locale/mbtowc.3

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  36 .\" From @(#)multibyte.3        8.1 (Berkeley) 6/4/93
  37 .\" From FreeBSD: src/lib/libc/locale/multibyte.3,v 1.22 2003/11/08 03:23:11 tjr Exp
  38 .\" $FreeBSD: src/lib/libc/locale/mbtowc.3,v 1.4 2004/07/05 06:36:36 ru Exp $
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  40 .Dd April 11, 2004
  41 .Dt MBTOWC 3
  42 .Os
  43 .Sh NAME
  44 .Nm mbtowc ,
  45 .Nm mbtowc_l
  46 .Nd convert a character to a wide-character code
  47 .Sh LIBRARY
  48 .Lb libc
  49 .Sh SYNOPSIS
  50 .In stdlib.h
  51 .Ft int
  52 .Fo mbtowc
  53 .Fa "wchar_t *restrict pwc"
  54 .Fa "const char *restrict s"
  55 .Fa "size_t n"
  56 .Fc
  57 .In stdlib.h
  58 .In xlocale.h
  59 .Ft int
  60 .Fo mbtowc_l
  61 .Fa "wchar_t *restrict pwc"
  62 .Fa "const char *restrict s"
  63 .Fa "size_t n"
  64 .Fa "locale_t loc"
  65 .Fc
  66 .Sh DESCRIPTION
  67 The
  68 .Fn mbtowc
  69 function converts a multibyte character
  70 .Fa s
  71 into a wide character, according to the current conversion state,
  72 and stores the result
  73 in the object pointed to by
  74 .Fa pwc .
  75 Up to
  76 .Fa n
  77 bytes are examined.
  78 .Pp
  79 A call with a null
  80 .Fa s
  81 pointer returns nonzero if the current encoding requires shift states,
  82 zero otherwise;
  83 if shift states are required, the shift state is reset to the initial state.
  84 .Pp
  85 While the
  86 .Fn mbtowc
  87 function uses the current locale, the
  88 .Fn mbtowc_l
  89 function may be passed a locale directly. See
  90 .Xr xlocale 3
  91 for more information.
  92 .Sh RETURN VALUES
  93 If
  94 .Fa s
  95 is
  96 .Dv NULL ,
  97 the
  98 .Fn mbtowc
  99 function returns nonzero if shift states are supported,
 100 zero otherwise.
 101 .Pp
 102 Otherwise, if
 103 .Fa s
 104 is not a null pointer,
 105 .Fn mbtowc
 106 either returns 0 if
 107 .Fa s
 108 represents the null wide character, or returns
 109 the number of bytes processed in
 110 .Fa s ,
 111 or returns \-1 if no multibyte character
 112 could be recognized or converted.
 113 In this case,
 114 .Fn mbtowc Ns 's
 115 internal conversion state is undefined.
 116 .Sh ERRORS
 117 The
 118 .Fn mbtowc
 119 function will fail if:
 120 .Bl -tag -width Er
 121 .It Bq Er EILSEQ
 122 An invalid multibyte sequence was detected.
 123 .It Bq Er EINVAL
 124 The internal conversion state is invalid.
 125 .El
 126 .Sh SEE ALSO
 127 .Xr btowc 3 ,
 128 .Xr mblen 3 ,
 129 .Xr mbrtowc 3 ,
 130 .Xr mbstowcs 3 ,
 131 .Xr multibyte 3 ,
 132 .Xr wctomb 3 ,
 133 .Xr xlocale 3
 134 .Sh STANDARDS
 135 The
 136 .Fn mbtowc
 137 function conforms to
 138 .St -isoC-99 .