XtDisplayInitialize(XXVersion 11 (ReleaseXtDisplayInitialize(3Xt)
NAME
XtDisplayInitialize, XtOpenDisplay, XtDatabase,
XtScreenDatabase, XtCloseDisplay - initialize, open, or
close a display
SYNTAX
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;
int *argc;
String *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;
int *argc;
String *argv;
void XtCloseDisplay(display)
Display *display;
XrmDatabase XtDatabase(display)
Display *display;
XrmDatabase XtScreenDatabase(screen)
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.
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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.
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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 initilized by
XtDisplayInitialize, the results are undefined.
SEE ALSO
XtAppCreateShell(3Xt), XtCreateApplicationContext(3Xt)
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface
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