mirror of https://github.com/mkerrisk/man-pages
125 lines
2.6 KiB
Groff
125 lines
2.6 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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.\" ISO/IEC 9899:1999
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.\"
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.TH WCRTOMB 3 2014-03-18 "GNU" "Linux Programmer's Manual"
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.SH NAME
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wcrtomb \- convert a wide character to a multibyte sequence
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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 wcrtomb(char *" s ", wchar_t " wc ", mbstate_t *" ps );
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.fi
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.SH DESCRIPTION
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The main case for this function is when
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.I s
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is
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not NULL and
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.I wc
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is not a null wide character (L\(aq\\0\(aq).
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In this case, the
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.BR wcrtomb ()
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function
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converts the wide character
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.I wc
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to its multibyte representation and stores it
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at the beginning of the character
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array pointed to by
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.IR s .
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It updates the shift state
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.IR *ps ,
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and
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returns the length of said multibyte representation,
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that is, the number of bytes
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written at
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.IR s .
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.PP
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A different case is when
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.I s
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is not NULL,
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but
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.I wc
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is a null wide character (L\(aq\\0\(aq).
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In this case, the
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.BR wcrtomb ()
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function stores at
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the character array pointed to by
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.I s
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the shift sequence needed to
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bring
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.I *ps
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back to the initial state,
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followed by a \(aq\\0\(aq byte.
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It updates the shift state
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.I *ps
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(i.e., brings
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it into the initial state),
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and returns the length of the shift sequence plus
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one, that is, the number of bytes written at
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.IR s .
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.PP
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A third case is when
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.I s
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is NULL.
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In this case,
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.I wc
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is ignored,
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and the function effectively returns
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wcrtomb(buf, L\(aq\\0\(aq, ps)
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where
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.I buf
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is an internal anonymous buffer.
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.PP
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In all 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 wcrtomb ()
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function is used instead.
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.SH RETURN VALUE
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The
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.BR wcrtomb ()
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function returns the number of
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bytes that have been or would
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have been written to the byte array at
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.IR s .
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If
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.I wc
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can not be
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represented as a multibyte sequence (according to the current locale),
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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 CONFORMING TO
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C99.
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.SH NOTES
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The behavior of
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.BR wcrtomb ()
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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 mbsinit (3),
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.BR wcsrtombs (3)
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