mirror of https://github.com/mkerrisk/man-pages
85 lines
2.5 KiB
Groff
85 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 WCRTOMB 3 1999-07-25 "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 \fIs\fP is
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not NULL and \fIwc\fP is not
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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 \fIwc\fP
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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 \fIs\fP.
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It updates the shift state \fI*ps\fP, 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 \fIs\fP.
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.PP
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A different case is when \fIs\fP is not NULL but \fIwc\fP is L\(aq\\0\(aq.
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In this
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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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\fIs\fP the shift sequence needed to
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bring \fI*ps\fP 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 \fI*ps\fP (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 \fIs\fP.
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.PP
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A third case is when \fIs\fP is NULL.
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In this case \fIwc\fP is ignored,
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and the function effectively returns wcrtomb(buf,L\(aq\\0\(aq,\fIps\fP) where
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buf is an internal anonymous buffer.
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.PP
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In all of the above cases, if \fIps\fP is a NULL pointer, a static anonymous
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state only known 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 \fIs\fP.
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If \fIwc\fP 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 \fIerrno\fP set to \fBEILSEQ\fP.
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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 \fIps\fP is not multi-thread safe.
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.SH "SEE ALSO"
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.BR wcsrtombs (3)
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