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CONTENTS

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.

In addition, Linux boxes have extra items, as follows. (When called from other platform types, these return a stub value, of not much use.)

_NL_ADDRESS_POSTAL_FMT
_NL_ADDRESS_COUNTRY_NAME
_NL_ADDRESS_COUNTRY_POST
_NL_ADDRESS_COUNTRY_AB2
_NL_ADDRESS_COUNTRY_AB3
_NL_ADDRESS_COUNTRY_CAR
_NL_ADDRESS_COUNTRY_NUM
_NL_ADDRESS_COUNTRY_ISBN
_NL_ADDRESS_LANG_NAME
_NL_ADDRESS_LANG_AB
_NL_ADDRESS_LANG_TERM
_NL_ADDRESS_LANG_LIB

On Linux boxes, these return information about the country for the current locale. Further information is found in langinfo.h

_NL_IDENTIFICATION_TITLE
_NL_IDENTIFICATION_SOURCE
_NL_IDENTIFICATION_ADDRESS
_NL_IDENTIFICATION_CONTACT
_NL_IDENTIFICATION_EMAIL
_NL_IDENTIFICATION_TEL
_NL_IDENTIFICATION_FAX
_NL_IDENTIFICATION_LANGUAGE
_NL_IDENTIFICATION_TERRITORY
_NL_IDENTIFICATION_AUDIENCE
_NL_IDENTIFICATION_APPLICATION
_NL_IDENTIFICATION_ABBREVIATION
_NL_IDENTIFICATION_REVISION
_NL_IDENTIFICATION_DATE
_NL_IDENTIFICATION_CATEGORY

On Linux boxes, these return meta information about the current locale, such as how to get in touch with its maintainers. Further information is found in langinfo.h

_NL_MEASUREMENT_MEASUREMENT

On Linux boxes, it returns 1 if the metric system of measurement prevails in the locale; or 2 if US customary units prevail.

_NL_NAME_NAME_FMT
_NL_NAME_NAME_GEN
_NL_NAME_NAME_MR
_NL_NAME_NAME_MRS
_NL_NAME_NAME_MISS
_NL_NAME_NAME_MS

On Linux boxes, these return information about how names are formatted and the personal salutations used in the current locale. Further information is found in locale(7) and langinfo.h

_NL_PAPER_HEIGHT
_NL_PAPER_WIDTH

On Linux boxes, these return the standard size of sheets of paper (in millimeters) in the current locale.

_NL_TELEPHONE_TEL_INT_FMT
_NL_TELEPHONE_TEL_DOM_FMT
_NL_TELEPHONE_INT_SELECT
_NL_TELEPHONE_INT_PREFIX

On Linux boxes, these return information about how telephone numbers are formatted (both domestically and international calling) in the current locale. Further information is found in langinfo.h

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.

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.

All _NL_foo items

These return the same values as they do on boxes that don't have the appropriate underlying locale categories.

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.