osx man page for wcwidth

WCWIDTH(3)						   BSD Library Functions Manual 						WCWIDTH(3)

NAME
     wcwidth, wcwidth_l -- number of column positions of a wide-character code

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <wchar.h>

     int
     wcwidth(wchar_t wc);

     #include <wchar.h>
     #include <xlocale.h>

     int
     wcwidth_l(wchar_t wc, locale_t loc);

DESCRIPTION
     The wcwidth() function determines the number of column positions required to display the wide character wc.

     Although the wcwidth() function uses the current locale, the wcwidth_l() function may be passed a locale directly. See xlocale(3) for more
     information.

RETURN VALUES
     The wcwidth() function returns 0 if the wc argument is a null wide character (L''), -1 if wc is not printable; otherwise, it returns the
     number of column positions the character occupies.

EXAMPLES
     This code fragment reads text from standard input and breaks lines that are more than 20 column positions wide, similar to the fold(1) util-
     ity:

	   wint_t ch;
	   int column, w;

	   column = 0;
	   while ((ch = getwchar()) != WEOF) {
		   w = wcwidth(ch);
		   if (w > 0 && column + w >= 20) {
			   putwchar(L'
');
			   column = 0;
		   }
		   putwchar(ch);
		   if (ch == L'
')
			   column = 0;
		   else if (w > 0)
			   column += w;
	   }

SEE ALSO
     iswprint(3), wcswidth(3), xlocale(3)

STANDARDS
     The wcwidth() function conforms to IEEE Std 1003.1-2001 (``POSIX.1'').

BSD
								  August 17, 2004							       BSD