XOpenDisplay(3X11)  RISC/os Reference Manual   XOpenDisplay(3X11)



NAME
     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 deter-
               mines the display and communications domain to be
               used.  On a POSIX 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 con-
     nects 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 XOpen-
     Display does not succeed, it returns NULL.  After a success-
     ful 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 ele-
     ments 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.





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XOpenDisplay(3X11)  RISC/os Reference Manual   XOpenDisplay(3X11)



     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
     reported as XCloseDisplay performs a final XSync operation.

     XCloseDisplay can generate a BadGC error.

SEE ALSO
     AllPlanes(3X11), XFlush(3X11), XSetCloseDownMode(3X11)
     Xlib - C Language X Interface






































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