#16306: Fix multiple error messages when unknown command line parameters where passed to the interpreter.  Patch by Hieu Nguyen.
diff --git a/Python/getopt.c b/Python/getopt.c
index cc42431..037aa5d 100644
--- a/Python/getopt.c
+++ b/Python/getopt.c
@@ -45,7 +45,7 @@
 
 void _PyOS_ResetGetOpt(void)
 {
-    _PyOS_opterr = 1;
+    _PyOS_opterr = 0;  /* prevent printing the error in 2nd loop in main.c */
     _PyOS_optind = 1;
     _PyOS_optarg = NULL;
     opt_ptr = L"";
@@ -90,18 +90,18 @@
         opt_ptr = &argv[_PyOS_optind++][1];
     }
 
-    if ( (option = *opt_ptr++) == L'\0')
+    if ((option = *opt_ptr++) == L'\0')
         return -1;
 
     if (option == 'J') {
-        fprintf(stderr, "-J is reserved for Jython\n");
+        if (_PyOS_opterr)
+            fprintf(stderr, "-J is reserved for Jython\n");
         return '_';
     }
 
     if ((ptr = wcschr(optstring, option)) == NULL) {
         if (_PyOS_opterr)
-          fprintf(stderr, "Unknown option: -%c\n", (char)option);
-
+            fprintf(stderr, "Unknown option: -%c\n", (char)option);
         return '_';
     }