Originální popis anglicky:
strfmon - convert monetary value to a string
Návod, kniha: POSIX Programmer's Manual
#include <monetary.h>
ssize_t strfmon(char *restrict
s, size_t
maxsize ,
const char *restrict
format, ...);
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
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 the U.S., 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.
- 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.
- #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 "$***123.45" . 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>s to make their positive and negative formats an equal length.
- .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.
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 U.S.: 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 U.S.: $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 %% .
The
LC_MONETARY category of the program's 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 4217:1995 standard.
If the value of
maxsize is greater than {SSIZE_MAX}, the result is
implementation-defined.
If the total number of resulting bytes including the terminating null byte is
not more than
maxsize,
strfmon() shall return the number of
bytes placed into the array pointed to by
s, not including the
terminating null byte. Otherwise, -1 shall be returned, the contents of the
array are unspecified, and
errno shall be set to indicate the error.
The
strfmon() function shall fail if:
- E2BIG
- Conversion stopped due to lack of space in the buffer.
The following sections are informative.
Given a locale for the U.S. 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().
None.
None.
Lowercase conversion characters are reserved for future standards use and
uppercase for implementation-defined use.
fprintf() ,
localeconv() , the Base Definitions volume of
IEEE Std 1003.1-2001,
<monetary.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 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
.
