nl_langinfo, nl_langinfo_l - query language and locale information
#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(1). 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.
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 |
POSIX.1-2001, POSIX.1-2008, SUSv2.
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(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);
}
locale(1),
localeconv(3),
setlocale(3),
charsets(7),
locale(7)
The GNU C Library Reference Manual