XOpenDisplay(3)

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 (::) sepa-
       rates the hostname and display number, XOpenDisplay connects using DEC-
       net.  A single X server can support any or all of these transport mech-
       anisms 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 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 win-
       dows, resource IDs (Window, Font, Pixmap, Colormap, Cursor, and GCon-
       text), or other resources that the client has created on this display,
       unless the close-down mode of the resource has been changed (see XSet-
       CloseDownMode).  Therefore, these windows, resource IDs, and other
       resources should never be referenced again or an error will be gener-
       ated.  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

X Version 11                     libX11 1.1.1                  XOpenDisplay(3)