fwprintf(3C)fwprintf(3C)NAMEfwprintf(), wprintf(), swprintf() - print formatted wide-character out‐
put
SYNOPSISDESCRIPTION
The function places output on the named output stream.
The function places output on the standard output stream stdout.
The function places output followed by the null wide-character in con‐
secutive wide-characters starting at no more than n wide-characters are
written, including a terminating null wide-character, which is always
added (unless n is zero).
Each of these functions converts, formats and prints its arguments
under control of the format wide-character string. The format is com‐
posed of zero or more directives: ordinary wide-characters, which are
simply copied to the output stream and conversion specifications, each
of which results in the fetching of zero or more arguments.
Conversions can be applied to the nth argument after the format in the
argument list, rather than to the next unused argument. In this case,
the conversion wide-character (see below) is replaced by the sequence
where n is a decimal integer in the range 1 through giving the position
of the argument in the argument list. This feature provides for the
definition of format wide-character strings that select arguments in an
order appropriate to specific languages (see the section).
In format wide-character strings containing the form of conversion
specifications, numbered arguments in the argument list can be refer‐
enced from the format wide-character string as many times as required.
In format wide-character strings containing the form of conversion
specifications, each argument in the argument list is used exactly
once.
All forms of the functions allow for the insertion of a language-depen‐
dent radix character in the output string, output as a wide-character
value. The radix character is defined in the program's locale (cate‐
gory
In the POSIX locale, or in a locale where the radix character is not
defined, the radix character defaults to a period
Each conversion specification is introduced by the wide-character or by
the wide-character sequence after which the following appear in
sequence:
1. Zero or more flags (in any order), which modify the meaning
of the conversion specification.
2. An optional minimum field width. If the converted value
has fewer wide-characters than the field width, it will be
padded with spaces by default on the left.
3. An optional precision that gives the minimum number of dig‐
its to appear for the and conversions.
4. Zero or more of the following optional character specifica‐
tions:
· an optional specifying that a following conversion
wide-character applies to a pointer to a type short
int argument
· an optional specifying that a following or conversion
wide-character applies to a type short int or type
unsigned short int argument (the argument will have
been promoted according to the integral promotions,
and its value will be converted to type short int or
unsigned short int before printing)
· an optional specifying that a following or conversion
specifier applies to a signed char or unsigned char
argument ( the argument will have been promoted
according to the integer promotions, but its value
will be converted to short or unsigned short before
printing)
· an optional specifying that a following conversion
specifier applies to a pointer to a signed char argu‐
ment
· an optional specifying that a following or conversion
wide-character applies to a type which is the 80-bit
IEEE-754 double-extended type in the architecture
· an optional specifying that a following or conversion
specifier applies to an intmax_t or uintmax_t argument
· an optional specifying that a following conversion
specifier applies to a pointer to an intmax_t argument
· an optional (ell) specifying that a following conver‐
sion wide-character applies to a wint_t argument
· an optional (ell) specifying that a following conver‐
sion wide-character applies to a wchar_t argument
· an optional (ell-ell) specifying that following or
conversion specifier applies to a long long or
unsigned long long argument
· an optional (ell-ell) specifying that following con‐
version specifier applies to a pointer to a long long
argument
· an optional specifying that a following or conversion
specifier applies to a ptrdiff_t or the corresponding
unsigned type argument
· an optional specifying that a following conversion
specifier applies to a pointer to a ptrdiff_t argument
· an optional specifying that a following or conversion
specifier applies to a size_t argument or the corre‐
sponding signed integer type argument
· an optional specifying that a following conversion
specifier applies to a pointer to a size_t argument
For Itanium(R)-based systems if the optional decimal
floating point feature is installed and enabled, the fol‐
lowing optional character specifications are allowed:
· an optional specifying that a following or conver‐
sion specifier applies to a argument.
· an optional specifying that a following or conver‐
sion specifier applies to a argument.
· an optional specifying that a following or conver‐
sion specifier applies to a argument.
5. A conversion wide-character that indicates the type of con‐
version to be applied.
A field width, or precision, or both, may be indicated by an asterisk
(*). In this case an argument of type int supplies the field width or
precision. Arguments specifying field width, or precision, or both
must appear in that order before the argument, if any, to be converted.
A negative field width is taken as a flag followed by a positive field
width. A negative precision is taken as if the precision were omitted.
