International Components for Unicode
ICU 2.8 ReadMe

Version: 2004-Apr-01
Copyright © 1997-2004 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 (ICU) libraries provide robust and full-featured Unicode services on a wide variety of platforms to help this design goal. The ICU libraries provide 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/index.html
ICU4J Homepage http://oss.software.ibm.com/icu4j/index.html
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/index.html
Download ICU Releases http://oss.software.ibm.com/icu/download/index.html
API Documentation Online http://oss.software.ibm.com/icu/apiref/index.html
Online ICU Demos http://oss.software.ibm.com/icu/demo/index.html
Contacts and Bug Reports/Feature Requests http://oss.software.ibm.com/icu/archives/index.html

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 2.8 download page.

Locale Identifier Changes

The ICU locale identifier format has recently changed. In order to improve support for RFC 3066 identifiers and to support keyword identifiers, some minor breaking changes have been introduced. When your application is working with POSIX locale identifiers or .NET locale identifiers, you should use uloc_canonicalize() to convert it to an ICU locale identifier. It was an undocumented feature that you could pass a POSIX locale to ICU, and ICU would convert it for you automatically. For example, if you used @EURO or @PREEURO to identify certain currencies, you should now be using the "@currency=" keyword for the locale identifiers. If you use the uloc_canonicalize() function, it will convert the @PREEURO variants to the proper ICU locale identifier. For example, it will convert "fr-fr@PREEURO" to "fr_FR@currency=FRF". More information about keywords can be found in the Locale Section of the User's Guide and on the OpenI18N site.

Some ISO 15924 script codes are used in some RFC 3066 language tags. This is especially helpful when you need to differentiate cases where a language can be written with more than one script. Since ICU now supports ISO 15924 script codes in the locale identifier, you can now specify locales like "zh_Hant" to specify Traditional Chinese. Previously, people had to use "zh_TW" to specify Traditional Chinese, which isn't quite correct because the locale identifier is specifying the language of a region and not the type of language. The current locale identifiers, like en_US, still work, and do not require any changes in your code. Future versions of ICU will move the data into the proper locale resources, and the locale infrastructure will be improved.

In order to differentiate between the two library names on all platforms, static libraries now use an "s" as a prefix to differentiate between the shared and static libraries. For example, "libicuuc.a" is now "libsicuuc.a". This means that if you used "-licuuc" to link the common library into your application, you now need to use "-lsicuuc".

ICUIO Library Changes

The ICUIO library is still unsupported (this was previously called the ustdio library), and some breaking fixes have been made to the library. %S should be used for UTF-16 strings, and %C should be used for UChar for the format strings. The %K and %U format specifiers are deprecated and will be removed in a future version of ICU. Also u_fgets now uses the same argument ordering as stdio fgets, which will make it easier for people to migrate their existing stdio implementations to use ICUIO. Fortunately, u_fgets now follows the Unicode algorithm for detecting hard line breaks, and some performance enhancements to this library have been implemented so that most of the formatting and parsing functions will run faster.

Library Initialization

ICU4C 2.6 introduces a library initialization function. It is required to call it before using any ICU services in a multi-threaded environment. For details please see the documentation of u_init() in the unicode/uclean.h header file.


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. You can also view the ICU Architectural Design section of the User's Guide to see which libraries you need for your software product. You need at least the data ([lib]icudt) and the common ([lib]icuuc) libraries in order to use ICU.

The following files describe the code drop.
File Description
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.
Directory Description
<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/data/

This directory contains the source data in text format, which is compiled into binary form during the ICU build process. It contains several subdirectories, in which the data files are grouped by function. Note that the build process must be run again after any changes are made to this directory.

