|
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | VERSIONS | CONFORMING TO | NOTES | EXAMPLE | SEE ALSO | COLOPHON |
|
DUPLOCALE(3) Linux Programmer's Manual DUPLOCALE(3)
duplocale - duplicate a locale object
#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
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).
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.
ENOMEM Insufficient memory to create the duplicate locale object.
The duplocale() function first appeared in version 2.3 of the GNU C
library.
POSIX.1-2008.
Duplicating a locale can serve the following purposes:
* To create a copy of a locale object in which one of more
categories are to be modified (using newlocale(3)).
* To obtain a handle for the current locale which can used in other
functions that employ a locale handle, such as toupper_l(3). This
is done by applying duplocale() to the value returned by the
following call:
loc = uselocale((locale_t) 0);
This technique is necessary, because the above uselocale(3) call
may return the value LC_GLOBAL_LOCALE, which results in undefined
behavior if passed to functions such as toupper_l(3). Calling
duplocale() can be used to ensure that the LC_GLOBAL_LOCALE value
is converted into a usable locale object. See EXAMPLE, below.
Each locale object created by duplocale() should be deallocated using
freelocale(3).
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);
}
freelocale(3), newlocale(3), setlocale(3), uselocale(3), locale(5),
locale(7)
This page is part of release 4.15 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/.
Linux 2017-09-15 DUPLOCALE(3)
Pages that refer to this page: isalpha(3), newlocale(3), strfmon(3), toupper(3), towlower(3), towupper(3), uselocale(3), locale(7)
Copyright and license for this manual page
|
HTML rendering created 2018-02-02 by Michael Kerrisk, author of The Linux Programming Interface, maintainer of the Linux man-pages project. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH.
|
|