458 lines
13 KiB
C
458 lines
13 KiB
C
/*
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that the above copyright notice and this paragraph are
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* duplicated in all such forms and that any documentation,
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* advertising materials, and other materials related to such
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* distribution and use acknowledge that the software was developed
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* by the University of California, Berkeley. The name of the
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* University may not be used to endorse or promote products derived
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* from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*/
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/*
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FUNCTION
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<<swscanf>>, <<fwscanf>>, <<wscanf>>---scan and format wide character input
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INDEX
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wscanf
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INDEX
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_wscanf_r
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INDEX
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fwscanf
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INDEX
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_fwscanf_r
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INDEX
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swscanf
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INDEX
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_swscanf_r
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SYNOPSIS
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#include <stdio.h>
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int wscanf(const wchar_t *__restrict <[format]>, ...);
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int fwscanf(FILE *__restrict <[fd]>,
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const wchar_t *__restrict <[format]>, ...);
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int swscanf(const wchar_t *__restrict <[str]>,
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const wchar_t *__restrict <[format]>, ...);
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int _wscanf_r(struct _reent *<[ptr]>, const wchar_t *<[format]>, ...);
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int _fwscanf_r(struct _reent *<[ptr]>, FILE *<[fd]>,
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const wchar_t *<[format]>, ...);
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int _swscanf_r(struct _reent *<[ptr]>, const wchar_t *<[str]>,
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const wchar_t *<[format]>, ...);
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DESCRIPTION
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<<wscanf>> scans a series of input fields from standard input,
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one wide character at a time. Each field is interpreted according to
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a format specifier passed to <<wscanf>> in the format string at
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<<*<[format]>>>. <<wscanf>> stores the interpreted input from
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each field at the address passed to it as the corresponding argument
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following <[format]>. You must supply the same number of
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format specifiers and address arguments as there are input fields.
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There must be sufficient address arguments for the given format
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specifiers; if not the results are unpredictable and likely
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disasterous. Excess address arguments are merely ignored.
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<<wscanf>> often produces unexpected results if the input diverges from
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an expected pattern. Since the combination of <<gets>> or <<fgets>>
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followed by <<swscanf>> is safe and easy, that is the preferred way
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to be certain that a program is synchronized with input at the end
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of a line.
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<<fwscanf>> and <<swscanf>> are identical to <<wscanf>>, other than the
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source of input: <<fwscanf>> reads from a file, and <<swscanf>>
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from a string.
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The routines <<_wscanf_r>>, <<_fwscanf_r>>, and <<_swscanf_r>> are reentrant
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versions of <<wscanf>>, <<fwscanf>>, and <<swscanf>> that take an additional
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first argument pointing to a reentrancy structure.
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The string at <<*<[format]>>> is a wide character sequence composed
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of zero or more directives. Directives are composed of
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one or more whitespace characters, non-whitespace characters,
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and format specifications.
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Whitespace characters are blank (<< >>), tab (<<\t>>), or
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newline (<<\n>>).
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When <<wscanf>> encounters a whitespace character in the format string
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it will read (but not store) all consecutive whitespace characters
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up to the next non-whitespace character in the input.
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Non-whitespace characters are all other ASCII characters except the
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percent sign (<<%>>). When <<wscanf>> encounters a non-whitespace
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character in the format string it will read, but not store
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a matching non-whitespace character.
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Format specifications tell <<wscanf>> to read and convert characters
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from the input field into specific types of values, and store then
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in the locations specified by the address arguments.
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Trailing whitespace is left unread unless explicitly
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matched in the format string.
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The format specifiers must begin with a percent sign (<<%>>)
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and have the following form:
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. %[*][<[width]>][<[size]>]<[type]>
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Each format specification begins with the percent character (<<%>>).
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The other fields are:
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O+
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o *
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an optional marker; if present, it suppresses interpretation and
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assignment of this input field.
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o <[width]>
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an optional maximum field width: a decimal integer,
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which controls the maximum number of characters that
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will be read before converting the current input field. If the
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input field has fewer than <[width]> characters, <<wscanf>>
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reads all the characters in the field, and then
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proceeds with the next field and its format specification.
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If a whitespace or a non-convertable wide character occurs
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before <[width]> character are read, the characters up
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to that character are read, converted, and stored.
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Then <<wscanf>> proceeds to the next format specification.
