XLIB Programming Manual, Rel. 5, Third Edition

10.2 Locale Management in X

An internationalized X application begins in the same way as a ANSI-C terminal-based internationalized program: with a call to setlocale. An X program, however, generally goes two steps further.

Immediately after calling setlocale, an application should call XSupportsLocale() to determine if the Xlib implementation supports the current locale. This function takes no arguments and return a Bool. If this function returns False, an application will typically print a “Locale not supported” message and exit.

After verifying that the locale is supported, an application should call XSetLocaleModifiers(). A “locale modifier” can be thought of as an extension to the name of a locale; it specifies more information about the desired localized behavior of an application. R5 as shipped by MIT recognizes one locale modifier, used to specify the input method (see Chapter 10) to be used for internationalized text input for the locale.

XSetLocaleModifiers() allows the programmer to specify a list of modifiers (usually none) which will be concatenated with a list of user-specified modifiers from an operating system environment variable (XMODIFIERS in POSIX). The strings passed to XSetLocaleModifiers() and set in the XMODIFIERS environment variable are a series of concatenated “@category=value" strings. Thus to specify that the “Xwnmo” input method should be used by an application, a user might set the XMODIFIERS as follows:

setenv XMODIFIERS @im=_XWNMO

Example 10-1 shows code ...