man XOpenDisplay (Fonctions bibliothèques) - connect or disconnect to X server
NAME
XOpenDisplay, XCloseDisplay - connect or disconnect to X server
SYNTAX
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 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. 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.
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.
can generate a error.