NL_LANGINFO(3)

NAME
nl_langinfo, nl_langinfo_l - query language and locale information

SYNOPSIS
#include <langinfo.h>

char *nl_langinfo(nl_item item);

char *nl_langinfo_l(nl_item item, locale_t locale);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

nl_langinfo_l():
    Since glibc 2.24:
        _POSIX_C_SOURCE >= 200809L
    Glibc 2.23 and earlier:
        _POSIX_C_SOURCE >= 200112L

DESCRIPTION
The nl_langinfo() and nl_langinfo_l() functions provide access to locale information in a more flexible way than localeconv(3). nl_langinfo() returns a string which is the value corresponding to item in the program's current global locale. nl_langinfo() returns a string which is the value corresponding to item for the locale identified by the locale object locale, which was previously created by newlocale(1). Individual and additional elements of the locale categories can be queried. setlocale(3) needs to be executed with proper arguments before.

Examples for the locale elements that can be specified in item using the constants defined in <langinfo.h> are:

CODESET (LC_CTYPE)
    Return a string with the name of the character encoding used in the selected locale, such as "UTF-8", "ISO-8859-1", or "ANSI_X3.4-1968" (better known as US-ASCII). This is the same string that you get with "locale charmap". For a list of character encoding names, try "locale -m" (see locale(1)).

D_T_FMT (LC_TIME)
    Return a string that can be used as a format string for strftime(3) to represent time and date in a locale-specific way.

D_FMT (LC_TIME)
    Return a string that can be used as a format string for strftime(3) to represent a date in a locale-specific way.

T_FMT (LC_TIME)
    Return a string that can be used as a format string for strftime(3) to represent a time in a locale-specific way.

DAY_{1–7} (LC_TIME)
    Return name of the n-th day of the week. [Warning: this follows the US convention DAY_1 = Sunday, not the international convention (ISO 8601) that Monday is the first day of the week.]

ABDAY_{1–7} (LC_TIME)
    Return abbreviated name of the n-th day of the week.

MON_{1–12} (LC_TIME)
    Return name of the n-th month.

ABMON_{1–12} (LC_TIME)
    Return abbreviated name of the n-th month.

RADIXCHAR (LC_NUMERIC)
    Return radix character (decimal dot, decimal comma, etc.).

THOUSEP (LC_NUMERIC)
    Return separator character for thousands (groups of three digits).

YESEXPR (LC_MESSAGES)
    Return a regular expression that can be used with the regex(3) function to recognize a positive response to a yes/no question.

NOEXPR (LC_MESSAGES)
    Return a regular expression that can be used with the regex(3) function to recognize a negative response to a yes/no question.

CRNCYSTR (LC_MONETARY)
    Return the currency symbol, preceded by "-" if the symbol should appear before the value, "+" if the symbol should appear after the value, or "." if the symbol should replace the radix character.

The above list covers just some examples of items that can be requested. For a more detailed list, consult The GNU C Library Reference Manual.

RETURN VALUE
On success, these functions return a pointer to a string which is the value corresponding to item in the specified locale.

If no locale has been selected by setlocale(3) for the appropriate category, nl_langinfo() return a pointer to the corresponding string in the "C" locale. The same is true of nl_langinfo_l() if locale specifies a locale where langinfo data is not defined.

If item is not valid, a pointer to an empty string is returned.

The pointer returned by these functions may point to static data that may be overwritten, or the pointer itself may be invalidated, by a subsequent call to nl_langinfo(), nl_langinfo_l(), or setlocale(3). The same statements apply to nl_langinfo_l() if the locale object referred to by locale is freed or modified by freelocale(3) or newlocale(3).

POSIX specifies that the application may not modify the string returned by these functions.

ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
Interface | Attribute | Value
 | Thread safety | MT-Safe locale

CONFORMING TO
POSIX.1-2001, POSIX.1-2008, SUSv2.

NOTES
The behavior of nl_langinfo_l() is undefined if locale is the special locale object LC_GLOBAL_LOCALE or is not a valid locale object handle.

EXAMPLE
The following program sets the character type and the numeric locale according to the environment and queries the terminal character set and the radix character.

    #include <langinfo.h>
    #include <locale.h>
    #include <stdio.h>
    #include <stdlib.h>
    int
    main(int argc, char *argv[])
    {
        setlocale(LC_CTYPE, "");
        setlocale(LC_NUMERIC, "");
        printf("%s\n", nl_langinfo(CODESET));
        printf("%s\n", nl_langinfo(RADIXCHAR));
        exit(EXIT_SUCCESS);
    }

SEE ALSO
locale(1), localeconv(3), setlocale(3), charsets(7), locale(7)

The GNU C Library Reference Manual

COLOPHON
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