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
, ...
)
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
)
)
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).
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:
NUL
character.
The input string stops at white space
or at the maximum field width, whichever occurs first.
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.
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
.
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.
),
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'') .
),
vsscanf(
)
and
vfscanf(
)
appeared in
4.4BSD
or even
4.3BSD.