Writing Software for the International Market

Product Version: Digital UNIX Version 4.0 or higher March 1996

This guide provides an overview of writing international software and discusses using the tools provided on Digital UNIX (formerly known as DEC OSF/1) systems.

The following are trademarks of Digital Equipment Corporation: ALL-IN-1, Alpha AXP, AlphaGeneration, AXP, Bookreader, CDA, DDIS, DEC, DEC Ada, DEC Fortran, DEC FUSE, DECnet, DECstation, DECsystem, DECterm, DECUS, DECwindows, DTIF, Massbus, MicroVAX, OpenVMS, POLYCENTER, Q-bus, TruCluster, ULTRIX, ULTRIX Mail Connection, ULTRIX Worksystem Software, UNIBUS, VAX, VAXstation, VMS, XUI, and the Digital logo.

Open Software Foundation, OSF, OSF/1, OSF/Motif, and Motif are trademarks of the Open Software Foundation, Inc. UNIX is a registered trademark in the United States and other countries, licensed exclusively through X/Open Company, Ltd. X/Open is a trademark of X/Open Company Limited. Adobe, PostScript, and Display PostScript are registered trademarks of Adobe Systems, Inc.

Restricted Rights: Use, duplication, or disclosure by the U.S. Government is subject to restrictions as set forth in subparagraph (c) (1) (ii).

Digital Equipment Corporation makes no representations that the use of its products in the manner described in this publication will not infringe on existing or future patent rights, nor do the descriptions contained in this publication imply the granting of licenses to make, use, or sell equipment or software in accordance with the description.

Possession, use, or copying of the software described in this publication is authorized only pursuant to a valid written license from Digital or an authorized sublicensor.

Digital conducts its business in a manner that conserves the environment and protects the safety and health of its employees, customers, and the community.

About This Manual

The Digital UNIX internationalization features are tools and routines that allow you to write programs for use in a number of nations. These features let you write programs with:

An interface that appears to a nation's users as if it was designed for them
Source code that is independent of specific native languages and customs

Audience

This guide is intended for experienced applications developers writing programs intended for multinational or non-English language use. Translators who translate the messages displayed by international programs might also find this guide useful.

New and Changed Features

This manual contains information related to the following new software features:

Locales and other software to support Catalan, Lithuanian, and Slovene
Support for character processing in UCS-4 format
Curses library routines that handle multibyte characters and also conform to the X/Open Curses CAE specification
Support for X11R6 libraries
Support for the Common Desktop Environment (CDE)
Internationalization enhancements to the printing and mail subsystems
Font renderers for use by X applications
Multilingual Emacs editor (mule)
Codeset conversion improvements to support better the multiple codesets available for Chinese and Japanese
Functions added to the Standard C Library by the 1994 amendment to the ISO C standard

In addition, this manual includes the following documentation changes:

Text revisions to correct errors and omissions in the previous version
A glossary

Organization

This guide includes seven chapters, two appendixes, and a glossary.

Chapter 1	Introduction Introduces the basic concepts and procedures for writing programs that meet the needs of international users.
Chapter 2	Developing Internationalized Software Discusses techniques for handling character sets, cultural data, and language in an application.
Chapter 3	Creating and Using Message Catalogs Explains how to extract and translate text for messages, and how to generate and access message catalogs.
Chapter 4	Using Screen-Handling Routines for Character-Cell Terminals Describes the `curses` library routines for handling wide-character data and discusses terminal-programming extensions for drawing ruled lines in a DECterm window.
Chapter 5	Creating a Graphical User Interface (GUI) With X and OSF/Motif Libraries Discusses how to use GUI programming libraries (X, OSF/Motif, and DECwindows Extensions to OSF/Motif) when writing internationalized programs.
Chapter 6	Using Internationalized Software From a programmer's perspective, discusses setup requirements for using applications in different language environments. This chapter also explains how to use Digital UNIX commands and other applications in a multilanguage working environment.
Chapter 7	Creating Locales Discusses the source files for a locale and how to process them with the `localedef` utility.
Appendix A	Summary Tables of Worldwide Portability Interfaces Lists and summarizes internationalized functions for locale initialization, character classification, case conversion, character collation, language information, date and time interpretation, printing and scanning text strings, number conversion, handling multibyte characters, input/output, and string manipulation.
Appendix B	Sample Locale Source Files Contains complete source files for the sample locale discussed in Chapter 7.
Glossary	Defines terms and acronyms used in this book.

Related Documentation

The following manuals in the Digital UNIX documentation set provide information about using the C compiler and other program development tools on a Digital UNIX system. If you are developing internationalized applications, refer to these manuals for general programming information.

Programmer's Guide
Programming Support Tools
OSF/Motif Programmer's Guide
DECwindows Motif Guide to Application Programming
X Window System
X Window System Toolkit
Programmer's Supplement for Release 5 of the X Window System, Version 11
This book is published by O'Reilly and Associates, Inc.

The following standards or draft standards apply to software components discussed in this guide. This guide refers to some of these documents.

