NAME
setlocale —
select character encoding
SYNOPSIS
#include
<locale.h>
char *
setlocale(int
category, const char
*locale);
DESCRIPTION
The
setlocale()
function sets and retrieves the active locale for the
current process. The locale modifies the behaviour of some functions in the
C library with respect to the character encoding, and on other operating
systems also with respect to some language and cultural conventions. For
more information about locales in general, see the
locale(1) manual page.
On OpenBSD, the only useful value for the
category is LC_CTYPE. It sets
the locale used for character encoding, character classification, and case
conversion. For compatibility with natural language support in
packages(7), all other categories —
LC_COLLATE, LC_MESSAGES,
LC_MONETARY, LC_NUMERIC, and
LC_TIME — can be set and retrieved, too, but
their values are ignored by the OpenBSD C library. A
category of LC_ALL sets the entire locale
generically.
The syntax and semantics of the
locale argument are not standardized and vary among
operating systems. On OpenBSD, if the
locale string ends with ".UTF-8", the UTF-8
locale is selected; otherwise, the "C" locale is selected, which
uses the ASCII character set. If the locale contains a
dot but does not end with ".UTF-8",
setlocale()
fails.
If locale is an empty string (""),
the value of the environment variable LC_ALL, with a
fallback to the variable corresponding to category,
and with a further fallback to LANG, is used
instead, as documented in the
locale(1) manual page.
If locale is NULL,
the locale remains unchanged. This can be used to determine the currently
active 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 other routine.
RETURN VALUES
In case of success, setlocale() returns a
pointer to a static string describing the locale that is in force after the
call. Subsequent calls to setlocale() may change the
content of the string. The format of the string is not standardized and
varies among operating systems.
On OpenBSD, if
setlocale() was never called with a
non-NULL locale argument, the
string "C" is returned. Otherwise, if the
category was not LC_ALL or if
the locale is the same for all categories, a copy of the
locale argument is returned. Otherwise, the locales
for the six categories LC_COLLATE,
LC_CTYPE, LC_MESSAGES,
LC_MONETARY, LC_NUMERIC,
LC_TIME are concatenated in that order, with slash
(‘/’) characters in between.
In case of failure, setlocale() returns
NULL. On OpenBSD, that can
only happen if the category is invalid, if a character
encoding other than UTF-8 is requested, if the requested
locale name is of excessive length, or if memory
allocation fails.
EXAMPLES
Calling
setlocale(LC_CTYPE,
"en_US.UTF-8");at the beginning of a program selects the UTF-8 locale and returns "en_US.UTF-8". Calling
setlocale(LC_ALL, NULL);right afterwards leaves the locale unchanged and returns "C/en_US.UTF-8/C/C/C/C".
SEE ALSO
STANDARDS
The setlocale() function conforms to
ANSI X3.159-1989
(“ANSI C89”).
HISTORY
The setlocale() function first appeared in
4.4BSD.