NAME
XtDisplayInitialize, XtOpenDisplay, XtDatabase, XtScreenDatabase, XtCloseDisplay
- initialize, open, or close a display
SYNTAX
void
XtDisplayInitialize(XtAppContext app_context, Display * display,
String application_name, String application_class,
XrmOptionDescRec * options, Cardinal num_options, int
*argc, String * argv);
Display
*XtOpenDisplay(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);
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