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 .