diff --git a/src/poc/wcwidth.c b/src/poc/wcwidth.c
index 94b4c5cea..df4bbcbcc 100644
--- a/src/poc/wcwidth.c
+++ b/src/poc/wcwidth.c
@@ -2,15 +2,34 @@
 #include <wchar.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <locale.h>
 
-int main(void){
+int main(int argc, char **argv){
   if(!setlocale(LC_ALL, "")){
     return EXIT_FAILURE;
   }
+  if(argc > 1){
+    while(*++argv){
+      const char* arg = *argv;
+      while(*arg){
+        mbstate_t mbs = {};
+        wchar_t w;
+        size_t conv = mbrtowc(&w, arg, strlen(arg), &mbs);
+        if(conv == (size_t)-1 || conv == (size_t)-2){
+          fprintf(stderr, "Invalid UTF-8: %s\n", arg);
+          return EXIT_FAILURE;
+        }
+        int width = wcwidth(w);
+        printf("w(0x%05x): %d %lc\n", w, width, w);
+        arg += conv;
+      }
+    }
+    return EXIT_SUCCESS;
+  }
   for(int i = 0 ; i < 128 ; ++i){
     wchar_t w = i;
-    printf("w('%02x'): %d%c\t", i, wcwidth(w), iscntrl(i) ? '!' : ' ');
+    printf("w(0x%02x): %d%c\t", i, wcwidth(w), iscntrl(i) ? '!' : ' ');
     if(i % 4 == 3){
       printf("\n");
     }