locale/FreeBSD/wcwidth.3

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  25 .\" $FreeBSD: src/lib/libc/locale/wcwidth.3,v 1.6 2004/08/17 04:56:03 trhodes Exp $
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  27 .Dd August 17, 2004
  28 .Dt WCWIDTH 3
  29 .Os
  30 .Sh NAME
  31 .Nm wcwidth ,
  32 .Nm wcwidth_l
  33 .Nd "number of column positions of a wide-character code"
  34 .Sh LIBRARY
  35 .Lb libc
  36 .Sh SYNOPSIS
  37 .In wchar.h
  38 .Ft int
  39 .Fo wcwidth
  40 .Fa "wchar_t wc"
  41 .Fc
  42 .In wchar.h
  43 .In xlocale.h
  44 .Ft int
  45 .Fo wcwidth_l
  46 .Fa "wchar_t wc"
  47 .Fa "locale_t loc"
  48 .Fc
  49 .Sh DESCRIPTION
  50 The
  51 .Fn wcwidth
  52 function determines the number of column positions required to
  53 display the wide character
  54 .Fa wc .
  55 .Pp
  56 Although the
  57 .Fn wcwidth
  58 function uses the current locale, the
  59 .Fn wcwidth_l
  60 function may be passed a locale directly. See
  61 .Xr xlocale 3
  62 for more information.
  63 .Sh RETURN VALUES
  64 The
  65 .Fn wcwidth
  66 function returns 0 if the
  67 .Fa wc
  68 argument is a null wide character (L'\e0'),
  69 \-1 if
  70 .Fa wc
  71 is not printable;
  72 otherwise, it returns the number of column positions the
  73 character occupies.
  74 .Sh EXAMPLES
  75 This code fragment reads text from standard input and
  76 breaks lines that are more than 20 column positions wide,
  77 similar to the
  78 .Xr fold 1
  79 utility:
  80 .Bd -literal -offset indent
  81 wint_t ch;
  82 int column, w;
  83
  84 column = 0;
  85 while ((ch = getwchar()) != WEOF) {
  86         w = wcwidth(ch);
  87         if (w > 0 && column + w >= 20) {
  88                 putwchar(L'\en');
  89                 column = 0;
  90         }
  91         putwchar(ch);
  92         if (ch == L'\en')
  93                 column = 0;
  94         else if (w > 0)
  95                 column += w;
  96 }
  97 .Ed
  98 .Sh SEE ALSO
  99 .Xr iswprint 3 ,
 100 .Xr wcswidth 3 ,
 101 .Xr xlocale 3
 102 .Sh STANDARDS
 103 The
 104 .Fn wcwidth
 105 function conforms to
 106 .St -p1003.1-2001 .