| WSCANF(3) | Library Functions Manual | WSCANF(3) |
fwscanf, swscanf,
vfwscanf, vswscanf,
vwscanf, wscanf —
wide character input format conversion
Standard C Library (libc, -lc)
#include <stdio.h>
#include <wchar.h>
int
fwscanf(FILE *restrict stream,
const wchar_t *restrict format,
...);
int
swscanf(const wchar_t *restrict
ws, const wchar_t *restrict format,
...);
int
wscanf(const wchar_t *restrict
format, ...);
#include
<stdarg.h>
#include <stdio.h>
#include <wchar.h>
int
vfwscanf(FILE *restrict stream,
const wchar_t *restrict format,
va_list arg);
int
vswscanf(const wchar_t *restrict
ws, const wchar_t *restrict format,
va_list arg);
int
vwscanf(const wchar_t *restrict
format, va_list arg);
The
wscanf()
family of functions scans input, according to a format
as described below. This format may contain
conversion
specifiers; the results from such conversions, if any, are stored
through the pointer arguments. The
wscanf() function reads input from the standard
input stream stdin,
fwscanf()
reads input from the stream pointer stream, and
swscanf()
reads its input from the wide character string pointed to by
ws.
The
vfwscanf()
function is analogous to vfwprintf(3) and reads input from
the stream pointer stream using a variable argument
list of pointers (see stdarg(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. White space (such as blanks, tabs, or newlines) in the format string match any amount of white space, 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).
Extended locale versions of these functions are documented in wscanf_l(3). See xlocale(3) for more information.
Following the % character introducing a
conversion, there may be a number of
flag
characters, as follows:
*hhdioux
or n and the next pointer is a pointer to a
char (rather than int).hdioux
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 a,
e, f, or
g 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).La,
e, f, or
g and the next pointer is a pointer to
long double.jdioux
or n and the next pointer is a pointer to a
intmax_t (rather than
int).tdioux
or n and the next pointer is a pointer to a
ptrdiff_t (rather than
int).zdioux
or n and the next pointer is a pointer to a
size_t (rather than int).qdioux 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 white space; this white space 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.di0x’ or
‘0X’, in base 8 if it begins with
‘0’, and in base 10 otherwise. Only
characters that correspond to the base are used.oux,
Xa,
A, e,
E, f,
F, g,
Gl or
L is specified.)sNUL character. The input
string stops at white space or at the maximum field width, whichever
occurs first.
If an l qualifier is present, the next
pointer must be a pointer to wchar_t, into which
the input will be placed.
Sls.cNUL is added). The usual skip of leading white
space is suppressed. To skip white space first, use an explicit space in
the format.
If an l qualifier is present, the next
pointer must be a pointer to wchar_t, into which
the input will be placed.
Clc.[NUL character. The usual skip of
leading white space is suppressed. 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 the (or, with a circumflex, in) 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.The decimal point character is defined in the program's locale
(category LC_NUMERIC).
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), wscanf_l(3)
The fwscanf(),
wscanf(), swscanf(),
vfwscanf(), vwscanf(), and
vswscanf() functions conform to
ISO/IEC 9899:1999
(“ISO C99”).
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
(‘%[’).
| July 5, 2003 | Mac OS X 12 |