XtDisplayInitialize(Xt) X Version 11 (Release 5) XtDisplayInitialize(Xt)
6 January 1993
Name
XtDisplayInitialize - initialize, open, or close a display
Syntax
void XtToolkitInitialize()
void XtDisplayInitialize(app_context, display, application_name,
application_class, options, num_options,
argc, argv)
XtAppContext app_context;
Display display;
String application_name;
String application_class;
XrmOptionDescRec *options;
Cardinal num_options;
Cardinal *argc;
char **argv;
Display *XtOpenDisplay(app_context, display_string, application_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;
Cardinal *argc;
String *argv;
void XtCloseDisplay(display)
Display *display;
XrmDatabase XtDatabase(display)
Display *display;
Arguments
argc Specifies a pointer to the number of command line parameters.
argv Specifies the command line parameters.
appcontext
Specifies the application context.
applicationclass
Specifies the class name of this application, which usually is
the generic name for all instances of this application.
applicationname
Specifies the name of the application instance.
display Specifies the display. Note that a display can be in at most
one application context.
numoptions
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 param-
eter to XrmParseCommand. For further information, see Xlib - C
Language X Interface.
Description
The XtDisplayInitialize function builds the resource database, calls the
Xlib XrmParseCommand function to parse the command line, and performs
other per display initialization. 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 component
of argv[0]. If the synchronize resource is True for the specified appli-
cation, XtDisplayInitialize calls the Xlib XSynchronize function to put
Xlib into synchronous mode for this display connection. If the rever-
seVideo resource is True, the Intrinsics exchange XtDefaultForeground and
XtDefaultBackground for widgets created on this display. (See Section
9.7.1 of X Toolkit Intrinsics - C Language Interface).
The XtOpenDisplay function calls XOpenDisplay with the specified display
name. If display_string is NULL, XtOpenDisplay 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 applica-
tion 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
dispatch is complete. Note that applications need only call XtCloseDis-
play if they are to continue executing after closing the display; other-
wise, they should call XtDestroyApplicationContext 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 XtDis-
playInitialize, the results are not defined.
XtToolkitInitialize initializes internal Toolkit data structures. It
does not set up an application context or open a display. The semantics
of calling XtToolkitInitialize more than once are undefined.
See also
XtAppCreateShell(Xt), XtAppInitialize(Xt), XtCre-
ateApplicationContext(Xt), XtLanguageProc(Xt) and XtScreenDatabase(Xt).
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface