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.
N Environment DISPLAY
DESCRIPTION
The
function returns a
structure that serves as the
connection to the X server and that contains all the information
about that X server.
connects your application to the X server through TCP
or DECnet communications protocols,
or through some local inter-process communication protocol.
N Protocol TCP
N Protocol DECnet
If the hostname is a host machine name and a single colon (:)
separates the hostname and display number,
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,
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.
N Display
If successful,
returns a pointer to a
structure,
which is defined in
If
does not succeed, it returns NULL.
After a successful call to
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
macro (or the
function).
You can access elements of the
and
structures only by using the information macros or functions.
For information about using macros and functions to obtain information from
the
structure,
see section 2.2.1.
The
function closes the connection to the X server for the display specified in the
structure and destroys all windows, resource IDs
and
or other resources that the client has created
on this display, unless the close-down mode of the resource has been changed
(see
Therefore, these windows, resource IDs, and other resources should never be
referenced again or an error will be generated.
Before exiting, you should call
explicitly so that any pending errors are reported as
performs a final
operation.
N Resource IDs
N XCloseDisplay
can generate a
error.
SEE ALSO
AllPlanes(3X11),
XFlush(3X11),
XSetCloseDownMode(3X11)
