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WCWIDTH(3) Library Functions Manual WCWIDTH(3)

wcwidth, wcwidth_lnumber of column positions of a wide-character code

library “libc”

#include <wchar.h>

int
wcwidth(wchar_t wc);

#include <xlocale.h>

int
wcwidth_l(wchar_t wc, locale_t locale);

The () and wcwidth_l() functions determine the number of column positions required to display the wide character wc.

The () function takes an explicit locale argument, whereas the wcwidth() function uses the current global or per-thread locale.

The wcwidth() and wcwidth_l() functions return 0 if the wc argument is a null wide character (L'\0'), -1 if wc is not printable, otherwise they return the number of column positions the character occupies.

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

wint_t ch;
int column, w;

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

iswprint(3), wcswidth(3), xlocale(3)

The wcwidth() function conforms to IEEE Std 1003.1-2001 (“POSIX.1”).

December 27, 2013 DragonFly-5.6.1