Provided by: manpages-posix-dev_2017a-2_all 
PROLOG
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.
NAME
newlocale — create or modify a locale object
SYNOPSIS
#include <locale.h>
locale_t newlocale(int category_mask, const char *locale,
locale_t base);
DESCRIPTION
The newlocale() function shall create a new locale object or modify an existing one. If the base
argument is (locale_t)0, a new locale object shall be created. It is unspecified whether the locale
object pointed to by base shall be modified, or freed and a new locale object created.
The category_mask argument specifies the locale categories to be set or modified. Values for
category_mask shall be constructed by a bitwise-inclusive OR of the symbolic constants LC_CTYPE_MASK,
LC_NUMERIC_MASK, LC_TIME_MASK, LC_COLLATE_MASK, LC_MONETARY_MASK, and LC_MESSAGES_MASK, or any of the
implementation-defined mask values defined in <locale.h>.
For each category with the corresponding bit set in category_mask the data from the locale named by
locale shall be used. In the case of modifying an existing locale object, the data from the locale named
by locale shall replace the existing data within the locale object. If a completely new locale object is
created, the data for all sections not requested by category_mask shall be taken from the default locale.
The following preset values of locale are defined for all settings of category_mask:
"POSIX" Specifies the minimal environment for C-language translation called the POSIX locale.
"C" Equivalent to "POSIX".
"" Specifies an implementation-defined native environment. This corresponds to the value of the
associated environment variables, LC_* and LANG; see the Base Definitions volume of
POSIX.1‐2017, Chapter 7, Locale and Chapter 8, Environment Variables.
If the base argument is not (locale_t)0 and the newlocale() function call succeeds, the contents of base
are unspecified. Applications shall ensure that they stop using base as a locale object before calling
newlocale(). If the function call fails and the base argument is not (locale_t)0, the contents of base
shall remain valid and unchanged.
The behavior is undefined if the base argument is the special locale object LC_GLOBAL_LOCALE, or is not a
valid locale object handle and is not (locale_t)0.
RETURN VALUE
Upon successful completion, the newlocale() function shall return a handle which the caller may use on
subsequent calls to duplocale(), freelocale(), and other functions taking a locale_t argument.
Upon failure, the newlocale() function shall return (locale_t)0 and set errno to indicate the error.
ERRORS
The newlocale() function shall fail if:
ENOMEM There is not enough memory available to create the locale object or load the locale data.
EINVAL The category_mask contains a bit that does not correspond to a valid category.
ENOENT For any of the categories in category_mask, the locale data is not available.
The newlocale() function may fail if:
EINVAL The locale argument is not a valid string pointer.
The following sections are informative.
EXAMPLES
Constructing a Locale Object from Different Locales
The following example shows the construction of a locale where the LC_CTYPE category data comes from a
locale loc1 and the LC_TIME category data from a locale loc2:
#include <locale.h>
...
locale_t loc, new_loc;
/* Get the "loc1" data. */
loc = newlocale (LC_CTYPE_MASK, "loc1", (locale_t)0);
if (loc == (locale_t) 0)
abort ();
/* Get the "loc2" data. */
new_loc = newlocale (LC_TIME_MASK, "loc2", loc);
if (new_loc != (locale_t) 0)
/* We don t abort if this fails. In this case this
simply used to unchanged locale object. */
loc = new_loc;
...
Freeing up a Locale Object
The following example shows a code fragment to free a locale object created by newlocale():
#include <locale.h>
...
/* Every locale object allocated with newlocale() should be
* freed using freelocale():
*/
locale_t loc;
/* Get the locale. */
loc = newlocale (LC_CTYPE_MASK | LC_TIME_MASK, "locname", (locale_t)0);
/* ... Use the locale object ... */
...
/* Free the locale object resources. */
freelocale (loc);
APPLICATION USAGE
Handles for locale objects created by the newlocale() function should either be released by a
corresponding call to freelocale(), or be used as a base locale to another newlocale() call.
The special locale object LC_GLOBAL_LOCALE must not be passed for the base argument, even when returned
by the uselocale() function.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
duplocale(), freelocale(), uselocale()
The Base Definitions volume of POSIX.1‐2017, Chapter 7, Locale, Chapter 8, Environment Variables,
<locale.h>
COPYRIGHT
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 .
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 2017 NEWLOCALE(3POSIX)