setlocale, localeconv - natural language formatting for C
#include <locale.h>
char *
setlocale(int category, const char *locale);
struct lconv *
localeconv(void);
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 localeconv() routine returns the current locale's parameters
for formatting numbers.
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) functions. This
controls
recognition of upper and lower case, alphabetic
or non-alphabetic
characters, and so on. The real work
is done by
the setrunelocale() 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.
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 other
routine.
The localeconv() function returns a pointer to a structure
which provides
parameters for formatting numbers, especially currency values:
struct lconv {
char *decimal_point;
char *thousands_sep;
char *grouping;
char *int_curr_symbol;
char *currency_symbol;
char *mon_decimal_point;
char *mon_thousands_sep;
char *mon_grouping;
char *positive_sign;
char *negative_sign;
char int_frac_digits;
char frac_digits;
char p_cs_precedes;
char p_sep_by_space;
char n_cs_precedes;
char n_sep_by_space;
char p_sign_posn;
char n_sign_posn;
};
The individual fields have the following meanings:
decimal_point The decimal point character, except for
currency values.
thousands_sep The separator between groups of digits
before the decimal
point, except for currency values.
grouping The sizes of the groups of digits, except
for currency
values. This is a pointer to a vector of
integers,
each of size char, representing group
size from low
order digit groups to high order (right
to left). The
list may be terminated with 0 or
CHAR_MAX. If the
list is terminated with 0, the last group
size before
the 0 is repeated to account for all the
digits. If
the list is terminated with CHAR_MAX, no
more grouping
is performed.
int_curr_symbol The standardized international currency
symbol.
currency_symbol The local currency symbol.
mon_decimal_point The decimal point character for currency
values.
mon_thousands_sep The separator for digit groups in currency values.
mon_grouping Like grouping but for currency values.
positive_sign The character used to denote non-negative
currency
values, usually the empty string.
negative_sign The character used to denote negative
currency values,
usually a minus sign.
int_frac_digits The number of digits after the decimal
point in an international-style
currency value.
frac_digits The number of digits after the decimal
point in the
local style for currency values.
p_cs_precedes 1 if the currency symbol precedes the
currency value
for non-negative values, 0 if it follows.
p_sep_by_space 1 if a space is inserted between the currency symbol
and the currency value for non-negative
values, 0 otherwise.
n_cs_precedes Like p_cs_precedes but for negative values.
n_sep_by_space Like p_sep_by_space but for negative values.
p_sign_posn The location of the positive_sign with
respect to a
non-negative quantity and the
currency_symbol, coded
as follows:
0 Parentheses around the entire
string.
1 Before the string.
2 After the string.
3 Just before currency_symbol.
4 Just after currency_symbol.
n_sign_posn Like p_sign_posn but for negative currency values.
Unless mentioned above, an empty string as a value for a
field indicates
a zero length result or a value that is not in the current
locale. A
CHAR_MAX result similarly denotes an unavailable value.
The setlocale() function returns NULL and fails to change
the locale if
the given combination of category and locale makes no sense.
The
localeconv() function returns a pointer to a static object
which may be
altered by later calls to setlocale() or localeconv().
The setlocale() and localeconv() functions conform to ANSI
X3.159-1989
(``ANSI C'').
The setlocale() and localeconv() functions first appeared in
4.4BSD.
The current implementation supports only the "C" and "POSIX"
locales for
all but the LC_CTYPE locale.
In spite of the gnarly currency support in localeconv(), the
standards
don't include any functions for generalized currency formatting.
LC_COLLATE does not make sense for many languages. Use of
LC_MONETARY
could lead to misleading results until we have a real time
currency conversion
function. LC_NUMERIC and LC_TIME are personal
choices and should
not be wrapped up with the other categories.
OpenBSD 3.6 June 9, 1993
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