470 lines
14 KiB
C
470 lines
14 KiB
C
/*
|
|
* Copyright (c) 1990 The Regents of the University of California.
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms are permitted
|
|
* provided that the above copyright notice and this paragraph are
|
|
* duplicated in all such forms and that any documentation,
|
|
* advertising materials, and other materials related to such
|
|
* distribution and use acknowledge that the software was developed
|
|
* by the University of California, Berkeley. The name of the
|
|
* University may not be used to endorse or promote products derived
|
|
* from this software without specific prior written permission.
|
|
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
|
|
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
|
|
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
|
|
*/
|
|
|
|
/*
|
|
FUNCTION
|
|
<<sscanf>>, <<fscanf>>, <<scanf>>---scan and format input
|
|
|
|
INDEX
|
|
scanf
|
|
INDEX
|
|
_scanf_r
|
|
INDEX
|
|
fscanf
|
|
INDEX
|
|
_fscanf_r
|
|
INDEX
|
|
sscanf
|
|
INDEX
|
|
_sscanf_r
|
|
|
|
ANSI_SYNOPSIS
|
|
#include <stdio.h>
|
|
|
|
int scanf(const char *<[format]>, ...);
|
|
int fscanf(FILE *<[fd]>, const char *<[format]>, ...);
|
|
int sscanf(const char *<[str]>, const char *<[format]>, ...);
|
|
|
|
int _scanf_r(struct _reent *<[ptr]>, const char *<[format]>, ...);
|
|
int _fscanf_r(struct _reent *<[ptr]>, FILE *<[fd]>,
|
|
const char *<[format]>, ...);
|
|
int _sscanf_r(struct _reent *<[ptr]>, const char *<[str]>,
|
|
const char *<[format]>, ...);
|
|
|
|
|
|
TRAD_SYNOPSIS
|
|
#include <stdio.h>
|
|
|
|
int scanf(<[format]> [, <[arg]>, ...])
|
|
char *<[format]>;
|
|
|
|
int fscanf(<[fd]>, <[format]> [, <[arg]>, ...]);
|
|
FILE *<[fd]>;
|
|
char *<[format]>;
|
|
|
|
int sscanf(<[str]>, <[format]> [, <[arg]>, ...]);
|
|
char *<[str]>;
|
|
char *<[format]>;
|
|
|
|
int _scanf_r(<[ptr]>, <[format]> [, <[arg]>, ...])
|
|
struct _reent *<[ptr]>;
|
|
char *<[format]>;
|
|
|
|
int _fscanf_r(<[ptr]>, <[fd]>, <[format]> [, <[arg]>, ...]);
|
|
struct _reent *<[ptr]>;
|
|
FILE *<[fd]>;
|
|
char *<[format]>;
|
|
|
|
int _sscanf_r(<[ptr]>, <[str]>, <[format]> [, <[arg]>, ...]);
|
|
struct _reent *<[ptr]>;
|
|
char *<[str]>;
|
|
char *<[format]>;
|
|
|
|
|
|
DESCRIPTION
|
|
<<scanf>> scans a series of input fields from standard input,
|
|
one character at a time. Each field is interpreted according to
|
|
a format specifier passed to <<scanf>> in the format string at
|
|
<<*<[format]>>>. <<scanf>> stores the interpreted input from
|
|
each field at the address passed to it as the corresponding argument
|
|
following <[format]>. You must supply the same number of
|
|
format specifiers and address arguments as there are input fields.
|
|
|
|
There must be sufficient address arguments for the given format
|
|
specifiers; if not the results are unpredictable and likely
|
|
disasterous. Excess address arguments are merely ignored.
|
|
|
|
<<scanf>> often produces unexpected results if the input diverges from
|
|
an expected pattern. Since the combination of <<gets>> or <<fgets>>
|
|
followed by <<sscanf>> is safe and easy, that is the preferred way
|
|
to be certain that a program is synchronized with input at the end
|
|
of a line.
|
|
|
|
<<fscanf>> and <<sscanf>> are identical to <<scanf>>, other than the
|
|
source of input: <<fscanf>> reads from a file, and <<sscanf>>
|
|
from a string.
|
|
|
|
The routines <<_scanf_r>>, <<_fscanf_r>>, and <<_sscanf_r>> are reentrant
|
|
versions of <<scanf>>, <<fscanf>>, and <<sscanf>> that take an additional
|
|
first argument pointing to a reentrancy structure.
