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XInternalConnectionNumbers(3)


NAME

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

SYNTAX

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

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

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

   void XProcessInternalConnection(Display *display, int fd);

   Status XInternalConnectionNumbers(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 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



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