XtDisplayInitialize(3Xt) XT FUNCTIONS XtDisplayInitialize(3Xt)
NAME
XtDisplayInitialize, XtOpenDisplay, XtDatabase, XtScreen-
Database, 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 argu-
ment is passed as a parameter to XrmParseCommand.
For further information, see Xlib - C Language X
Interface.
XFree86 Version 4.5.0 1
XtDisplayInitialize(3Xt) XT FUNCTIONS XtDisplayInitialize(3Xt)
screen Specifies the screen whose resource database is to
be returned.
DESCRIPTION
The XtDisplayInitialize function builds the resource data-
base, 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 syn-
chronize 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 XtOpen-
Display. 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 applica-
tion 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; 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 XtDisplayInitialize, the results are not
XFree86 Version 4.5.0 2
XtDisplayInitialize(3Xt) XT FUNCTIONS XtDisplayInitialize(3Xt)
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
XFree86 Version 4.5.0 3