|
|
|
|
The string at <<*<[format]>>> is a character sequence composed
|
|
of zero or more directives. Directives are composed of
|
|
one or more whitespace characters, non-whitespace characters,
|
|
and format specifications.
|
|
|
|
Whitespace characters are blank (<< >>), tab (<<\t>>), or
|
|
newline (<<\n>>).
|
|
When <<scanf>> encounters a whitespace character in the format string
|
|
it will read (but not store) all consecutive whitespace characters
|
|
up to the next non-whitespace character in the input.
|
|
|
|
Non-whitespace characters are all other ASCII characters except the
|
|
percent sign (<<%>>). When <<scanf>> encounters a non-whitespace
|
|
character in the format string it will read, but not store
|
|
a matching non-whitespace character.
|
|
|
|
Format specifications tell <<scanf>> to read and convert characters
|
|
from the input field into specific types of values, and store then
|
|
in the locations specified by the address arguments.
|
|
|
|
Trailing whitespace is left unread unless explicitly
|
|
matched in the format string.
|
|
|
|
The format specifiers must begin with a percent sign (<<%>>)
|
|
and have the following form:
|
|
|
|
. %[*][<[width]>][<[size]>]<[type]>
|
|
|
|
Each format specification begins with the percent character (<<%>>).
|
|
The other fields are:
|
|
o+
|
|
o *
|
|
an optional marker; if present, it suppresses interpretation and
|
|
assignment of this input field.
|
|
|
|
o <[width]>
|
|
an optional maximum field width: a decimal integer,
|
|
which controls the maximum number of characters that
|
|
will be read before converting the current input field. If the
|
|
input field has fewer than <[width]> characters, <<scanf>>
|
|
reads all the characters in the field, and then
|
|
proceeds with the next field and its format specification.
|
|
|
|
If a whitespace or a non-convertable character occurs
|
|
before <[width]> character are read, the characters up
|
|
to that character are read, converted, and stored.
|
|
Then <<scanf>> proceeds to the next format specification.
|
|
|
|
o size
|
|
<<h>>, <<j>>, <<l>>, <<L>>, <<t>>, and <<z>> are optional size
|
|
characters which override the default way that <<scanf>>
|
|
interprets the data type of the corresponding argument.
|
|
|
|
|
|
.Modifier Type(s)
|
|
. hh d, i, o, u, x, n convert input to char,
|
|
. store in char object
|
|
.
|
|
. h d, i, o, u, x, n convert input to short,
|
|
. store in short object
|
|
.
|
|
. h D, I, O, U, X no effect
|
|
. e, f, c, s, p
|
|
.
|
|
. j d, i, o, u, x, n convert input to intmax_t,
|
|
. store in intmax_t object
|
|
.
|
|
. j all others no effect
|
|
.
|
|
. l d, i, o, u, x, n convert input to long,
|
|
. store in long object
|
|
.
|
|
. l e, f, g convert input to double
|
|
. store in a double object
|
|
.
|
|
. l D, I, O, U, X no effect
|
|
. c, s, p
|
|
.
|
|
. ll d, i, o, u, x, n convert to long long,
|
|
. store in long long
|
|
.
|
|
. L d, i, o, u, x, n convert to long long,
|
|
. store in long long
|
|
.
|
|
. L e, f, g, E, G convert to long double,
|
|
. store in long double
|
|
.
|
|
. L all others no effect
|
|
.
|
|
. t d, i, o, u, x, n convert input to ptrdiff_t,
|
|
. store in ptrdiff_t object
|
|
.
|
|
. t all others no effect
|
|
.
|
|
. z d, i, o, u, x, n convert input to size_t,
|
|
. store in size_t object
|
|
.
|
|
. z all others no effect
|
|
.
|
|
|
|
|
|
o <[type]>
|
|
|
|
A character to specify what kind of conversion
|
|
<<scanf>> performs. Here is a table of the conversion
|
|
characters:
|
|
|
|
o+
|
|
o %
|
|
No conversion is done; the percent character (<<%>>) is stored.
|
|
|
|
o c
|
|
Scans one character. Corresponding <[arg]>: <<(char *arg)>>.
|
|
|
|
o s
|
|
Reads a character string into the array supplied.
|
|
Corresponding <[arg]>: <<(char arg[])>>.
|
|
|
|
o [<[pattern]>]
|
|
Reads a non-empty character string into memory
|
|
starting at <[arg]>. This area must be large
|
|
enough to accept the sequence and a
|
|
terminating null character which will be added
|
|
automatically. (<[pattern]> is discussed in the paragraph following
|
|
this table). Corresponding <[arg]>: <<(char *arg)>>.
