XOpenDisplay(3)

1XOpenDisplay(3)                 XLIB FUNCTIONS                 XOpenDisplay(3)
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NAME

6       XOpenDisplay, XCloseDisplay - connect or disconnect to X server
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SYNTAX

9       Display *XOpenDisplay(_Xconst char *display_name);
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11       int XCloseDisplay(Display *display);
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ARGUMENTS

14       display   Specifies the connection to the X server.
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16       display_name
17                 Specifies  the  hardware  display  name, which determines the
18                 display and communications domain to be used.   On  a  POSIX-
19                 conformant  system,  if the display_name is NULL, it defaults
20                 to the value of the DISPLAY environment variable.
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DESCRIPTION

23       The XOpenDisplay function returns a Display structure  that  serves  as
24       the  connection  to  the X server and that contains all the information
25       about that X server.  XOpenDisplay connects your application to  the  X
26       server  through TCP or DECnet communications protocols, or through some
27       local inter-process communication protocol.  If the hostname is a  host
28       machine  name and a single colon (:) separates the hostname and display
29       number, XOpenDisplay connects using TCP streams.  If  the  hostname  is
30       not specified, Xlib uses whatever it believes is the fastest transport.
31       If the hostname is a host machine name and a double  colon  (::)  sepa‐
32       rates the hostname and display number, XOpenDisplay connects using DEC‐
33       net.  A single X server can support any or all of these transport mech‐
34       anisms  simultaneously.   A  particular Xlib implementation can support
35       many more of these transport mechanisms.
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37       If successful, XOpenDisplay returns a pointer to a  Display  structure,
38       which  is  defined in X11/Xlib.h.  If XOpenDisplay does not succeed, it
39       returns NULL.  After a successful call  to  XOpenDisplay,  all  of  the
40       screens  in  the  display can be used by the client.  The screen number
41       specified in the display_name argument is returned by the DefaultScreen
42       macro (or the XDefaultScreen function).  You can access elements of the
43       Display and Screen structures only by using the information  macros  or
44       functions.   For information about using macros and functions to obtain
45       information from the Display structure, see section 2.2.1.
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47       The XCloseDisplay function closes the connection to the  X  server  for
48       the  display  specified  in the Display structure and destroys all win‐
49       dows, resource IDs (Window, Font, Pixmap, Colormap, Cursor,  and  GCon‐
50       text),  or other resources that the client has created on this display,
51       unless the close-down mode of the resource has been changed (see  XSet‐
52       CloseDownMode).   Therefore, these windows, resource IDs, and other re‐
53       sources should never be referenced again or an error will be generated.
54       Before  exiting,  you  should call XCloseDisplay explicitly so that any
55       pending errors are reported as XCloseDisplay performs a final XSync op‐
56       eration.
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58       XCloseDisplay can generate a BadGC error.
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NAME

SYNTAX

ARGUMENTS

DESCRIPTION

SEE ALSO