AIX Version 4.3 Differences Guide

abandoning its standards-based internationalization support, ULS will add
support for a set of UCS locales as an extension to the existing
internationalization language support.
10.3.3 Universal Locale
The Universal Locale is a method of using Unicode as a wchar_t or wide
character encoding. As mentioned earlier, Unicode is based on a 16-bit encoding,
whereas an ASCII character is based on an a 7-bit encoding.
For AIX to use Unicode across the entire system, it uses the UTF-8 encoding for
files and uses Unicode as the process code. Process code is the actual code that
is being executed in memory.
Note: All supported locales will function correctly in both their current code as
well as UTF-8.
10.3.3.1 Locale Definitions
The following can be said about locale definitions:
• Unicode-based locales must be compiled based on a UTF-8 charmap
containing all characters currently defined in Unicode 2.0. The names for such
characters must be the exact character names as outlined in the standard,
with any spaces imbedded in the character name changed to underscores. For
example, the correct symbol name for the Unicode value U+00A1 would be
.
• Character symbol names that are currently required to be defined by the
localedef command must be defined with both the Unicode and POSIX symbol
names in the charmap. For example, the value U+0041 would be defined as
both and .
• To ensure that multiple locales can be built from a given locale, all existing
charmaps must be modified to use the Unicode names. Each charmap will
define only those actually contained within the code set.
Many of the locale definitions have similar characteristics across multiple locales,
especially in the LC_CTYPE section. From a maintenance perspective, it is highly
desirable to be able to maintain a common source for these and allow them to
have an include facility. The C preprocessor can be used for this purpose,
provided that the localedef comment character and escape character (line
continuation) be changed to values that do not conflict with the C preprocessor.
Currently, the default comment character for locales is "#", and the default
continuation character is "\". By changing these to "*" and "/", respectively, you
can use C preprocessor directives in the context of a localedef source file, such
as #include and #ifdef statements to tailor the locale definition based on the
characters available in the codeset. Thus, before running localedef, each locale
source is run through the C preprocessor with the code set name to be used
specified as an option to the C preprocessor through -D on the command line. For
example, suppose your locale definition was to be compiled with four different
code sets, ISO8859-1 (Latin), ISO8859-5 (Cyrillic), ISO8859-7 (Greek), and
UTF-8 (Unicode). Moreover, suppose that in the LC_CTYPE section you wanted
to declare the following three characters as uppercase:
244 AIX Version 4.3 Differences Guide