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123 lines
4.0 KiB
Plaintext
123 lines
4.0 KiB
Plaintext
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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.TH "MBRTOWC" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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.\" mbrtowc
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.SH NAME
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mbrtowc \- convert a character to a wide-character code (restartable)
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.SH SYNOPSIS
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.LP
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\fB#include <wchar.h>
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.br
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.sp
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size_t mbrtowc(wchar_t *restrict\fP \fIpwc\fP\fB, const char *restrict\fP
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\fIs\fP\fB,
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.br
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\ \ \ \ \ \ size_t\fP \fIn\fP\fB, mbstate_t *restrict\fP \fIps\fP\fB);
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.br
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\fP
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.SH DESCRIPTION
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.LP
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If \fIs\fP is a null pointer, the \fImbrtowc\fP() function shall be
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equivalent to the call:
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.sp
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.RS
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.nf
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\fBmbrtowc(NULL, "", 1, ps)
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\fP
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.fi
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.RE
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.LP
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In this case, the values of the arguments \fIpwc\fP and \fIn\fP are
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ignored.
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.LP
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If \fIs\fP is not a null pointer, the \fImbrtowc\fP() function shall
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inspect at most \fIn\fP bytes beginning at the byte
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pointed to by \fIs\fP to determine the number of bytes needed to complete
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the next character (including any shift sequences). If
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the function determines that the next character is completed, it shall
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determine the value of the corresponding wide character and
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then, if \fIpwc\fP is not a null pointer, shall store that value in
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the object pointed to by \fIpwc\fP. If the corresponding wide
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character is the null wide character, the resulting state described
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shall be the initial conversion state.
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.LP
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If \fIps\fP is a null pointer, the \fImbrtowc\fP() function shall
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use its own internal \fBmbstate_t\fP object, which shall be
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initialized at program start-up to the initial conversion state. Otherwise,
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the \fBmbstate_t\fP object pointed to by \fIps\fP
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shall be used to completely describe the current conversion state
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of the associated character sequence. The implementation shall
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behave as if no function defined in this volume of IEEE\ Std\ 1003.1-2001
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calls \fImbrtowc\fP().
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.LP
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The behavior of this function is affected by the \fILC_CTYPE\fP category
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of the current locale.
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.SH RETURN VALUE
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.LP
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The \fImbrtowc\fP() function shall return the first of the following
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that applies:
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.TP 7
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0
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If the next \fIn\fP or fewer bytes complete the character that corresponds
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to the null wide character (which is the value
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stored).
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.TP 7
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between 1 and \fIn\fP inclusive
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.sp
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If the next \fIn\fP or fewer bytes complete a valid character (which
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is the value stored); the value returned shall be the number
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of bytes that complete the character.
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.TP 7
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(\fBsize_t\fP)-2
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If the next \fIn\fP bytes contribute to an incomplete but potentially
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valid character, and all \fIn\fP bytes have been
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processed (no value is stored). When \fIn\fP has at least the value
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of the {MB_CUR_MAX} macro, this case can only occur if
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\fIs\fP points at a sequence of redundant shift sequences (for implementations
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with state-dependent encodings).
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.TP 7
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(\fBsize_t\fP)-1
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If an encoding error occurs, in which case the next \fIn\fP or fewer
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bytes do not contribute to a complete and valid character
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(no value is stored). In this case, [EILSEQ] shall be stored in \fIerrno\fP
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and the conversion state is undefined.
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.sp
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.SH ERRORS
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.LP
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The \fImbrtowc\fP() function may fail if:
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.TP 7
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.B EINVAL
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\fIps\fP points to an object that contains an invalid conversion state.
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.TP 7
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.B EILSEQ
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Invalid character sequence is detected.
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.sp
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.LP
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\fIThe following sections are informative.\fP
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.SH EXAMPLES
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.LP
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None.
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.SH APPLICATION USAGE
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.LP
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None.
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.SH RATIONALE
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.LP
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None.
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.SH FUTURE DIRECTIONS
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.LP
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None.
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.SH SEE ALSO
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.LP
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\fImbsinit\fP() , the Base Definitions volume of IEEE\ Std\ 1003.1-2001,
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\fI<wchar.h>\fP
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.SH COPYRIGHT
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Portions of this text are reprinted and reproduced in electronic form
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from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
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-- Portable Operating System Interface (POSIX), The Open Group Base
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Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
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Electrical and Electronics Engineers, Inc and The Open Group. In the
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event of any discrepancy between this version and the original IEEE and
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The Open Group Standard, the original IEEE and The Open Group Standard
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is the referee document. The original Standard can be obtained online at
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http://www.opengroup.org/unix/online.html .
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