NAME

localeconv — return locale-specific information

SYNOPSIS

#include <locale.h>

struct lconv *localeconv(void);


DESCRIPTION

^[CX] The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1-2024 defers to the ISO C standard.

The localeconv() function shall set the components of an object with the type struct lconv with the values appropriate for the formatting of numeric quantities (monetary and otherwise) according to the rules of the current locale.

The members of the structure with type char * are pointers to strings, any of which (except decimal_point) can point to "", to indicate that the value is not available in the current locale or is of zero length. The members with type char are non-negative numbers, any of which can be {CHAR_MAX} to indicate that the value is not available in the current locale.

The members include the following:

char *decimal_point

The radix character used to format non-monetary quantities.

char *thousands_sep

The character used to separate groups of digits before the decimal-point character in formatted non-monetary quantities.

char *grouping

A string whose elements taken as one-byte integer values indicate the size of each group of digits in formatted non-monetary quantities.

char *int_curr_symbol

The international currency symbol applicable to the current locale. The first three characters contain the alphabetic international currency symbol in accordance with those specified in the ISO 4217:2015 standard. The fourth character (immediately preceding the null byte) is the character used to separate the international currency symbol from the monetary quantity.

char *currency_symbol

The local currency symbol applicable to the current locale.

char *mon_decimal_point

The radix character used to format monetary quantities.

char *mon_thousands_sep

The separator for groups of digits before the decimal-point in formatted monetary quantities.

char *mon_grouping

A string whose elements taken as one-byte integer values indicate the size of each group of digits in formatted monetary quantities.

char *positive_sign

The string used to indicate a non-negative valued formatted monetary quantity.

char *negative_sign

The string used to indicate a negative valued formatted monetary quantity.

char int_frac_digits

The number of fractional digits (those after the decimal-point) to be displayed in an internationally formatted monetary quantity.

char frac_digits

The number of fractional digits (those after the decimal-point) to be displayed in a formatted monetary quantity.

char p_cs_precedes

Set to 1 if the currency_symbol precedes the value for a non-negative formatted monetary quantity. Set to 0 if the symbol succeeds the value.

char p_sep_by_space

Set to a value indicating the separation of the currency_symbol, the sign string, and the value for a non-negative formatted monetary quantity.

char n_cs_precedes

Set to 1 if the currency_symbol precedes the value for a negative formatted monetary quantity. Set to 0 if the symbol succeeds the value.

char n_sep_by_space

Set to a value indicating the separation of the currency_symbol, the sign string, and the value for a negative formatted monetary quantity.

char p_sign_posn

Set to a value indicating the positioning of the positive_sign for a non-negative formatted monetary quantity.

char n_sign_posn

Set to a value indicating the positioning of the negative_sign for a negative formatted monetary quantity.

char int_p_cs_precedes

Set to 1 or 0 if the int_curr_symbol respectively precedes or succeeds the value for a non-negative internationally formatted monetary quantity.

char int_n_cs_precedes

Set to 1 or 0 if the int_curr_symbol respectively precedes or succeeds the value for a negative internationally formatted monetary quantity.

char int_p_sep_by_space

Set to a value indicating the separation of the int_curr_symbol, the sign string, and the value for a non-negative internationally formatted monetary quantity.

char int_n_sep_by_space

Set to a value indicating the separation of the int_curr_symbol, the sign string, and the value for a negative internationally formatted monetary quantity.

char int_p_sign_posn

Set to a value indicating the positioning of the positive_sign for a non-negative internationally formatted monetary quantity.

char int_n_sign_posn

Set to a value indicating the positioning of the negative_sign for a negative internationally formatted monetary quantity.

The elements of grouping and mon_grouping are interpreted according to the following:

{CHAR_MAX}

No further grouping is to be performed.

0

The previous element is to be repeatedly used for the remainder of the digits.

other

The integer value is the number of digits that comprise the current group. The next element is examined to determine the size of the next group of digits before the current group.

The values of p_sep_by_space, n_sep_by_space, int_p_sep_by_space, and int_n_sep_by_space are interpreted according to the following:

0

No space separates the currency symbol and value.

1

If the currency symbol and sign string are adjacent, a space separates them from the value; otherwise, a space separates the currency symbol from the value.

2

If the currency symbol and sign string are adjacent, a space separates them; otherwise, a space separates the sign string from the value.

For int_p_sep_by_space and int_n_sep_by_space, the fourth character of int_curr_symbol is used instead of a space.

The values of p_sign_posn, n_sign_posn, int_p_sign_posn, and int_n_sign_posn are interpreted according to the following:

0

Parentheses surround the quantity and currency_symbol or int_curr_symbol.

