International Components for Unicode
ICU 2.0 ReadMe

Version: 2001-Nov-16
Copyright © 1995-2001 International Business Machines Corporation and others. All Rights Reserved.


Table of Contents


Introduction

Today's software market is a global one in which it is desirable to develop and maintain one application (single source/single binary) that supports a wide variety of languages. The International Components for Unicode (C/C++) provides tools to help write platform-independent applications that are internationalized and localized, with support for:

ICU has a sister project ICU4J that extends the internationalization capabilities of Java to a level similar to ICU. The ICU C/C++ project is also called ICU4C when a distinction is necessary.

Getting started

This document describes how to build and install ICU on your machine. For other information about ICU please see the following table of links.
The ICU homepage also links to related information about writing internationalized software.

Here are some useful links regarding ICU and internationalization in general.
ICU Homepage http://oss.software.ibm.com/icu/
ICU4J Homepage http://oss.software.ibm.com/icu4j/
FAQ - Frequently Asked Questions about ICU http://oss.software.ibm.com/icu/userguide/icufaq.html
ICU User's Guide http://oss.software.ibm.com/icu/userguide/
Download ICU Releases http://oss.software.ibm.com/icu/download/
API Documentation Online http://oss.software.ibm.com/icu/apiref/
Online ICU Demos http://oss.software.ibm.com/icu/demo/
Contacts & Bug Reports/Feature Requests http://oss.software.ibm.com/icu/archives/

Important: Please make sure you understand the Copyright and License Information.

What is new in this release?

The following list concentrates on changes that affect existing applications migrating from previous ICU releases. For more news about this release, see the ICU 2.0 download page.

Support for Unicode 3.1.1

ICU 2.0 has been upgraded to support Unicode 3.1.1, which includes the addition of 44,946 new encoded characters. These characters cover several historic scripts, several sets of symbols, and a very large collection of additional CJK ideographs.

As part of this upgrade, a number of ICU services have been reviewed and improved with regards to handling supplementary characters (surrogate pairs). Especially, normalization is revamped for support of supplementary characters and higher performance.

Euro transition

Locale data for countries that are switching their national currencies to the Euro is updated to use the Euro symbol and appropriate currency formatting. The old data is available in _PREEURO locale variants. The _EURO variant selector can still be used to unambiguously get Euro currency symbol formatting. For some time around the transition, software should explicitly specify _PREEURO and _EURO variants to make sure to get the intended currency format.

For more on this topic see the developerWorks article "Are you really ready for the Euro?".

API changes

Functions that take C-style string input arguments with const UChar *src and int32_t srcLength now consistently treat srcLength==-1 to mean that the input string is NUL-terminated and get srcLength=u_strlen(src).

Functions that take C-style string output arguments with UChar *dest and int32_t destCapacity now handle NUL-termination of the output string consistently. If the output length is equal to destCapacity, then dest is filled with the output string and a warning code is set. For details about string handling see the User's Guide Strings chapter.

Some APIs have been deprecated for a long time (more than a year) and have been removed now.
Some other APIs have been marked as deprecated because they are replaced by improved APIs; the newly deprecated APIs will be available for another year. In particular, the C++ classes UnicodeConverter, Unicode, and BiDi are deprecated in favor of the equally powerful C APIs.
A few draft APIs have changed, especially for transliteration.

APIs that take a rules or pattern string (for collation, transliteration, message formats, etc.) now also take a UParseError structure that is filled with useful debugging information when a rule syntax error is detected. This makes it easier in large rules to find problems. As a result, the signatures of some functions have changed. The old signatures will be available for about a year by #defining a constant. See affected header files for details.

The C++ Normalizer class had a partially broken model for iterative normalization; this is redone in a more consistent way. See the Normalizer API documentation for details.

Memory and resource cleanup

ICU is carefully tested for memory leaks. Some memory is held in internal caches that do not normally get released during normal operation. These are not leaks because ICU continues to use them as necessary.

For testing purposes (for memory leaks) and for a small number of applications it can be useful to close all the memory that is allocated for a library. ICU 2.0 supports this with a new function u_cleanup() that may be called after an application has released all ICU objects. u_cleanup() will then release all of ICU's internal memory. The ICU libraries can then even be unloaded cleanly without shutting down the process.

