mirror of https://github.com/mkerrisk/man-pages
194 lines
3.9 KiB
Groff
194 lines
3.9 KiB
Groff
.\" Copyright (c) Bruno Haible <haible@clisp.cons.org>
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.\"
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.\" %%%LICENSE_START(GPLv2+_DOC_ONEPARA)
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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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.\" %%%LICENSE_END
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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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.\"
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.TH MBSNRTOWCS 3 2015-04-19 "GNU" "Linux Programmer's Manual"
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.SH NAME
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mbsnrtowcs \- 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 <wchar.h>
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.sp
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.BI "size_t mbsnrtowcs(wchar_t *" dest ", const char **" src ,
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.BI " size_t " nms ", size_t " len ", mbstate_t *" ps );
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.fi
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.sp
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.in -4n
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Feature Test Macro Requirements for glibc (see
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.BR feature_test_macros (7)):
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.in
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.sp
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.BR mbsnrtowcs ():
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.PD 0
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.ad l
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.RS 4
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.TP 4
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Since glibc 2.10:
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_XOPEN_SOURCE\ >=\ 700 || _POSIX_C_SOURCE\ >=\ 200809L
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.TP
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Before glibc 2.10:
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_GNU_SOURCE
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.RE
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.ad
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.PD
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.SH DESCRIPTION
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The
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.BR mbsnrtowcs ()
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function is like the
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.BR mbsrtowcs (3)
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function, except that
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the number of bytes to be converted, starting at
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.IR *src ,
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is limited to
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.IR nms .
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.PP
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If
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.I dest
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is not NULL, the
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.BR mbsnrtowcs ()
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function converts at
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most
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.I nms
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bytes from the
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multibyte string
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.I *src
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to a wide-character string starting at
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.IR dest .
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At most
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.I len
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wide characters are written to
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.IR dest .
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The shift state
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.I *ps
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is updated.
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The conversion is effectively performed by repeatedly
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calling
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.I "mbrtowc(dest, *src, n, ps)"
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where
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.I n
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is some
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positive number, as long as this call succeeds, and then incrementing
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.I dest
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by one and
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.I *src
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by the number of bytes consumed.
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The
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conversion can stop for three reasons:
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.IP 1. 3
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An invalid multibyte sequence has been encountered.
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In this case,
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.I *src
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is left pointing to the invalid multibyte sequence,
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.I (size_t)\ \-1
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is returned,
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and
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.I errno
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is set to
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.BR EILSEQ .
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.IP 2.
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The
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.I nms
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limit forces a stop,
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or
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.I len
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non-L\(aq\\0\(aq wide characters
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have been stored at
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.IR dest .
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In this case,
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.I *src
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is left pointing to the
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next multibyte sequence to be converted, and the number of wide characters
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written to
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.I dest
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is returned.
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.IP 3.
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The multibyte string has been completely converted, including the
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terminating null wide character (\(aq\\0\(aq)
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(which has the side effect of bringing back
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.I *ps
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to the
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initial state).
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In this case,
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.I *src
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is set to NULL, and the number of wide
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characters written to
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.IR dest ,
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excluding the terminating null wide character,
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is returned.
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.PP
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If
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.IR dest
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is NULL,
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.I len
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is ignored, and the conversion proceeds as
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above, except that the converted wide characters
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are not written out to memory,
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and that no destination length limit exists.
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.PP
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In both of the above cases, if
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.I ps
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is NULL, a static anonymous
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state known only to the
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.BR mbsnrtowcs ()
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function is used instead.
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.PP
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The programmer must ensure that there is room for at least
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.I len
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wide
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characters at
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.IR dest .
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.SH RETURN VALUE
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The
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.BR mbsnrtowcs ()
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function returns the number of wide characters
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that make up the converted part of the wide-character string,
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not including the terminating null wide character.
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If an invalid multibyte sequence was
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encountered,
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.I (size_t)\ \-1
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is returned, and
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.I errno
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set to
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.BR EILSEQ .
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.SH ATTRIBUTES
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For an explanation of the terms used in this section, see
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.BR attributes (7).
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.TS
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allbox;
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lb lb lbw29
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l l l.
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Interface Attribute Value
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T{
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.BR mbsnrtowcs ()
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T} Thread safety MT-Unsafe race:mbsnrtowcs/!ps
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.TE
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.SH CONFORMING TO
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POSIX.1-2008.
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.SH NOTES
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The behavior of
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.BR mbsnrtowcs ()
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depends on the
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.B LC_CTYPE
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category of the
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current locale.
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.PP
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Passing NULL as
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.I ps
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is not multithread safe.
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.SH SEE ALSO
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.BR iconv (3),
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.BR mbrtowc (3)
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.BR mbsinit (3),
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.BR mbsrtowcs (3)
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