Info Catalog gettext: Importing gettext: Sources gettext: Preparing Strings

gettext: Triggering

 
 4.2 Triggering ‘gettext’ Operations
 ===================================
 
    The initialization of locale data should be done with more or less
 the same code in every program, as demonstrated below:
 
      int
      main (int argc, char *argv[])
      {
        ...
        setlocale (LC_ALL, "");
        bindtextdomain (PACKAGE, LOCALEDIR);
        textdomain (PACKAGE);
        ...
      }
 
    PACKAGE and LOCALEDIR should be provided either by ‘config.h’ or by
 the Makefile.  For now consult the ‘gettext’ or ‘hello’ sources for more
 information.
 
    The use of ‘LC_ALL’ might not be appropriate for you.  ‘LC_ALL’
 includes all locale categories and especially ‘LC_CTYPE’.  This latter
 category is responsible for determining character classes with the
 ‘isalnum’ etc.  functions from ‘ctype.h’ which could especially for
 programs, which process some kind of input language, be wrong.  For
 example this would mean that a source code using the ç (c-cedilla
 character) is runnable in France but not in the U.S.
 
    Some systems also have problems with parsing numbers using the
 ‘scanf’ functions if an other but the ‘LC_ALL’ locale category is used.
 The standards say that additional formats but the one known in the ‘"C"’
 locale might be recognized.  But some systems seem to reject numbers in
 the ‘"C"’ locale format.  In some situation, it might also be a problem
 with the notation itself which makes it impossible to recognize whether
 the number is in the ‘"C"’ locale or the local format.  This can happen
 if thousands separator characters are used.  Some locales define this
 character according to the national conventions to ‘'.'’ which is the
 same character used in the ‘"C"’ locale to denote the decimal point.
 
    So it is sometimes necessary to replace the ‘LC_ALL’ line in the code
 above by a sequence of ‘setlocale’ lines
 
      {
        ...
        setlocale (LC_CTYPE, "");
        setlocale (LC_MESSAGES, "");
        ...
      }
 
 On all POSIX conformant systems the locale categories ‘LC_CTYPE’,
 ‘LC_MESSAGES’, ‘LC_COLLATE’, ‘LC_MONETARY’, ‘LC_NUMERIC’, and ‘LC_TIME’
 are available.  On some systems which are only ISO C compliant,
 ‘LC_MESSAGES’ is missing, but a substitute for it is defined in GNU
 gettext’s ‘<libintl.h>’ and in GNU gnulib’s ‘<locale.h>’.
 
    Note that changing the ‘LC_CTYPE’ also affects the functions declared
 in the ‘<ctype.h>’ standard header and some functions declared in the
 ‘<string.h>’ and ‘<stdlib.h>’ standard headers.  If this is not
 desirable in your application (for example in a compiler’s parser), you
 can use a set of substitute functions which hardwire the C locale, such
 as found in the modules ‘c-ctype’, ‘c-strcase’, ‘c-strcasestr’,
 ‘c-strtod’, ‘c-strtold’ in the GNU gnulib source distribution.
 
    It is also possible to switch the locale forth and back between the
 environment dependent locale and the C locale, but this approach is
 normally avoided because a ‘setlocale’ call is expensive, because it is
 tedious to determine the places where a locale switch is needed in a
 large program’s source, and because switching a locale is not
 multithread-safe.
 

Info Catalog gettext: Importing gettext: Sources gettext: Preparing Strings