XtDisplayInitialize(3) XT FUNCTIONS XtDisplayInitialize(3)

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

X Version 11 libXt 1.1.5 XtDisplayInitialize(3)