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