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o <[size]>
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<<h>>, <<j>>, <<l>>, <<L>>, <<t>>, and <<z>> are optional size
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characters which override the default way that <<wscanf>>
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interprets the data type of the corresponding argument.
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@multitable @columnfractions 0.18 0.30 0.52
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@headitem
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Modifier
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@tab
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Type(s)
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@tab
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@item
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hh
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@tab
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d, i, o, u, x, n
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@tab
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convert input to char, store in char object
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@item
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h
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@tab
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d, i, o, u, x, n
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@tab
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convert input to short, store in short object
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@item
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h
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@tab
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e, f, c, s, p
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@tab
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no effect
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@item
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j
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@tab
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d, i, o, u, x, n
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@tab
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convert input to intmax_t, store in intmax_t object
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@item
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j
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@tab
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all others
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@tab
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no effect
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@item
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l
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@tab
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d, i, o, u, x, n
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@tab
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convert input to long, store in long object
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@item
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l
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@tab
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e, f, g
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@tab
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convert input to double, store in a double object
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@item
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l
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@tab
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c, s, [
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@tab
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the input is stored in a wchar_t object
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@item
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l
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@tab
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p
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@tab
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no effect
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@item
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ll
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@tab
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d, i, o, u, x, n
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@tab
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convert to long long, store in long long object
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@item
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L
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@tab
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d, i, o, u, x, n
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@tab
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convert to long long, store in long long object
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@item
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L
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@tab
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e, f, g, E, G
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@tab
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convert to long double, store in long double object
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@item
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L
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@tab
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all others
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@tab
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no effect
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@item
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t
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@tab
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d, i, o, u, x, n
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@tab
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convert input to ptrdiff_t, store in ptrdiff_t object
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@item
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t
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@tab
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all others
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@tab
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no effect
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@item
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z
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@tab
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d, i, o, u, x, n
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@tab
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convert input to size_t, store in size_t object
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@item
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z
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@tab
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all others
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@tab
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no effect
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@end multitable
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o <[type]>
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A character to specify what kind of conversion
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<<wscanf>> performs. Here is a table of the conversion
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characters:
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o+
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o %
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No conversion is done; the percent character (<<%>>) is stored.
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o c
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Scans one wide character. Corresponding <[arg]>: <<(char *arg)>>.
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Otherwise, if an <<l>> specifier is present, the corresponding
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<[arg]> is a <<(wchar_t *arg)>>.
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o s
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Reads a character string into the array supplied.
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Corresponding <[arg]>: <<(char arg[])>>.
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If an <<l>> specifier is present, the corresponding <[arg]> is a <<(wchar_t *arg)>>.
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o [<[pattern]>]
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Reads a non-empty character string into memory
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starting at <[arg]>. This area must be large
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enough to accept the sequence and a
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terminating null character which will be added
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automatically. (<[pattern]> is discussed in the paragraph following
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this table). Corresponding <[arg]>: <<(char *arg)>>.
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If an <<l>> specifier is present, the corresponding <[arg]> is
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a <<(wchar_t *arg)>>.
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o d
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Reads a decimal integer into the corresponding <[arg]>: <<(int *arg)>>.
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o o
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Reads an octal integer into the corresponding <[arg]>: <<(int *arg)>>.
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o u
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Reads an unsigned decimal integer into the corresponding
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<[arg]>: <<(unsigned int *arg)>>.
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o x,X
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Read a hexadecimal integer into the corresponding <[arg]>:
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<<(int *arg)>>.
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o e, f, g
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Read a floating-point number into the corresponding <[arg]>:
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<<(float *arg)>>.
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o E, F, G
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Read a floating-point number into the corresponding <[arg]>:
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<<(double *arg)>>.
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o i
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Reads a decimal, octal or hexadecimal integer into the
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corresponding <[arg]>: <<(int *arg)>>.
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o n
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Stores the number of characters read in the corresponding
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<[arg]>: <<(int *arg)>>.
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o p
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Stores a scanned pointer. ANSI C leaves the details
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to each implementation; this implementation treats
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<<%p>> exactly the same as <<%U>>. Corresponding
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<[arg]>: <<(void **arg)>>.
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o-
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A <[pattern]> of characters surrounded by square brackets can be used
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instead of the <<s>> type character. <[pattern]> is a set of
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characters which define a search set of possible characters making up
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the <<wscanf>> input field. If the first character in the brackets is a
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caret (<<^>>), the search set is inverted to include all ASCII characters
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except those between the brackets. There is no range facility as is
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defined in the corresponding non-wide character scanf functions.
