nl_langinfo(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ATTRIBUTES | CONFORMING TO | NOTES | EXAMPLES | SEE ALSO | COLOPHON

NL_LANGINFO(3)          Linux Programmer's Manual         NL_LANGINFO(3)

NAME         top

       nl_langinfo, nl_langinfo_l - query language and locale
       information

SYNOPSIS         top

       #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         top

       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_l()
       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(3).  Individual and additional
       elements of the locale categories can be queried.

       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 (%c conversion specification).

       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
              (%x conversion specification).

       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
              (%X conversion specification).

       AM_STR (LC_TIME)
              Return a string that represents affix for ante meridiem
              (before noon, "AM") time.  (Used in %p strftime(3)
              conversion specification.)

       PM_STR (LC_TIME)
              Return a string that represents affix for post meridiem
              (before midnight, "PM") time.  (Used in %p strftime(3)
              conversion specification.)

       T_FMT_AMPM (LC_TIME)
              Return a string that can be used as a format string for
              strftime(3) to represent a time in a.m. or p.m. notation a
              locale-specific way (%r conversion specification).

       ERA (LC_TIME)
              Return era description, which contains information about
              how years are counted and displayed for each era in a
              locale.  Each era description segment shall have the
              format:

                     direction:offset:start_date:end_date:era_name:era_format

              according to the definitions below:

              direction
                     Either a "+" or a "-" character.  The "+" means
                     that years increase from the start_date towards the
                     end_date, "-" means the opposite.

              offset The epoch year of the start_date.

              start_date
                     A date in the form yyyy/mm/dd, where yyyy, mm, and
                     dd are the year, month, and day numbers
                     respectively of the start of the era.

              end_date
                     The ending date of the era, in the same format as
                     the start_date, or one of the two special values
                     "-*" (minus infinity) or "+*" (plus infinity).

              era_name
                     The name of the era, corresponding to the %EC
                     strftime(3) conversion specification.

              era_format
                     The format of the year in the era, corresponding to
                     the %EY strftime(3) conversion specification.

              Era description segments are separated by semicolons.
              Most locales do not define this value.  Examples of
              locales that do define this value are the Japanese and
              Thai locales.

       ERA_D_T_FMT (LC_TIME)
              Return a string that can be used as a format string for
              strftime(3) for alternative representation of time and
              date in a locale-specific way (%Ec conversion
              specification).

       ERA_D_FMT (LC_TIME)
              Return a string that can be used as a format string for
              strftime(3) for alternative representation of a date in a
              locale-specific way (%Ex conversion specification).

       ERA_T_FMT (LC_TIME)
              Return a string that can be used as a format string for
              strftime(3) for alternative representation of a time in a
              locale-specific way (%EX conversion specification).

       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.]  (Used in %A strftime(3)
              conversion specification.)

       ABDAY_{1–7} (LC_TIME)
              Return abbreviated name of the n-th day of the week.
              (Used in %a strftime(3) conversion specification.)

       MON_{1–12} (LC_TIME)
              Return name of the n-th month.  (Used in %B strftime(3)
              conversion specification.)

       ABMON_{1–12} (LC_TIME)
              Return abbreviated name of the n-th month.  (Used in %b
              strftime(3) conversion specification.)

       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         top

       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         top

       For an explanation of the terms used in this section, see
       attributes(7).

       ┌───────────────────────────────┬───────────────┬────────────────┐
       │Interface                      Attribute     Value          │
       ├───────────────────────────────┼───────────────┼────────────────┤
       │nl_langinfo()                  │ Thread safety │ MT-Safe locale │
       └───────────────────────────────┴───────────────┴────────────────┘

CONFORMING TO         top

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

NOTES         top

       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.

EXAMPLES         top

       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         top

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

       The GNU C Library Reference Manual

COLOPHON         top

       This page is part of release 5.11 of the Linux man-pages project.
       A description of the project, information about reporting bugs,
       and the latest version of this page, can be found at
       https://www.kernel.org/doc/man-pages/.

GNU                            2021-03-22                 NL_LANGINFO(3)

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