ICU versioning - C++ namespaces

Beginning with ICU 2.0, multiple releases of ICU can be used in the same process. Together with an arbitrary number of post-2.0 releases, one pre-2.0 release can be loaded and active.

This is achieved by renaming all library exports to include a release number suffix. Each global function and each class is renamed in this way using a header file with #defines. For C++, if the compiler supports namespaces, all ICU C++ classes are defined in the "icu" namespace. If the compiler does not support namespaces, then the classes are renamed instead. This change also reduces the chance of naming collisions with other libraries.

For details see the User's Guide Design Chapter.

Data loading changed

ICU data loading is simplified for most users. By default, the ICU build creates a DLL/shared library that is linked directly with the common library ([lib]icuuc). By placing all ICU libraries including the data library into the same folder, ICU should start up and find its data immediately. Dynamic loading of data from DLLs/shared libraries is not supported any more.

Before ICU 2.0, ICU did not itself link directly with its data library, but some ICU applications did (like the Xerces XML parser) and called udata_setCommonData(). This is not necessary any more in the default case.
On the other hand, this same technique can now be used to efficiently load application data (e.g., for its own localization). An application can build a data DLL/library of its own, link it, and call the new API udata_setAppData().

For details on finding and loading ICU data and on options for portable, common data files etc. see the User's Guide ICU Data Chapter.

Collation improvements

The performance of Japanese Katakana collation is improved, and the Japanese collation is changed for conformance with the JIS X 4061 standard.

License Change (for ICU 1.8.1 and up)

The ICU projects (ICU4C and ICU4J) have changed their licenses from the IPL (IBM Public License) to the X license. The X license is a non-viral and recommended free software license that is compatible with the GNU GPL license. This is effective starting with release 1.8.1 of ICU4C and release 1.3.1 of ICU4J. All previous ICU releases will continue to utilize the IPL. New ICU releases will adopt the X license. The users of previous releases of ICU will need to accept the terms and conditions of the X license in order to adopt the new ICU releases.

The main effect of the change is to provide GPL compatibility. The X license is listed as GPL compatible, see the gnu page at http://www.gnu.org/philosophy/license-list.html#GPLCompatibleLicenses.

The text of the X license is available at http://www.x.org/terms.htm. The IBM version contains the essential text of the license, omitting the X-specific trademarks and copyright notices.

For more details please see the press announcement and the Project FAQ.

Transliterator improvements

The transliterator service has undergone an extensive overhaul, in both the rule-based engine and the built-in system rules. For a complete description see the User's Guide chapter on transliteration.

UnicodeSet Improvements


How to Download the Source Code

There are two ways to download ICU releases:

ICU Source Code Organization

In the descriptions below, <ICU> is the full path name of the icu directory - the top level directory from the distribution archives - in your file system.

The following files describe the code drop.
readme.html Describes the International Components for Unicode (this file)
license.html Contains the text of the ICU license


The following directories contain source code and data files.
<ICU>/source/common/ The core Unicode and support functionality, such as resource bundles, character properties, locales, codepage conversion, normalization, Unicode properties, Locale, and UnicodeString.
<ICU>/source/i18n/ Modules in i18n are generally the more data-driven, that is to say resource bundle driven, components. These deal with higher level internationalization issues such as formatting, collation, text break analysis, and transliteration.
<ICU>/source/test/intltest/ A test suite including all C++ APIs. For information about running the test suite, see the users' guide.
<ICU>/source/test/cintltst/ A test suite written in C, including all C APIs. For information about running the test suite, see the users' guide.
<ICU>/data/ This directory contains the source data in text format, which is compiled into binary form during the ICU build process. The output from these files is stored in <ICU>/source/data/build while awaiting further packaging.
  • unidata/ This directory contains the Unicode data files. Please see http://www.unicode.org/ for more information.
  • Resource Bundle sources .txt files containing ICU language and culture-specific localization data. Two special bundles are root, which is the fallback data and parent of other bundles, and index which contains a list of installed bundles. resfiles.txt contains the list of resource bundle files.

    Also here are transliteration bundles, and the list of installed transliteration files in translit_index.txt.

    All resource bundles are compiled into .res files. The ucmfiles.txt file contains the list of converter files.

