1.\" Copyright (c) 2002 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.\" $FreeBSD$ 26.\" 27.Dd November 11, 2002 28.Dt MBRLEN 3 29.Os 30.Sh NAME 31.Nm mbrlen 32.Nd "get number of bytes in a character (restartable)" 33.Sh LIBRARY 34.Lb libc 35.Sh SYNOPSIS 36.In wchar.h 37.Ft size_t 38.Fn mbrlen "const char * restrict s" "size_t n" "mbstate_t * restrict ps" 39.Sh DESCRIPTION 40The 41.Fn mbrlen 42function determines the number of bytes constituting the 43multibyte character sequence pointed to by 44.Fa s , 45examining at most 46.Fa n 47bytes. 48.Pp 49The 50.Vt mbstate_t 51argument, 52.Fa ps , 53is used to keep track of the shift state. 54If it is 55.Dv NULL , 56.Fn mbrlen 57uses an internal, static 58.Vt mbstate_t 59object. 60.Pp 61It is equivalent to: 62.Pp 63.Dl "mbrtowc(NULL, s, n, ps);" 64.Pp 65Except that when 66.Fa ps 67is a 68.Dv NULL 69pointer, 70.Fn mbrlen 71uses its own static, internal 72.Vt mbstate_t 73object to keep track of the shift state. 74.Sh RETURN VALUES 75The 76.Fn mbrlen 77functions returns: 78.Bl -tag -width indent 79.It 0 80The first 81.Fa n 82or fewer bytes of 83.Fa s 84represent the null wide character 85.Pq Li "L'\e0'" . 86.It >0 87The first 88.Fa n 89or fewer bytes of 90.Fa s 91represent a valid character, 92.Fn mbrtowc 93returns the length (in bytes) of the multibyte sequence. 94.It Po Vt size_t Pc Ns \-2 95The first 96.Fa n 97bytes of 98.Fa s 99are an incomplete multibyte sequence. 100.It Po Vt size_t Pc Ns \-1 101The byte sequence pointed to by 102.Fa s 103is an invalid multibyte sequence. 104.El 105.Sh EXAMPLES 106A function which calculates the number of characters in a multibyte 107character string: 108.Bd -literal -offset indent 109size_t 110nchars(const char *s) 111{ 112 size_t charlen, chars; 113 mbstate_t mbs; 114 115 chars = 0; 116 memset(&mbs, 0, sizeof(mbs)); 117 while ((charlen = mbrlen(s, MB_CUR_MAX, &mbs)) != 0 && 118 charlen != (size_t)-1 && charlen != (size_t)-2) { 119 s += charlen; 120 chars++; 121 } 122 123 return (chars); 124} 125.Ed 126.Sh ERRORS 127The 128.Fn mbrlen 129function will fail if: 130.Bl -tag -width Er 131.\".It Bq Er EINVAL 132.\"Invalid argument. 133.It Bq Er EILSEQ 134An invalid multibyte sequence was detected. 135.El 136.Sh SEE ALSO 137.Xr mblen 3 , 138.Xr mbrtowc 3 139.Sh STANDARDS 140The 141.Fn mbrlen 142function conforms to 143.St -isoC-99 . 144.Sh BUGS 145The current implementation does not support shift states. 146