[444] | 1 | /* |
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| 2 | * Copyright (c) 1990 The Regents of the University of California. |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms are permitted |
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| 6 | * provided that the above copyright notice and this paragraph are |
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| 7 | * duplicated in all such forms and that any documentation, |
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| 8 | * advertising materials, and other materials related to such |
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| 9 | * distribution and use acknowledge that the software was developed |
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| 10 | * by the University of California, Berkeley. The name of the |
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| 11 | * University may not be used to endorse or promote products derived |
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| 12 | * from this software without specific prior written permission. |
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| 13 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR |
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| 14 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED |
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| 15 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
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| 16 | */ |
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| 17 | |
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| 18 | /* |
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| 19 | FUNCTION |
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| 20 | <<sscanf>>, <<fscanf>>, <<scanf>>---scan and format input |
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| 21 | |
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| 22 | INDEX |
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| 23 | scanf |
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| 24 | INDEX |
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| 25 | _scanf_r |
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| 26 | INDEX |
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| 27 | fscanf |
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| 28 | INDEX |
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| 29 | _fscanf_r |
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| 30 | INDEX |
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| 31 | sscanf |
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| 32 | INDEX |
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| 33 | _sscanf_r |
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| 34 | |
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| 35 | SYNOPSIS |
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| 36 | #include <stdio.h> |
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| 37 | |
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| 38 | int scanf(const char *restrict <[format]>, ...); |
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| 39 | int fscanf(FILE *restrict <[fd]>, const char *restrict <[format]>, ...); |
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| 40 | int sscanf(const char *restrict <[str]>, const char *restrict <[format]>, ...); |
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| 41 | |
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| 42 | int _scanf_r(struct _reent *<[ptr]>, const char *restrict <[format]>, ...); |
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| 43 | int _fscanf_r(struct _reent *<[ptr]>, FILE *restrict <[fd]>, |
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| 44 | const char *restrict <[format]>, ...); |
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| 45 | int _sscanf_r(struct _reent *<[ptr]>, const char *restrict <[str]>, |
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| 46 | const char *restrict <[format]>, ...); |
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| 47 | |
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| 48 | DESCRIPTION |
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| 49 | <<scanf>> scans a series of input fields from standard input, |
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| 50 | one character at a time. Each field is interpreted according to |
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| 51 | a format specifier passed to <<scanf>> in the format string at |
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| 52 | <<*<[format]>>>. <<scanf>> stores the interpreted input from |
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| 53 | each field at the address passed to it as the corresponding argument |
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| 54 | following <[format]>. You must supply the same number of |
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| 55 | format specifiers and address arguments as there are input fields. |
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| 56 | |
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| 57 | There must be sufficient address arguments for the given format |
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| 58 | specifiers; if not the results are unpredictable and likely |
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| 59 | disasterous. Excess address arguments are merely ignored. |
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| 60 | |
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| 61 | <<scanf>> often produces unexpected results if the input diverges from |
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| 62 | an expected pattern. Since the combination of <<gets>> or <<fgets>> |
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| 63 | followed by <<sscanf>> is safe and easy, that is the preferred way |
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| 64 | to be certain that a program is synchronized with input at the end |
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| 65 | of a line. |
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| 66 | |
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| 67 | <<fscanf>> and <<sscanf>> are identical to <<scanf>>, other than the |
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| 68 | source of input: <<fscanf>> reads from a file, and <<sscanf>> |
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| 69 | from a string. |
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| 70 | |
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| 71 | The routines <<_scanf_r>>, <<_fscanf_r>>, and <<_sscanf_r>> are reentrant |
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| 72 | versions of <<scanf>>, <<fscanf>>, and <<sscanf>> that take an additional |
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| 73 | first argument pointing to a reentrancy structure. |
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| 74 | |
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| 75 | The string at <<*<[format]>>> is a character sequence composed |
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| 76 | of zero or more directives. Directives are composed of |
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| 77 | one or more whitespace characters, non-whitespace characters, |
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| 78 | and format specifications. |
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| 79 | |
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| 80 | Whitespace characters are blank (<< >>), tab (<<\t>>), or |
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| 81 | newline (<<\n>>). |
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| 82 | When <<scanf>> encounters a whitespace character in the format string |
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| 83 | it will read (but not store) all consecutive whitespace characters |
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| 84 | up to the next non-whitespace character in the input. |
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| 85 | |
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| 86 | Non-whitespace characters are all other ASCII characters except the |
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| 87 | percent sign (<<%>>). When <<scanf>> encounters a non-whitespace |
