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Diffstat (limited to 'lib/libc/locale/mbrlen.3')
| -rw-r--r-- | lib/libc/locale/mbrlen.3 | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/lib/libc/locale/mbrlen.3 b/lib/libc/locale/mbrlen.3 new file mode 100644 index 0000000..524d2c7 --- /dev/null +++ b/lib/libc/locale/mbrlen.3 @@ -0,0 +1,145 @@ +.\" Copyright (c) 2002-2004 Tim J. Robbins +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" $FreeBSD$ +.\" +.Dd April 7, 2004 +.Dt MBRLEN 3 +.Os +.Sh NAME +.Nm mbrlen +.Nd "get number of bytes in a character (restartable)" +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In wchar.h +.Ft size_t +.Fn mbrlen "const char * restrict s" "size_t n" "mbstate_t * restrict ps" +.Sh DESCRIPTION +The +.Fn mbrlen +function inspects at most +.Fa n +bytes pointed to by +.Fa s +to determine the number of bytes needed to complete the next +multibyte character. +.Pp +The +.Vt mbstate_t +argument, +.Fa ps , +is used to keep track of the shift state. +If it is +.Dv NULL , +.Fn mbrlen +uses an internal, static +.Vt mbstate_t +object, which is initialized to the initial conversion state +at program startup. +.Pp +It is equivalent to: +.Pp +.Dl "mbrtowc(NULL, s, n, ps);" +.Pp +Except that when +.Fa ps +is a +.Dv NULL +pointer, +.Fn mbrlen +uses its own static, internal +.Vt mbstate_t +object to keep track of the shift state. +.Sh RETURN VALUES +The +.Fn mbrlen +functions returns: +.Bl -tag -width indent +.It 0 +The next +.Fa n +or fewer bytes +represent the null wide character +.Pq Li "L'\e0'" . +.It >0 +The next +.Fa n +or fewer bytes +represent a valid character, +.Fn mbrlen +returns the number of bytes used to complete the multibyte character. +.It Po Vt size_t Pc Ns \-2 +The next +.Fa n +contribute to, but do not complete, a valid multibyte character sequence, +and all +.Fa n +bytes have been processed. +.It Po Vt size_t Pc Ns \-1 +An encoding error has occurred. +The next +.Fa n +or fewer bytes do not contribute to a valid multibyte character. +.El +.Sh EXAMPLES +A function that calculates the number of characters in a multibyte +character string: +.Bd -literal -offset indent +size_t +nchars(const char *s) +{ + size_t charlen, chars; + mbstate_t mbs; + + chars = 0; + memset(&mbs, 0, sizeof(mbs)); + while ((charlen = mbrlen(s, MB_CUR_MAX, &mbs)) != 0 && + charlen != (size_t)-1 && charlen != (size_t)-2) { + s += charlen; + chars++; + } + + return (chars); +} +.Ed +.Sh ERRORS +The +.Fn mbrlen +function will fail if: +.Bl -tag -width Er +.It Bq Er EILSEQ +An invalid multibyte sequence was detected. +.It Bq Er EINVAL +The conversion state is invalid. +.El +.Sh SEE ALSO +.Xr mblen 3 , +.Xr mbrtowc 3 , +.Xr multibyte 3 +.Sh STANDARDS +The +.Fn mbrlen +function conforms to +.St -isoC-99 . |
