially
          registered.


          The XProcessInternalConnection function processes input
          available on an internal connection.  This function should
          be called for an internal connection only after an operating
          system facility (for example, select or poll) has indicated
          that input is available; otherwise, the effect is not
          defined.

          The XProcessInternalConnection function processes input
          available on an internal connection.  This function should
          be called for an internal connection only after an operating
          system facility (for example, select or poll) has indicated
          that input is available; otherwise, the effect is not
          defined.
          The XInternalConnectionNumbers function returns a list of
          the file descriptors for all internal connections currently
          open for the specified display.  When the allocated list is
          no longer needed, free it by using XFree.  This functions
          returns a nonzero status if the list is successfully
          allocated; otherwise, it returns zero.

     SEE ALSO
          Xlib - C Language X Interface