Provided by: libintl-perl_1.33-1build3_all bug

NAME

       Locale::Messages - Gettext Like Message Retrieval

SYNOPSIS

        use Locale::Messages qw(:locale_h :libintl_h);

        gettext $msgid;
        dgettext $textdomain, $msgid;
        dcgettext $textdomain, $msgid, LC_MESSAGES;
        ngettext $msgid, $msgid_plural, $count;
        dngettext $textdomain, $msgid, $msgid_plural, $count;
        dcngettext $textdomain, $msgid, $msgid_plural, $count, LC_MESSAGES;
        pgettext $msgctxt, $msgid;
        dpgettext $textdomain, $msgctxt, $msgid;
        dcpgettext $textdomain, $msgctxt, $msgid, LC_MESSAGES;
        npgettext $msgctxt, $msgid, $msgid_plural, $count;
        dnpgettext $textdomain, $msgctxt, $msgid, $msgid_plural, $count;
        dcnpgettext $textdomain, $msgctxt, $msgid, $msgid_plural, $count, LC_MESSAGES;
        textdomain $textdomain;
        bindtextdomain $textdomain, $directory;
        bind_textdomain_codeset $textdomain, $encoding;
        bind_textdomain_filter $textdomain, \&filter, $data;
        turn_utf_8_on ($variable);
        turn_utf_8_off ($variable);
        nl_putenv ('OUTPUT_CHARSET=koi8-r');
        my $category = LC_CTYPE;
        my $category = LC_NUMERIC;
        my $category = LC_TIME;
        my $category = LC_COLLATE;
        my $category = LC_MONETARY;
        my $category = LC_MESSAGES;
        my $category = LC_ALL;

DESCRIPTION

       The module Locale::Messages is a wrapper around the interface to message translation
       according to the Uniforum approach that is for example used in GNU gettext and Sun's
       Solaris.  It is intended to allow Locale::Messages(3) to switch between different
       implementations of the lower level libraries but this is not yet implemented.

       Normally you should not use this module directly, but the high level interface
       Locale::TextDomain(3) that provides a much simpler interface.  This description is
       therefore deliberately kept brief.  Please refer to the GNU gettext documentation
       available at <http://www.gnu.org/manual/gettext/> for in-depth and background information
       on the topic.

       The lower level module Locale::gettext_pp(3) provides the Perl implementation of gettext()
       and related functions.

FUNCTIONS

       The module exports by default nothing.  Every function has to be imported explicitly or
       via an export tag ("EXPORT TAGS").

       gettext MSGID
           Returns the translation for MSGID.  Example:

               print gettext "Hello World!\n";

           If no translation can be found, the unmodified MSGID is returned, i. e. the function
           can never fail, and will never mess up your original message.

           Note for Perl 5.6 and later: The returned string will always have the UTF-8 flag off
           by default.  See the documentation for function bind_textdomain_filter() for a way to
           change this behavior.

           One common mistake is this:

               print gettext "Hello $name!";

           Perl will interpolate the variable $name before the function will see the string.
           Unless the corresponding message catalog contains a message "Hello Tom!", "Hello
           Dick!" or "Hello Harry!", no translation will be found.

           Using printf() and friends has its own problems:

               print sprintf (gettext ("This is the %s %s."), $color, $thing);

           (The example is stupid because neither color nor thing will get translated here ...).

           In English the adjective (the color) will precede the noun, many other languages (for
           example French or Italian) differ here.  The translator of the message may therefore
           have a hard time to find a translation that will still work and not sound stupid in
           the target language.  Many C implementations of printf() allow one to change the order
           of the arguments, and a French translator could then say:

               "C'est le %2$s %1$s."

           Perl printf() implements this feature as of version 5.8 or better.  Consequently you
           can only use it, if you are sure that your software will run with Perl 5.8 or a later
           version.

           Another disadvantage of using printf() is its cryptic syntax (maybe not for you but
           translators of your software may have their own opinion).

           See the description of the function "__x()" in Locale::TextDomain(3) for a much better
           way to get around this problem.

           Non-ASCII message ids ...

