Manpages - nl_langinfo.3p

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

nl_langinfo, nl_langinfo_l — language information

  #include <langinfo.h>
  char *nl_langinfo(nl_item item);
  char *nl_langinfo_l(nl_item item, locale_t locale);

The /nl_langinfo/() and /nl_langinfo_l/() functions shall return a pointer to a string containing information relevant to the particular language or cultural area defined in the current locale, or in the locale represented by locale, respectively (see <langinfo.h>). The manifest 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.

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 subsequent 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_langinfo/() 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/(). The returned pointer and the string content might also be invalidated if the calling thread is terminated.

No errors are defined.

The following sections are informative.

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.

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.

None.

/setlocale ( )/, /uselocale ( )/

The Base Definitions volume of POSIX.1‐2017, Chapter 7, Locale, <langinfo.h>, <locale.h>, <nl_types.h>

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology – Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. 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 Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

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