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| 88 | character in the format string it will read, but not store |
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| 89 | a matching non-whitespace character. |
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| 90 | |
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| 91 | Format specifications tell <<scanf>> to read and convert characters |
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| 92 | from the input field into specific types of values, and store then |
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| 93 | in the locations specified by the address arguments. |
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| 94 | |
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| 95 | Trailing whitespace is left unread unless explicitly |
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| 96 | matched in the format string. |
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| 97 | |
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| 98 | The format specifiers must begin with a percent sign (<<%>>) |
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| 99 | and have the following form: |
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| 100 | |
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| 101 | . %[*][<[width]>][<[size]>]<[type]> |
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| 102 | |
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| 103 | Each format specification begins with the percent character (<<%>>). |
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| 104 | The other fields are: |
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| 105 | O+ |
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| 106 | o * |
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| 107 | |
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| 108 | an optional marker; if present, it suppresses interpretation and |
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| 109 | assignment of this input field. |
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| 110 | |
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| 111 | o <[width]> |
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| 112 | |
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| 113 | an optional maximum field width: a decimal integer, |
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| 114 | which controls the maximum number of characters that |
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| 115 | will be read before converting the current input field. If the |
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| 116 | input field has fewer than <[width]> characters, <<scanf>> |
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| 117 | reads all the characters in the field, and then |
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| 118 | proceeds with the next field and its format specification. |
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| 119 | |
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| 120 | If a whitespace or a non-convertable character occurs |
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| 121 | before <[width]> character are read, the characters up |
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| 122 | to that character are read, converted, and stored. |
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| 123 | Then <<scanf>> proceeds to the next format specification. |
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| 124 | |
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| 125 | o <[size]> |
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| 126 | |
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| 127 | <<h>>, <<j>>, <<l>>, <<L>>, <<t>>, and <<z>> are optional size |
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| 128 | characters which override the default way that <<scanf>> |
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| 129 | interprets the data type of the corresponding argument. |
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| 130 | |
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| 131 | @multitable @columnfractions 0.18 0.30 0.52 |
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| 132 | @headitem |
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| 133 | Modifier |
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| 134 | @tab |
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| 135 | Type(s) |
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| 136 | @tab |
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| 137 | @item |
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| 138 | hh |
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| 139 | @tab |
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| 140 | d, i, o, u, x, n |
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| 141 | @tab |
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| 142 | convert input to char, store in char object |
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| 143 | @item |
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| 144 | h |
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| 145 | @tab |
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| 146 | d, i, o, u, x, n |
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| 147 | @tab |
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| 148 | convert input to short, store in short object |
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| 149 | @item |
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| 150 | h |
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| 151 | @tab |
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| 152 | D, I, O, U, X, e, f, c, s, p |
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| 153 | @tab |
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| 154 | no effect |
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| 155 | @item |
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| 156 | j |
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| 157 | @tab |
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| 158 | d, i, o, u, x, n |
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| 159 | @tab |
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| 160 | convert input to intmax_t, store in intmax_t object |
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| 161 | @item |
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| 162 | j |
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| 163 | @tab |
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| 164 | all others |
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| 165 | @tab |
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| 166 | no effect |
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| 167 | @item |
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| 168 | l |
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| 169 | @tab |
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| 170 | d, i, o, u, x, n |
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| 171 | @tab |
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| 172 | convert input to long, store in long object |
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| 173 | @item |
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| 174 | l |
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| 175 | @tab |
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| 176 | e, f, g |
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| 177 | @tab |
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| 178 | convert input to double, store in a double object |
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| 179 | @item |
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| 180 | l |
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| 181 | @tab |
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| 182 | D, I, O, U, X, c, s, p |
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| 183 | @tab |
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| 184 | no effect |
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| 185 | @item |
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| 186 | ll |
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| 187 | @tab |
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| 188 | d, i, o, u, x, n |