           You should note that the function (and all other similar functions in this module)
           does a bytewise comparison of the MSGID for the lookup in the translation catalog, no
           matter whether obscure utf-8 flags are set on it, whether the string looks like utf-8,
           whether the utf8(3pm) pragma is used, or whatever other weird method past or future
           perl(1) versions invent for guessing character sets of strings.

           Using other than us-ascii characters in Perl source code is a call for trouble, a
           compatibility nightmare.  Furthermore, GNU gettext only lately introduced support for
           non-ascii character sets in sources, and support for this feature may not be available
           everywhere.  If you absolutely want to use MSGIDs in non-ascii character sets, it is
           wise to choose utf-8.  This will minimize the risk that perl(1) itself will mess with
           the strings, and it will also be a guaranty that you can later translate your project
           into arbitrary target languages.

           Other character sets can theoretically work.  Yet, using another character set in the
           Perl source code than the one used in your message catalogs will never work, since the
           lookup is done bytewise, and all strings with non-ascii characters will not be found.

           Even if you have solved all these problems, there is still one show stopper left: The
           gettext runtime API lacks a possibility to specify the character set of the source
           code (including the original strings).  Consequently - in absence of a hint for the
           input encoding - strings without a translation are not subject to output character set
           conversion.  In other words: If the (non-determinable) output character set differs
           from the character set used in the source code, output can be a mixture of two
           character sets.  There is no point in trying to address this problem in the pure Perl
           version of the gettext functions.  because breaking compatibility between the Perl and
           the C version is a price too high to pay.

           This all boils down to: Only use ASCII characters in your translatable strings!

       dgettext TEXTDOMAIN, MSGID
           Like gettext(), but retrieves the message for the specified TEXTDOMAIN instead of the
           default domain.  In case you wonder what a textdomain is, you should really read on
           with Locale::TextDomain(3).

       dcgettext TEXTDOMAIN, MSGID, CATEGORY
           Like dgettext() but retrieves the message from the specified CATEGORY instead of the
           default category "LC_MESSAGES".

       ngettext MSGID, MSGID_PLURAL, COUNT
           Retrieves the correct translation for COUNT items.  In legacy software you will often
           find something like:

               print "$count file(s) deleted.\n";

           or

               printf "$count file%s deleted.\n", $count == 1 ? '' : 's';

           The first example looks awkward, the second will only work in English and languages
           with similar plural rules.  Before ngettext() was introduced, the best practice for
           internationalized programs was:

               if ($count == 1) {
                   print gettext "One file deleted.\n";
               } else {
                   printf gettext "%d files deleted.\n";
               }

           This is a nuisance for the programmer and often still not sufficient for an adequate
           translation.  Many languages have completely different ideas on numerals.  Some
           (French, Italian, ...) treat 0 and 1 alike, others make no distinction at all
           (Japanese, Korean, Chinese, ...), others have two or more plural forms (Russian,
           Latvian, Czech, Polish, ...).  The solution is:

               printf (ngettext ("One file deleted.\n",
                                "%d files deleted.\n",
                                $count), # argument to ngettext!
                       $count);          # argument to printf!

           In English, or if no translation can be found, the first argument (MSGID) is picked if
           $count is one, the second one otherwise.  For other languages, the correct plural form
           (of 1, 2, 3, 4, ...)  is automatically picked, too.  You don't have to know anything
           about the plural rules in the target language, ngettext() will take care of that.

           This is most of the time sufficient but you will have to prove your creativity in
           cases like

               printf "%d file(s) deleted, and %d file(s) created.\n";

       dngettext TEXTDOMAIN, MSGID, MSGID_PLURAL, COUNT
           Like ngettext() but retrieves the translation from the specified textdomain instead of
           the default domain.

       dcngettext TEXTDOMAIN, MSGID, MSGID_PLURAL, COUNT, CATEGORY
           Like dngettext() but retrieves the translation from the specified category, instead of
           the default category "LC_MESSAGES".

       pgettext MSGCTXT, MSGID
           Returns the translation of MSGID, given the context of MSGCTXT.

           Both items are used as a unique key into the message catalog.

           This allows the translator to have two entries for words that may translate to
           different foreign words based on their context. For example, the word "View" may be a
           noun or a verb, which may be used in a menu as File->View or View->Source.

               pgettext "Verb: To View", "View\n";
               pgettext "Noun: A View", "View\n";

           The above will both lookup different entries in the message catalog.