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Ranges are not part of the POSIX standard.
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Here are some <[pattern]> examples:
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o+
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o %[abcd]
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matches wide character strings containing only
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<<a>>, <<b>>, <<c>>, and <<d>>.
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o %[^abcd]
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matches wide character strings containing any characters except
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<<a>>, <<b>>, <<c>>, or <<d>>.
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o %[A-DW-Z]
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Note: No wide character ranges, so this expression matches wide
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character strings containing <<A>>, <<->>, <<D>>, <<W>>, <<Z>>.
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o-
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Floating point numbers (for field types <<e>>, <<f>>, <<g>>, <<E>>,
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<<F>>, <<G>>) must correspond to the following general form:
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. [+/-] ddddd[.]ddd [E|e[+|-]ddd]
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where objects inclosed in square brackets are optional, and <<ddd>>
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represents decimal, octal, or hexadecimal digits.
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O-
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RETURNS
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<<wscanf>> returns the number of input fields successfully
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scanned, converted and stored; the return value does
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not include scanned fields which were not stored.
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If <<wscanf>> attempts to read at end-of-file, the return
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value is <<EOF>>.
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If no fields were stored, the return value is <<0>>.
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<<wscanf>> might stop scanning a particular field before
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reaching the normal field end character, or may
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terminate entirely.
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<<wscanf>> stops scanning and storing the current field
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and moves to the next input field (if any)
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in any of the following situations:
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O+
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o The assignment suppressing character (<<*>>) appears
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after the <<%>> in the format specification; the current
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input field is scanned but not stored.
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o <[width]> characters have been read (<[width]> is a
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width specification, a positive decimal integer).
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o The next wide character read cannot be converted
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under the the current format (for example,
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if a <<Z>> is read when the format is decimal).
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o The next wide character in the input field does not appear
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in the search set (or does appear in the inverted search set).
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O-
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When <<wscanf>> stops scanning the current input field for one of
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these reasons, the next character is considered unread and
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used as the first character of the following input field, or the
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first character in a subsequent read operation on the input.
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<<wscanf>> will terminate under the following circumstances:
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O+
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o The next wide character in the input field conflicts
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with a corresponding non-whitespace character in the
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format string.
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o The next wide character in the input field is <<WEOF>>.
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o The format string has been exhausted.
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O-
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When the format string contains a wide character sequence that is
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not part of a format specification, the same wide character
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sequence must appear in the input; <<wscanf>> will
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scan but not store the matched characters. If a
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conflict occurs, the first conflicting wide character remains in the
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input as if it had never been read.
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PORTABILITY
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<<wscanf>> is C99, POSIX-1.2008.
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Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
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<<lseek>>, <<read>>, <<sbrk>>, <<write>>.
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*/
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#include <_ansi.h>
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#include <reent.h>
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#include <stdio.h>
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#include <wchar.h>
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#include <stdarg.h>
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#include "local.h"
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#ifndef _REENT_ONLY
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int
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swscanf (const wchar_t *__restrict str, const wchar_t *__restrict fmt, ...)
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{
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int ret;
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va_list ap;
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FILE f;
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f._flags = __SRD | __SSTR;
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f._bf._base = f._p = (unsigned char *) str;
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f._bf._size = f._r = wcslen (str) * sizeof (wchar_t);
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f._read = __seofread;
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f._ub._base = NULL;
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f._lb._base = NULL;
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f._file = -1; /* No file. */
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va_start (ap, fmt);
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ret = __ssvfwscanf_r (_REENT, &f, fmt, ap);
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va_end (ap);
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return ret;
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}
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#endif /* !_REENT_ONLY */
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int
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_swscanf_r (struct _reent *ptr, const wchar_t *str, const wchar_t *fmt, ...)
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{
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int ret;
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va_list ap;
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FILE f;
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f._flags = __SRD | __SSTR;
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f._bf._base = f._p = (unsigned char *) str;
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f._bf._size = f._r = wcslen (str) * sizeof (wchar_t);
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f._read = __seofread;
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f._ub._base = NULL;
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f._lb._base = NULL;
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f._file = -1; /* No file. */
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va_start (ap, fmt);
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ret = __ssvfwscanf_r (ptr, &f, fmt, ap);
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va_end (ap);
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return ret;
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}
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