duplocale — duplicate a locale object

Synopsis

#include <locale.h>

locale_t duplocale(locale_t locobj);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

duplocale():

Since glibc 2.10:

_XOPEN_SOURCE >= 700

Before glibc 2.10:

_GNU_SOURCE

Description

The duplocale() function creates a duplicate of the locale object referred to by locobj.

If locobj is LC_GLOBAL_LOCALE, duplocale() creates a locale object containing a copy of the global locale determined by setlocale(3).

Return Value

On success, duplocale() returns a handle for the new locale object. On error, it returns (locale_t) 0, and sets errno to indicate the cause of the error.

Errors

ENOMEM

Insufficient memory to create the duplicate locale object.

Versions

The duplocale() function first appeared in version 2.3 of the GNU C library.

Conforming to

POSIX.1-2008.

Notes

Duplicating a locale can serve the following purposes:

Each locale object created by duplocale() should be deallocated using freelocale(3).

Example

The program below uses uselocale(3) and duplocale() to obtain a handle for the current locale which is then passed to toupper_l(3). The program takes one command-line argument, a string of characters that is converted to uppercase and displayed on standard output. An example of its use is the following:

$ ./a.out abc
ABC

Program source

#define _XOPEN_SOURCE 700
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <locale.h>

#define errExit(msg)    do { perror(msg); exit(EXIT_FAILURE); \
                        } while (0)

int
main(int argc, char *argv[])
{
    locale_t loc, nloc;
    char *p;

    if (argc != 2) {
        fprintf(stderr, "Usage: %s string\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    /* This sequence is necessary, because uselocale() might return
       the value LC_GLOBAL_LOCALE, which can't be passed as an
       argument to toupper_l() */

    loc = uselocale((locale_t) 0);
    if (loc == (locale_t) 0)
        errExit("uselocale");

    nloc = duplocale(loc);
    if (nloc == (locale_t) 0)
        errExit("duplocale");

    for (p = argv[1]; *p; p++)
        putchar(toupper_l(*p, nloc));

    printf("\n");

    freelocale(nloc);

    exit(EXIT_SUCCESS);
}

See Also

freelocale(3), newlocale(3), setlocale(3), uselocale(3), locale(5), locale(7)

Colophon

This page is part of release 5.04 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

Referenced By

isalpha(3), locale(7), newlocale(3), strfmon(3), toupper(3), towlower(3), towupper(3), uselocale(3).

2019-03-06 Linux Programmer's Manual