NAME

       I18N::Langinfo - query locale information

SYNOPSIS

         use I18N::Langinfo;

DESCRIPTION

       The langinfo() function queries various locale information that can be used to localize output and user
       interfaces.  It uses the current underlying locale, regardless of whether or not it was called from
       within the scope of "use locale".  The langinfo() function requires one numeric argument that identifies
       the locale constant to query: if no argument is supplied, $_ is used.  The numeric constants appropriate
       to be used as arguments are exportable from I18N::Langinfo.

       The following example will import the langinfo() function itself and three constants to be used as
       arguments to langinfo(): a constant for the abbreviated first day of the week (the numbering starts from
       Sunday = 1) and two more constants for the affirmative and negative answers for a yes/no question in the
       current locale.

           use I18N::Langinfo qw(langinfo ABDAY_1 YESSTR NOSTR);

           my ($abday_1, $yesstr, $nostr) =
               map { langinfo($_) } (ABDAY_1, YESSTR, NOSTR);

           print "$abday_1? [$yesstr/$nostr] ";

       In other words, in the "C" (or English) locale the above will probably print something like:

           Sun? [yes/no]

       but under a French locale

           dim? [oui/non]

       The usually available constants are as follows.

       •   For abbreviated and full length days of the week and months of the year:

               ABDAY_1 ABDAY_2 ABDAY_3 ABDAY_4 ABDAY_5 ABDAY_6 ABDAY_7
               ABMON_1 ABMON_2 ABMON_3 ABMON_4 ABMON_5 ABMON_6
               ABMON_7 ABMON_8 ABMON_9 ABMON_10 ABMON_11 ABMON_12
               DAY_1 DAY_2 DAY_3 DAY_4 DAY_5 DAY_6 DAY_7
               MON_1 MON_2 MON_3 MON_4 MON_5 MON_6
               MON_7 MON_8 MON_9 MON_10 MON_11 MON_12

       •   For the date-time, date, and time formats used by the strftime() function (see POSIX):

               D_T_FMT D_FMT T_FMT

       •   For the locales for which it makes sense to have ante meridiem and post meridiem time formats:

               AM_STR PM_STR T_FMT_AMPM

       •   For the character code set being used (such as "ISO8859-1", "cp850", "koi8-r", "sjis", "utf8", etc.),
           and for the currency string:

               CODESET CRNCYSTR

       •   For  an  alternate representation of digits, for the radix character used between the integer and the
           fractional part of decimal numbers, the group separator string for large-ish floating  point  numbers
           (yes, the final two are redundant with POSIX::localeconv()):

               ALT_DIGITS RADIXCHAR THOUSEP

       •   For the affirmative and negative responses and expressions:

               YESSTR YESEXPR NOSTR NOEXPR

       •   For  the  eras based on typically some ruler, such as the Japanese Emperor (naturally only defined in
           the appropriate locales):

               ERA ERA_D_FMT ERA_D_T_FMT ERA_T_FMT

   For systems without "nl_langinfo"
       This module originally was just a wrapper for the libc  "nl_langinfo"  function,  and  did  not  work  on
       systems lacking it, such as Windows.

       Starting  in Perl 5.28, this module works on all platforms.  When "nl_langinfo" is not available, it uses
       various methods to construct what that function, if present,  would  return.   But  there  are  potential
       glitches.  These are the items that could be different:

       "ERA"
           Unimplemented, so returns "".

       "CODESET"
           This  should  work  properly  for  Windows  platforms.  On almost all other modern platforms, it will
           reliably return "UTF-8" if that is the code set.  Otherwise, it depends on  the  locale's  name.   If
           that  is of the form "foo.bar", it will assume "bar" is the code set; and it also knows about the two
           locales "C" and "POSIX".  If none of those apply it returns "".

       "YESEXPR"
       "YESSTR"
       "NOEXPR"
       "NOSTR"
           Only the values for English are returned.  "YESSTR" and "NOSTR" have been removed  from  POSIX  2008,
           and  are  retained  here  for backwards compatibility.  Your platform's "nl_langinfo" may not support
           them.

       "D_FMT"
           Always evaluates to %x, the locale's appropriate date representation.

       "T_FMT"
           Always evaluates to %X, the locale's appropriate time representation.

       "D_T_FMT"
           Always evaluates to %c, the locale's appropriate date and time representation.

       "CRNCYSTR"
           The return may be incorrect for those rare locales where  the  currency  symbol  replaces  the  radix
           character.   If  you  have  examples  of  it  needing  to  work  differently, please file a report at
           <https://github.com/Perl/perl5/issues>.

       "ALT_DIGITS"
           Currently this gives the same results as Linux does.  If you have examples  of  it  needing  to  work
           differently, please file a report at <https://github.com/Perl/perl5/issues>.

       "ERA_D_FMT"
       "ERA_T_FMT"
       "ERA_D_T_FMT"
       "T_FMT_AMPM"
           These  are derived by using strftime(), and not all versions of that function know about them.  "" is
           returned for these on such systems.

       See your nl_langinfo(3) for more information about the available constants.  (Often this means having  to
       look directly at the langinfo.h C header file.)

   EXPORT
       By default only the langinfo() function is exported.

BUGS

       Before Perl 5.28, the returned values are unreliable for the "RADIXCHAR" and "THOUSEP" locale constants.

       Starting  in  5.28,  changing  locales  on threaded builds is supported on systems that offer thread-safe
       locale functions.  These include POSIX 2008 systems and Windows starting with  Visual  Studio  2005,  and
       this  module  will  work  properly  in  such situations.  However, on threaded builds on Windows prior to
       Visual Studio 2015, retrieving the items "CRNCYSTR" and "THOUSEP" can result in a race with a thread that
       has converted to use the global locale.  It is quite uncommon for a thread to have done this.   It  would
       be  possible  to  construct  a  workaround  for  this;  patches welcome: see "switch_to_global_locale" in
       perlapi.

SEE ALSO

       perllocale, "localeconv" in POSIX, "setlocale" in POSIX, nl_langinfo(3).

AUTHOR

       Jarkko Hietaniemi, <jhi@hut.fi>.  Now maintained by Perl 5 porters.

COPYRIGHT AND LICENSE

       Copyright 2001 by Jarkko Hietaniemi

       This library is free software; you can redistribute it and/or modify it under  the  same  terms  as  Perl
       itself.

perl v5.38.2                                       2025-07-25                              I18N::Langinfo(3perl)