  • brkitr/ Data files for character, word, sentence, title casing and line boundary analysis.
  • locales/ These .txt files contain 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. The makefile resfiles.mk contains the list of resource bundle files.
  • mappings/ Here are the code page converter tables. These .ucm files contain 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.icu. The makefiles ucmfiles.mk, ucmcore.mk, and ucmebcdic.mk contain the list of converters to be built.
  • translit/ This directory contains transliterator rules as resource bundles, a makefile trnsfiles.mk containing the list of installed system translitaration files, and as well the special bundle translit_index which lists the system transliterator aliases.
  • unidata/ This directory contains the Unicode data files. Please see http://www.unicode.org/ for more information.
  • misc/ The misc directory contains other data files which did not fit into the above categories. Currently it only contains time zone information, and a name preperation file for IDNA.
  • out/ This directory contains the assembled memory mapped files.
  • out/build/ This directory contains intermediate (compiled) files, such as .cnv, .res, etc.

If you are creating a special ICU build, you can set the ICU_DATA environment variable to the out/ or the out/build/ directories, but this is generally discouraged because most people set it incorrectly. You can view the ICU Data Management section of the ICU User's Guide for details.

<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>/source/test/testdata/ Source text files for data, which are read by the tests. It contains the subdirectories out/build/ which is used for intermediate files, and out/ which contains testdata.dat.
<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 workspace and project files, for instance to build all of ICU under one MSVC project.
<ICU>/include/ Contains the headers needed for developing software that uses ICU on Windows.
<ICU>/lib/ Contains the import libraries for linking ICU into your Windows application.
<ICU>/bin/ Contains the libraries and executables for using ICU on Windows.

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 2000/XP Microsoft Visual C++ 6.0 Reference platform
Windows XP Microsoft Visual C++ .NET 2002 (7.0) Reference platform
Red Hat Linux 7.2 gcc 2.96 Reference platform
AIX 5.1.0 L Visual Age C++ 5.0 Reference platform
Solaris 7 (SunOS 5.7) Workshop Pro (Forte) CC 6.0 Reference platform
HP-UX 11.01 aCC A.03.13
cc A.11.01.00
Reference platform
Windows NT/98 Microsoft Visual C++ 6.0 Regularly tested
Windows 2000 with CygWin Microsoft Visual C++ 6.0 Regularly tested
Mac OS X (10.2) gcc 3.1
(Developer Tools, July 2002)
Regularly tested
Solaris 8 (SunOS 5.8) Workshop Pro CC 4.2
(use 'runConfigureICU SOLARISCC/W4.2')
Regularly tested
Solaris 2.6 (SunOS 5.6) gcc 2.95.2 Regularly tested
FreeBSD 4.8 gcc 2.95.4 Regularly tested
Red Hat Alpha Linux 7.2 gcc 2.96 Regularly tested
z/OS 1.2 cxx 1.2 Regularly tested
OS/400 (iSeries) V5R1 iCC Regularly tested
Red Hat Alpha Linux 7.2 Compaq C++ Compiler 3.2
Compaq C Compiler 6.5.6
Rarely tested
AIX 4.3.3 xlC_r 4.0.2.1 Rarely tested
QNX gcc Rarely tested
NetBSD, OpenBSD gcc Rarely tested
BeOS gcc Rarely tested
CygWin gcc 2.95.3 Rarely tested
SGI/IRIX   Rarely tested
Tru64 (OSF) Compaq's cxx compiler Rarely tested
HP-UX 11.01 CC A.03.10 Rarely tested
MP-RAS NCR MP-RAS C/C++ Compiler Rarely tested


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:

(If you want to build with Microsoft Visual C++ .NET, please refer to the note about building with Visual Studio .NET below.)

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. 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.
  4. 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.
  5. Set the active configuration to "Win32 Debug" or "Win32 Release" (See Windows configuration note below).
  6. Choose the "Build" menu and select "Rebuild All". If you want to build the Debug and Release at the same time, see the batch configuration note below.
  7. Run the C++ test suite, "intltest". To do this: set the active project to "intltest", and press F5 to run it.
  8. Run the C test suite, "cintltst". To do this: set the active project to "cintltst", and press F5 to run it.
  9. 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).
  10. You are now able to develop applications with ICU by using the libraries and tools in <ICU>\bin\. The headers are in <ICU>\include\ and the link libraries are in <ICU>\lib\. To install the ICU runtime on a machine, or ship it with your application, copy the needed components from <ICU>\bin\ to a location on the system PATH or to your application directory.