|
|
|
|
o d
|
|
Reads a decimal integer into the corresponding <[arg]>: <<(int *arg)>>.
|
|
|
|
o D
|
|
Reads a decimal integer into the corresponding
|
|
<[arg]>: <<(long *arg)>>.
|
|
|
|
o o
|
|
Reads an octal integer into the corresponding <[arg]>: <<(int *arg)>>.
|
|
|
|
o O
|
|
Reads an octal integer into the corresponding <[arg]>: <<(long *arg)>>.
|
|
|
|
o u
|
|
Reads an unsigned decimal integer into the corresponding
|
|
<[arg]>: <<(unsigned int *arg)>>.
|
|
|
|
|
|
o U
|
|
Reads an unsigned decimal integer into the corresponding <[arg]>:
|
|
<<(unsigned long *arg)>>.
|
|
|
|
o x,X
|
|
Read a hexadecimal integer into the corresponding <[arg]>:
|
|
<<(int *arg)>>.
|
|
|
|
o e, f, g
|
|
Read a floating-point number into the corresponding <[arg]>:
|
|
<<(float *arg)>>.
|
|
|
|
o E, F, G
|
|
Read a floating-point number into the corresponding <[arg]>:
|
|
<<(double *arg)>>.
|
|
|
|
o i
|
|
Reads a decimal, octal or hexadecimal integer into the
|
|
corresponding <[arg]>: <<(int *arg)>>.
|
|
|
|
o I
|
|
Reads a decimal, octal or hexadecimal integer into the
|
|
corresponding <[arg]>: <<(long *arg)>>.
|
|
|
|
o n
|
|
Stores the number of characters read in the corresponding
|
|
<[arg]>: <<(int *arg)>>.
|
|
|
|
o p
|
|
Stores a scanned pointer. ANSI C leaves the details
|
|
to each implementation; this implementation treats
|
|
<<%p>> exactly the same as <<%U>>. Corresponding
|
|
<[arg]>: <<(void **arg)>>.
|
|
o-
|
|
|
|
A <[pattern]> of characters surrounded by square brackets can be used
|
|
instead of the <<s>> type character. <[pattern]> is a set of
|
|
characters which define a search set of possible characters making up
|
|
the <<scanf>> input field. If the first character in the brackets is a
|
|
caret (<<^>>), the search set is inverted to include all ASCII characters
|
|
except those between the brackets. There is also a range facility
|
|
which you can use as a shortcut. <<%[0-9] >> matches all decimal digits.
|
|
The hyphen must not be the first or last character in the set.
|
|
The character prior to the hyphen must be lexically less than the
|
|
character after it.
|
|
|
|
Here are some <[pattern]> examples:
|
|
o+
|
|
o %[abcd]
|
|
matches strings containing only <<a>>, <<b>>, <<c>>, and <<d>>.
|
|
|
|
o %[^abcd]
|
|
matches strings containing any characters except <<a>>, <<b>>,
|
|
<<c>>, or <<d>>
|
|
|
|
o %[A-DW-Z]
|
|
matches strings containing <<A>>, <<B>>, <<C>>, <<D>>, <<W>>,
|
|
<<X>>, <<Y>>, <<Z>>
|
|
|
|
o %[z-a]
|
|
matches the characters <<z>>, <<->>, and <<a>>
|
|
o-
|
|
|
|
Floating point numbers (for field types <<e>>, <<f>>, <<g>>, <<E>>,
|
|
<<F>>, <<G>>) must correspond to the following general form:
|
|
|
|
. [+/-] ddddd[.]ddd [E|e[+|-]ddd]
|
|
|
|
where objects inclosed in square brackets are optional, and <<ddd>>
|
|
represents decimal, octal, or hexadecimal digits.
|
|
o-
|
|
|
|
RETURNS
|
|
<<scanf>> returns the number of input fields successfully
|
|
scanned, converted and stored; the return value does
|
|
not include scanned fields which were not stored.
|
|
|
|
If <<scanf>> attempts to read at end-of-file, the return
|
|
value is <<EOF>>.
|
|
|
|
If no fields were stored, the return value is <<0>>.
|
|
|
|
<<scanf>> might stop scanning a particular field before
|
|
reaching the normal field end character, or may
|
|
terminate entirely.