           A typical usage are GUI programs.  Imagine a program with a main menu and the
           notorious "Open" entry in the "File" menu.  Now imagine, there is another menu entry
           Preferences->Advanced->Policy where you have a choice between the alternatives "Open"
           and "Closed".  In English, "Open" is the adequate text at both places.  In other
           languages, it is very likely that you need two different translations.  Therefore, you
           would now write:

               pgettext "File|", "Open";
               pgettext "Preferences|Advanced|Policy", "Open";

           In English, or if no translation can be found, the second argument (MSGID) is
           returned.

           The function was introduced with libintl-perl version 1.17.

       dpgettext TEXTDOMAIN, MSGCTXT, MSGID
           Like pgettext(), but retrieves the message for the specified TEXTDOMAIN instead of the
           default domain.

           The function was introduced with libintl-perl version 1.17.

       dcpgettext TEXTDOMAIN, MSGCTXT, MSGID, CATEGORY
           Like dpgettext() but retrieves the message from the specified CATEGORY instead of the
           default category "LC_MESSAGES".

           The function was introduced with libintl-perl version 1.17.

       npgettext MSGCTXT, MSGID, MSGID_PLURAL, COUNT
           Like ngettext() with the addition of context as in pgettext().

           In English, or if no translation can be found, the second argument (MSGID) is picked
           if $count is one, the third one otherwise.

           The function was introduced with libintl-perl version 1.17.

       dnpgettext TEXTDOMAIN, MSGCTXT, MSGID, MSGID_PLURAL, COUNT
           Like npgettext() but retrieves the translation from the specified textdomain instead
           of the default domain.

           The function was introduced with libintl-perl version 1.17.

       dcnpgettext TEXTDOMAIN, MSGCTXT, MSGID, MSGID_PLURAL, COUNT, CATEGORY
           Like dnpgettext() but retrieves the translation from the specified category, instead
           of the default category "LC_MESSAGES".

           The function was introduced with libintl-perl version 1.17.

       textdomain TEXTDOMAIN
           Sets the default textdomain (initially 'messages').

       bindtextdomain TEXTDOMAIN, DIRECTORY
           Binds TEXTDOMAIN to DIRECTORY.  Huh? An example:

               bindtextdomain "my-package", "./mylocale";

           Say, the selected locale (actually the selected locale for category "LC_MESSAGES") of
           the program is 'fr_CH', then the message catalog will be expected in
           ./mylocale/fr_CH/LC_MESSAGES/my-package.mo.

       bind_textdomain_codeset TEXTDOMAIN, ENCODING
           Sets the output encoding for TEXTDOMAIN to ENCODING.

       bind_textdomain_filter TEXTDOMAN, CODEREF, DATA
       bind_textdomain_filter TEXTDOMAN, CODEREF
           By default, Locale::Messages will turn the utf-8 flag of all returned messages off.
           If you want to change this behavior, you can pass a reference to a subroutine that
           does different things - for example turn the utf-8 flag on, or leave it untouched.
           The callback function will be called with DATA as the first, and the possibly
           translated string as the second argument.  It should return the possibly modified
           string.

           If you want an object method to be called, pass the object itself in the data
           parameter and write a wrapper function.  Example:

               sub wrapper {
                   my ($string, $obj) = @_;

                   $obj->filterMethod ($string);
               }
               my $obj = MyPackage->new;

               bind_textdomain_filter ('mydomain', \&wrapper, $obj);

           The function cannot fail and always returns a true value.

           Attention: If you use the function for setting the utf-8 flag, it is your
           responsibility to ensure that the output is really utf-8.  You should only use it, if
           you have set the environment variable OUTPUT_CHARSET to "utf-8".  Additionally you
           should call bind_textdomain_codeset() with "utf-8" as the second argument.

           Steven Haryanto has written a module Locale::TextDomain::UTF8(3pm) that addresses the
           same problem.

           This function has been introduced in libintl-perl 1.16 and it is not part of the
           standard gettext API.

       turn_utf_8_on VARIABLE
           Returns VARIABLE but with the UTF-8 flag (only known in Perl >=5.6) guaranteed to be
           turned on.  This function does not really fit into the module, but it is often handy
           nevertheless.

