STRFMON(3)                 POSIX Programmer's Manual                STRFMON(3)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

NAME
       strfmon, strfmon_l -- convert monetary value to a string

SYNOPSIS
       #include <monetary.h>

       ssize_t strfmon(char *restrict _s, size_t maxsize,
           const char *restrict format, ...);
       ssize_t strfmon_l(char *restrict _s, size_t maxsize,
           locale_t locale, const char *restrict format, ...);

DESCRIPTION
       The strfmon() function shall place characters into the array pointed to
       by _s as controlled by the string pointed to by format.  No more than
       maxsize bytes are placed into the array.

       The format is a character string, beginning and ending in its initial
       state, if any, that contains two types of objects: plain characters,
       which are simply copied to the output stream, and conversion
       specifications, each of which shall result in the fetching of zero or
       more arguments which are converted and formatted. The results are
       undefined if there are insufficient arguments for the format. If the
       format is exhausted while arguments remain, the excess arguments are
       simply ignored.

       The application shall ensure that a conversion specification consists
       of the following sequence:

        *  A ''%%'' character

        *  Optional flags

        *  Optional field width

        *  Optional left precision

        *  Optional right precision

        *  A required conversion specifier character that determines the
           conversion to be performed

       The strfmon___l() function shall be equivalent to the strfmon() function,
       except that the locale data used is from the locale represented by
       locale.

   Flags
       One or more of the following optional flags can be specified to control
       the conversion:

       =_f      An ''=='' followed by a single character _f which is used as the
               numeric fill character. In order to work with precision or
               width counts, the fill character shall be a single byte
               character; if not, the behavior is undefined. The default
               numeric fill character is the <space>.  This flag does not
               affect field width filling which always uses the <space>.  This
               flag is ignored unless a left precision (see below) is
               specified.

       ^       Do not format the currency amount with grouping characters. The
               default is to insert the grouping characters if defined for the
               current locale.

       + or (  Specify the style of representing positive and negative
               currency amounts. Only one of ''++'' or ''(('' may be specified. If
               ''++'' is specified, the locale's equivalent of ''++'' and ''--'' are
               used (for example, in many locales, the empty string if
               positive and ''--'' if negative). If ''(('' is specified, negative
               amounts are enclosed within parentheses. If neither flag is
               specified, the ''++'' style is used.

       !       Suppress the currency symbol from the output conversion.

       -       Specify the alignment. If this flag is present the result of
               the conversion is left-justified (padded to the right) rather
               than right-justified. This flag shall be ignored unless a field
               width (see below) is specified.

   Field Width
       _w       A decimal digit string _w specifying a minimum field width in
               bytes in which the result of the conversion is right-justified
               (or left-justified if the flag ''--'' is specified). The default
               is 0.

   Left Precision
       #_n      A ''##'' followed by a decimal digit string _n specifying a maximum
               number of digits expected to be formatted to the left of the
               radix character. This option can be used to keep the formatted
               output from multiple calls to the strfmon() function aligned in
               the same columns. It can also be used to fill unused positions
               with a special character as in ""$$******112233..4455"".  This option
               causes an amount to be formatted as if it has the number of
               digits specified by _n.  If more than _n digit positions are
               required, this conversion specification is ignored.  Digit
               positions in excess of those actually required are filled with
               the numeric fill character (see the =_f flag above).

               If grouping has not been suppressed with the ''^^'' flag, and it
               is defined for the current locale, grouping separators are
               inserted before the fill characters (if any) are added.
               Grouping separators are not applied to fill characters even if
               the fill character is a digit.

               To ensure alignment, any characters appearing before or after
               the number in the formatted output such as currency or sign
               symbols are padded as necessary with <space> characters to make
               their positive and negative formats an equal length.

   Right Precision
       ._p      A <period> followed by a decimal digit string _p specifying the
               number of digits after the radix character. If the value of the
               right precision _p is 0, no radix character appears. If a right
               precision is not included, a default specified by the current
               locale is used. The amount being formatted is rounded to the
               specified number of digits prior to formatting.

