XOpenDisplay(3X) — A/UX 3.0.1




XOpenDisplay(3X)                                 XOpenDisplay(3X)



NAME
     XOpenDisplay, XCloseDisplay - connect to and disconnect from
     the X server

SYNOPSIS
     Display *XOpenDisplay (display-name)
     char *display-name;

     XCloseDisplay (display)
     Display *display;

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 con-
     nects the specified hardware display to the server or
                      r
     through TCP, UNIX  domain through some local inter-process
     communication protocol.  If the host name is a host machine
     name and a single colon (:)  separates the host name and
     display number, XOpenDisplay connects using TCP streams.  If
     the host name is not specified, Xlib uses whatever it be-
     lieves is the fastest transport.  A single X server can sup-
     port any or all transport mechanisms simultaneously.  A par-
     ticular 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
     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 speci-
     fied in the display-name argument is returned by the De-
     faultScreen 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 in Xlib - C
     Language Interface.

     The XCloseDisplay function closes the connection to the X
     server for the display specified in the Display structure
     and destroys all windows, resource IDs (Window, Font, Pix-
     map, 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 re-
     ported as XCloseDisplay performs a final XSync operation.





November, 1990                                                  1




XOpenDisplay(3X)                                 XOpenDisplay(3X)



   Arguments
     These functions accept the following arguments:

     display Specifies the connection to the X server.

     display-name
             Specifies the hardware display name, which deter-
             mines the display and communications domain to be
             used.  On a UNIX-based system, if the display-name
             is null, it defaults to the value of the DISPLAY en-
             vironment
             variable.

ERRORS
     BadGC   A value for a GC argument does not name a defined
             graphic context.

     The XCloseDisplay function can generate a BadGC error.

SEE ALSO
     Xlib - C Language Interface


































2                                                  November, 1990

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