NAME

       XOpenDisplay, XCloseDisplay - connect or disconnect to X server

SYNTAX

       Display *XOpenDisplay(char *display_name);

       int XCloseDisplay(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 If XOpenDisplay
       does not succeed, it returns NULL.  After a successful call to XOpenDisplay, all of the  screens  in  the
       display  can be used by the client.  The screen number specified 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 and destroys all windows, resource IDs Font, Pixmap, Colormap, Cursor, and GContext), or  other
       resources  that  the  client  has created on this display, unless the close-down mode of the resource has
       been changed (see XSetCloseDownMode).  Therefore, these windows, resource IDs, and other resources should
       never be referenced again or an error will be generated.  Before exiting, you should  call  XCloseDisplay
       explicitly so that any pending errors are reported as XCloseDisplay performs a final XSync operation.

       XCloseDisplay can generate a BadGC error.

SEE ALSO

       AllPlanes(3), XFlush(3), XSetCloseDownMode(3)
       Xlib - C Language X Interface

X Version 11                                      libX11 1.6.9                                   XOpenDisplay(3)