wcswidth - determine columns needed for a fixed-size wide-character string
#define _XOPEN_SOURCE /* See feature_test_macros(7) */
#include <wchar.h>
int wcswidth(const wchar_t *s, size_t n);The wcswidth() function returns the number of
columns needed to represent the wide-character string pointed to by
s, but at most n wide characters. If a nonprintable
wide character occurs among these characters, -1 is returned.
The wcswidth() function returns the number of column
positions for the wide-character string s, truncated to at most
length n.