           The flag does not mean that the string is in fact valid utf-8!

           The function was introduced with libintl-perl version 1.16.

       turn_utf_8_off VARIABLE
           Returns VARIABLE but with the UTF-8 flag (only known in Perl >=5.6) guaranteed to be
           turned off.  This function does not really fit into the module, but it is often handy
           nevertheless.

           The function was introduced with libintl-perl version 1.07.

       select_package PACKAGE
           By default, Locale::Messages will try to load the XS version of the gettext
           implementation, i. e. Locale::gettext_xs(3) and will fall back to the pure Perl
           implementation Locale::gettext_pp(3).  You can override this behavior by passing the
           string "gettext_pp" or "gettext_xs" to the function select_package().  Passing
           "gettext_pp" here, will prefer the pure Perl implementation.

           You will normally want to use that in a BEGIN block of your main script.

           The function was introduced with libintl-perl version 1.03 and is not part of the
           standard gettext API.

           Beginning with version 1.22 you can pass other package names than "gettext_pp" or
           "gettext_xs" and use a completely different backend.  It is the caller's
           responsibility to make sure that the selected package offers the same interface as the
           two standard packages.

           One package that offers that functionality is Locale::gettext_dumb(3pm).

       nl_putenv ENVSPEC
           Resembles the ANSI C putenv(3) function.  The sole purpose of this function is to work
           around some ideosyncrasies in the environment processing of Windows systems.  If you
           want to portably set or unset environment variables, use this function instead of
           directly manipulating %ENV.

           The argument ENVSPEC may have three different forms.

           LANGUAGE=fr_CH
                   This would set the environment variable "LANGUAGE" to "fr_CH".

           LANGUAGE=
                   Normally, this will set the environment variable "LANGUAGE" to an empty
                   string.  Under Windows, however, the environment variable will be deleted
                   instead (and is no longer present in %ENV).  Since within libintl-perl empty
                   environment variables are useless, consider this usage as deprecated.

           LANGUAGE
                   This will delete the environment variable LANGUAGE.  If you are familiar with
                   the brain-damaged implementation of putenv(3) (resp.  _putenv()) in the so-
                   called standard C library of MS-Windows, you may suspect that this is an
                   invalid argument.  This is not the case!  Passing a variable name not followed
                   by an equal sign will always delete the variable, no matter which operating
                   system you use.

           The function returns true for success, and false for failure.  Possible reasons for
           failure are an invalid syntax or - only under Windows - failure to allocate space for
           the new environment entry ($! will be set accordingly in this case).

           Why all this hassle?  The 32-bit versions of MS-DOS (currently Windows
           95/98/ME/NT/2000/XP/CE/.NET) maintain two distinct blocks of environment variables per
           process.  Which block is considered the "correct" environment is a compile-time option
           of the Perl interpreter.  Unfortunately, if you have build the XS version
           Locale::gettext_xs(3) under Windows, the underlying library may use a different
           environment block, and changes you make to %ENV may not be visible to the library.

           The function nl_putenv() is mostly a funny way of saying

               LANGUAGE=some_value

           but it does its best, to pass this information to the gettext library.  Under other
           operating systems than Windows, it only operates on %ENV, under Windows it will call
           the C library function _putenv() (after doing some cleanup to its arguments), before
           manipulating %ENV.

           Please note, that your %ENV is updated by nl_putenv() automatically.

           The function has been introduced in libintl-perl version 1.10.

       setlocale
           Modifies and queries program's locale, see the documentation for setlocale() in
           POSIX(3pm) instead.

           On some systems, when using GNU gettext, a call from C to setlocale() is - with the
           help of the C preprocessor - really a call to libintl_setlocale(), which is in turn a
           wrapper around the system setlocale(3).  Failure to call libintl_setlocale() may lead
           to certain malfunctions.  On such systems, Locale::Messages::setlocale() will call the
           wrapper libintl_setlocale().  If you want to avoid problems, you should therefore
           always call the setlocale() implementation in Locale::Messages(3pm).

