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NAMEfwprintf(), wprintf(), swprintf() — print formatted wide-character output SYNOPSIS#include <stdio.h>
#include <wchar.h>
int fwprintf(
FILE *__restrict stream,
const wchar_t *__restrict format,
...);
int wprintf(
const wchar_t *__restrict format,
...);
int swprintf(
wchar_t *__restrict s,
size_t n,
const wchar_t *__restrict format,
...); DESCRIPTIONThe
fwprintf
function places output on the named output
stream. The
wprintf()
function places output on the standard output stream
stdout. The
swprintf()
function places output followed by the null wide-character
in consecutive wide-characters starting at
*s;
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 composed 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
%n$,
where
n
is a decimal integer in the range 1 through
{NL_ARGMAX},
giving the position of the argument in the argument list.
This feature provides for the definition of format wide-character strings
that select arguments in an order appropriate to
specific languages (see the
EXAMPLES
section). In format wide-character strings containing the
%n$
form of conversion
specifications, numbered arguments in the argument list can be
referenced 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
fwprintf()
functions allow for the insertion of a language-dependent radix character
in the output string, output as a wide-character value.
The radix character is defined in the program's locale (category
LC_NUMERIC). 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
%n$,
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 digits to appear for the
d,
i,
o,
u,
x
and
X
conversions. - 4.
Zero or more of the following optional character specifications:
an optional
h
specifying that a following
n
conversion wide-character applies to a pointer to a type short int argument an optional
h
specifying that a following
d,
i,
o,
u,
x
or
X
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
hh
specifying that a following
d,
i,
o,
u,
x
or
X
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
hh
specifying that a following
n
conversion specifier applies to a pointer to a signed char argument an optional
hL
specifying that a following
e,
f,
or
g
conversion wide-character applies to a type
extended
which is the 80-bit IEEE-754 double-extended type in the
Itanium(®
architecture an optional
j
specifying that a following
d,
i,
o,
u,
x
or
X
conversion specifier applies to an intmax_t or uintmax_t argument an optional
j
specifying that a following
n
conversion specifier applies to a pointer to an intmax_t argument an optional
l
(ell) specifying that a following
c
conversion wide-character applies to a wint_t argument an optional
l
(ell) specifying that a following
s
conversion wide-character applies to a
wchar_t argument an optional
ll
(ell-ell) specifying that following
d,
i,
o,
u,
x
or
X
conversion specifier applies to a long long or unsigned long long argument an optional
ll
(ell-ell) specifying that following
n
conversion specifier applies to a pointer to a long long argument an optional
t
specifying that a following
d,
i,
o,
u,
x
or
X
conversion specifier applies to a ptrdiff_t or the corresponding unsigned type argument an optional
t
specifying that a following
n
conversion specifier applies to a pointer to a ptrdiff_t argument an optional
z
specifying that a following
d,
i,
o,
u,
x
or
X
conversion specifier applies to a size_t argument or the corresponding signed integer type argument an optional
z
specifying that a following
n
conversion specifier applies to a pointer to a size_t argument
- 5.
A conversion wide-character that indicates the type of conversion 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
%n$
form of a conversion specification, a
field width
or
precision
may be indicated by the sequence
%n$,
where
m
is a decimal integer in the range
[1, {NL_ARGMAX}]
giving the position in the argument list (after the format argument) of
an integer argument containing the
field width
or
precision,
for example: wprintf(L"%1$d:%2$. *3$d:%4$, *3$d\n", hour, min, precision, sec); The
format
can contain either numbered argument specifications
(that is,
%n$
and
*m$),
or unnumbered argument specifications (that is,
%
and
*),
but normally not both.
The only exception to this is that
%%
can be mixed with the
%n$
form.
The results of mixing numbered and unnumbered argument specifications
in a format wide-character string are undefined.
When numbered 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 thousands' grouping
wide-characters.
For other conversions 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. - space
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
o
conversion, it increases the precision (if necessary) to force
the first digit of the result to be 0.
For
x
or
X
conversions,
a non-zero result will have 0x (or 0X) prefixed to it.
For
e,
E,
f,
F,
g
or
G
conversions, the result will always contain a radix character,
even if no digits follow it.
Without this flag, a radix character appears in the result of these conversions
only if a digit follows it.
For
g
and
G
conversions, trailing zeros will not be removed from the result as
they normally are.
