/*FUNCTION	<<wcswidth>>---number of column positions of a wide-character string	INDEX	wcswidthANSI_SYNOPSIS	#include <wchar.h>	int wcswidth(const wchar_t *<[pwcs]>, size_t <[n]>);TRAD_SYNOPSIS	#include <wchar.h>	int wcswidth(<[pwcs]>, <[n]>)	wchar_t *<[wc]>;	size_t <[n]>;DESCRIPTION	The <<wcswidth>> function shall determine the number of column	positions required for n wide-character codes (or fewer than n	wide-character codes if a null wide-character code is encountered	before n wide-character codes are exhausted) in the string pointed	to by pwcs.RETURNS	The <<wcswidth>> function either shall return 0 (if pwcs points to a	null wide-character code), or return the number of column positions	to be occupied by the wide-character string pointed to by pwcs, or	return -1 (if any of the first n wide-character codes in the	wide-character string pointed to by pwcs is not a printable	wide-character code).PORTABILITY<<wcswidth>> has been introduced in the Single UNIX Specification Volume 2<<wcswidth>> has been marked as extension in Single UNIX Specification Volume 3*/#include <_ansi.h>#include <wchar.h>int_DEFUN (wcswidth, (pwcs, n),	_CONST wchar_t *pwcs _AND	size_t n){  int w, len = 0;  if (!pwcs || n == 0)    return 0;  do {    if ((w = wcwidth (*pwcs)) < 0)      return -1;    len += w;  } while (*pwcs++ && --n > 0);  return len;}