WSCANF(3) | Library Functions Manual | WSCANF(3) |
wscanf
, fwscanf
,
swscanf
, vwscanf
,
vswscanf
, vfwscanf
—
wide character input format conversion
#include <stdio.h>
#include <wchar.h>
int
wscanf
(const
wchar_t * restrict format,
...);
int
fwscanf
(FILE
* restrict stream, const
wchar_t * restrict format,
...);
int
swscanf
(const
wchar_t * restrict str,
const wchar_t * restrict
format, ...);
#include
<stdarg.h>
int
vwscanf
(const
wchar_t * restrict format,
va_list ap);
int
vswscanf
(const
wchar_t * restrict str,
const wchar_t * restrict
format, va_list
ap);
int
vfwscanf
(FILE
* restrict stream, const
wchar_t * restrict format,
va_list ap);
The
wscanf
()
family of functions read input according to the given
format as described below. This format may contain
“conversion specifiers”; the results of such conversions, if
any, are stored through a set of pointer arguments.
The
wscanf
()
function reads input from the standard input stream
stdin,
fwscanf
()
reads input from the supplied stream pointer stream,
and
swscanf
()
reads its input from the wide character string pointed to by
str.
The
vfwscanf
()
function is analogous to vfwprintf(3)
and reads input from the stream pointer stream using a
variable argument list of pointers (see
va_start(3)). The
vwscanf
()
function scans a variable argument list from the standard input and the
vswscanf
()
function scans it from a wide character string; these are analogous to the
vwprintf
()
and
vswprintf
()
functions, respectively.
Each successive
pointer argument
must correspond properly with each successive conversion specifier (but see
the *
conversion below). All conversions are
introduced by the %
(percent sign) character. The
format string may also contain other characters.
Whitespace (such as blanks, tabs, or newlines) in the
format string match any amount of whitespace,
including none, in the input. Everything else matches only itself. Scanning
stops when an input character does not match such a format character.
Scanning also stops when an input conversion cannot be made (see below).
Following the %
character, introducing a
conversion, there may be a number of
flag
characters, as follows:
*
hh
dioux
or n
and the next pointer is a pointer to a
char (rather than int).h
dioux
or n
and the next pointer is a pointer to a
short int (rather than
int).l
(ell)dioux
or n
and the next pointer is a pointer to a
long int (rather than int),
that the conversion will be one of aefg
and the
next pointer is a pointer to double (rather than
float), or that the conversion will be one of
c
or s
and the next
pointer is a pointer to an array of wchar_t (rather
than char).ll
(ell ell)dioux
or n
and the next pointer is a pointer to a
long long int (rather than
int).L
aefg
and the next pointer is a pointer to long
double.j
dioux
or n
and the next pointer is a pointer to an
intmax_t (rather than
int).t
dioux
or n
and the next pointer is a pointer to a
ptrdiff_t (rather than
int).z
dioux
or n
and the next pointer is a pointer to a
size_t (rather than int).q
dioux
or n
and the next
pointer is a pointer to a long long int (rather than
int).In addition to these flags, there may be an optional maximum field
width, expressed as a decimal integer, between the %
and the conversion. If no width is given, a default of
“infinity” is used (with one exception, below); otherwise at
most this many characters are scanned in processing the conversion. Before
conversion begins, most conversions skip whitespace; this whitespace is not
counted against the field width.
The following conversions are available:
%
%
’. That is,
“%%
” in the format string matches a
single input ‘%
’ character. No
conversion is done, and assignment does not occur.d
i
0x
’ or
‘0X
’, in base 8 if it begins with
‘0
’, and in base 10 otherwise. Only
characters that correspond to the base are used.o
u
xX
a
,
A
, e
,
E
, f
,
F
, g
,
G
l
or L
is specified.)s
If an l
qualifier is present, the next
pointer must be a pointer to wchar_t, into which
the input will be placed.
c
If an l
qualifier is present, the next
pointer must be a pointer to wchar_t, into which
the input will be placed.
[
The string is to be made up of characters in (or
not in) a particular set; the set is defined by the characters between
the open bracket [
character and a close bracket
]
character. The set
excludes
those characters if the first character after the open bracket is a
circumflex ^
. To include a close bracket in the
set, make it the first character after the open bracket or the
circumflex; any other position will end the set. To include a hyphen in
the set, make it the last character before the final close bracket; some
implementations of
wscanf
()
use “A-Z
” to represent the range
of characters between ‘A
’ and
‘Z
’. The string ends with the
appearance of a character not in (or, with a circumflex, in) the set or
when the field width runs out.
If an l
qualifier is present, the next
pointer must be a pointer to wchar_t, into which
the input will be placed.
p
%p
’ in
wprintf(3)); the next pointer must be
a pointer to void.n
*
flag.For backwards compatibility, a “conversion” of
‘%\0
’ causes an immediate return of
EOF
.
These functions return the number of input items assigned, which
can be fewer than provided for, or even zero, in the event of a matching
failure. Zero indicates that, while there was input available, no
conversions were assigned; typically this is due to an invalid input
character, such as an alphabetic character for a
‘%d
’ conversion. The value
EOF
is returned if an input failure occurs before
any conversion such as an end-of-file occurs. If an error or end-of-file
occurs after conversion has begun, the number of conversions which were
successfully completed is returned.
fgetwc(3), scanf(3), wcrtomb(3), wcstod(3), wcstol(3), wcstoul(3), wprintf(3)
The functions wscanf
(),
fwscanf
(), swscanf
(),
vwscanf
(), vfwscanf
(), and
vswscanf
() conform to ISO/IEC
9899:1999 (“ISO C99”).
On systems other than OpenBSD, the
LC_NUMERIC
locale(1) category can cause parsing
failures; see CAVEATS in setlocale(3)
for details.
In addition to the bugs documented in
scanf(3), wscanf
()
does not support the “A-Z
” notation
for specifying character ranges with the character class conversion
(‘%[
’).
August 30, 2019 | OpenBSD-current |