diff --git a/lib/curl_setup.h b/lib/curl_setup.h
index c4be90b655..829650aee4 100644
--- a/lib/curl_setup.h
+++ b/lib/curl_setup.h
@@ -519,9 +519,13 @@
 #endif
 
 #if SIZEOF_CURL_SOCKET_T < 8
+#ifdef _WIN32
+#  define FMT_SOCKET_T "u"
+#else
 #  define FMT_SOCKET_T "d"
-#elif defined(__MINGW32__)
-#  define FMT_SOCKET_T "zd"
+#endif
+#elif defined(_WIN32)
+#  define FMT_SOCKET_T "zu"
 #else
 #  define FMT_SOCKET_T "qd"
 #endif