Volume 7A: XView Programming Manual

22

Internationalization

In this chapter, I discuss the features in XView that allow applications to be international-

ized. For additional information on internationalization for XView Version 3.2, refer to the

XView 3.2 Developer’s Notes, Part II “Internationalization,” distributed by Sun Microsys-

tems, Inc. It describes the internationalization modifications by package as well as XView’s

wide character support. Internationalized applications do not have to be redesigned or

recompiled to run in a different language or locale. The goal is to make a single object ver-

sion of an application support any number of languages. The attribute XV_USE_LOCALE

enables the internationalization features. All internationalized applications must set this

attribute to TRUE.

The basic idea in internationalization is to separate language-specific data from the rest of

the application code. Adapting the application to any supported language, or localization,

then requires modification of only the language-specific data. The task of internationaliza-

tion includes translation of application-specific strings and modification of layout files. All

other aspects of the user interface are handled by XView.

The internationalization features discussed in this chapter are:

Locale Setting

Before running an internationalized application, a user must choose what language

to run in. This is done by the locale setting mechanism of XView.

Localized Text Handling

Developers need to be able to write application strings (error messages, menu labels,

etc.) in their native language and have those strings retrieved in the language speci-

fied by the locale. This process is described in Section 22.2, “Localized Text Hand-

ling.”

Object Layout and Customization

When an application is run in a non-native language, the dimensions of its strings

may change (among other things). This may cause the dimensions of objects with

text strings in them, such as buttons and panels, to change. Object Layout is the

mechanism by which the screen location of objects is modified to accommodate

these kinds of changes. Section 22.3, “Object Layout and Customization,” describes

how an application can be customized to accommodate various object layouts.

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22.1 Locale Setting

This section describes the following internationalization topics:

• Locale definition.

• How to enable internationalization features in XView.

• How to switch the locale from the OpenWindows Localization Properties Sheet.

• How the locale is set in XView using locale attributes, command-line options, XView

locale resources, and the ANSI-C/POSIX setlocale() function.

• Locale implementation limits and restrictions.

22.1.1 Locale Definition

In an internationalized program, the locale specifies the language and cultural conventions

used in a program. Locale setting affects the display and manipulation of language-depen-

dent features.

XView defines a program’s locale and the categories within each locale. These categories

refer to the language-dependent features defined by ANSI-C and OPEN LOOK. These features

include the display characteristics of monetary, numeric, and time fields.

XView offers several methods of setting locale. In order of priority, locale is set as follows:

1. XView locale attributes.

2. Locale command-line options.

3. XView locale resources (using the OpenWindows Workspace Property Sheet or an entry

in the X resource database).

22.1.2 Enabling Internationalization

The attribute XV_USE_LOCALE enables the internationalization features in XView. For inter-

nationalized applications to work properly, this attribute must be set to TRUE. This attribute is

only valid for xv_init(). The following is an example:

xv_init(XV_INIT_ARGC_PTR_ARGV, &argc, argv,

XV_USE_LOCALE, TRUE,

NULL);

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22.1.2.1 Setting path of locale-specific files

The attribute XV_LOCALE_DIR specifies the location of an application’s locale-specific files.

The directory structure referenced by XV_LOCALE_DIR is:

<XV_LOCALE_DIR>/locale/LC_MESSAGES

<XV_LOCALE_DIR>/locale/app-defaults

<XV_LOCALE_DIR>/locale/app-defaults/<application name>

where locale is expanded differently depending on which internationalized feature is using

XV_LOCALE_DIR. For a discussion of the specific use of XV_LOCALE_DIR, refer to Section

22.2, “Localized Text Handling,” and to Section 22.3, “Object Layout and Customization.”

22.1.3 OpenWindows Localization Properties Sheet

The OpenWindows Localization Properties Sheet, shown in Figure 22-1, provides the

OPEN LOOK user interface for setting locale. To set locale, bring up the OpenWindows

Workspace Property sheet and choose “Localization” from the menu. The system then

allows you to specify the following categories within the Localization Menu:

Basic Setting

Specifies the country of the user interface. Once the Basic Setting is specified, the user

can set the specific settings. The specific settings define properties for each locale.

Display Language

Specifies the language in which labels, messages, menu items, help text, and so on, are

shown.

Input Language

Specifies the language used for input.

Time Format

Specifies the format for time and date displays.

Numeric Format

Defines the numeric format.

Supplementary Settings

Provides a selection of additional settings for any of the Specific Settings. That is, if

additional selections are required to specify Display Language, Input Language, Time

or Numeric Format, pressing the Supplementary Settings button will display them.

The Localization Property Sheet sets locale via XView locale resources in the X

resource manager database. This process is described later in this chapter. Once a set-

ting is made in the Localization Properties Sheet, subsequent applications will adopt

the new environmental settings.

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Category: Localization

Basic Setting:

Specific Setting:

Display Language:

Input Language:

Time Format:

Numeric Format:

English

English

12/31/89 21:30:30

10,000.0

U.S.A.

U.S.A.

France

Workspace Properties

Supplementary...

ResetApply

Figure 22-1.

OPENLOOK

localization menu

22.1.4 XView Locale Attributes

Several attributes let you specify the locale from within an application. Each of these locale

attributes corresponds to the locale parameters described for the OpenWindows property

sheet. The attributes are shown in Table 22-1.

Table 22-1. XView Locale Attributes

Locale Parameter XView Attribute

Basic Setting XV_LC_BASIC_LOCALE

Display Language XV_LC_DISPLAY_LANG

Input Language XV_LC_INPUT_LANG

Numeric Format XV_LC_NUMERIC

Time Format XV_LC_TIME_FORMAT

These attributes specify the different

OPEN LOOK locale categories. They can only be set at

creation time through xv_init(), but can be queried at any time with xv_get() on any

object that is a subclass of WINDOW or SERVER. The value that is set using the above attri-

butes must be a valid locale name in the system.*

Locale attributes are used in situations when an application developer needs to force a pro-

gram to operate in a specific locale. For example, if a program only works in the French

locale, then the locale attributes can be used to hardwire the locale to French, preventing

*The valid locale names are dependent upon the operating system used.

540 XView Programming Manual

anyone from switching the locale using X resources or command-line options. Each of these

attributes takes a char * argument. Once again, these attributes are only valid for

xv_init() and xv_get(). For example, set the basic locale to French with the follow-

ing code:

xv_init( XV_USE_LOCALE, TRUE,

XV_LC_BASIC_LOCALE, "fr",

XV_INIT_ARGC_PTR_ARGV, &argc, argv,

NULL);

22.1.5 Command-line Options for Specifying Locale

The locale command-line options allow the locale to be set when an application is started.

These options may be used to override the system environment for a specific program. The

command-line options are shown in Table 22-2, and in Section 6, Command-line Arguments

and XView Resources, in the XView Reference Manual.

Table 22-2. Locale Command-line Options

Locale Parameter Command-line Option

Basic Setting –lc_basiclocale

Display Language –lc_displaylang

Input Language –lc_inputlang

Numeric Format –lc_numeric

Time Format –lc_timeformat

An example of these command-line options follows:

% textedit –lc_basiclocale fr –lc_displaylang C –lc_inputlang fr

This command line brings up a text editor with messages and panel labels in English. The

user’s input would be in French.

22.1.5.1 XView locale resources

Locale can also be set through resources written in the X11 Resource Manager database

(˜/.Xdefaults). The workspace property sheet uses the XView Locale Resources to set locale

parameters. Resources are shown in Table 22-3.

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