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| 189 | @tab |
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| 190 | convert to long long, store in long long object |
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| 191 | @item |
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| 192 | L |
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| 193 | @tab |
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| 194 | d, i, o, u, x, n |
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| 195 | @tab |
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| 196 | convert to long long, store in long long object |
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| 197 | @item |
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| 198 | L |
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| 199 | @tab |
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| 200 | e, f, g, E, G |
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| 201 | @tab |
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| 202 | convert to long double, store in long double object |
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| 203 | @item |
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| 204 | L |
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| 205 | @tab |
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| 206 | all others |
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| 207 | @tab |
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| 208 | no effect |
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| 209 | @item |
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| 210 | t |
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| 211 | @tab |
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| 212 | d, i, o, u, x, n |
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| 213 | @tab |
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| 214 | convert input to ptrdiff_t, store in ptrdiff_t object |
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| 215 | @item |
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| 216 | t |
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| 217 | @tab |
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| 218 | all others |
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| 219 | @tab |
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| 220 | no effect |
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| 221 | @item |
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| 222 | z |
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| 223 | @tab |
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| 224 | d, i, o, u, x, n |
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| 225 | @tab |
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| 226 | convert input to size_t, store in size_t object |
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| 227 | @item |
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| 228 | z |
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| 229 | @tab |
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| 230 | all others |
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| 231 | @tab |
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| 232 | no effect |
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| 233 | @end multitable |
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| 234 | |
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| 235 | o <[type]> |
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| 236 | |
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| 237 | A character to specify what kind of conversion |
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| 238 | <<scanf>> performs. Here is a table of the conversion |
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| 239 | characters: |
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| 240 | |
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| 241 | o+ |
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| 242 | o % |
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| 243 | No conversion is done; the percent character (<<%>>) is stored. |
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| 244 | |
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| 245 | o c |
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| 246 | Scans one character. Corresponding <[arg]>: <<(char *arg)>>. |
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| 247 | |
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| 248 | o s |
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| 249 | Reads a character string into the array supplied. |
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| 250 | Corresponding <[arg]>: <<(char arg[])>>. |
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| 251 | |
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| 252 | o [<[pattern]>] |
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| 253 | Reads a non-empty character string into memory |
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| 254 | starting at <[arg]>. This area must be large |
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| 255 | enough to accept the sequence and a |
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| 256 | terminating null character which will be added |
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| 257 | automatically. (<[pattern]> is discussed in the paragraph following |
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| 258 | this table). Corresponding <[arg]>: <<(char *arg)>>. |
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| 259 | |
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| 260 | o d |
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| 261 | Reads a decimal integer into the corresponding <[arg]>: <<(int *arg)>>. |
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| 262 | |
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| 263 | o D |
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| 264 | Reads a decimal integer into the corresponding |
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| 265 | <[arg]>: <<(long *arg)>>. |
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| 266 | |
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| 267 | o o |
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| 268 | Reads an octal integer into the corresponding <[arg]>: <<(int *arg)>>. |
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| 269 | |
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| 270 | o O |
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| 271 | Reads an octal integer into the corresponding <[arg]>: <<(long *arg)>>. |
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| 272 | |
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| 273 | o u |
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| 274 | Reads an unsigned decimal integer into the corresponding |
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| 275 | <[arg]>: <<(unsigned int *arg)>>. |
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| 276 | |
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| 277 | o U |
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| 278 | Reads an unsigned decimal integer into the corresponding <[arg]>: |
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| 279 | <<(unsigned long *arg)>>. |
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| 280 | |
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| 281 | o x,X |
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| 282 | Read a hexadecimal integer into the corresponding <[arg]>: |
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| 283 | <<(int *arg)>>. |
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| 284 | |
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| 285 | o e, f, g |
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| 286 | Read a floating-point number into the corresponding <[arg]>: |
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| 287 | <<(float *arg)>>. |
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| 288 | |
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| 289 | o E, F, G |
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| 290 | Read a floating-point number into the corresponding <[arg]>: |
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| 291 | <<(double *arg)>>. |
