# International Components for Unicode
ReadMe

Version: 2001-Mar-21
Copyright © 1997-2001 International Business Machines Corporation and others. All Rights Reserved.

## Contents

- Late Breaking News And What Is New?
- Introduction
- What the International Components for Unicode Contain
- Platform Dependencies
- Important Installation Notes
- How to Build And Install ICU
- Where To Find More Information
- Submitting Comments, Requesting Features and Reporting Bugs

## Late Breaking News And What Is New?

- Library names are changed and moved on Win32
- Using Shared Data Libraries
- Important Change Of Error Codes From Streaming Conversion Functions (change for ICU 1.6)
- The collation implementation is being reworked
- We have improved or added support for country variants of ISO-2022, HZ, UTF-32, UTF-7, and GB 18030
- Updated API documentation
- For more news about this release, see the online release notes.

## Introduction

Today's software market is a global one in which it is desirable to develop and maintain one application that supports a wide variety of national languages. International Components for Unicode provides the following tools to help you write language independent applications:

- UnicodeString supporting the Unicode 3.0 standard
- Resource bundles for storing and accessing localized information
- Number formatters for converting binary numbers into text strings for meaningful display
- Date and time formatters for converting internal time data into text strings for meaningful display
- Message formatters for putting together sequences of strings, numbers dates and other format to create messages
- Text collation supporting language sensitive comparison of strings
- Text boundary analysis for finding characters, word and sentence boundaries
- Changing simple data files rather than modifying program code easily localizes applications written using these tools
- Over 160 locales supported. Visit the LocaleExplorer (http://oss.software.ibm.com/developerworks/opensource/icu/localeexplorer) site for a demonstration and a full list of supported locales or see the index file with the supported locales. Also see the User Guide.

It is possible to support additional locales by adding more locale data files, with no code changes.

Please refer to POSIX programmer's Guide for details on what the ISO locale ID means.

Your comments are important to making this release successful. We are committed to fixing any bugs, and will also use your feedback to help plan future releases.

IMPORTANT: Please make sure you understand the Copyright and License information.

## What the International Components for Unicode Contain

There are two ways to download the ICU releases,

- Official Release Snapshot:
  If you want to use ICU (as opposed to developing it), you should download an official packaged version of the ICU source code. These versions are tested more thoroughly than day-to-day development builds of the system, and they are packaged in zip and tar files for convenient download. These packaged files can be found at http://oss.software.ibm.com/icu/download/.
  If packaged snapshot is named ICUXXXXXX.zip or ICUXXXXXX.tgz , XXXXXX is the release version number.
  Please unzip this file. It will reconstruct the source directory, including anonymous CVS control directories (see below).
- CVS Source Repository:
  If you are interested in developing features, patches, or bug fixes for ICU, you should probably be working with the latest version of the ICU source code. You will need to check the code out of our CVS repository to ensure that you have the most recent version of all of the files. There are several ways to do this:
- - WebCVS:
    If you want to browse the code and only make occasional downloads, you may want to use WebCVS. It provides a convenient, web-based interface for browsing and downloading the latest version of the ICU source code and documentation. You can also view each file's revision history, display the differences between individual revisions, determine which revisions were part of which official release, and so on.
  - WinCVS:
    If you will be doing serious work on ICU, you should probably install a CVS client on your own machine so that you can do batch operations without going through the WebCVS interface. On Windows, we suggest the WinCVS client. The following is the example instruction on how to download ICU via WinCVS:
    1. Install the WinCVS client, which you can download from the WinCVS home page.
    2. In the WinCVS preferences, specify your CVSRoot to be ":pserver:anoncvs@oss.software.ibm.com:/usr/cvs/icu"
       with the password "anoncvs". To enter the CVSRoot value, select "Preferences" from the "Cvs Admin" pull-down menu. Authentication should be set to "'passwd' file on the cvs server".
    3. To "extract" the most recent version of ICU, select "Checkout module" from the "Cvs Admin" menu. Specify "icu" for the module name.
  - CVS command line:
    You can also check out the repository anonymously on UNIX using the following commands, after first setting your CVSROOT to point to the ICU repository:
    export CVSROOT=:pserver:anoncvs@oss.software.ibm.com:/usr/cvs/icu
    cvs login CVS password: anoncvs
    cvs checkout icu
    cvs logout

For more details on how to download ICU directly from the web site, please also see http:/oss.software.ibm.com/icu/download/

Below, $Root is the placement of the icu directory in your file system, like "drive:\...\icu" in your environment. "drive:\..." stands for any drive and any directory on that drive that you chose to install icu into.

