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.Dd October 4, 2002 27.Dt MBRLEN 3 28.Os 29.Sh NAME 30.Nm mbrlen 31.Nd "get number of bytes in a character (restartable)" 32.Sh LIBRARY 33.Lb libc 34.Sh SYNOPSIS 35.In wchar.h 36.Ft size_t 37.Fn mbrlen "const char * restrict s" "size_t n" "mbstate_t * restrict ps" 38.Sh DESCRIPTION 39The 40.Fn mbrlen 41function determines the the number of bytes constituting the 42multibyte character sequence pointed to by 43.Fa s . 44.Pp 45It is equivalent to: 46.Pp 47.Dl "mbrtowc(NULL, s, n, ps);" 48.Pp 49Except that when 50.Fa ps 51is a NULL pointer, 52.Fn mbrlen 53uses its own static, internal 54.Ft mbstate_t 55object to keep track of shift state. 56.Sh RETURN VALUES 57The 58.Fn mbrlen 59functions returns: 60.Bl -tag -width indent 61.It 0 62The first 63.Fa n 64or fewer bytes of 65.Fa s 66represent the null wide character (L'\e0'). 67.It >0 68The first 69.Fa n 70or fewer bytes of 71.Fa s 72represent a valid character, 73.Fn mbrtowc 74returns the length (in bytes) of the multibyte sequence. 75.It Xo 76.No ( Ns 77.Ft size_t Ns 78.No ) Ns \&-2 79.Xc 80The first 81.Fa n 82bytes of 83.Fa s 84are an incomplete multibyte sequence. 85.It Xo 86.No ( Ns 87.Ft size_t Ns 88.No ) Ns \&-1 89.Xc 90The byte sequence pointed to by 91.Fa s 92is an invalid multibyte sequence. 93.El 94.Sh EXAMPLES 95A function which calculates the number of characters in a multibyte 96character string: 97.Bd -literal -offset indent 98size_t 99nchars(const char *s) 100{ 101 size_t charlen, chars; 102 mbstate_t mbs; 103 104 chars = 0; 105 memset(&mbs, 0, sizeof(mbs)); 106 while ((charlen = mbrlen(s, MB_CUR_MAX, &mbs)) != 0 && 107 charlen != (size_t)-1 && charlen != (size_t)-2) { 108 s += charlen; 109 chars++; 110 } 111 112 return (chars); 113} 114.Ed 115.Sh ERRORS 116The 117.Fn mbrlen 118function will fail if: 119.Bl -tag -width Er 120.\".It Bq Er EINVAL 121.\"Invalid argument. 122.It Bq Er EILSEQ 123An invalid multibyte sequence was detected. 124.El 125.Sh SEE ALSO 126.Xr mblen 3 , 127.Xr mbrtowc 3 128.Sh STANDARDS 129The 130.Fn mbrlen 131function conforms to 132.St -isoC-99 . 133.Sh BUGS 134The current implementation does not support shift states. 135