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| 292 | |
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| 293 | o i |
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| 294 | Reads a decimal, octal or hexadecimal integer into the |
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| 295 | corresponding <[arg]>: <<(int *arg)>>. |
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| 296 | |
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| 297 | o I |
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| 298 | Reads a decimal, octal or hexadecimal integer into the |
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| 299 | corresponding <[arg]>: <<(long *arg)>>. |
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| 300 | |
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| 301 | o n |
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| 302 | Stores the number of characters read in the corresponding |
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| 303 | <[arg]>: <<(int *arg)>>. |
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| 304 | |
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| 305 | o p |
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| 306 | Stores a scanned pointer. ANSI C leaves the details |
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| 307 | to each implementation; this implementation treats |
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| 308 | <<%p>> exactly the same as <<%U>>. Corresponding |
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| 309 | <[arg]>: <<(void **arg)>>. |
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| 310 | o- |
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| 311 | |
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| 312 | A <[pattern]> of characters surrounded by square brackets can be used |
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| 313 | instead of the <<s>> type character. <[pattern]> is a set of |
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| 314 | characters which define a search set of possible characters making up |
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| 315 | the <<scanf>> input field. If the first character in the brackets is a |
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| 316 | caret (<<^>>), the search set is inverted to include all ASCII characters |
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| 317 | except those between the brackets. There is also a range facility |
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| 318 | which you can use as a shortcut. <<%[0-9] >> matches all decimal digits. |
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| 319 | The hyphen must not be the first or last character in the set. |
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| 320 | The character prior to the hyphen must be lexically less than the |
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| 321 | character after it. |
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| 322 | |
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| 323 | Here are some <[pattern]> examples: |
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| 324 | o+ |
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| 325 | o %[abcd] |
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| 326 | matches strings containing only <<a>>, <<b>>, <<c>>, and <<d>>. |
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| 327 | |
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| 328 | o %[^abcd] |
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| 329 | matches strings containing any characters except <<a>>, <<b>>, |
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| 330 | <<c>>, or <<d>> |
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| 331 | |
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| 332 | o %[A-DW-Z] |
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| 333 | matches strings containing <<A>>, <<B>>, <<C>>, <<D>>, <<W>>, |
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| 334 | <<X>>, <<Y>>, <<Z>> |
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| 335 | |
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| 336 | o %[z-a] |
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| 337 | matches the characters <<z>>, <<->>, and <<a>> |
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| 338 | o- |
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| 339 | |
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| 340 | Floating point numbers (for field types <<e>>, <<f>>, <<g>>, <<E>>, |
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| 341 | <<F>>, <<G>>) must correspond to the following general form: |
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| 342 | |
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| 343 | . [+/-] ddddd[.]ddd [E|e[+|-]ddd] |
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| 344 | |
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| 345 | where objects inclosed in square brackets are optional, and <<ddd>> |
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| 346 | represents decimal, octal, or hexadecimal digits. |
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| 347 | O- |
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| 348 | |
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| 349 | RETURNS |
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| 350 | <<scanf>> returns the number of input fields successfully |
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| 351 | scanned, converted and stored; the return value does |
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| 352 | not include scanned fields which were not stored. |
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| 353 | |
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| 354 | If <<scanf>> attempts to read at end-of-file, the return |
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| 355 | value is <<EOF>>. |
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| 356 | |
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| 357 | If no fields were stored, the return value is <<0>>. |
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| 358 | |
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| 359 | <<scanf>> might stop scanning a particular field before |
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| 360 | reaching the normal field end character, or may |
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| 361 | terminate entirely. |
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| 362 | |
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| 363 | <<scanf>> stops scanning and storing the current field |
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| 364 | and moves to the next input field (if any) |
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| 365 | in any of the following situations: |
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| 366 | |
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| 367 | O+ |
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| 368 | o The assignment suppressing character (<<*>>) appears |
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| 369 | after the <<%>> in the format specification; the current |
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| 370 | input field is scanned but not stored. |
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| 371 | |
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| 372 | o <[width]> characters have been read (<[width]> is a |
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| 373 | width specification, a positive decimal integer). |
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| 374 | |
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| 375 | o The next character read cannot be converted |
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| 376 | under the the current format (for example, |
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| 377 | if a <<Z>> is read when the format is decimal). |
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| 378 | |
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| 379 | o The next character in the input field does not appear |
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| 380 | in the search set (or does appear in the inverted search set). |
