You are viewing the version of this documentation from Perl 5.30.1. View the latest version



I18N::Langinfo - query locale information


use I18N::Langinfo;


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.

Starting in Perl 5.28, this module is available even on systems that lack a native nl_langinfo. On such systems, 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:


Unimplemented, so returns "".


Unimplemented, except on Windows, due to the vagaries of vendor locale names, returning "" on non-Windows.


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.


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


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


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


The return may be incorrect for those rare locales where the currency symbol replaces the radix character. Send email to if you have examples of it needing to work differently.


Currently this gives the same results as Linux does. Send email to if you have examples of it needing to work differently.


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.)


By default only the langinfo() function is exported.


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.


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

The langinfo() function is just a wrapper for the C nl_langinfo() interface.


Jarkko Hietaniemi, <>. Now maintained by Perl 5 porters.


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.