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 November 11, 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 , 44examining at most 45.Fa n 46bytes. 47.Pp 48The 49.Ft mbstate_t 50argument, 51.Fa ps , 52is used to keep track of the shift state. 53If it is 54.Dv NULL , 55.Fn mbrlen 56uses an internal, static 57.Ft mbstate_t 58object. 59.Pp 60It is equivalent to: 61.Pp 62.Dl "mbrtowc(NULL, s, n, ps);" 63.Pp 64Except that when 65.Fa ps 66is a NULL pointer, 67.Fn mbrlen 68uses its own static, internal 69.Ft mbstate_t 70object to keep track of shift state. 71.Sh RETURN VALUES 72The 73.Fn mbrlen 74functions returns: 75.Bl -tag -width indent 76.It 0 77The first 78.Fa n 79or fewer bytes of 80.Fa s 81represent the null wide character (L'\e0'). 82.It >0 83The first 84.Fa n 85or fewer bytes of 86.Fa s 87represent a valid character, 88.Fn mbrtowc 89returns the length (in bytes) of the multibyte sequence. 90.It Xo 91.No ( Ns 92.Ft size_t Ns 93.No ) Ns \&-2 94.Xc 95The first 96.Fa n 97bytes of 98.Fa s 99are an incomplete multibyte sequence. 100.It Xo 101.No ( Ns 102.Ft size_t Ns 103.No ) Ns \&-1 104.Xc 105The byte sequence pointed to by 106.Fa s 107is an invalid multibyte sequence. 108.El 109.Sh EXAMPLES 110A function which calculates the number of characters in a multibyte 111character string: 112.Bd -literal -offset indent 113size_t 114nchars(const char *s) 115{ 116 size_t charlen, chars; 117 mbstate_t mbs; 118 119 chars = 0; 120 memset(&mbs, 0, sizeof(mbs)); 121 while ((charlen = mbrlen(s, MB_CUR_MAX, &mbs)) != 0 && 122 charlen != (size_t)-1 && charlen != (size_t)-2) { 123 s += charlen; 124 chars++; 125 } 126 127 return (chars); 128} 129.Ed 130.Sh ERRORS 131The 132.Fn mbrlen 133function will fail if: 134.Bl -tag -width Er 135.\".It Bq Er EINVAL 136.\"Invalid argument. 137.It Bq Er EILSEQ 138An invalid multibyte sequence was detected. 139.El 140.Sh SEE ALSO 141.Xr mblen 3 , 142.Xr mbrtowc 3 143.Sh STANDARDS 144The 145.Fn mbrlen 146function conforms to 147.St -isoC-99 . 148.Sh BUGS 149The current implementation does not support shift states. 150