In format wide-character strings containing the form of a conversion
specification, a field width or precision may be indicated by the
sequence where m is a decimal integer in the range giving the position
in the argument list (after the format argument) of an integer argument
containing the field width or precision, for example:
The format can contain either numbered argument specifications (that
is, and or unnumbered argument specifications (that is, and but nor‐
mally not both. The only exception to this is that can be mixed with
the form. The results of mixing numbered and unnumbered argument spec‐
ifications in a format wide-character string are undefined. When num‐
bered argument specifications are used, specifying the Nth argument
requires that all the leading arguments, from the first to the (N-1)th,
are specified in the format wide-character string.
The flag wide-characters and their meanings are:
The integer portion of the result of a decimal conversion
(%i, %d, %u, %g, or %G ) will be formatted with thou‐
sands' grouping wide-characters. For other conver‐
sions the behavior is undefined. The non-monetary
grouping wide-character is used.
The result of the conversion will be left-justified within the
field.
The conversion will be right-justified if this flag is
not specified.
The result of a signed conversion will always begin with
a sign (+ or -). The conversion will begin with a
sign only when a negative value is converted if this
flag is not specified.
If the first wide-character of a signed conversion is not a sign
or
if a signed conversion results in no wide-characters,
a space will be prefixed to the result. This means
that if the space and flags both appear, the space
flag will be ignored.
This flag specifies that the value is to be converted to an
alternative form.
For conversion, it increases the precision (if neces‐
sary) to force the first digit of the result to be 0.
For or conversions, a non-zero result will have 0x (or
0X) prefixed to it. For or conversions, the result
will always contain a radix character, even if no dig‐
its follow it. Without this flag, a radix character
appears in the result of these conversions only if a
digit follows it. For and conversions, trailing zeros
will not be removed from the result as they normally
are. For other conversions, the behavior is unde‐
fined.
For and conversions, leading zeros (following any indica‐
tion of sign or base) are used to pad to the field
width; no space padding is performed. If the and
flags both appear, the flag will be ignored. For and
conversions, if a precision is specified, the flag
will be ignored. If the and flags both appear, the
grouping wide-characters are inserted before zero pad‐
ding. For other conversions, the behavior is unde‐
fined.
The conversion wide-characters and their meanings are:
The int argument is converted to a signed decimal in the style
[-]dddd. The precision specifies the minimum number
of digits to appear; if the value being converted can
be represented in fewer digits, it will be expanded
with leading zeros. The default precision is 1. The
result of converting 0 with an explicit precision of 0
is no wide-characters.
The unsigned int argument is converted to unsigned octal format
in the style dddd. The precision specifies the mini‐
mum number of digits to appear; if the value being
converted can be represented in fewer digits, it will
be expanded with leading zeros. The default precision
is 1. The result of converting 0 with an explicit
precision of 0 is no wide-characters.
The unsigned int argument is converted to unsigned decimal for‐
mat in
the style dddd. The precision specifies the minimum
number of digits to appear; if the value being con‐
verted can be represented in fewer digits, it will be
expanded with leading zeros. The default precision is
1. The result of converting 0 with an explicit preci‐
sion of 0 is no wide-characters.
The unsigned int argument is converted to unsigned hexadecimal
format in
the style dddd; the letters are used. The precision
specifies the minimum number of digits to appear; if
the value being converted can be represented in fewer
digits, it will be expanded with leading zeros. The
default precision is 1. The result of converting 0
with an explicit precision of 0 is no wide-characters.
Behaves the same as the
conversion wide-character except that letters are used
instead of
The double argument is converted to decimal notation in
the style [-]ddd.ddd, where the number of digits after
the radix character is equal to the precision specifi‐
cation. If the precision is missing, it is taken as
6; if the precision is explicitly 0 and no flag is
present, no radix character appears. If a radix char‐
acter appears, at least one digit appears before it.
The value is rounded to the appropriate number of dig‐
its. The conversion specifier produces "INF", "INFIN‐
ITY", or "NAN" instead of "inf", "infinity", or "nan",
respectively. The family of functions may make avail‐
able wide-character string representations for infin‐
ity and NaN.
The double argument is converted in the style
[-]d.ddde_dd, where there is one digit before the
radix character (which is non-zero if the argument is
non-zero) and the number of digits after it is equal
to the precision; if the precision is missing, it is
taken as 6; if the precision is 0 and no flag is
present, no radix character appears. The value is
rounded to the appropriate number of digits. The con‐
version wide-character will produce a number with
instead of introducing the exponent. The exponent
always contains at least two digits. If the value is
0, the exponent is 0. The family of functions may
make available wide-character string representations
for infinity and NaN.
The double argument is converted in the style
or (or in the style in the case of a conversion wide-
character), with the precision specifying the number
of significant digits. If an explicit precision is 0,
it is taken as 1. The style used depends on the value
converted; style (or will be used only if the exponent
resulting from such a conversion is less than -4 or
greater than or equal to the precision. Trailing
zeros are removed from the fractional portion of the
result; a radix character appears only if it is fol‐
lowed by a digit. The family of functions may make
available wide-character string representations for
infinity and NaN.
