Table of Contents
XtDisplayInitialize, XtOpenDisplay,
XtDatabase, XtScreenDatabase, XtCloseDisplay - initialize, open, or close
a display
- 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);
- 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 displayDi. 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.
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.
XtAppCreateShell(3Xt)
, XtCreateApplicationContext(3Xt)
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface
Table of Contents