The following files describe the code drop
readme.html | Describes the International Components for Unicode (this file)
license.html | Contains IBM's public license

The following directories contain source code and data files
$Root/source/common/ | The core Unicode and support functionality, such as resource bundles, character properties, locales, codepage conversion, and normalization.Unicode, Locale, UnicodeString.
$Root/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.
$Root/source/test/intltest/ | A test suite including all C++ APIs. For information about running the test suite, see the users' guide.
$Root/source/test/cintltst/ | A test suite written in C, including all C APIs. For information about running the test suite, see the users' guide.

$Root/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 $Root/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.

$Root/source/data | This directory is where the final, packaged version of the ICU binary data ends up. If the ICU_DATA environment variable is used, then it should be set to this directory. The intermediate individual data files (.res, .cnv) are kept in the subdirectory "$Root/source/data/build" prior to packaging.
$Root/source/tools | Tools for generating the data files. Data files are generated by invoking $Root/source/data/build/makedata.bat on Win32 or $Root/source/make on unix.
$Root/source/samples | Various sample programs that use ICU
$Root/source/extra | Non-supported API additions. Currently, it contains the 'ustdio' file i/o library
$Root/source/layout | Contains the ICU layout engine (not a rasterizer).
$Root/packaging $Root/debian | These directories contain scripts and tools for packaging the final ICU build for various release platforms.
$Root/source/config | Contains helper makefiles for platform specific build commands. Used by 'configure'.
$Root/source/allinone | Contains top-level ICU project files, for instance to build all of ICU under one MSVC project.

## Platform Dependencies

The platform dependencies have been mostly isolated into the following files:

- platform.h.in: (autoconf'ed platforms)
  pXXXX.h (others: pwin32.h, pos2.h, pmacos.h, ..): Platform-dependent typedefs and defines:
  - XP_CPLUSPLUS for C++ only.
  - TRUE and FALSE, bool_t, int8_t, int16_t etc.
  - U_EXPORT and U_IMPORT for specifying dynamic library import and export
- putil.c: platform-dependent implementations of various functions that are platform dependent: (declared in putil.h)
  - icu_isNaN, icu_isInfinite(double), icu_getNaN(); icu_getInfinity for handling special floating point values.
  - icu_tzset, icu_timezone, icu_tzname and time for reading platform specific time and timezone information.
  - icu_getDefaultDataDirectory, icu_getDefaultLocaleID for reading the locale setting and data directory.
  - icu_isBigEndian for finding the endianess of the platform.
  - icu_nextDouble is used specifically by the ChoiceFormat API.
- umutex.h and umutex.c: Code for doing synchronization in multithreaded applications. If you wish to use International Components for Unicode in a multithreaded application, you must provide a synchronization primitive that the classes can use to protect their global data against simultaneous modifications. See Users' guide for more information.
  - We supply sample implementations for WinNT, Win95, Win98, Sun/Solaris, RedHat/Linux, HP-UX and for AIX on an RS/6000.
- udata.h and udata.c: The data-accessing interface in ICU is implemented such that there is a lot of flexibility for reading a data file. Each platform can tune the performance of file accessing for its environment by choosing to implement one of the following options:
  - DLL
  - Memory map
  - Plain text
- If you are changing the platform-dependent files, utypes.h and putil.h may also be interesting, but they shouldn't have to be changed. If you think any other files than the ones mentioned above have platform dependencies, please contact us.
- For the Intltest test suite, intltest.cpp in "icu/source/test/intltest/" contains the method pathnameInContext, which must also be adapted to any new platform.

## Important Installation Notes

### Win32 Platform

### BREAKING NEWS: Library names are changed and libraries are moved on Win32

As it was previously mentioned and proposed on ICU list, ICU libraries on Win32 are now renamed and relocated. The following changes took place in ICU 1.7:

1. in icu\lib:
   - Debug\icuuc.lib -> icuucd.lib
   - Release\icuuc.lib -> icuuc.lib
   - Debug\icui18n.lib -> icuind.lib
   - Release\icui18n.lib -> icuin.lib
   - Debug\ustdio.lib -> icuiod.lib
   - Release\ustdio.lib -> icuio.lib
2. in icu\bin:
   - Debug\icuuc.dll -> icuuc17d.dll
   - Release\icuuc.dll -> icuuc17.dll
   - Debug\icui18n.dll -> icuin17d.dll
   - Release\icui18n.dll -> icuin17.dll
   - Debug\ustdio.dll -> icuio17d.dll
   - Release\ustdio.dll -> icuio17.dll

Also, ctestfw and ex toolutil (now icutu17) libraries appeared in icu\bin and icu\lib dirs, but this shouldn't concern regular users of ICU.

