locale/FreeBSD/wcwidth.3

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  27 .Dd August 17, 2004
  28 .Dt WCWIDTH 3
  29 .Os
  30 .Sh NAME
  31 .Nm wcwidth
  32 .Nd "number of column positions of a wide-character code"
  33 .Sh LIBRARY
  34 .Lb libc
  35 .Sh SYNOPSIS
  36 .In wchar.h
  37 .Ft int
  38 .Fn wcwidth "wchar_t wc"
  39 .Sh DESCRIPTION
  40 The
  41 .Fn wcwidth
  42 function determines the number of column positions required to
  43 display the wide character
  44 .Fa wc .
  45 .Sh RETURN VALUES
  46 The
  47 .Fn wcwidth
  48 function returns 0 if the
  49 .Fa wc
  50 argument is a null wide character (L'\e0'),
  51 \-1 if
  52 .Fa wc
  53 is not printable,
  54 otherwise it returns the number of column positions the
  55 character occupies.
  56 .Sh EXAMPLES
  57 This code fragment reads text from standard input and
  58 breaks lines that are more than 20 column positions wide,
  59 similar to the
  60 .Xr fold 1
  61 utility:
  62 .Bd -literal -offset indent
  63 wint_t ch;
  64 int column, w;
  65
  66 column = 0;
  67 while ((ch = getwchar()) != WEOF) {
  68         w = wcwidth(ch);
  69         if (w > 0 && column + w >= 20) {
  70                 putwchar(L'\en');
  71                 column = 0;
  72         }
  73         putwchar(ch);
  74         if (ch == L'\en')
  75                 column = 0;
  76         else if (w > 0)
  77                 column += w;
  78 }
  79 .Ed
  80 .Sh SEE ALSO
  81 .Xr iswprint 3 ,
  82 .Xr wcswidth 3
  83 .Sh STANDARDS
  84 The
  85 .Fn wcwidth
  86 function conforms to
  87 .St -p1003.1-2001 .