|
|
|
|
<<scanf>> stops scanning and storing the current field
|
|
and moves to the next input field (if any)
|
|
in any of the following situations:
|
|
|
|
O+
|
|
o The assignment suppressing character (<<*>>) appears
|
|
after the <<%>> in the format specification; the current
|
|
input field is scanned but not stored.
|
|
|
|
o <[width]> characters have been read (<[width]> is a
|
|
width specification, a positive decimal integer).
|
|
|
|
o The next character read cannot be converted
|
|
under the the current format (for example,
|
|
if a <<Z>> is read when the format is decimal).
|
|
|
|
o The next character in the input field does not appear
|
|
in the search set (or does appear in the inverted search set).
|
|
O-
|
|
|
|
When <<scanf>> stops scanning the current input field for one of
|
|
these reasons, the next character is considered unread and
|
|
used as the first character of the following input field, or the
|
|
first character in a subsequent read operation on the input.
|
|
|
|
<<scanf>> will terminate under the following circumstances:
|
|
|
|
O+
|
|
o The next character in the input field conflicts
|
|
with a corresponding non-whitespace character in the
|
|
format string.
|
|
|
|
o The next character in the input field is <<EOF>>.
|
|
|
|
o The format string has been exhausted.
|
|
O-
|
|
|
|
When the format string contains a character sequence that is
|
|
not part of a format specification, the same character
|
|
sequence must appear in the input; <<scanf>> will
|
|
scan but not store the matched characters. If a
|
|
conflict occurs, the first conflicting character remains in the input
|
|
as if it had never been read.
|
|
|
|
PORTABILITY
|
|
<<scanf>> is ANSI C.
|
|
|
|
Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
|
|
<<lseek>>, <<read>>, <<sbrk>>, <<write>>.
|
|
*/
|
|
|
|
#include <_ansi.h>
|
|
#include <reent.h>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#ifdef _HAVE_STDC
|
|
#include <stdarg.h>
|
|
#else
|
|
#include <varargs.h>
|
|
#endif
|
|
#include "local.h"
|
|
|
|
#ifndef _REENT_ONLY
|
|
|
|
#ifdef _HAVE_STDC
|
|
int
|
|
_DEFUN(sscanf, (str, fmt),
|
|
_CONST char *str _AND
|
|
_CONST char *fmt _DOTS)
|
|
#else
|
|
int
|
|
sscanf(str, fmt, va_alist)
|
|
_CONST char *str;
|
|
_CONST char *fmt;
|
|
va_dcl
|
|
#endif
|
|
{
|
|
int ret;
|
|
va_list ap;
|
|
FILE f;
|
|
|
|
f._flags = __SRD | __SSTR;
|
|
f._bf._base = f._p = (unsigned char *) str;
|
|
f._bf._size = f._r = strlen (str);
|
|
f._read = __seofread;
|
|
f._ub._base = NULL;
|
|
f._lb._base = NULL;
|
|
f._file = -1; /* No file. */
|
|
#ifdef _HAVE_STDC
|
|
va_start (ap, fmt);
|
|
#else
|
|
va_start (ap);
|
|
#endif
|
|
ret = __ssvfscanf_r (_REENT, &f, fmt, ap);
|
|
va_end (ap);
|
|
return ret;
|
|
}
|
|
|
|
#endif /* !_REENT_ONLY */
|
|
|
|
#ifdef _HAVE_STDC
|
|
int
|
|
_DEFUN(_sscanf_r, (ptr, str, fmt),
|
|
struct _reent *ptr _AND
|
|
_CONST char *str _AND
|
|
_CONST char *fmt _DOTS)
|
|
#else
|
|
int
|
|
_sscanf_r(ptr, str, fmt, va_alist)
|
|
struct _reent *ptr;
|
|
_CONST char *str;
|
|
_CONST char *fmt;
|
|
va_dcl
|
|
#endif
|
|
{
|
|
int ret;
|
|
va_list ap;
|
|
FILE f;
|
|
|
|
f._flags = __SRD | __SSTR;
|
|
f._bf._base = f._p = (unsigned char *) str;
|
|
f._bf._size = f._r = strlen (str);
|
|
f._read = __seofread;
|
|
f._ub._base = NULL;
|
|
f._lb._base = NULL;
|
|
f._file = -1; /* No file. */
|
|
#ifdef _HAVE_STDC
|
|
va_start (ap, fmt);
|
|
#else
|
|
va_start (ap);
|
|
#endif
|
|
ret = __ssvfscanf_r (ptr, &f, fmt, ap);
|
|
va_end (ap);
|
|
return ret;
|
|
}
|