#### What to do, and how to cope?

When you first try to compile your programs with new version of icu, compilation will fail. The following steps are required:

1. Change your path from ...\icu\bin\debug or ...\icu\bin\release to just ...\icu\bin
2. Make the same change for MSVC executable directory setting (tools->options->directories)
3. In all your .dsp files (project settings), on linker tab change input libraries according to the above scheme. You want to do it for both debug and release versions.

When a new, binary incompatible version appears after 1.7, the libraries will change the version number. Make sure that you reference the correct version independent *.lib file when you have more than one version of ICU built on your machine. Each *.lib file references its correct version dependent shared library. The libraries with debug information contain a "d" on the end of the base DLL name (e.g. icuuc.lib vs. icuucd.lib).

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

DLL directories and the PATH setting: As delivered, the International Components for Unicode build as several DLLs. These DLLs 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.

To change your PATH:

- Windows 2000: Use the System Icon in the Control Panel. Pick the "Advanced" tab. Select the "Environment Variables..." button. Select the variable PATH in the lower box, and select the lower "Edit..." button. In the "Variable Value" box, append the string ";$Root\bin" to the end of the path string. If there is nothing there, just type in "$Root\bin". Click the Set button, then the OK button.
- Windows NT: Use the System Icon in the Control Panel. Pick the "Environment" tab, and select the variable PATH in the lower box. In the "value" box, append the string ";$Root\bin" at the end of the path string. If there is nothing there, just type in "$Root\bin". Click the Set button, then the OK button.
- Windows 95/98/ME: Edit the autoexec.bat, and add the following line to the end of file, "SET PATH=%PATH%;$Root\bin"

Link 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 seemingly get memory errors when you run the executable.

### Collation Improvements

We are reimplementing the collation implementation to make it faster (much of this is done with ICU 1.7), to comply with the Unicode Collation Algorithm (ICU 1.8), and also to make the locale-specific collation data smaller (by separating it from the shared UCA data, also for ICU 1.8).
This means that sort keys and even some collation results are changing from ICU 1.6 and will change again for ICU 1.8.
For details, see our collation design document.

### API documentation

We are updating our API documentation, generated JavaDoc-style from the public header files. It is available for online browsing as well as for download from the release folder.

Also, as a more general and comprehensive documentation, we are working on improving the ICU User Guide.

### OS/390 Platform

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

- The gnu utilities gmake and gzip/gunzip are needed and can be obtained for OS/390 from http://www.mks.com/. Search for OS/390, register, and follow download directions.
- Encoding considerations: The source code assumes that it is compiled with codepage ibm-1047 (to be exact, the UNIX System Services variant of it). The pax command converts all of the source code files from ASCII to codepage ibm-1047 (USS) EBCDIC. However, some files are binary files and must not be converted, or must be converted back to their original state. Those files are:
  - All the .brk files located in the icu/data directory (icu/data/*.brk)
  - icu/source/test/testdata/uni-text.txt
  - icu/source/test/testdata/th18057.txt
  Such a conversion can be done using iconv:
  `iconv -f IBM-1047 -t ISO8859-1 uni-text.txt > uni-text.txt`
- DLL directories and the LIBPATH setting: Building and testing ICU needs the ICU libraries on the LIBPATH. In other words, the LIBPATH should contain (each path prepended with the root directory that contains the icu directory):
  - icu/source/common
  - icu/source/i18n
  - icu/source/tools/ctestfw
  - icu/source/tools/toolutil
  - icu/source/extra/ustdio

- OS/390 supports both native S/390 hexadecimal floating point and, (with Version 2.6 and later) IEEE binary floating point. This is a compile time option. Applications built with IEEE should use ICU dlls that are built with IEEE (and vice versa). The environment variable IEEE390=1 will cause the OS/390 version of ICU to be built with IEEE floating point. The default is native hexadecimal floating point.
  Important: Currently (ICU 1.4.2), native floating point support is sufficient for codepage conversion, resource bundle and UnicodeString operations, but the Format APIs, especially ChoiceFormat, require IEEE binary floating point.

