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strfmon - Man Page

convert monetary value to a string


Standard C library (libc, -lc)


#include <monetary.h>

ssize_t strfmon(char s[restrict .max], size_t max,
                const char *restrict format, ...);
ssize_t strfmon_l(char s[restrict .max], size_t max, locale_t locale,
                const char *restrict format, ...);


The strfmon() function formats the specified monetary amount according to the current locale and format specification format and places the result in the character array s of size max.

The strfmon_l() function performs the same task, but uses the locale specified by locale. The behavior of strfmon_l() is undefined if locale is the special locale object LC_GLOBAL_LOCALE (see duplocale(3)) or is not a valid locale object handle.

Ordinary characters in format are copied to s without conversion. Conversion specifiers are introduced by a '%' character. Immediately following it there can be zero or more of the following flags:


The single-byte character f is used as the numeric fill character (to be used with a left precision, see below). When not specified, the space character is used.


Do not use any grouping characters that might be defined for the current locale. By default, grouping is enabled.

( or +

The ( flag indicates that negative amounts should be enclosed between parentheses. The + flag indicates that signs should be handled in the default way, that is, amounts are preceded by the locale's sign indication, for example, nothing for positive, "-" for negative.


Omit the currency symbol.


Left justify all fields. The default is right justification.

Next, there may be a field width: a decimal digit string specifying a minimum field width in bytes. The default is 0. A result smaller than this width is padded with spaces (on the left, unless the left-justify flag was given).

Next, there may be a left precision of the form "#" followed by a decimal digit string. If the number of digits left of the radix character is smaller than this, the representation is padded on the left with the numeric fill character. Grouping characters are not counted in this field width.

Next, there may be a right precision of the form "." followed by a decimal digit string. The amount being formatted is rounded to the specified number of digits prior to formatting. The default is specified in the frac_digits and int_frac_digits items of the current locale. If the right precision is 0, no radix character is printed. (The radix character here is determined by LC_MONETARY, and may differ from that specified by LC_NUMERIC.)

Finally, the conversion specification must be ended with a conversion character. The three conversion characters are


(In this case, the entire specification must be exactly "%%".) Put a '%' character in the result string.


One argument of type double is converted using the locale's international currency format.


One argument of type double is converted using the locale's national currency format.

Return Value

The strfmon() function returns the number of characters placed in the array s, not including the terminating null byte, provided the string, including the terminating null byte, fits. Otherwise, it sets errno to E2BIG, returns -1, and the contents of the array is undefined.


For an explanation of the terms used in this section, see attributes(7).

strfmon()Thread safetyMT-Safe locale
strfmon_l()Thread safetyMT-Safe






The call

strfmon(buf, sizeof(buf), "[%^=*#6n] [%=*#6i]",
        1234.567, 1234.567);


[€ **1234,57] [EUR **1 234,57]

in the nl_NL locale. The de_DE, de_CH, en_AU, and en_GB locales yield

[ **1234,57 €] [ **1.234,57 EUR]
[ Fr. **1234.57] [ CHF **1'234.57]
[ $**1234.57] [ AUD**1,234.57]
[ £**1234.57] [ GBP**1,234.57]

See Also

duplocale(3), setlocale(3), sprintf(3), locale(7)

Referenced By

locale(7), localeconv(3).

The man page strfmon_l(3) is an alias of strfmon(3).

2024-05-02 Linux man-pages 6.9.1