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 libraries, test programs and various ICU tools (e.g. genrb for generating binary locale data files).

Microsoft Visual Studio .NET Note: ICU will build with Microsoft Visual Studio .NET 2002. It is recommended that you use the "<ICU>\source\allinone\allinone.sln" solution workspace to build ICU. The instructions for building with Visual Studio .NET are similar to the instructions for Visual Studio .NET. If you have Microsoft Visual Studio .NET 2003 the Visual Studio .NET 2002 project files will automatically be converted to 2003 project files when you open the solution workspace for the first time.

How To Build And Install On Windows XP on IA64

Building International Components for Unicode requires:

The steps are:

  1. Follow steps 1-3 in the in the previous section.
  2. Open the "Set Windows XP 64-bit Build Environment (Retail)" command window from the Microsoft Platform SDK.
  3. If your computer is not set up to do command line builds, then run "set PATH=C:\Program Files (x86)\Microsoft Visual Studio\Common\MSDev98\Bin;%PATH%" or include the path where MSDEV.EXE is located.
  4. Use cd to get into the <ICU> directory.
  5. Run this command: 'msdev /USEENV <ICU>\source\allinone\allinone.dsw /MAKE "all - Win64 Release"'
  6. Run "cd source\test\intltest\Release"
  7. Run the C++ test suite, "intltest". There should be no errors.
  8. Run "cd ..\..\cintltst\Release"
  9. Run the C test suite, "cintltst". There should be no errors.
  10. Follow the last step in the in the previous section.

How To Build And Install On Windows with Cygwin

Building International Components for Unicode with this configuration requires:

There are two ways you can build ICU with Cygwin. You can build with gcc or Microsoft Visual C++. If you use gcc, the resulting libraries and tools will depend on the Cygwin environment. If you use Microsoft Visual C++, the resulting libraries and tools do not depend on Cygwin and can be more easily distributed to other Windows computers (the generated man pages and shell scripts still need Cygwin). To build with gcc, please follow the "How To Build And Install On UNIX" instructions, while you are inside a Cygwin bash shell. To build with Microsoft Visual C++, please use the following instructions:

  1. Start the Windows "Command Prompt" window (this is different from the gcc build, which requires the Cygwin Bash Shell).
  2. If the computer isn't set up to use Visual C++ from the command line, you need to run VCVARS32.BAT (for example: "C:\Program Files\Microsoft Visual Studio\VC98\Bin\VCVARS32.BAT").
  3. 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.
  4. Change directory to "icu/source", which is where you unzipped ICU.
  5. Run "bash ./runConfigureICU Cygwin/MSVC" (See configuration note below).
  6. Type "make" to compile the libraries and all the data files. This make command should be GNU make.
  7. Optionally, type "make check" to run the test suite, which checks for ICU's functionality integrity (See testing note below).
  8. Type "make install" to install ICU. If you used the --prefix= option on configure or runConfigureICU, ICU will be installed to the directory you specified. (See installation note below).

How To Build And Install On UNIX

Building International Components for Unicode on UNIX requires:

Here are the steps to build ICU:

  1. Decompress the icu-X.Y.tgz (or icu-X.Y.tar.gz) file. For example, "gunzip -d < icu-X.Y.tgz | tar xvf -"
  2. Change directory to the "icu/source".
  3. Run "chmod +x runConfigureICU configure install-sh" because these files may have the wrong permissions.
  4. Run the runConfigureICU script for your platform. (See configuration note below).
  5. Type "gmake" (or "make" if GNU make is the default make on your platform) to compile the libraries and all the data files. The proper name of the GNU make command is printed at the end of the configuration run, as in "You must use gmake to compile ICU".
  6. Optionally, type "gmake check" to run the test suite, which checks for ICU's functionality integrity (See testing note below).
  7. Type "gmake install" to install ICU. If you used the --prefix= option on configure or runConfigureICU, ICU will be installed to the directory you specified. (See installation note below).

Configuring ICU NOTE: Type "./runConfigureICU --help" for help on how to run it and a list of supported platforms. You may also want to type "./configure --help" to print the available configure options that you may want to give runConfigureICU. If you are not using the runConfigureICU script, or your platform is not supported by the script, you may need to set your CC, CXX, CFLAGS and CXXFLAGS environment variables, and type "./configure". Some of the more frequently used options to configure are --disable-64bit-libs to create 32-bit libraries, and --srcdir to do out of source builds (build the libraries in the current location). HP-UX user's, please see this note regarding multithreaded build issues with newer compilers. Solaris user's, please see this note regarding multithreaded build issues.

Running The Tests From The Command Line NOTE: You may have to set certain variables if you with to run test programs individually, that is apart from "gmake check". The environment variable ICU_DATA can be set to the full pathname of the data directory to indicate where the locale data files and conversion mapping tables are when you are not using the shared library (e.g. by using the .dat archive or the individual data files). The trailing "/" is required after the directory name (e.g. "$Root/source/data/out/" will work, but the value "$Root/source/data/out" is not acceptable). You do not need to set ICU_DATA if the complete shared data library is in your library path.

Installing ICU NOTE: 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).

How To Build And Install On z/OS (OS/390)

You can install ICU on z/OS or OS/390 (the previous name of z/OS), but IBM tests only the z/OS installation. These platforms commonly are called "MVS". You install ICU in a z/OS UNIX system services file system such as HFS or zFS. On this platform, it is important that you understand a few details:

z/OS (Batch/PDS) support outside the UNIX system services environment

By default, ICU builds its libraries into the UNIX file system (HFS). In addition, there is a z/OS specific environment variable (OS390BATCH) to build some libraries into the z/OS native file system. This is useful, for example, when your application is externalized via Job Control Language (JCL).

The OS390BATCH environment variable enables non-UNIX support including the batch environment. When OS390BATCH is set, the libicuucXX.dll, libicudtXXe.dll, and libicudtXXe_stub.dll binaries are built into data sets (the native file system). Turning on OS390BATCH does not turn off the normal z/OS UNIX build. This means that the z/OS UNIX (HFS) DLLs will always be created.

Two additional environment variables indicate the names of the z/OS data sets to use. The LOADMOD environment variable identifies the name of the data set that contains the dynamic link libraries (DLLs) and the LOADEXP environment variable identifies the name of the data set that contains the side decks, which are normally the files with the .x suffix in the UNIX file system.

A data set is roughly equivalent to a UNIX or Windows file. For most kinds of data sets the operating system maintains record boundaries. UNIX and Windows files are byte streams. Two kinds of data sets are PDS and PDSE. Each data set of these two types contains a directory. It is like a UNIX directory. Each "file" is called a "member". Each member name is limited to eight bytes, normally EBCDIC.

Here is an example of some environment variables that you can set prior to building ICU:

OS390BATCH=1
LOADMOD=USER.ICU.LOAD
LOADEXP=USER.ICU.EXP

The PDS member names for the DLL file names are as follows:

IXMIXXIN --> libicui18nXX.dll
IXMIXXUC --> libicuucXX.dll
IXMIXXDA --> libicudtXXe.dll
IXMIXXD1 --> libicudtXXe_stub.dll (Only when OS390_STUBDATA=1)

You should point the LOADMOD environment variable at a partitioned data set extended (PDSE) and point the LOADEXP environment variable at a partitioned data set (PDS). The PDSE can be allocated with the following attributes:

Data Set Name . . . : USER.ICU.LOAD
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: 1
Secondary cylinders : 5
Data set name type  : LIBRARY

The PDS can be allocated with the following attributes:

Data Set Name . . . : USER.ICU.EXP
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

How To Build And Install On OS/400 (iSeries)

Before you start building ICU, ICU requires the following:

The following describes how to setup and build ICU. For background information, you should look at the UNIX build instructions.

