XtDisplayInitialize
Section: XT FUNCTIONS (3)
Updated: libXt 1.2.0
Page Index
NAME
XtDisplayInitialize, XtOpenDisplay, XtDatabase, XtScreenDatabase, XtCloseDisplay - initialize, open, or close a display
SYNTAX
#include <
X11/Intrinsic.h>
-
- void XtDisplayInitialize(XtAppContext app_context,
Display *display,
const char *application_name,
const char *application_class,
XrmOptionDescRec *options, Cardinal num_options,
int *argc, char **argv);
-
- Display *XtOpenDisplay(XtAppContext app_context,
const char *display_string,
const char *application_name,
const char *application_class,
XrmOptionDescRec *options, Cardinal num_options,
int *argc, char **argv);
-
- void XtCloseDisplay(Display *display);
-
- XrmDatabase XtDatabase(Display *display);
-
- XrmDatabase XtScreenDatabase(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 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 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
XtDefaultForeground
and
XtDefaultBackground
for widgets created on this display.
(See Section 9.6.1).
The
XtOpenDisplay
function calls
XOpenDisplay
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 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 dispatch is complete.
Note that applications need only call
XtCloseDisplay
if they are to continue executing after closing the display;
otherwise, 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
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
initialized by
XtDisplayInitialize,
the results are undefined.
SEE ALSO
XtAppCreateShell(3),
XtCreateApplicationContext(3)
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface