XOpenDisplay, XCloseDisplay - connect or disconnect to X
       server


SYNTAX

       Display *XOpenDisplay(display_name)
             char *display_name;

       XCloseDisplay(display)
             Display *display;


ARGUMENTS

       display   Specifies the connection to the X server.

       display_name
                 Specifies the hardware display name, which
                 determines the display and communications domain
                 to be used.  On a POSIX-conformant system, if
                 the display_name is NULL, it defaults to the
                 value of the DISPLAY environment variable.


DESCRIPTION

       The XOpenDisplay function returns a Display structure that
       serves as the connection to the X server and that contains
       all the information about that X server.  XOpenDisplay
       connects your application to the X server through TCP or
       DECnet communications protocols, or through some local
       inter-process communication protocol.  If the hostname is
       a host machine name and a single colon (:) separates the
       hostname and display number, XOpenDisplay connects using
       TCP streams.  If the hostname is not specified, Xlib uses
       whatever it believes is the fastest transport.  If the
       hostname is a host machine name and a double colon (::)
       separates the hostname and display number, XOpenDisplay
       connects using DECnet.  A single X server can support any
       or all of these transport mechanisms simultaneously.  A
       particular Xlib implementation can support many more of
       these transport mechanisms.

       If successful, XOpenDisplay returns a pointer to a Display
       structure, which is defined in <X11/Xlib.h>.  If XOpenDis-
       play does not succeed, it returns NULL.  After a success-
       ful call to XOpenDisplay, all of the screens in the dis-
       play can be used by the client.  The screen number speci-
       fied in the display_name argument is returned by the
       DefaultScreen macro (or the XDefaultScreen function).  You
       can access elements of the Display and Screen structures
       only by using the information macros or functions.  For
       information about using macros and functions to obtain
       information from the Display structure, see section 2.2.1.

       The XCloseDisplay function closes the connection to the X
       server for the display specified in the Display structure
       AllPlanes(3X11), XFlush(3X11), XSetCloseDownMode(3X11)
       Xlib - C Language X Interface



X Version 11               Release 6.4                          1