  Examples for configuring ICU:
  Debug build: `IEEE390=1 ./configure`
  Release build: `CFLAGS=-2 IEEE390=1 ./configure`

- Since the default make on OS/390 is not gmake, pkgdata tool requires that the environment variable MAKE be set to fully qualified path to gmake.
- The makedep executable that is used with the OS/390 ICU build process is not shipped with ICU. It is available at the OS/390 UNIX - Tools and Toys site. The PATH environment variable should be updated to contain the location of this executable prior to build. Alternatively, makedep may be moved into an existing PATH directory.
- To run all of the tests for ICU, use "gmake check". When running individual tests of the test suite, the TZ environment variable should be set to export TZ="PST8PDT" so that time zone comparisons are correct.

#### 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 Platform

ICU Reference Release 1.4.0 contains partial support for the 400 platform, but additional work by the user is currently needed to get it to build completely. A future release of ICU should work out-of-the-box under OS/400.

- Requirements:
  - QSHELL interpreter installed (install base option 30, operating system)
  - QShell Utilities, PRPQ 5799-XEH
  - ILE C++ for AS/400, PRPQ 5799-GDW
  - GNU facilities (You can get the GNU facilities for OS/400 from http://www.as400.ibm.com/developer/porting/gnu_utilities.html).
- Build environment setup:
  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(ICU_DATA) VALUE('/icu/source/data')
     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') identifies target as400 library for *module, *pgm and *srvpgm objects
  3. Add QCXXN, to your build process library list. This results in the resolution of CRTCPPMOD used by the icc compiler
  4. For timezones to work correctly, the QUTCOFFSET needs to be set to the proper UTC(Coordinated univeral time) offset.
     To check your QUTCOFFSET:
     DSPSYSVAL SYSVAL(QUTCOFFSET)
     To change your QUTCOFFSET:
     CHGSYSVAL SYSVAL(QUTCOFFSET) VALUE('+/-hh:mm')
     The +/- represents either + or - from UTC. The "hh" represents the number of hours from UTC, and "mm" represents the minutes from UTC.
  5. Run 'QSH'
  6. Configure the Makefiles (see configure below) Note: Verify that the mh-os400 configure file is used.
     - Run 'configure --host=as400-os400'
     - The 'clean' and 'install' targets will not work without changes because of symbolic links. To delete the target module, program, or service programs replace `rm -rf` with $(RMV), and in the library installation targets (install-library) change `$(INSTALL)` to `$(INSTALL-S)`.
  7. Run 'gmake -e'. The '-e' option is needed to pickup the compilers.
  8. Run 'gmake -e check' to run the tests.

## How To Build And Install ICU

### How To Build And Install On Windows

Building International Components for Unicode requires:

- Microsoft NT 3.51 or above
- Microsoft Visual C++ 6.0 (Service Pack 2 is required to work with the release build of max speed optimization).

The steps are:

1. Unzip the icu-XXXX.zip file, type "unzip -a icu-XXXX.zip -d drive:\directory" under command prompt or use WinZip. drive:\directory\icu is the root ($Root) directory (you may but don't need to place "icu" into another directory). If you change the root, you will change the project settings accordingly in EACH makefile in the project, updating the "include" and "library" paths.
2. Set the environment variable ICU_DATA to the full pathname of the data directory. The trailing "\" is required after the directory name (e.g. "$Root\source\data\" will work, but the value "$Root\source\data" is not acceptable). This environment variable indicates where the locale data files and conversion mapping tables are located.
3. Be sure that the ICU binary directory, $Root\bin\, is included in the PATH environment variable. The tests may not work without the DLL files in the path.
4. Set the TZ environment variable to PST8PDT. The tests will not work in any other timezone.
5. Use Microsoft Visual C++ 6.0 to open the "$Root\source\allinone\allinone.dsw" workspace (This workspace includes all the International Components for Unicode libraries, necessary ICU building tools, and the intltest and cintltest test suite projects).
6. 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.
7. Set the active configuration to "Win32 Debug" or "Win32 Release" (See note below).
8. Choose the "Build" menu and select "Rebuild All". 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.
9. Run the C++ test suite, "intltest". To do this: set the active project to "intltest", and press F5 to run it.
10. Run the C test suite, "cintltst". To do this: set the active project to "cintltst", and press F5 to run it.
11. 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.
12. Reset the TZ environment variable to its original value, unless you plan on testing ICU any further.
13. You are now able to develop applications with ICU.

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

- Choose "Build" menu, select "Set Active Configuration", and select "Win32 Release" or "Win32 Debug".
- Another way is to select "Customize" in the "Tools" menu, select the "Toolbars" tab, enable "Build" instead of "Build Minibar", and click on "Close". This will bring up a toolbar which you can move aside the other permanent toolbars at the top of the MSVC window. The advantage is that you now have an easy-to-reach pop-up menu that will always show the currently selected active configuration. Or, you can drag the project and configuration selections and drop them on the menu bar for later selection.