   Conversion Specifier Characters
       The conversion specifier characters and their meanings are:

       i       The double argument is formatted according to the locale's
               international currency format (for example, in the US: USD
               1,234.56). If the argument is +-Inf or NaN, the result of the
               conversion is unspecified.

       n       The double argument is formatted according to the locale's
               national currency format (for example, in the US: $1,234.56).
               If the argument is +-Inf or NaN, the result of the conversion
               is unspecified.

       %       Convert to a ''%%''; no argument is converted. The entire
               conversion specification shall be %%%%.

   Locale Information
       The LC__MONETARY category of the current locale affects the behavior of
       this function including the monetary radix character (which may be
       different from the numeric radix character affected by the LC__NUMERIC
       category), the grouping separator, the currency symbols, and formats.
       The international currency symbol should be conformant with the
       ISO 4217:2001 standard.

       If the value of maxsize is greater than {SSIZE_MAX}, the result is
       implementation-defined.

       The behavior is undefined if the locale argument to strfmon___l() is the
       special locale object LC_GLOBAL_LOCALE or is not a valid locale object
       handle.

RETURN VALUE
       If the total number of resulting bytes including the terminating null
       byte is not more than maxsize, these functions shall return the number
       of bytes placed into the array pointed to by _s, not including the
       terminating NUL character. Otherwise, -1 shall be returned, the
       contents of the array are unspecified, and errno shall be set to
       indicate the error.

ERRORS
       These functions shall fail if:

       E2BIG  Conversion stopped due to lack of space in the buffer.

       The following sections are informative.

EXAMPLES
       Given a locale for the US and the values 123.45, -123.45, and 3456.781,
       the following output might be produced. Square brackets (""[[]]"") are used
       in this example to delimit the output.


           %n         [$123.45]         Default formatting
                      [-$123.45]
                      [$3,456.78]

           %11n       [    $123.45]     Right align within an 11-character field
                      [   -$123.45]
                      [  $3,456.78]

           %#5n       [ $   123.45]     Aligned columns for values up to 99999
                      [-$   123.45]
                      [ $ 3,456.78]

           %=*#5n     [ $***123.45]     Specify a fill character
                      [-$***123.45]
                      [ $*3,456.78]

           %=0#5n     [ $000123.45]     Fill characters do not use grouping
                      [-$000123.45]     even if the fill character is a digit
                      [ $03,456.78]

           %^#5n      [ $  123.45]      Disable the grouping separator
                      [-$  123.45]
                      [ $ 3456.78]

           %^#5.0n    [ $  123]         Round off to whole units
                      [-$  123]
                      [ $ 3457]

           %^#5.4n    [ $  123.4500]    Increase the precision
                      [-$  123.4500]
                      [ $ 3456.7810]

           %(#5n      [ $   123.45 ]    Use an alternative pos/neg style
                      [($   123.45)]
                      [ $ 3,456.78 ]

           %!(#5n     [    123.45 ]     Disable the currency symbol
                      [(   123.45)]
                      [  3,456.78 ]

           %-14#5.4n  [ $   123.4500 ]  Left-justify the output
                      [-$   123.4500 ]
                      [ $ 3,456.7810 ]

           %14#5.4n   [  $   123.4500]  Corresponding right-justified output
                      [ -$   123.4500]
                      [  $ 3,456.7810]

       See also the EXAMPLES section in fprintf().

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       Lowercase conversion characters are reserved for future standards use
       and uppercase for implementation-defined use.

SEE ALSO
       fprintf(), localeconv()

       The Base Definitions volume of POSIX.1-2017, <monetary.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  In the event of any discrepancy between this version and the
       original IEEE and The Open Group Standard, the original IEEE and The
       Open Group Standard is the referee document. The original Standard can
       be obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017                           STRFMON(3)