  • Code page converter tables .ucm files containing mappings to and from Unicode. These are compiled into .cnv files.
  • convrtrs.txt is the alias mapping table from various converter name formats to ICU internal format and vice versa. It produces cnvalias.dat.
  • timezone.txt is a generated file which is compiled into tz.dat, containing time zone information.
<ICU>/source/data This directory is where the final, packaged version of the ICU binary data ends up. The intermediate individual data files (.res, .cnv) are kept in the subdirectory "<ICU>/source/data/build" prior to packaging.
<ICU>/source/tools Tools for generating the data files. Data files are generated by invoking <ICU>/source/data/build/makedata.bat on Win32 or <ICU>/source/make on Unix.
<ICU>/source/samples Various sample programs that use ICU
<ICU>/source/extra Non-supported API additions. Currently, it contains the 'ustdio' file i/o library
<ICU>/source/layout Contains the ICU layout engine (not a rasterizer).
<ICU>/packaging
<ICU>/debian
These directories contain scripts and tools for packaging the final ICU build for various release platforms.
<ICU>/source/config Contains helper makefiles for platform specific build commands. Used by 'configure'.
<ICU>/source/allinone Contains top-level ICU project files, for instance to build all of ICU under one MSVC project.

How To Build And Install ICU

Supported Platforms

Here is a status of functionality of ICU on several different platforms.
Operating system Compiler Testing frequency
Windows 98/NT/2000 Microsoft Visual C++ 6.0 Reference platform
Red Hat Linux 6.1 gcc 2.95.2 Reference platform
AIX 4.3.3 xlC 3.6.4 Reference platform
Solaris 2.6 Workshop Pro CC 4.2 Reference platform
HP/UX 11.01 aCC A.12.10 Reference platform
AIX 5.1.0 L Visual Age C++ 5.0 Regularly tested
Solaris 2.7 Workshop Pro CC 6.0 Regularly tested
Solaris 2.6 gcc 2.91.66 Regularly tested
FreeBSD 4.4 gcc 2.95.3 Regularly tested
HP/UX 11.01 CC A.03.10 Regularly tested
OS/390 (zSeries) CC Regularly tested
AS/400 (iSeries) V5R1 iCC Rarely tested
NetBSD, OpenBSD   Rarely tested
SGI/IRIX   Rarely tested
PTX   Rarely tested
OS/2 Visual Age Rarely tested
Macintosh   Needs help to port


Key to testing frequency

Reference platform
ICU will work on these platforms with these compilers
Regularly tested
ICU should work on these platforms with these compilers
Rarely tested
ICU has been ported to these platforms but may not have been tested there recently

How To Build And Install On Windows

Building International Components for Unicode requires:

The steps are:

  1. Unzip the icu-XXXX.zip file into any convenient location. Using command line zip, type "unzip -a icu-XXXX.zip -d drive:\directory", or just use WinZip.
  2. Be sure that the ICU binary directory, <ICU>\bin\, is included in the PATH environment variable. The tests will not work without the location of the ICU dll files in the path.
  3. Set the TZ environment variable to PST8PDT. The tests will not work in any other timezone.
  4. Open the "<ICU>\source\allinone\allinone.dsw" workspace file in Microsoft Visual C++ 6.0. (This workspace includes all the International Components for Unicode libraries, necessary ICU building tools, and the intltest and cintltest test suite projects). Please see the note below if you want to build from the command line instead.
  5. Set the active Project to the "all" project. To do this: Choose "Project" menu, and select "Set active project". In the submenu, select the "all" workspace.
  6. Set the active configuration to "Win32 Debug" or "Win32 Release" (See note below).
  7. Choose the "Build" menu and select "Rebuild All". If you want to build the Debug and Release at the same time, see the note below.
  8. Run the C++ test suite, "intltest". To do this: set the active project to "intltest", and press F5 to run it.
  9. Run the C test suite, "cintltst". To do this: set the active project to "cintltst", and press F5 to run it.
  10. Make sure that both "cintltst" and "intltest" passed without any errors. The return codes are non-zero when they do not pass. Visual C++ will display the return codes in the debug tag of the output window. When "intltest" and "cintltest" return 0, it means that everything is installed correctly. You can press Ctrl+F5 on the test project to run the test and see what error messages were displayed (if any tests failed).
  11. Reset the TZ environment variable to its original value, unless you plan on testing ICU any further.
  12. You are now able to develop applications with ICU.

