locale/FreeBSD/mbtowc.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/mbtowc.3,v 1.5 2007/01/09 00:28:00 imp Exp $
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  36 .Dd April 11, 2004
  37 .Dt MBTOWC 3
  38 .Os
  39 .Sh NAME
  40 .Nm mbtowc ,
  41 .Nm mbtowc_l
  42 .Nd convert a character to a wide-character code
  43 .Sh LIBRARY
  44 .Lb libc
  45 .Sh SYNOPSIS
  46 .In stdlib.h
  47 .Ft int
  48 .Fo mbtowc
  49 .Fa "wchar_t *restrict pwc"
  50 .Fa "const char *restrict s"
  51 .Fa "size_t n"
  52 .Fc
  53 .In stdlib.h
  54 .In xlocale.h
  55 .Ft int
  56 .Fo mbtowc_l
  57 .Fa "wchar_t *restrict pwc"
  58 .Fa "const char *restrict s"
  59 .Fa "size_t n"
  60 .Fa "locale_t loc"
  61 .Fc
  62 .Sh DESCRIPTION
  63 The
  64 .Fn mbtowc
  65 function converts a multibyte character
  66 .Fa s
  67 into a wide character, according to the current conversion state,
  68 and stores the result
  69 in the object pointed to by
  70 .Fa pwc .
  71 Up to
  72 .Fa n
  73 bytes are examined.
  74 .Pp
  75 A call with a null
  76 .Fa s
  77 pointer returns nonzero if the current encoding requires shift states,
  78 zero otherwise;
  79 if shift states are required, the shift state is reset to the initial state.
  80 .Pp
  81 While the
  82 .Fn mbtowc
  83 function uses the current locale, the
  84 .Fn mbtowc_l
  85 function may be passed a locale directly. See
  86 .Xr xlocale 3
  87 for more information.
  88 .Sh RETURN VALUES
  89 If
  90 .Fa s
  91 is
  92 .Dv NULL ,
  93 the
  94 .Fn mbtowc
  95 function returns nonzero if shift states are supported,
  96 zero otherwise.
  97 .Pp
  98 Otherwise, if
  99 .Fa s
 100 is not a null pointer,
 101 .Fn mbtowc
 102 either returns 0 if
 103 .Fa s
 104 represents the null wide character, or returns
 105 the number of bytes processed in
 106 .Fa s ,
 107 or returns \-1 if no multibyte character
 108 could be recognized or converted.
 109 In this case,
 110 .Fn mbtowc Ns 's
 111 internal conversion state is undefined.
 112 .Sh ERRORS
 113 The
 114 .Fn mbtowc
 115 function will fail if:
 116 .Bl -tag -width Er
 117 .It Bq Er EILSEQ
 118 An invalid multibyte sequence was detected.
 119 .It Bq Er EINVAL
 120 The internal conversion state is invalid.
 121 .El
 122 .Sh SEE ALSO
 123 .Xr btowc 3 ,
 124 .Xr mblen 3 ,
 125 .Xr mbrtowc 3 ,
 126 .Xr mbstowcs 3 ,
 127 .Xr multibyte 3 ,
 128 .Xr wctomb 3 ,
 129 .Xr xlocale 3
 130 .Sh STANDARDS
 131 The
 132 .Fn mbtowc
 133 function conforms to
 134 .St -isoC-99 .