  1. Create AS400 target library. This library will be the target for the resulting modules, programs and service programs. You will specify this library on the OUTPUTDIR environment variable in step 2.
    CRTLIB LIB(libraryname)
    

  2. Set up the following environment variables in your build process (use the libraryname from the previous step)
    ADDENVVAR ENVVAR(CC) VALUE('/usr/bin/icc')
    ADDENVVAR ENVVAR(CXX) VALUE('/usr/bin/icc')
    ADDENVVAR ENVVAR(MAKE) VALUE('/usr/bin/gmake')
    ADDENVVAR ENVVAR(OUTPUTDIR) VALUE('libraryname')
    
    libraryname identifies target as400 library for *module, *pgm and *srvpgm objects.

  3. Run 'CHGJOB CCSID(37)'
  4. Run 'QSH'
  5. Run gunzip on the ICU source code compressed tar archive (icu-X.Y.tgz or icu-X.Y.tar.gz).
  6. Run unpax-icu.sh on the tar file from the ICU download page.
  7. Change your current directory to icu/source.
  8. Run 'export CFLAGS=-O4 CXXFLAGS=-O4' to optimize your build of ICU. If the build fails, rerun these build steps without this step before asking the icu4c-support mailing list for help.
  9. Run 'cp ../as_is/os400/configure .'
  10. Run './configure --host=as400-os400'
  11. If you specified --with-data-packaging=archive to configure, you can skip this step. In a future release of ICU, we hope to eliminate this complicated step. Any suggestions to improve the ICU installation are greatly appreciated, and you can send those suggestions to the icu4c-support mailing list.
    1. Run 'mv data/Makefile data/Makefile.hide'
    2. Run 'gmake' to build some of the ICU libraries.
    3. When the gmake command fails in icu/source/data, run the following commands to setup and build the data library:
      cd data
      mv Makefile.hide Makefile
      system CRTLIB "LIB(datalibraryname)"
      gmake OUTPUTDIR=datalibraryname
      system CRTSRVPGM "SRVPGM(libraryname/LIBICUDATA)" "MODULE(datalibraryname/*ALL)"
                       "EXPORT(*ALL)" "TEXT('ICU 2.8 DATA')" "OPTION(*DUPPROC *DUPVAR)"
      ln -fs /qsys.lib/libraryname.lib/libicudata.srvpgm out/libicudata.so
      cd ..
      del common/libicuuc.so
      
      
    4. Your data library should now be usable. Go to the next step, which is needed to rebind to the actual data library and finish the build.
  12. Run 'gmake' to build ICU.
  13. Run 'gmake check' to build the tests.
  14. The "utility/MultithreadTest" test in intltest may have failed during 'gmake check'. In order to make this test pass, please use 'gmake check QIBM_MULTI_THREADED=Y' after you built the tests with 'gmake check' from the previous step. You can look at the iSeries Information Center for more details.

How To Package ICU

There are many ways that a person can package ICU with their software products. Usually only the libraries need to be considered for packaging.

On UNIX, you should have used "gmake install" to make it easier to develop and package ICU. The bin, lib and include directories are needed to develop applications that use ICU. These directories will be created relative to the "--prefix=dir" configure option (See the UNIX build instructions). When ICU is built on Windows, a similar directory structure is built.

When changes have been made to the standard ICU distribution, it is recommended that at least one of the following guidelines be followed for special packaging.

  1. Add a suffix name to the library names. This can be done with the --with-library-suffix configure option.
  2. The installation script should install the ICU libraries into the application's directory.

Following these guidelines prevents other applications that use a standard ICU distribution from conflicting any libraries that you need. On operating systems that do not have a standard C++ ABI (name mangling) for compilers, it is recommended to do this special packaging anyway. More details on customizing ICU are available in the User's Guide. The ICU Source Code Organization section of this readme.html gives a more complete description of the libraries.