ANS X3.159 Programming Language C
ISO/IEC 646: 1983
Information processing - ISO 7-bit coded character set for information interchange.
ISO 6937: 1983
Information processing - Coded character sets for text communication.
ISO 8859-1: 1987
Information processing - ISO 8-bit single-byte coded graphic character sets - Latin alphabet No. 1.
ISO/IEC 9899: 1990
Information technology - Programming Languages - C.
ISO/IEC 9945-1: 1990
Information technology - Portable operating system interface (POSIX) - Part 1: System application programming interface (API) [C Language].
ISO/IEC 9945-2: 1993
Information technology - Portable operating system interface (POSIX) - Part 2: Shells and Utilities.
Code for Information Interchange, JIS X0201-1976; Japanese national standard.
Code of the Japanese Graphic Character Set for Information Interchange, JIS X0208-1990; Japanese national standard.
Code of the Supplementary Japanese Graphic Character Set, JIS X0212-1990; Japanese national standard.
Codes of Chinese Graphic Characters for Information Interchange, Primary Set (GB2312-80); National Standards Bureau of China, Beijing, 1980.
Standard Codes of Common Chinese Characters for Information Interchange, CNS 11643; Taiwan, 1986, 1992.
Standard Codes of Korean Characters for Information Interchange, KSC 5601 ; Korea, 1987.
Thai Industrial Standard, TIS 620-2533; Standard for a primary set of graphic characters used for Thai information interchange.
X/Open UNIX CAE specifications, specifically:
- Commands and Utilities, Issue 4, Version 2 (C436)
- Systems Interfaces and Headers, Issue 4, Version 2 (C435)
- System Interface Definitions, Issue 4, Version 2 (C434)
- Networking Services, Issue 4 (C438)
- X/Open Curses, Issue 4 (C437)

The following guide is an introduction to internationalization and is available from the X/Open Company, Ltd:

Guide to Internationalisation

Articles in the following technical journal cover topics related to product internationalization:

Digital Technical Journal, Volume 5 Number 3 (published Summer 1993)
The Digital Technical Journal is published quarterly by Digital Equipment Corporation. You can order individual issues through DECdirect. Recent back issues are also available on the Internet at gatekeeper.dec.com in the directory /pub/DEC/DECinfo/DTJ.

The printed version of the Digital UNIX documentation set is color coded to help specific audiences quickly find the books that meet their needs. (You can order the printed documentation from Digital.) This color coding is reinforced with the use of an icon on the spines of books. The following list describes this convention:

Audience	Icon	Color Code
General users	G	Blue
System and network administrators	S	Red
Programmers	P	Purple
Device driver writers	D	Orange
Reference page users	R	Green

Some books in the documentation set help meet the needs of several audiences. For example, the information in some system books is also used by programmers. Keep this in mind when searching for information on specific topics.

The Documentation Overview, Glossary, and Master Index provides information on all of the books in the Digital UNIX documentation set.

Reader's Comments

Digital welcomes any comments and suggestions you have on this and other Digital UNIX manuals.

You can send your comments in the following ways:

Fax: 603-881-0120 Attn: UEG Publications, ZK03-3/Y32
Internet electronic mail: readers_comment@zk3.dec.com
A Reader's Comment form is located on line in the following location:
```
/usr/doc/readers_comment.txt
```
Mail:
```
Digital Equipment Corporation
UEG Publications Manager
ZK03-3/Y32
110 Spit Brook Road
Nashua, NH 03062-9987
```
A Reader's Comment form is located in the back of each printed manual. The form is postage paid if you mail it in the United States.

Please include the following information along with your comments:

The full title of the book and the order number. (The order number is printed on the title page of this book and on its back cover.)
The section numbers and page numbers of the information on which you are commenting.
The version of Digital UNIX that you are using.
If known, the type of processor that is running the Digital UNIX software.

The Digital UNIX Publications group cannot respond to system problems or technical support inquiries. Please address technical questions to your local system vendor or to the appropriate Digital technical support office. Information provided with the software media explains how to send problem reports to Digital.

Conventions

The following conventions are used in this manual:

%
$: A percent sign represents the C shell system prompt. A dollar sign represents the system prompt for the Bourne and Korn shells.
#: A number sign represents the superuser prompt.
% cat: Boldface type in interactive examples indicates typed user input.
file: Italic (slanted) type indicates variable values, placeholders, and function argument names.
[|]
{|}: In syntax definitions, brackets indicate items that are optional and braces indicate items that are required. Vertical bars separating items inside brackets or braces indicate that you choose one item from among those listed.
...: In syntax definitions, a horizontal ellipsis indicates that the preceding item can be repeated one or more times.
. . .: A vertical ellipsis indicates that a portion of an example that would normally be present is not shown.
cat(1): A cross-reference to a reference page includes the appropriate section number in parentheses. For example, cat(1) indicates that you can find information on the cat command in Section 1 of the reference pages.
Return: In an example, a key name enclosed in a box indicates that you press that key.
Ctrl/x: This symbol indicates that you hold down the first named key while pressing the key or mouse button that follows the slash. In examples, this key combination is enclosed in a box; for example, Ctrl/C.
Alt x: Multiple key or mouse button names separated by spaces indicate that you press and release each in sequence. In examples, each key in the sequence is enclosed in a box; for example, Alt Q.