mirror of https://github.com/mkerrisk/man-pages
64 lines
2.5 KiB
Groff
64 lines
2.5 KiB
Groff
.\" Copyright (c) Bruno Haible <haible@clisp.cons.org>
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.\"
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.\" This is free documentation; you can redistribute it and/or
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.\" modify it under the terms of the GNU General Public License as
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.\" published by the Free Software Foundation; either version 2 of
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.\" the License, or (at your option) any later version.
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.\"
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.\" References consulted:
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.\" GNU glibc-2 source code and manual
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.\" Dinkumware C library reference http://www.dinkumware.com/
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.\" OpenGroup's Single Unix specification http://www.UNIX-systems.org/online.html
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.\" ISO/IEC 9899:1999
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.\"
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.TH MBSTOWCS 3 1999-07-25 "GNU" "Linux Programmer's Manual"
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.SH NAME
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mbstowcs \- convert a multibyte string to a wide character string
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.SH SYNOPSIS
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.nf
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.B #include <stdlib.h>
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.sp
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.BI "size_t mbstowcs(wchar_t *" dest ", const char *" src ", size_t " n );
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.fi
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.SH DESCRIPTION
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If \fIdest\fP is not a NULL pointer, the \fBmbstowcs\fP function converts the
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multibyte string \fIsrc\fP to a wide-character string starting at \fIdest\fP.
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At most \fIn\fP wide characters are written to \fIdest\fP. The conversion starts
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in the initial state. The conversion can stop for three reasons:
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.PP
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1. An invalid multibyte sequence has been encountered. In this case
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(size_t)(-1) is returned.
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.PP
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2. \fIn\fP non-L'\\0' wide characters have been stored at \fIdest\fP. In this
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case the number of wide characters written to \fIdest\fP is returned, but the
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shift state at this point is lost.
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.PP
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3. The multibyte string has been completely converted, including the
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terminating '\\0'. In this case the number of wide characters written to
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\fIdest\fP, excluding the terminating L'\\0' character, is returned.
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.PP
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The programmer must ensure that there is room for at least \fIn\fP wide
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characters at \fIdest\fP.
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.PP
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If \fIdest\fP is NULL, \fIn\fP is ignored, and the conversion proceeds as
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above, except that the converted wide characters are not written out to memory,
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and that no length limit exists.
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.PP
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In order to avoid the case 2 above, the programmer should make sure \fIn\fP is
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greater or equal to \fImbstowcs(NULL,src,0)+1\fP.
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.SH "RETURN VALUE"
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The \fBmbstowcs\fP function returns the number of wide characters that make
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up the converted part of the wide character string, not including the
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terminating null wide character. If an invalid multibyte sequence was
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encountered, (size_t)(-1) is returned.
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.SH "CONFORMING TO"
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ISO/ANSI C, UNIX98
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.SH "SEE ALSO"
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.BR mbsrtowcs (3)
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.SH NOTES
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The behaviour of \fBmbstowcs\fP depends on the LC_CTYPE category of the
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current locale.
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.PP
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The function \fBmbsrtowcs\fP provides a better interface to the same
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functionality.
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