Version: 2004-Apr-01
Copyright © 1997-2004 International Business Machines Corporation and
others. All Rights Reserved.
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.
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.
| 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.
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.
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".
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.
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.
There are two ways to download ICU releases:
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.
| File | Description |
|---|---|
| readme.html | Describes the International Components for Unicode (this file) |
| license.html | Contains the text of the ICU license |
| 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.
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. |
| 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 |
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:
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.
Building International Components for Unicode requires:
The steps are:
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:
Building International Components for Unicode on UNIX requires:
Here are the steps to build ICU:
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).
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 supports both native S/390 hexadecimal floating point and (with OS/390 2.6 and later) IEEE 754 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=0 will cause the z/OS version of ICU to be built without IEEE floating point support and use the native hexadecimal floating point. By default ICU is built with IEEE 754 support.
Important: Currently (ICU 1.4.2), native floating point support is sufficient for codepage conversion, resource bundle and UnicodeString operations, but the Format APIs require IEEE binary floating point.
Examples for configuring ICU:
Debug build: ./runConfigureICU --enable-debug zOS
Release build: ./runConfigureICU zOS
z/OS introduced the concept of Extra Performance Linkage (XPLINK) to
bring performance improvement opportunities to call-intensive C and C++
applications such as ICU. XPLINK is enabled on a DLL-by-DLL basis, so
if you are considering using XPLINK in your application that uses ICU,
you should consider building the XPLINK-enabled version of ICU. You
need to set ICU's environment variable OS390_XPLINK=1
prior to invoking the make process to produce binaries that are enabled
for XPLINK.
Note: XPLINK, which is enabled for z/OS 1.2 and later, requires the PTF PQ69418 to build XPLINK-enabled binaries.
When you build ICU on a system such as z/OS 1.2, the binaries that result can run on that level of the operating system and later, such as z/OS 1.3 and z/OS 1.4. It's possible that you may have a z/OS 1.4 system, but you may need to deliver binaries on z/OS 1.2 and above. z/OS gives you this ability by targeting the complier and linker to run at the older level, thereby producing the desired binaries.
To set the compiler and LE environment to OS/390 2.10, specify the
following, "./runConfigureICU OS390V2R10"
To set the compiler and LE environment to z/OS 1.2 specify the
following, "./runConfigureICU zOSV1R2"
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
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.
CRTLIB LIB(libraryname)
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.
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
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.
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.
| 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.
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.
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.
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.
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
The C/C++ languages do not provide a portable way to specify Unicode code point or string literals other than with arrays of numeric constants. For convenience, ICU4C tends to use char * strings in places where only "invariant characters" (a portable subset of the 7-bit ASCII repertoire) are used. This allows locale IDs, charset names, resource bundle item keys and similar items to be easily specified as string literals in the source code. The same types of strings are also stored as "invariant character" char * strings in the ICU data files.
ICU has hard coded mapping tables in source/common/putil.c
to convert invariant characters to and from Unicode without using a full
ICU converter. These tables must match the encoding of string literals in
the ICU code as well as in the ICU data files.
Important: ICU assumes that at least the invariant characters always have the same codes as is common on platforms with the same charset family (ASCII vs. EBCDIC). ICU has not been tested on platforms where this is not the case.
Some usage of char * strings in ICU assumes the system charset instead of invariant characters. Such strings are only handled with the default converter (See the following section). The system charset is usually a superset of the invariant characters.
The following are the ASCII and EBCDIC byte values for all of the invariant characters (see also unicode/utypes.h):
| Character(s) | ASCII | EBCDIC |
|---|---|---|
| a..i | 61..69 | 81..89 |
| j..r | 6A..72 | 91..99 |
| s..z | 73..7A | A2..A9 |
| A..I | 41..49 | C1..C9 |
| J..R | 4A..52 | D1..D9 |
| S..Z | 53..5A | E2..E9 |
| 0..9 | 30..39 | F0..F9 |
| (space) | 20 | 40 |
| " | 22 | 7F |
| % | 25 | 6C |
| & | 26 | 50 |
| ' | 27 | 7D |
| ( | 28 | 4D |
| ) | 29 | 5D |
| * | 2A | 5C |
| + | 2B | 4E |
| , | 2C | 6B |
| - | 2D | 60 |
| . | 2E | 4B |
| / | 2F | 61 |
| : | 3A | 7A |
| ; | 3B | 5E |
| < | 3C | 4C |
| = | 3D | 7E |
| > | 3E | 6E |
| ? | 3F | 6F |
| _ | 5F | 6D |
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,
char *
encodings there are two classes, called "ANSI" and "OEM" codepages. ICU
will use the ANSI codepage. Note that the OEM codepage is used by default
for console window output.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 z/OS (OS/390), 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.
If you are building on the Win32 platform, it is important that you understand a few of the following build details.
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.
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.
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.)
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.
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.
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:
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 without our Makefiles.
They must be built in the following order:
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