1

The sign string precedes the quantity and currency_symbol or int_curr_symbol.

2

The sign string succeeds the quantity and currency_symbol or int_curr_symbol.

3

The sign string immediately precedes the currency_symbol or int_curr_symbol.

4

The sign string immediately succeeds the currency_symbol or int_curr_symbol.

The implementation shall behave as if no function in this volume of POSIX.1-2024 calls localeconv().

The localeconv() function need not be thread-safe; however, localeconv() shall avoid data races with all other functions.

RETURN VALUE

The localeconv() function shall return a pointer to the filled-in object. The application shall not modify the structure to which the return value points, ^[CX]  nor any storage areas pointed to by pointers within the structure. The returned pointer, and pointers within the structure, might be invalidated or  the structure ^[CX]  or the storage areas  might be overwritten by a subsequent call to localeconv(). In addition, ^[CX]  the returned pointer, and pointers within the structure, might be invalidated or  the structure ^[CX]  or the storage areas  might be overwritten by subsequent calls to setlocale() with the categories LC_ALL, LC_MONETARY, or LC_NUMERIC, ^[CX]  or by calls to uselocale() which change the categories LC_MONETARY or LC_NUMERIC. The returned pointer, pointers within the structure, the structure, and the storage areas might also be invalidated if the calling thread is terminated.

ERRORS

No errors are defined.

EXAMPLES

None.

APPLICATION USAGE

The following table illustrates the rules which may be used by four countries to format monetary quantities.

Country	Positive Format	Negative Format	International Format
Italy	€.1.230	-€.1.230	EUR.1.230
Netherlands	€ 1.234,56	€ -1.234,56	EUR 1.234,56
Norway	kr1.234,56	kr1.234,56-	NOK 1.234,56
Switzerland	SFrs.1,234.56	SFrs.1,234.56C	CHF 1,234.56

For these four countries, the respective values for the monetary members of the structure returned by localeconv() are:

	Italy	Netherlands	Norway	Switzerland
int_curr_symbol	"EUR."	"EUR "	"NOK "	"CHF "
currency_symbol	"€."	"€"	"kr"	"SFrs."
mon_decimal_point	""	","	","	"."
mon_thousands_sep	"."	"."	"."	","
mon_grouping	"\3"	"\3"	"\3"	"\3"
positive_sign	""	""	""	""
negative_sign	"-"	"-"	"-"	"C"
int_frac_digits	0	2	2	2
frac_digits	0	2	2	2
p_cs_precedes	1	1	1	1
p_sep_by_space	0	1	0	0
n_cs_precedes	1	1	1	1
n_sep_by_space	0	1	0	0
p_sign_posn	1	1	1	1
n_sign_posn	1	4	2	2
int_p_cs_precedes	1	1	1	1
int_n_cs_precedes	1	1	1	1
int_p_sep_by_space	0	0	0	0
int_n_sep_by_space	0	0	0	0
int_p_sign_posn	1	1	1	1
int_n_sign_posn	1	4	4	2

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

fprintf , fscanf , isalpha , nl_langinfo , setlocale , strcat , strchr , strcmp , strcoll , strcpy , strftime , strlen , strpbrk , strspn , strtok , strxfrm , strtod , uselocale

XBD <langinfo.h> , <locale.h>

CHANGE HISTORY

First released in Issue 4. Derived from the ANSI C standard.

Issue 6

A note indicating that this function need not be reentrant is added to the DESCRIPTION.

The RETURN VALUE section is rewritten to avoid use of the term "must".

This reference page is updated for alignment with the ISO/IEC 9899:1999 standard.

ISO/IEC 9899:1999 standard, Technical Corrigendum 1 is incorporated.

IEEE Std 1003.1-2001/Cor 1-2002, item XSH/TC1/D6/31 is applied, removing references to int_curr_symbol and updating the descriptions of p_sep_by_space and n_sep_by_space. These changes are for alignment with the ISO C standard.

Issue 7

Austin Group Interpretation 1003.1-2001 #156 is applied.

The definitions of int_curr_symbol and currency_symbol are updated.

The examples in the APPLICATION USAGE section are updated.

POSIX.1-2008, Technical Corrigendum 1, XSH/TC1-2008/0362 [75] is applied.

POSIX.1-2008, Technical Corrigendum 2, XSH/TC2-2008/0200 [656] is applied.

Issue 8

Austin Group Defect 1302 is applied, aligning this function with the ISO/IEC 9899:2018 standard.