XtDisplayInitialize(Xt) UNIX System V
NAME
XtDisplayInitialize - a function that initializes the
o toolkit's view of a display and adds it to an application
context.
SYNOPSIS
#include <Xm/Xm.h>
Widget XtDisplayInitialize (app_context, display,
application_name, application_class, options, num_options,
argc, argv)
XtAppContext app_context;
Display * display;
String application_name;
String application_class;
XrmOptionDescRecoptions;
Cardinal num_options;
Cardinal * argc;
String argv;
DESCRIPTION
XtDisplayInitialize parses the command line that invoked the
application, and loads the resource database.
XtDisplayInitialize is a back-end routine that is usually
called be XtInitialize. It may be called directly if the
application needs to open more than one display.
XtDiplayInitialize is passed an open display. XtOpenDisplay
can be used in the case where an open display has not yet
been generated.
By passing the command line that invoked your application to
XtDisplayInitialize, the function can parse the line to
allow users to specify certain resources (such as fonts and
colors) for your application at run time.
XtDisplayInitialize scans the command line and removes those
options. The rest of your application sees only the
remaining options.
XtDisplayInitialize supports localization of defaults files
based on the value of the LANG environment variable. The
user can specify a language by using the LANG environment
variable. Elements of this variable are then used to
establish a path to the proper resource files. The
following substitutions are used in building the path:
⊕ %N is replaced by class_name of the application.
⊕ %L is replaced by the value of LANG environment variable.
⊕ %l is replaced by the language part of LANG environment
variable.
⊕ %t is replaced by the territory part of LANG environment
variable.
⊕ %c is replaced by the code set part of LANG environment
variable.
⊕ %% is replaced by %.
If the LANG environment variable is not defined, or if one
of its parts is missing, then a % element that references it
is replaced by NULL.
The paths contain a series of elements separated by colons.
Each element denotes a file name, and the file names are
looked up left to right till one of them succeeds. Before
doing the lookup, substitutions are performed.
NOTE: We are using the X/Open convention of collapsing
multiple adjoining slashes in a filename into one slash.
The XtInitalize function loads the resource database by
merging in resources from these sources:
⊕ Application-specific class resource file on the local
host.
⊕ Application-specific user resource file on the local
host.
⊕ Resource property on the server or user preference
resource file on the local host.
⊕ Per-host user environment resource file on the local
host.
⊕ The application command line (argv).
To load the application-specific class resource file,
XtDisplayInitialize performs the appropriate substitutions
on this path:
⊕ /usr/lib/X11/%L/app-defaults/%N:/usr/lib/X11/app-
defaults/%N
If LANG environment variable is not defined (or the first
path lookup using LANG fails), then the lookup will default
to the current non-language specific location
(/usr/lib/X11/app_defaults/%N).
To load the user's application resource file,
XtDisplayInitialize performs the following steps:
⊕ Use XAPPLRESLANGPATH environment variable to look up the
file. A possible value for XAPPLRESLANGDIR is:
./%N:$HOME/app-defaults/%L/%N:$HOME/app-defaults/%N:
$HOME/%L/%N:$HOME/%N
⊕ If that fails, or if XAPPLPRESLANGPATH is not defined,
and if XAPPLRESDIR is defined, use the following as the
path:
XAPPLRESDIR%L/%N:XAPPLRESDIR%N
⊕ else use:
$HOME/%L/%N:$HOME/%N
Note that if the XAPPLRESLANGPATH lookup is not successful
and LANG is not defined the lookup is then equivalent to
that used by the R3 specification of XtInitialize (actually
described under XtDisplayInitialize).
The parameters for XtDisplayInitialize are defined below:
app_context Specifies the application context.
display Specifies the display. Note that a display can
be in at most one application context.
application_name
Specifies the name of this application.
application_class
Specifies the class name of this application,
which usually is the generic name for all
instances of this application. By convention,
the class name is formed by reversing the case
of the application's first letter. The class
name is used to locate the files used to
initialize the resource database.
options Specifies how to parse the command line for any
application-specific resources. The options
argument is passed as a parameter to
XrmParseCommand.
num_options Specifies the number of entries in options list.
argc Specifies a pointer to the number of command
line parameters.
argv Specifies the command line parameters.
RELATED INFORMATION
XtInitialize(Xt).
(printed 2/19/90) XtDisplayInitialize(Xt)