nl_langinfo, nl_langinfo_l - query language and locale
information
Standard C library (libc, -lc)
#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
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 in 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.
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.
For an explanation of the terms used in this section, see
attributes(7).
| Interface |
Attribute |
Value |
| nl_langinfo () |
Thread safety |
MT-Safe locale |
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.
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(void)
{
setlocale(LC_CTYPE, "");
setlocale(LC_NUMERIC, "");
printf("%s\n", nl_langinfo(CODESET));
printf("%s\n", nl_langinfo(RADIXCHAR));
exit(EXIT_SUCCESS);
}
locale(1), localeconv(3), setlocale(3),
charsets(7), locale(7)
The GNU C Library Reference Manual