For other conversions, the behavior is undefined. - 0
For
d,
i,
o,
u,
x,
X,
e,
E,
f,
F,
g
and
G
conversions, leading zeros (following any indication of sign or base) are
used to pad to the field width; no space padding is performed.
If the
0
and
-
flags both appear, the
0
flag will be ignored.
For
d,
i,
o,
u,
x
and
X
conversions, if a precision is specified, the
0
flag will be ignored.
If the
0
and
i
flags both appear, the grouping wide-characters are
inserted before zero padding.
For other conversions, the behavior is undefined.
The conversion wide-characters and their meanings are:
- d,i
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. - o
The unsigned int argument is converted to unsigned octal format
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. - u
The unsigned int argument is converted to unsigned decimal format 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. - x
The unsigned int argument is converted to unsigned hexadecimal format in
the style
dddd;
the letters
abcdef
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. - X
Behaves the same as the
x
conversion wide-character except that
letters
ABCDEF
are used instead of
abcdef. - f,F
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 specification.
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 character
appears, at least one digit appears before it.
The value is rounded to the appropriate number of digits.
The
F
conversion specifier produces "INF", "INFINITY",
or "NAN" instead of "inf", "infinity", or "nan", respectively.
The
fwprintf()
family of functions may make available wide-character
string representations for infinity and NaN. - e,E
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
E
conversion wide-character will produce a number with
E
instead of
e
introducing the exponent.
The exponent always contains at least two digits.
If the value is 0, the exponent is 0.
The
fwprintf()
family of functions may make available wide-character string
representations for infinity and NaN. - g,G
The double argument is converted in the style
f,F
or
e
(or in the style
E
in the case of a
G
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
e
(or
E)
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 followed by a digit.
The
fwprintf()
family of functions may make available wide-character string
representations for infinity and NaN. - a,A
For Itanium-based
systems only.
The double
arg
is converted in the style
[-]0xhrhhhp±d,
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
double,
15 for
extended,
and 28 for
long double,
which is sufficient for an exact representation of the value;
if the precision is 0, no radix character appears.
The letters
abcdef
are used for
a
conversion and the letters
ABCDEF
for
A
conversion.
The
A
conversion specifier produces a number with
X
and
P
instead of
x
and
p.
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. - c
If no
l
qualifier is present, the int argument is converted to
a wide-character as if by calling the
btowc()
function and
the resulting wide-character is written.
Otherwise the wint_t argument is converted to wchar_t, and written. - s
If no
l
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
mbrtowc()
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
l
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 terminating null wide-character.
If no precision is specified or is greater than
the size of the array, the array must contain a null wide-character.
If a precision is specified, no more than that many wide-characters are
written. - p
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-dependent manner. - n
The argument must be a pointer to an integer into which is written
the number of wide-characters written to the output so far by this call to
one of the
fwprintf()
functions.
No argument is converted. - C
Same as
lc. - S
Same as
ls. - %
Output a
%
wide-character; no argument is converted.
The entire conversion specification must be
%%.
APPLICATION USAGEAfter
fwprintf()
or
wprintf()
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.
c99
conformant. - b.
Compiled with
-D_XOPEN_SOURCE
macro with a value >=500. - c.
Compiled with
-D_POSIX_C_SOURCE
macro with a value >= 200112.
RETURN VALUEUpon successful completion, these functions return the number of
wide-characters transmitted excluding the terminating null wide-character
in the case of
swprintf()
or a negative value if an output error was encountered. If
n
or more wide-characters were requested to be written,
swprintf()
returns a negative value. ERRORSFor the conditions under which
fwprintf()
and
wprintf()
fails, refer to
fputwc();
see
putwc(3C).
In addition, all forms of
fwprintf()
may fail if one of the following occurs:
- EILSEQ
A wide-character code that does not correspond to
a valid character has been detected. - EINVAL
There are insufficient arguments. - ENOMEM
Insufficient storage space is available.
In addition,
wprintf()
may fail if:
- EILSEQ
stdout
is byte-oriented.
fwprintf()
may fail if:
- EILSEQ
The stream pointed to by
stream
is byte-oriented.
EXAMPLESTo print the language-independent date and time format,
the following statement could be used:
wprintf(format, weekday, month, day, hour, min); 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-character string:
L"%1$s, %3$d. %2$s, %4$d:%5$.2d" producing the message:
AUTHORfwprintf(),
wprintf(),
swprintf()
were developed by HP and Mitsubishi Electric Corporation. |
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