For Itanium-based
systems only. The double arg is converted in the
style where r is the radix character. There is one
digit before the radix character and the number of
digits after it is equal to the precision. When the
precision is missing, 13 digits are produced for 15
for and 28 for which is sufficient for an exact repre‐
sentation of the value. If the precision is 0, no
radix character appears. The letters are used for
conversion and the letters for conversion. The con‐
version specifier produces a number with and instead
of and The exponent always contains at least one
digit, and only as many more digits as necessary to
represent the decimal exponent of 2. If the value is
zero, the exponent is zero.
For Itanium(R)-based systems if the optional decimal
floating point feature is installed and enabled, then
for an or specifier, if an or modifier is present and
the precision is missing, then for a decimal floating
type argument represented with an integral coefficient
c and quantum exponent q, where n is the number of
digits in the coefficient c:
· If 0 >= q >= -(n+5), use style formatting with
formatting precision equal to -q.
· Otherwise, use style formatting with formatting
precision equal to n - 1. Except if then the
digit-sequence in the exponent-part will have
the value q (rather than 0). That the exponent
is always expressed with the minimum number of
digits required to represent its value (the
exponent never contains a leading zero).
If the precision modifier is present and at least as
large as the precision of the decimal floating type,
the conversion is as if the precision modifier were
missing.
If the precision modifier is present and less than the
precision of the decimal floating type, the conversion
first rounds the input, in the type, according to the
current rounding direction for decimal floating-point
operations. The rounding occurs to the number of dig‐
its specified by the precision modifier, then converts
the result as if the precision modifier were missing.
If no qualifier is present, the int argument is converted to
a wide-character as if by calling the function and the
resulting wide-character is written. Otherwise the
wint_t argument is converted to wchar_t, and written.
If no qualifier is present, the argument must be a pointer
to a character array containing a character sequence
beginning in the initial shift state. Characters from
the array are converted as if by repeated calls to the
function, with the conversion state described by an
mbstate_t object initialized to zero before the first
character is converted, and written up to (but not
including) the terminating null wide-character. If
the precision is specified, no more than that many
wide-characters are written. If the precision is not
specified or is greater than the size of the array,
the array must contain a null wide-character. If an
qualifier is present, the argument must be a pointer
to an array of type wchar_t. Wide characters from the
array are written up to (but not including) a termi‐
nating null wide-character. If no precision is speci‐
fied or is greater than the size of the array, the
array must contain a null wide-character. If a preci‐
sion is specified, no more than that many wide-charac‐
ters are written.
The argument must be a pointer to void.
The value of the pointer is converted to a sequence of
printable wide-characters, in an implementation-depen‐
dent manner.
The argument must be a pointer to an integer into which is writ‐
ten
the number of wide-characters written to the output so
far by this call to one of the functions. No argument
is converted.
Same as
Same as
Output a wide-character; no argument is converted. The entire
conversion specification must be
For Itanium(R)-based systems if the optional decimal floating
point feature is installed and enabled, the behavior of the and
specifiers for decimal floating point numbers is the same as for
APPLICATION USAGE
After or is applied to a stream, the stream becomes wide-oriented (see
orientation(5)).
The prototypes of these functions are available to applications if they
are:
a. conformant.
b. Compiled with macro with a value >=500.
c. Compiled with macro with a value >= 200112.
RETURN VALUE
Upon successful completion, these functions return the number of wide-
characters transmitted excluding the terminating null wide-character in
the case of or a negative value if an output error was encountered.
If or more wide-characters were requested to be written, returns a neg‐
ative value.
ERRORS
For the conditions under which and fails, refer to see putwc(3C). In
addition, all forms of may fail if one of the following occurs:
A wide-character code that does not correspond to
a valid character has been detected.
There are insufficient arguments.
Insufficient storage space is available.
In addition, may fail if:
is byte-oriented.
may fail if:
The stream pointed to by
stream is byte-oriented.
EXAMPLES
To print the language-independent date and time format, the following
statement could be used:
For American usage, format could be a pointer to the wide-character
string:
producing the message:
whereas for German usage, format could be a pointer to the wide-charac‐
ter string:
producing the message:
AUTHOR
were developed by HP and Mitsubishi Electric Corporation.
SEE ALSObtowc(3C), fputwc(3C), fwscanf(3C), mbrtowc(3C), putwc(3C), setlo‐
cale(3C), orientation(5), thread_safety(5), glossary(9).
fwprintf(3C)
