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XOpenDisplay(3X11)	       XLIB FUNCTIONS		   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 determines the display
	    and communications domain to be used.  On a POSIX-conformant sys-
	    tem, 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 sin-
  gle colon (:) separates the hostname and display number, XOpenDisplay con-
  nects using TCP streams.  If the hostname is not specified, Xlib uses what-
  ever 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 &lt;X11/Xlib.h&gt;.  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 XDe-
  faultScreen function).  You can access elements of the Display and Screen
  structures only by using the information macros or functions.	 For informa-
  tion 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 (Window, 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(3X11), XFlush(3X11), XSetCloseDownMode(3X11)
  Xlib - C Language X Interface































































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