           See <https://rt.cpan.org/Public/Bug/Display.html?id=83980> or
           <https://savannah.gnu.org/bugs/?38162>, and
           <https://savannah.gnu.org/bugs/?func=detailitem&item_id=44645> for a discussion of the
           problem.

           The function has been introduced in libintl-perl version 1.24.

CONSTANTS

       You can (maybe) get the same constants from POSIX(3); see there for a detailed description

       LC_CTYPE
       LC_NUMERIC
       LC_TIME
       LC_COLLATE
       LC_MONETARY
       LC_MESSAGES
           This locale category was the reason that these constants from POSIX(3) were included
           here.  Even if it was present in your systems C include file locale.h, it was not
           provided by POSIX(3).  Perl 5.8 and later seems to export the constant if available,
           although it is not documented in POSIX(3).

           Locale::Messages(3) makes an attempt to guess the value of this category for all
           systems, and assumes the arbitrary value 1729 otherwise.

       LC_ALL
           If you specify the category LC_ALL as the first argument to POSIX::setlocale(), all
           locale categories will be affected at once.

EXPORT TAGS

       The module does not export anything unless explicitly requested.  You can import groups of
       functions via two tags:

       use Locale::Messages (':locale_h')
           Imports the functions that are normally defined in the C include file locale.h:

           gettext()
           dgettext()
           dcgettext()
           ngettext()
           dngettext()
           dcngettext()
           pgettext()
           dpgettext()
           dcpgettext()
           npgettext()
           dnpgettext()
           dcnpgettext()
           textdomain()
           bindtextdomain()
           bind_textdomain_codeset()
       use Locale::Messages (':libintl_h')
           Imports the locale category constants:

           LC_CTYPE
           LC_NUMERIC
           LC_TIME
           LC_COLLATE
           LC_MONETARY
           LC_MESSAGES
           LC_ALL

OTHER EXPORTS

       select_package PACKAGE

USAGE

       A complete example:

           1: use Locale::Messages qw(:locale_h :libintl_h);
           2: use POSIX qw (setlocale);
           3: setlocale (LC_MESSAGES, '');
           4: textdomain ('my-package');
           5: bindtextdomain ('my-package' => '/usr/local/share/locale');
           6:
           7: print gettext ("Hello world!\n");

       Step by step: Line 1 imports the necessary functions and constants.  In line 3 we set the
       locale for category LC_MESSAGES to the default user settings.  For C programs you will
       often read that LC_ALL is the best category here but this will also change the locale for
       LC_NUMERIC and many programs will not work reliably after changing that category in Perl;
       choose your own poison!

       In line 4 we say that all messages (translations) without an explicit domain specification
       should be retrieved from the message catalog for the domain 'my-package'.  Line 5 has the
       effect that the message catalog will be searched under the directory
       /usr/local/share/locale.

       If the user has selected the locale 'fr_CH', and if the file
       /usr/local/share/locale/fr_CH/LC_MESSAGES/my-package.mo exists, and if it contains a GNU
       message object file with a translation for the string "Hello world!\n", then line 7 will
       print the French translation (for Switzerland CH) to STDOUT.

       The documentation for GNU gettext explains how to extract translatable strings from your
       Perl files and how to create message catalogs.

       Another less portable example: If your system uses the GNU libc you should be able to find
       various files with the name libc.mo, the message catalog for the library itself.  If you
       have found these files under /usr/share/locale, then you can try the following:

           use Locale::Messages qw(:locale_h :libintl_h);
           use POSIX qw (setlocale);

           setlocale LC_MESSAGES, "";
           textdomain "libc";

           # The following is actually not needed, since this is
           # one of the default search directories.
           bindtextdomain libc => '/usr/share/locale';
           bind_textdomain_codeset libc => 'iso-8859-1';

           print gettext ("No such file or directory");

       See Locale::TextDomain(3) for much simpler ways.

AUTHOR

       Copyright (C) 2002-2017 Guido Flohr <http://www.guido-flohr.net/>
       (<mailto:guido.flohr@cantanea.com>), all rights reserved.  See the source code for
       details!code for details!

SEE ALSO

       Locale::TextDomain(3pm), Locale::gettext_pp(3pm), Encode(3pm), perllocale(3pm),
       POSIX(3pm), perl(1), gettext(1), gettext(3)