Using MSDEV At The Command Line Note: You can build ICU from the command line. Assuming that you have properly installed Microsoft Visual C++ to support command line execution, you can run the following command, 'msdev <ICU>\source\allinone\allinone.dsw /MAKE "ALL"'.

Setting Active Configuration Note: To set the active configuration, two different possibilities are:

Batch Configuration Note: If you want to build the Debug and Release configurations at the same time, choose "Build" menu and select "Batch Build..." instead (and mark all configurations as checked), then click the button named "Rebuild All". The "all" workspace will build all the test programs as well as the tools for generating binary locale data files. The "makedata" project will be run automatically to convert the locale data files from text format into icudata.dll.

How To Build And Install On Unix

Building International Components for Unicode on Unix requires:

A UNIX C++ compiler, (gcc, cc, xlc_r, etc...) installed on the target machine. A recent version of GNU make (3.7+). For a list of OS/390 tools please view the OS/390 build section of this document for further details.

The steps are:

  1. Decompress the icuXXXX.tar (or icuXXXX.tgz) file. For example, gunzip -d < icuXXXX.tgz | tar xvf -
  2. Change directory to the "icu/source".
  3. chmod +x runConfigureICU install-sh
  4. Run the runConfigureICU script for your platform. If you are not using the runConfigureICU script or your platform is not supported by the script, you need to set your CC, CXX, CFLAGS and CXXFLAGS environment variables, and type "./configure". You can type "./configure --help" to print the available options.
  5. Type "gmake" to compile the libraries and all the data files.
  6. Optionally, type "gmake check" to verify the test suite.
  7. Type "gmake install" to install.

Some platforms use package management tools to control the installation and uninstallation of files on the system, as well as the integrity of the system configuration. You may want to check if ICU can be packaged for your package management tools by looking into the "packaging" directory. (Please note that if you are using a snapshot of ICU from CVS, it is probable that the packaging scripts or related files are not up to date with the contents of ICU at this time, so use them with caution.)

OS/390 (zSeries) Platform

If you are building on the OS/390 UNIX System Services platform, it is important that you understand a few details:

OS/390 Batch (PDS) support

By default, ICU builds its libraries into the HFS. However, there is a 390-specific switch to build some libraries into PDS files. The switch is the environmental variable OS390BATCH, and if set, the following libraries are built into PDS files: libicuucXX.dll, libicudtXXe.dll, libicudtXXe_390.dll, and libtestdata.dll. Turning on OS390BATCH does not turn off the normal HFS build, thus the HFS dlls will always be created.

The names of the PDS files are determined by the value of the environmental variables LOADMOD and LOADEXP. These variables must contain the target PDS names whenever the OS390BATCH variable is set. LOADMOD is the library (.dll) target dataset and LOADEXP is the side deck (.x) target dataset.

The PDS member names are as follows:

IXMICUUC --> libicuucXX.dll
IXMICUDA --> libicudtXXe.dll
IXMICUD1 --> libicudtXXe_390.dll
IXMICUTE --> libtestdata.dll

Example PDS attributes are as follows:

Data Set Name . . . : USER.ICU.LOAD
General Data
Management class. . : **None**
Storage class . . . : BASE
Volume serial . . . : TSO007
Device type . . . . : 3390
Data class. . . . . : LOAD
Organization  . . . : PO
Record format . . . : U
Record length . . . : 0
Block size  . . . . : 32760
1st extent cylinders: 40
Secondary cylinders : 59
Data set name type  : PDS

Data Set Name . . . : USER.ICU.EXP
General Data
Management class. . : **None**
Storage class . . . : BASE
Volume serial . . . : TSO007
Device type . . . . : 3390
Data class. . . . . : **None**
Organization  . . . : PO
Record format . . . : FB
Record length . . . : 80
Block size  . . . . : 3200
1st extent cylinders: 3
Secondary cylinders : 3
Data set name type  : PDS

OS/400 (iSeries) Platform

ICU Reference Release 1.8.1 contains partial support for the 400 platform, but additional work by the user is currently needed to get it to build properly. A future release of ICU should work out-of-the-box under OS/400.

Important Notes About Using ICU

Windows Platform

If you are building on the Win32 platform, it is important that you understand a few of the following build details.

