SCANF(3) | Library Functions Manual | SCANF(3) |
scanf
, fscanf
,
sscanf
, vscanf
,
vsscanf
, vfscanf
—
#include <stdio.h>
int
scanf
(const
char * restrict format,
...);
int
fscanf
(FILE
* restrict stream, const
char * restrict format,
...);
int
sscanf
(const
char * restrict str,
const char * restrict
format, ...);
#include
<stdarg.h>
int
vscanf
(const
char * restrict format,
va_list ap);
int
vsscanf
(const
char * restrict str,
const char * restrict
format, va_list
ap);
int
vfscanf
(FILE
* restrict stream, const
char * restrict format,
va_list ap);
scanf
() 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 scanf
() function reads input from the
standard input stream stdin,
fscanf
() reads input from the stream pointer
stream, and sscanf
() reads its
input from the character string pointed to by str. The
vfscanf
() function is analogous to
vfprintf(3) and reads input
from the stream pointer stream using a variable
argument list of pointers (see
stdarg(3)). The
vscanf
() function scans a variable argument list
from the standard input and the vsscanf
() function
scans it from a string; these are analogous to the
vprintf
() and vsprintf
()
functions respectively.
Each successive pointer argument must correspond
properly with each successive conversion specifier (but see `suppression'
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).
%
character introducing a conversion there
may be a number of flag characters, as follows:
*
h
dioux
or n
and the next pointer is a pointer to a
short int (rather than int).hh
dioux
or n
and the next pointer is a pointer to a
char (rather than int).j
dioux
or n
and the next pointer is a pointer to an
intmax_t (rather than int).l
dioux
or n
and the next
pointer is a pointer to a long int (rather than
int), or that the conversion will be one of
efg
and the next pointer is a pointer to
double (rather than float).ll
dioux
or n
and the next pointer is a pointer to a
long long int (rather than int).q
dioux
or n
and the next pointer is a pointer to a
quad_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).L
efg
and the
next pointer is a pointer to long double.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:
%
d
D
ld
; this exists only for backwards
compatibility.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
O
lo
; this exists for backwards
compatibility.u
x
X
x
.f
e
f
.g
f
.E
f
.G
f
.s
NUL
character. The input string stops at white space or at the maximum field
width, whichever occurs first.c
NUL
is added). The usual skip of leading white
space is suppressed. To skip white space first, use an explicit space in
the format.[
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. The hyphen character
-
is also special; when placed between two other
characters, it adds all intervening characters to the set. To include a
hyphen, make it the last character before the final close bracket. For
instance, ‘[^]0-9-]
’ means the set
`everything except close bracket, zero through nine, and hyphen'. 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.p
%p
’ in
printf(3)); the next pointer
must be a pointer to void.n
*
flag.For backwards compatibility, other conversion characters (except
‘\0
’) are taken as if they were
‘%d
’ or, if uppercase,
‘%ld
’, and a `conversion' of
‘%\0
’ causes an immediate return of
EOF
.
The format string specifier macros described in inttypes(3) should be used for the standard “C99” fixed-size integers documented in stdint(3).
%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.
fscanf
(), scanf
(),
and sscanf
() conform to ISO/IEC
9899:1990 (“ISO C90”). The
%j
, %t
and
%z
conversion format modifiers conform to
ISO/IEC 9899:1999 (“ISO C99”).
The vfscanf
(), vscanf
() and
vsscanf
() functions conform to
ISO/IEC 9899:1999 (“ISO C99”).
vscanf
(),
vsscanf
() and vfscanf
()
appeared in 4.4BSD or even
4.3BSD.
%f
and %d
are implicitly
%512f
and %512d
.
March 21, 2010 | NetBSD 9.2 |