ok, even if the locale is C, unicode is most often supported.

os/chartypes.c

@@ -101,7 +101,7 @@ Term Yap_StringToNumberTerm(char *s, encoding_t *encp) {
 
 const char *encvs[] = {"LANG", "LC_ALL", "LC_CTYPE", NULL};
 
-// wher we can fins an encoding
+// where we can fins an encoding
 typedef struct enc_map {
   const char *s;
   encoding_t e;
@@ -124,43 +124,45 @@ static enc_map_t ematches[] = {
   #endif
 };
 
+static encoding_t enc_os_default( encoding_t rc)\
+{
+  // by default, return UTF-8
+  // except in _WIN32
+  // note that we match the C locale to UTF8/16, as all Unix maachines will work on UNICODE.
+
+  if (rc == ENC_ISO_ASCII) {
+#ifdef _WIN32
+      return = ENC_UTF16_BE;
+#else
+      return ENC_ISO_UTF8;
+#endif
+    }
+  return rc;
+}
+
 static encoding_t DefaultEncoding(void) {
-  encoding_t rc;
+  int i = 0;
-  int i = 0, j;
-  char *enc;
   while (encvs[i]) {
       char *v = getenv(encvs[i]);
       if (v) {
-      enc = strrchr(v, '.');
+          int j = 0;
-      /* that's how it is supposed to be, except in OSX */
+          size_t sz = strlen(v);
-      if (!enc)
+          const char *coding;
-        enc = v;
+          while ((coding = ematches[j].s) != NULL) {
-      else
+              size_t sz2 = strlen(coding);
-        enc++;
+              if (sz2 > sz) {
-      // now that we have one name, try to match it
+                  j++;
-      j = 0;
+                  continue;
-      while (ematches[j].s) {
+                }
-        if (!strcmp(ematches[j].s, enc))
+              if (!strcmp(coding+(sz-sz2), v) ) {
-          return ematches[j].e;
+                  return enc_os_default(ematches[j].e);
+                }
               j++;
             }
         }
       i++;
     }
-// by default, return UTF-8
+  return enc_os_default(ENC_ISO_ASCII);
-// except in _WIN32
-#ifdef _WIN32
-  rc = ENC_UTF16_BE;
-#else
-  rc = ENC_ISO_UTF8;
-#endif
-  {
-    int j = 0;
-    while (rc != ematches[j].e)
-      j++;
-    //    Yap_Warning("YAP will use default encoding %s", ematches[j].s);
-  }
-  return rc;
 }
 
 encoding_t Yap_DefaultEncoding(void) {