DLL directories and the PATH setting

As delivered, the International Components for Unicode build as several DLLs which are placed in the "<ICU>\bin" directory. You must add this directory to the PATH environment variable in your system, or any executables you build will not be able to access International Components for Unicode libraries. Alternatively, you can copy the DLL files into a directory already in your PATH, but we do not recommend this. You can wind up with multiple copies of the DLL and wind up using the wrong one.

Changing your PATH

Note: when packaging a Windows application for distribution and installation on user systems, copies of the ICU dlls should be included with the application, and installed for exclusive use by the application. This is the only way to insure that your app is running with the same version of ICU, built with exactly the same options, that you developed and tested with. Refer to Microsoft's guidelines on the usage of dlls, or search for the phrase "dll hell" on msdn.microsoft.com.

Linking with Runtime libraries

All the DLLs link with the C runtime library "Debug Multithreaded DLL" or "Multithreaded DLL." (This is changed through the Project Settings dialog, on the C/C++ tab, under Code Generation.) It is important that any executable or other DLL you build which uses the International Components for Unicode DLLs links with these runtime libraries as well. If you do not do this, you will get random memory errors when you run the executable.

Unix Type Platform

If you are building on a Unix platform, it is important that you add the location of your ICU libraries (including the data library) to your LD_LIBRARY_PATH environment variable. The ICU libraries may not link or load properly without doing this.

Using the default codepage

ICU has code to determine the default codepage of the system or process. This default codepage can be used to convert char * strings to and from Unicode.

Depending on system design, setup and APIs, it may not always be possible to find a default codepage that fully works as expected. For example,

If you have means of detecting a default codepage name that are more appropriate for your application, then you should set that name with ucnv_setDefaultName() as the first ICU function call. This makes sure that the internally cached default converter will be instantiated from your preferred name.

Starting in ICU 2.0, when a converter for the default codepage cannot be opened, a fallback default codepage name and converter will be used. On most platforms, this will be US-ASCII. For OS/390 (z/OS), ibm-1047-s390 is the default fallback codepage. For AS/400 (iSeries), ibm-37 is the default fallback codepage. This default fallback codepage is used when the operating system is using a non-standard name for a default codepage, or the converter was not packaged with ICU. The feature allows ICU to run in unusual computing environments without completely failing.

Methods for enabling deprecated APIs

C

Some deprecated C APIs can be enabled without recompiling the ICU libraries. This can be achieved by defining certain symbols before including the ICU header files. For example, to enable deprecated C APIs for formatting.

#ifndef U_USE_DEPRECATED_FORMAT_API
#  define U_USE_DEPRECATED_FORMAT_API 1
#endif

#include "unicode/udat.h"

int main(){
    UDateFormat *def, *fr, *fr_pat ;
    UErrorCode status = U_ZERO_ERROR;
    UChar temp[30];

    fr = udat_open(UDAT_FULL, UDAT_DEFAULT, "fr_FR", NULL,0, &status);
    if(U_FAILURE(status)){
        printf("Error creating the french dateformat using full time style\n %s\n",
            myErrorName(status) );
    }
    /* This is supposed to open default date format,
       but later on it treats it like it is "en_US".
       This is very bad when you try to run the tests
       on a machine where the default locale is NOT "en_US"
    */
    def = udat_open(UDAT_SHORT, UDAT_SHORT, "en_US", NULL, 0, &status);
    if(U_FAILURE(status)){
        .... /* handle the error */
    }
}

C++

Deprecated C++ APIs cannot be enabled without recompiling ICU libraries. Every service has a specific symbol that should be defined to enable the deprecated API of that service. For example: To enable deprecated APIs in Transliteration service, the U_USE_DEPRECATED_TRANSLITERATOR_API symbol should be defined before compiling ICU.

Platform Dependencies

The platform dependencies have been mostly isolated into the following files in the common library. This information can be useful if you are porting ICU to a new platform.

It is possible to build each library individually. They must be built in the following order:

  1. stubdata
  2. common
  3. i18n
  4. toolutil
  5. makeconv
  6. genrb
  7. gentz
  8. genccode
  9. gennames
  10. genuca
  11. gennorm
  12. makedata (a project on Windows, or source/data/Makefile on Unix)
  13. ctestfw, intltest and cintltst, if you want to run the test suite.

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