SETLOCALE(3) BSD Library Functions Manual SETLOCALE(3)NAMEsetlocale — natural language formatting for C
Standard C Library (libc, -lc)
setlocale(int category, const char *locale);
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
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, alpha‐
betic 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 for‐
matting 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
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. 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
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 combi‐
nation of category and locale makes no sense.
/usr/share/locale/locale/category locale file for the locale locale and
the category category.
No errors are defined.
SEE ALSOcolldef(1), mklocale(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”).
The setlocale() function first appeared in 4.4BSD.
BSD November 21, 2003 BSD