Here is an example of libraries that are frequently packaged.
Library Name Windows Filename Linux Filename Comment
Data Library icudtXYl.dll libicudata.so.XY.Z Data required by the Common and I18n libraries. There are many ways to package and customize this data, but by default this is all you need.
Common Library icuucXY.dll libicuuc.so.XY.Z Base library required by all other ICU libraries.
Internationalization (i18n) Library icuinXY.dll libicui18n.so.XY.Z A library that contains many locale based internationalization (i18n) functions.
Layout Engine iculeXY.dll libicule.so.XY.Z An optional engine for doing font layout.
Layout Extensions Engine iculxXY.dll libiculx.so.XY.Z An optional engine for doing font layout that uses parts of ICU.
ICU I/O (Unicode stdio) Library icuioXY.dll libicuio.so.XY.Z An optional library that provides a stdio like API with Unicode support.
Tool Utility Library icutuXY.dll libicutu.so.XY.Z An internal library that contains internal APIs that are only used by ICU's tools. If you do not use ICU's tools, you do not need this library.

Normally only the above ICU libraries need to be considered for packaging. The versionless symbolic links to these libraries are only needed for easier development. The X, Y and Z parts of the name are the version numbers of ICU. For example, ICU 2.0.2 would have the name libicuuc.so.20.2 for the common library. The exact format of the library names can vary between platforms due to how each platform can handles library versioning.

Important Notes About Using ICU

Using ICU in a Multithreaded Environment

Upon the first usage of most ICU APIs, the global mutex will get initialized properly, but you can use the u_init() function from uclean.h to ensure that it is initialized properly. Without calling this function from a single thread, the data caches inside ICU may get initialized more than once from multiple threads, which may cause memory leaks and other problems. There is no harm in calling u_init() in a single threaded application.

Using ICU in a Multithreaded Environment on HP-UX

If you are building ICU with a newer aCC compiler and you are planning on using the older <iostream.h> instead of the newer <iostream>, you will need to use a special configure flag before building ICU. By default, the aCC -AA flag is used on HP-UX when the compiler supports that option in order to make ICU thread safe with RogueWave and other libraries using the 2.0 Standard C++ library. Your applications that use ICU will also need to use the -AA compiler flag. To turn off this behavior in ICU, you will need to use the --with-iostream= old configure option when you first use runConfigureICU.

Using ICU in a Multithreaded Environment on Solaris

Solaris Deadlock Issues in Solaris 2.8, and Earlier

Solaris 2.8, and earlier, has outstanding thread deadlocking issues that MAY be problematic for applications using either native, or POSIX, threading on these platforms. Sun states that Solaris 2.9 DOES NOT have the deadlock problems. Deadlocks MAY occur either during initialization of the Solaris threading library, or at any other time.

Sun Microsystems has provided a Sun Alert Notification regarding the issue. Users SHOULD consider applying the latest OS patches to their Solaris installations in order to help avoid deadlock. Further information regarding the issue, and links to applicable patches, may be found at:

[1] "Applications Linked to libthread May Hang", Sun Alert Notification, Sun Microsystems, Inc., 04-Sep-2002
http://sunsolve.sun.com/pub-cgi/retrieve.pl?doc=fsalert%2F46867&zone_32=4663077

Sun is NOT providing patches for Solaris 2.6, or earlier.

Sun states that by applying the patch users will avoid the deadlock issues. However, with all applicable patches applied, deadlock MAY still be seen, as demonstrated by the ICU Mutex unit tests. The unit test will hang indefinitely. No bug exists in ICU. However, a latent bug still exists in Solaris, which Sun Microsystems has yet to resolve. In order to avoid this, users are SUGGESTED to modify their LD_LIBRARY_PATH according to the guidelines specified by Sun Microsystems in the Sun Alert Notification.

Linking on Solaris

In order to avoid synchronization and threading issues, developers are SUGGESTED to strictly follow the compiling and linking guidelines for multithreaded applications, specified in the following document from Sun Microsystems. Most notably, pay strict attention to the following statements from Sun:

To use libthread, specify -lthread before -lc on the ld command line, or last on the cc command line.

To use libpthread, specify -lpthread before -lc on the ld command line, or last on the cc command line.

