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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