diff --git a/src/msw/gsocket.cpp b/src/msw/gsocket.cpp
index 62f3bfb076..353128c754 100644
--- a/src/msw/gsocket.cpp
+++ b/src/msw/gsocket.cpp
@@ -870,9 +870,9 @@ GSocketEventFlags GSocket::Select(GSocketEventFlags flags)
       result |= GSOCK_INPUT_FLAG;
 
       if (m_server && m_stream)
-      { 
-        /* This is a TCP server socket that detected a connection. 
-           While the INPUT_FLAG is also set, it doesn't matter on 
+      {
+        /* This is a TCP server socket that detected a connection.
+           While the INPUT_FLAG is also set, it doesn't matter on
            this kind of  sockets, as we can only Accept() from them. */
         result |= GSOCK_CONNECTION_FLAG;
         m_detected |= GSOCK_CONNECTION_FLAG;
@@ -1451,7 +1451,7 @@ GSocketError GAddress_INET_SetPortName(GAddress *address, const char *port,
   se = getservbyname(port, protocol);
   if (!se)
   {
-    if (isdigit(port[0]))
+    if (isdigit((unsigned char) port[0]))
     {
       int port_int;