It is also possible to build each library individually, using the workspaces in each respective directory. They have to be built in the following order:

1. common
2. i18n
3. makedata (which invokes makeconv, genrb, genccode, etc.)
4. ctestfw
5. intltest and cintltst, if you want to run the test suite.

### How To Build And Install On Unix

There is a set of Makefiles for Unix that supports Linux w/gcc, Solaris w/gcc and Workshop CC, AIX w/xlc and OS/390 with C++.

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+). OS/390 gnu utilities for both make (gmake) and zip (gzip/gunzip) can be found at the MKS web site at http://www.mks.com. Please do a search on "os/390".

The steps are:

1. Decompress the icuXXXX.tar (or icuXXXX.tgz) file and use pax.
2. Before running the test programs or samples, please set the environment variable ICU_DATA, the full pathname of the data directory, to indicate where the locale data files and conversion mapping tables are. If this variable is not set, the default user data directory will be used. The trailing "/" is required after the directory name (e.g. "$Root/source/data/" will work, but the value "$Root/source/data" is not acceptable). When you are running individual tests, the TZ environment variable needs to be set to PST8PDT. Normally "make check" does this for you automatically.
3. Change directory to the "icu/source".
4. If it is not already set, please set the executable flag for the following files (by executing 'chmod +x' command): runConfigureICU, configure, install.sh and config.*,
5. You also need to set other environment variables for different build systems. See the User Guide or the provided script.
6. Type "./configure" or type "./configure --help" to print the available options.
7. Type "make" to compile the libraries and all the data files. On OS/390, both IEEE binary floating point and native S/390 hexadecimal floating point calculations are supported. The default is to build with native floating-point support. Please set the environment variable IEEE390=1 if you would like to make the ICU DLLs with IEEE floating point support.
8. Optionally, type "make check" to verify the test suite.
9. Type "make 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.)

It is also possible to build each library individually, using the Makefiles in each respective directory. They have to be built in the following order:

1. common
2. i18n
3. makeconv
4. genrb
5. gentz
6. genccode
7. ctestfw
8. intltest and cintltst, if you want to run the test suite.

### Using Shared Data Libraries

HP/UX has a documented characteristic where the shl_unload() function always unloads a library, regardless of how many times the library has been loaded. Most operating systems reference count libraries as they are opened. In the future (Jitterbug 414) this may be corrected in ICU, but at present, we work around this problem by simply NOT ever unloading shared libraries. This means that once a data library is loaded (ex: libicudata.sl) by a process, it cannot be unloaded and replaced without stopping and restarting the process.

### Important Change Of Error Codes From Streaming Conversion Functions (change for ICU 1.6)

We have decided to make a semantic change to the conversion API which affects applications using ICU that are migrated to use ICU versions 1.6 or later compared to earlier ICU versions before 1.6:
The error code that is set from streaming conversion like

    ucnv_fromUnicode() - ucnv_toUnicode()
    ucnv_fromUChars()  - ucnv_toUChars()
    scsu_compress()    - scsu_decompress()

when the target buffer is full but the source not empty is changed from `U_INDEX_OUTOFBOUNDS_ERROR` to `U_BUFFER_OVERFLOW_ERROR`. This change makes the error codes more consistent with their names and with their use in other icu APIs.

You need to test for this new error code if your code uses ICU for conversion and used the old error code. ucnv.h and scsu.h are updated with this information. Please search in your source code for `U_INDEX_OUTOFBOUNDS_ERROR`. If it is used with the above functions (not with `ucnv_getNextUChar()`), then you need to change it to `U_BUFFER_OVERFLOW_ERROR` in order to get your code to work with icu 1.6 or later.

See the updated sample code in `icu/source/samples`. All samples are updated. See jitterbug 516 for details. This was discussed in July 2000 on the icu mailing list. Please see the list archive for the discussion.

## Where To Find More Information

http://oss.software.ibm.com/icu/ is the homepage of the International Components for Unicode.

The API Documentation is available online or for download. The (draft of) the User Guide is available for browsing and as a PDF file.

http://www.ibm.com/developer/unicode/ is a pointer to information on how to make applications global.

## Submitting Comments, Requesting Features and Reporting Bugs

To submit comments, request features and report bugs, please contact us. The best forum is the ICU mailing list. See the information on how to browse and join the list. If you find a bug in the code that has not been submitted and/or fixed yet, then please submit a jitterbug.

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