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| 381 | O- |
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| 382 | |
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| 383 | When <<scanf>> stops scanning the current input field for one of |
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| 384 | these reasons, the next character is considered unread and |
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| 385 | used as the first character of the following input field, or the |
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| 386 | first character in a subsequent read operation on the input. |
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| 387 | |
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| 388 | <<scanf>> will terminate under the following circumstances: |
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| 389 | |
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| 390 | O+ |
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| 391 | o The next character in the input field conflicts |
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| 392 | with a corresponding non-whitespace character in the |
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| 393 | format string. |
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| 394 | |
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| 395 | o The next character in the input field is <<EOF>>. |
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| 396 | |
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| 397 | o The format string has been exhausted. |
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| 398 | O- |
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| 399 | |
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| 400 | When the format string contains a character sequence that is |
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| 401 | not part of a format specification, the same character |
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| 402 | sequence must appear in the input; <<scanf>> will |
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| 403 | scan but not store the matched characters. If a |
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| 404 | conflict occurs, the first conflicting character remains in the input |
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| 405 | as if it had never been read. |
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| 406 | |
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| 407 | PORTABILITY |
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| 408 | <<scanf>> is ANSI C. |
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| 409 | |
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| 410 | Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>, |
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| 411 | <<lseek>>, <<read>>, <<sbrk>>, <<write>>. |
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| 412 | */ |
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| 413 | |
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| 414 | #include <_ansi.h> |
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| 415 | #include <reent.h> |
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| 416 | #include <stdio.h> |
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| 417 | #include <string.h> |
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| 418 | #include <stdarg.h> |
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| 419 | #include "local.h" |
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| 420 | |
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| 421 | #ifndef _REENT_ONLY |
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| 422 | |
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| 423 | int |
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| 424 | sscanf (const char *__restrict str, |
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| 425 | const char * fmt, ...) |
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| 426 | { |
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| 427 | int ret; |
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| 428 | va_list ap; |
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| 429 | FILE f; |
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| 430 | |
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| 431 | f._flags = __SRD | __SSTR; |
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| 432 | f._bf._base = f._p = (unsigned char *) str; |
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| 433 | f._bf._size = f._r = strlen (str); |
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| 434 | f._read = __seofread; |
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| 435 | f._ub._base = NULL; |
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| 436 | f._lb._base = NULL; |
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| 437 | f._file = -1; /* No file. */ |
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| 438 | va_start (ap, fmt); |
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| 439 | ret = __ssvfscanf_r (_REENT, &f, fmt, ap); |
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| 440 | va_end (ap); |
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| 441 | return ret; |
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| 442 | } |
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| 443 | |
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| 444 | #ifdef _NANO_FORMATTED_IO |
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| 445 | int |
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| 446 | siscanf (const char *, const char *, ...) |
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| 447 | _ATTRIBUTE ((__alias__("sscanf"))); |
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| 448 | #endif |
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| 449 | |
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| 450 | #endif /* !_REENT_ONLY */ |
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| 451 | |
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| 452 | int |
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| 453 | _sscanf_r (struct _reent *ptr, |
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| 454 | const char *__restrict str, |
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| 455 | const char *__restrict fmt, ...) |
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| 456 | { |
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| 457 | int ret; |
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| 458 | va_list ap; |
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| 459 | FILE f; |
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| 460 | |
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| 461 | f._flags = __SRD | __SSTR; |
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| 462 | f._bf._base = f._p = (unsigned char *) str; |
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| 463 | f._bf._size = f._r = strlen (str); |
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| 464 | f._read = __seofread; |
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| 465 | f._ub._base = NULL; |
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| 466 | f._lb._base = NULL; |
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| 467 | f._file = -1; /* No file. */ |
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| 468 | va_start (ap, fmt); |
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| 469 | ret = __ssvfscanf_r (ptr, &f, fmt, ap); |
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| 470 | va_end (ap); |
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| 471 | return ret; |
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| 472 | } |
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| 473 | |
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| 474 | #ifdef _NANO_FORMATTED_IO |
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| 475 | int |
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| 476 | _siscanf_r (struct _reent *, const char *, const char *, ...) |
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| 477 | _ATTRIBUTE ((__alias__("_sscanf_r"))); |
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| 478 | #endif |
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