1.\" Copyright (c) 2002-2004 Tim J. Robbins 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD: head/lib/libc/locale/wcrtomb.3 250883 2013-05-21 19:59:37Z ed $ 26.\" 27.Dd May 4, 2019 28.Dt WCRTOMB 3 29.Os 30.Sh NAME 31.Nm wcrtomb , 32.Nm wcrtomb_l , 33.Nm c16rtomb , 34.Nm c16rtomb_l , 35.Nm c32rtomb , 36.Nm c32rtomb_l 37.Nd "convert a wide-character code to a character (restartable)" 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In wchar.h 42.Ft size_t 43.Fn wcrtomb "char * restrict s" "wchar_t c" "mbstate_t * restrict ps" 44.In uchar.h 45.Ft size_t 46.Fn c16rtomb "char * restrict s" "char16_t c" "mbstate_t * restrict ps" 47.Ft size_t 48.Fn c32rtomb "char * restrict s" "char32_t c" "mbstate_t * restrict ps" 49.In xlocale.h 50.Ft size_t 51.Fn wcrtomb_l "char * restrict s" "wchar_t c" "mbstate_t * restrict ps" "locale_t locale" 52.Ft size_t 53.Fn c16rtomb_l "char * restrict s" "char16_t c" "mbstate_t * restrict ps" "locale_t locale" 54.Ft size_t 55.Fn c32rtomb_l "char * restrict s" "char32_t c" "mbstate_t * restrict ps" "locale_t" 56.Sh DESCRIPTION 57The 58.Fn wcrtomb , 59.Fn wcrtomb_l , 60.Fn c16rtomb , 61.Fn c16rtomb_l , 62.Fn c32rtomb , 63and 64.Fn c32rtomb_l 65functions store a multibyte sequence representing the 66wide character 67.Fa c , 68including any necessary shift sequences, to the 69character array 70.Fa s , 71storing a maximum of 72.Dv MB_CUR_MAX 73bytes. 74.Pp 75If 76.Fa s 77is 78.Dv NULL , 79these functions behave as if 80.Fa s 81pointed to an internal buffer and 82.Fa c 83was a null wide character (L'\e0'). 84.Pp 85The 86.Ft mbstate_t 87argument, 88.Fa ps , 89is used to keep track of the shift state. 90If it is 91.Dv NULL , 92these functions use an internal, static 93.Vt mbstate_t 94object, which is initialized to the initial conversion state 95at program startup. 96.Pp 97As certain multibyte characters may only be represented by a series of 9816-bit characters, the 99.Fn c16rtomb 100may need to invoked multiple times before a multibyte sequence is 101returned. 102.Pp 103The 104.Fn wcrtomb_l , 105.Fn c16rtomb_l , 106and 107.Fn c32rtomb_l 108functions take an explicit 109.Fa locale 110argument, whereas the 111.Fn wcrtomb , 112.Fn c16rtomb , 113and 114.Fn c32rtomb 115functions use the current global or per-thread locale. 116.Sh RETURN VALUES 117These functions return the length (in bytes) of the multibyte sequence 118needed to represent 119.Fa c , 120or 121.Po Vt size_t Pc Ns \-1 122if 123.Fa c 124is not a valid wide character code. 125.Sh ERRORS 126The 127.Fn wcrtomb , 128.Fn wcrtomb_l , 129.Fn c16rtomb , 130.Fn c16rtomb_l , 131.Fn c32rtomb , 132and 133.Fn c32rtomb_l 134functions will fail if: 135.Bl -tag -width Er 136.It Bq Er EILSEQ 137An invalid wide character code was specified. 138.It Bq Er EINVAL 139The conversion state is invalid. 140.El 141.Sh SEE ALSO 142.Xr mbrtowc 3 , 143.Xr multibyte 3 , 144.Xr setlocale 3 , 145.Xr wcrtombin 3 , 146.Xr wcrtoutf8 3 , 147.Xr wctomb 3 , 148.Xr xlocale 3 149.Sh STANDARDS 150The 151.Fn wcrtomb , 152.Fn c16rtomb 153and 154.Fn c32rtomb 155functions conform to 156.St -isoC-2011 . 157