XtDisplayInitialize(3Xt)

NAME
       XtDisplayInitialize, XtOpenDisplay, XtDatabase, XtScreen-
       Database, XtCloseDisplay - initialize, open, or close a
       display

SYNTAX
       void XtDisplayInitialize(app_context, display, applica-
       tion_name, application_class,
                              options, num_options, argc, argv)
             XtAppContext app_context;
             Display *display;
             String application_name;
             String application_class;
             XrmOptionDescRec *options;
             Cardinal num_options;
             int *argc;
             String *argv;

       Display *XtOpenDisplay(app_context, display_string, appli-
       cation_name, application_class,
                              options, num_options, argc, argv)
              XtAppContext app_context;
              String display_string;
              String application_name;
              String application_class;
              XrmOptionDescRec *options;
              Cardinal num_options;
              int *argc;
              String *argv;

       void XtCloseDisplay(display)
             Display *display;

       XrmDatabase XtDatabase(display)
             Display *display;

       XrmDatabase XtScreenDatabase(screen)
             Screen* screen;

ARGUMENTS
       argc      Specifies a pointer to the number of command
                 line parameters.

       argv      Specifies the command line parameters.

       app_context
                 Specifies the application context.

       application_class
                 Specifies the class name of this application,
                 which usually is the generic name for all
                 instances of this application.

       application_name
                 Specifies the name of the application instance.

       display   Specifies the display.  Note that a display can
                 be in at most one application context.

       num_options
                 Specifies the number of entries in the options
                 list.

       options   Specifies how to parse the command line for any
                 application-specific resources.  The options
                 argument is passed as a parameter to
                 XrmParseCommand.  For further information, see
                 Xlib - C Language X Interface.

       screen    Specifies the screen whose resource database is
                 to be returned.

DESCRIPTION
       The XtDisplayInitialize function builds the resource
       database, calls the Xlib XrmParseCommand function to parse
       the command line, and performs other per display initial-
       ization.  After XrmParseCommand has been called, argc and
       argv contain only those parameters that were not in the
       standard option table or in the table specified by the
       options argument.  If the modified argc is not zero, most
       applications simply print out the modified argv along with
       a message listing the allowable options.  On UNIX-based
       systems, the application name is usually the final compo-
       nent of argv[0].  If the synchronize resource is True for
       the specified application, XtDisplayInitialize calls the
       Xlib XSynchronize function to put Xlib into synchronous
       mode for this display connection.  If the reverseVideo
       resource is True, the Intrinsics exchange XtDefaultFore-
       ground and XtDefaultBackground for widgets created on this
       display.  (See Section 9.6.1).

       The XtOpenDisplay function calls XOpenDisplay the speci-
       fied display name.  If display_string is NULL, XtOpen-
       Display uses the current value of the -display option
       specified in argv and if no display is specified in argv,
       uses the user's default display (on UNIX-based systems,
       this is the value of the DISPLAY environment variable).

       If this succeeds, it then calls XtDisplayInitialize and
       pass it the opened display and the value of the -name
       option specified in argv as the application name.  If no
       name option is specified, it uses the application name
       passed to XtOpenDisplay.  If the application name is NULL,
       it uses the last component of argv[0].  XtOpenDisplay
       returns the newly opened display or NULL if it failed.

       XtOpenDisplay is provided as a convenience to the

       application programmer.

       The XtCloseDisplay function closes the specified display
       as soon as it is safe to do so.  If called from within an
       event dispatch (for example, a callback procedure),
       XtCloseDisplay does not close the display until the dis-
       patch is complete.  Note that applications need only call
       XtCloseDisplay if they are to continue executing after
       closing the display; otherwise, they should call XtDe-
       stroyApplicationContext or just exit.

       The XtDatabase function returns the fully merged resource
       database that was built by XtDisplayInitialize associated
       with the display that was passed in.  If this display has
       not been initialized by XtDisplayInitialize, the results
       are not defined.

       The XtScreenDatabase function returns the fully merged
       resource database associated with the specified screen. If
       the screen does not belong to a Display initilized by
       XtDisplayInitialize, the results are undefined.

SEE ALSO
       XtAppCreateShell(3Xt) XtCreateApplicationContext(3Xt) 
       X Toolkit Intrinsics - C Language Interface
       Xlib - C Language X Interface