C/C++ では、 iswpunct() 関数の機能は、ワイド文字が句読点であるかどうかを判断することです。

int iswpunct(wint_t character);

#include<cwctype>
#include<stdio.h>
using namespace std;
int main() {
   wint_t a = &#39;!&#39;;
   wint_t b = &#39;a&#39;;
   if(iswpunct(a))
   printf("The character is a punctuation.");
   else
   printf("\nThe character is not a punctuation.");
   if(iswpunct(b))
   printf("\nThe character is a punctuation.");
   else
   printf("\nThe character is not a punctuation.");
   return 0;
}

The character is a punctuation.
The character is not a punctuation.