Name
duplocale — duplicate a locale object
Synopsis
#include <locale.h>
locale_t
duplocale( |
locale_t locobj); |
![[Note]](../stylesheet/note.png) |
Note | ||||
|---|---|---|---|---|---|
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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
error.
NOTES
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). Callingduplocale() can be used to ensure that theLC_GLOBAL_LOCALEvalue is converted into a usable locale object. See EXAMPLES, below.
Each locale object created by duplocale() should be deallocated using
freelocale(3).
EXAMPLES
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;
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 (char *p = argv[1]; *p; p++)
putchar(toupper_l(*p, nloc));
printf("\n");
freelocale(nloc);
exit(EXIT_SUCCESS);
}
COLOPHON
This page is part of release 5.11 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/.
|
Copyright (C) 2014 Michael Kerrisk <mtk.manpagesgmail.com> %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. %%%LICENSE_END |