NL_LANGINFO(3P) 					     POSIX Programmer's Manual						   NL_LANGINFO(3P)

PROLOG

       This  manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (consult the correspond-
       ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

NAME

       nl_langinfo, nl_langinfo_l -- language information

SYNOPSIS

       #include <langinfo.h>

       char *nl_langinfo(nl_item item);
       char *nl_langinfo_l(nl_item item, locale_t locale);

DESCRIPTION

       The nl_langinfo() and nl_langinfo_l() functions shall return a pointer to a string containing information relevant to the  particular  lan-
       guage  or  cultural area defined in the current locale, or in the locale represented by locale, respectively (see <langinfo.h>).  The mani-
       fest constant names and values of item are defined in <langinfo.h>.  For example:

	   nl_langinfo(ABDAY_1)

       would return a pointer to the string "Dom" if the identified language was Portuguese, and "Sun" if the identified language was English.

	   nl_langinfo_l(ABDAY_1, loc)

       would return a pointer to the string "Dom" if the identified language of the locale represented by loc was Portuguese,  and  "Sun"  if  the
       identified language of the locale represented by loc was English.

       The nl_langinfo() function need not be thread-safe.

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

RETURN VALUE

       In a locale where langinfo data is not defined, these functions shall return a pointer to the corresponding string in the POSIX locale.	In
       all locales, these functions shall return a pointer to an empty string if item contains an invalid setting.

       The  application  shall	not  modify  the string returned. The pointer returned by nl_langinfo() might be invalidated or the string content
       might be overwritten by a subsequent call to nl_langinfo() in any thread or to nl_langinfo_l() in the same thread or the initial thread, by
       subsequent calls to setlocale() with a category corresponding to the category of item (see <langinfo.h>) or the category LC_ALL, or by sub-
       sequent calls to uselocale() which change the category corresponding to the category of item.   The  pointer  returned  by  nl_langinfo_l()
       might  be  invalidated or the string content might be overwritten by a subsequent call to nl_langinfo_l() in the same thread or to nl_lang-
       info() in any thread, or by subsequent calls to freelocale() or newlocale() which free or modify the  locale  object  that  was	passed	to
       nl_langinfo_l().

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

   Getting Date and Time Formatting Information
       The  following example returns a pointer to a string containing date and time formatting information, as defined in the LC_TIME category of
       the current locale.

	   #include <time.h>
	   #include <langinfo.h>
	   ...
	   strftime(datestring, sizeof(datestring), nl_langinfo(D_T_FMT), tm);
	   ...

APPLICATION USAGE

       The array pointed to by the return value should not be modified by the program, but may be modified by further calls to these functions.

RATIONALE

       The possible interactions between internal data used by nl_langinfo() and nl_langinfo_l() are complicated by the fact that  nl_langinfo_l()
       must be thread-safe but nl_langinfo() need not be. The various implementation choices are:

	1. nl_langinfo_l()  and  nl_langinfo()	use separate buffers, or at least one of them does not use an internal string buffer. In this case
	   there are no interactions.

	2. nl_langinfo_l() and nl_langinfo() share an internal per-thread buffer. There can be interactions, but only in the same thread.

	3. nl_langinfo_l() uses an internal per-thread buffer, and nl_langinfo() uses (in all threads) the same buffer that  nl_langinfo_l()  uses
	   in the initial thread. There can be interactions, but only when nl_langinfo_l() is called in the initial thread.

FUTURE DIRECTIONS

       None.

SEE ALSO

       setlocale(), uselocale()

       The Base Definitions volume of POSIX.1-2008, Chapter 7, Locale, <langinfo.h>, <locale.h>, <nl_types.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C)  2013  by	the  Institute	of
       Electrical and Electronics Engineers, Inc and The Open Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
       event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Stan-
       dard is the referee document. The original Standard can be obtained online at http://www.unix.org/online.html .

       Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE
/The Open Group						       2013							   NL_LANGINFO(3P)