locale/FreeBSD/mblen.3

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  32 .\" From @(#)multibyte.3        8.1 (Berkeley) 6/4/93
  33 .\" From FreeBSD: src/lib/libc/locale/multibyte.3,v 1.22 2003/11/08 03:23:11 tjr Exp
  34 .\" $FreeBSD: src/lib/libc/locale/mblen.3,v 1.6 2007/01/09 00:28:00 imp Exp $
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  36 .Dd April 11, 2004
  37 .Dt MBLEN 3
  38 .Os
  39 .Sh NAME
  40 .Nm mblen ,
  41 .Nm mblen_l
  42 .Nd get number of bytes in a character
  43 .Sh LIBRARY
  44 .Lb libc
  45 .Sh SYNOPSIS
  46 .In stdlib.h
  47 .Ft int
  48 .Fo mblen
  49 .Fa "const char *s"
  50 .Fa "size_t n"
  51 .Fc
  52 .In stdlib.h
  53 .In xlocale.h
  54 .Ft int
  55 .Fo mblen_l
  56 .Fa "const char *s"
  57 .Fa "size_t n"
  58 .Fa "locale_t loc"
  59 .Fc
  60 .Sh DESCRIPTION
  61 The
  62 .Fn mblen
  63 function computes the length, in bytes,
  64 of a multibyte character
  65 .Fa s ,
  66 according to the current conversion state.
  67 Up to
  68 .Fa n
  69 bytes are examined.
  70 .Pp
  71 A call with a null
  72 .Fa s
  73 pointer returns nonzero if the current locale requires shift states,
  74 zero otherwise.
  75 If shift states are required, the shift state is reset to the initial state.
  76 .Pp
  77 Although the
  78 .Fn mblen
  79 function uses the current locale, the
  80 .Fn mblen_l
  81 function may be passed a locale directly. See
  82 .Xr xlocale 3
  83 for more information.
  84 .Sh RETURN VALUES
  85 If
  86 .Fa s
  87 is
  88 .Dv NULL ,
  89 the
  90 .Fn mblen
  91 function returns nonzero if shift states are supported,
  92 zero otherwise.
  93 .Pp
  94 Otherwise, if
  95 .Fa s
  96 is not a null pointer,
  97 .Fn mblen
  98 either returns 0 if
  99 .Fa s
 100 represents the null wide character, or returns
 101 the number of bytes processed in
 102 .Fa s ,
 103 or returns \-1 if no multibyte character
 104 could be recognized or converted.
 105 In this case,
 106 .Fn mblen Ns 's
 107 internal conversion state is undefined.
 108 .Sh ERRORS
 109 The
 110 .Fn mblen
 111 function will fail if:
 112 .Bl -tag -width Er
 113 .It Bq Er EILSEQ
 114 An invalid multibyte sequence was detected.
 115 .It Bq Er EINVAL
 116 The internal conversion state is not valid.
 117 .El
 118 .Sh SEE ALSO
 119 .Xr mbrlen 3 ,
 120 .Xr mbtowc 3 ,
 121 .Xr multibyte 3 ,
 122 .Xr xlocale 3
 123 .Sh STANDARDS
 124 The
 125 .Fn mblen
 126 function conforms to
 127 .St -isoC-99 .