SETLOCALE(3) FreeBSD Library Functions Manual SETLOCALE(3)
NAME
setlocale - natural language formatting for C
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <locale.h>
char *
setlocale(int category, const char *locale);
DESCRIPTION
The setlocale() function sets the C library's notion of natural language
formatting style for particular sets of routines. Each such style is
called a `locale' and is invoked using an appropriate name passed as a C
string.
The setlocale() function recognizes several categories of routines.
These are the categories and the sets of routines they select:
LC_ALL Set the entire locale generically.
LC_COLLATE Set a locale for string collation routines. This controls
alphabetic ordering in strcoll() and strxfrm().
LC_CTYPE Set a locale for the ctype(3) and multibyte(3) functions.
This controls recognition of upper and lower case,
alphabetic or non-alphabetic characters, and so on.
LC_MESSAGES Set a locale for message catalogs, see catopen(3) function.
LC_MONETARY Set a locale for formatting monetary values; this affects
the localeconv() function.
LC_NUMERIC Set a locale for formatting numbers. This controls the
formatting of decimal points in input and output of floating
point numbers in functions such as printf() and scanf(), as
well as values returned by localeconv().
LC_TIME Set a locale for formatting dates and times using the
strftime() function.
LANG Sets the generic locale category for native language, local
customs and coded character set in the absence of more
specific locale variables.
Only three locales are defined by default, the empty string "" which
denotes the native environment, and the "C" and "POSIX" locales, which
denote the C language environment. A locale argument of NULL causes
setlocale() to return the current locale.
The option -a to the locale(1) command can be used to display all further
possible names for the locale argument that are recognized. Specifying
any unrecognized value for locale makes setlocale() fail.
By default, C programs start in the "C" locale.
The only function in the library that sets the locale is setlocale(); the
locale is never changed as a side effect of some other routine.
RETURN VALUES
Upon successful completion, setlocale() returns the string associated
with the specified category for the requested locale. The setlocale()
function returns NULL and fails to change the locale if the given
combination of category and locale makes no sense.
FILES
$PATH_LOCALE/locale/category
/usr/share/locale/locale/category locale file for the locale locale and
the category category.
EXAMPLES
The following code illustrates how a program can initialize the
international environment for one language, while selectively modifying
the program's locale such that regular expressions and string operations
can be applied to text recorded in a different language:
setlocale(LC_ALL, "de");
setlocale(LC_COLLATE, "fr");
When a process is started, its current locale is set to the C or POSIX
locale. An internationalized program that depends on locale data not
defined in the C or POSIX locale must invoke the setlocale subroutine in
the following manner before using any of the locale-specific information:
setlocale(LC_ALL, "");
ERRORS
No errors are defined.
SEE ALSO
locale(1), localedef(1), catopen(3), ctype(3), localeconv(3),
multibyte(3), strcoll(3), strxfrm(3), euc(5), utf8(5), environ(7)
STANDARDS
The setlocale() function conforms to ISO/IEC 9899:1999 ("ISO C99").
HISTORY
The setlocale() function first appeared in 4.4BSD.
FreeBSD 15.1-STABLE-HBSD August 7, 2020 SETLOCALE(3)