Failure to do this may cause spurious lock conflicts, recursive mutex failure, and deadlock.

[2] "Solaris Multithreaded Programming Guide, Compiling and Debugging", Sun Microsystems, Inc., Apr 2004
http://docs.sun.com/db/doc/806-6867/6jfpgdcob?a=view

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 application 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.

UNIX Type Platform

If you are building on a UNIX platform, and if you are installing ICU in a non-standard location, you may need to add the location of your ICU libraries to your LD_LIBRARY_PATH or LIBPATH environment variable (or the equivalent runtime library path environment variable for your system). The ICU libraries may not link or load properly without doing this.

Note that if you do not want to have to set this variable, you may instead use the --enable-rpath option at configuration time. This option will instruct the linker to always look for the libraries where they are installed. You will need to use the appropriate linker options when linking your own applications and libraries against ICU, too. Please refer to your system's linker manual for information about runtime paths. The use of rpath also means that when building a new version of ICU you should not have an older version installed in the same place as the new version's installation directory, as the older libraries will used during the build, instead of the new ones, likely leading to an incorrectly build ICU. (This is the proper behavior of rpath.)

Platform Dependencies

Porting To A New Platform

If you are using ICU's Makefiles to build ICU on a new platform, there are a few places where you will need to add or modify some files. If you need more help, you can always ask the icu4c-support mailing list. Once you have finished porting ICU to a new platform, it is recommended that you contribute your changes back to ICU via the icu4c-support mailing list. This will make it easier for everyone to benefit from your work.

Data For a New Platform

For some people, it may not be necessary for completely build ICU. Most of the makefiles and build targets are for tools that are used for building ICU's data, and an application's data (when an application uses ICU resource bundles for its data).

Data files can be built on a different platform when both platforms share the same endianness and the same charset family. This assertion does not include platform dependent DLLs/shared/static libraries. For details see the User Guide ICU Data chapter.

ICU 2.8 removes the requirement that ICU be completely built in the native operating environment. It adds the icuswap tool which can be run on any platform to turn binary ICU data files from any one of the three formats into any one of the other data formats. This allows a application to use ICU data built anywhere to be used for any other target platform.

WARNING! Building ICU without running the tests is not recommended. The tests verify that ICU is safe to use. It is recommended that you try to completely port and test ICU before using the libraries for your own application.

Adapting Makefiles For a New Platform

Try to follow the build steps from the UNIX build instructions. If the configure script fails, then you will need to modify some files. Here are the usual steps for porting to a new platform:

  1. Create an mh file in icu/source/config/. You can use mh-linux or a similar mh file as your base configuration.
  2. Modify icu/source/aclocal.m4 to recognize your platform's mh file.
  3. Modify icu/source/configure.in to properly set your platform C Macro define.
  4. Run autoconf in icu/source/ without any options. The autoconf tool is standard on most Linux systems.
  5. If you have any optimization options that you want to normally use, you can modify icu/source/runConfigureICU to specify those options for your platform.
  6. Build and test ICU on your platform. It is very important that you run the tests. If you don't run the tests, there is no guarentee that you have properly ported ICU.

Platform Dependent Implementations

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.

Build Order Without Using ICU's Makefiles

It is possible to build each library individually without our Makefiles. They must be built in the following order:

  1. stubdata
  2. common
  3. i18n
  4. toolutil
  5. makeconv
  6. gencnval
  7. genprops
  8. gennames
  9. genpname
  10. gennorm
  11. gensprep
  12. genbrk
  13. genuca
  14. genrb
  15. genccode
  16. gencmn
  17. pkgdata
  18. makedata (a project on Windows, or source/data/Makefile on UNIX)
  19. layout (optional)
  20. layoutex (optional)
  21. ctestfw, intltest and cintltst, if you want to run the test suite.
  22. uconv, icuswap and icuio (ustdio) can also be optionally built.

Copyright © 1997-2004 International Business Machines Corporation and others. All Rights Reserved.
IBM Globalization Center of Competency - San José
5600 Cottle Road
San José, CA 95193
USA