diff --git a/windows/winmme/JackWinMMEInputPort.cpp b/windows/winmme/JackWinMMEInputPort.cpp
index 395980c0..df1db58e 100644
--- a/windows/winmme/JackWinMMEInputPort.cpp
+++ b/windows/winmme/JackWinMMEInputPort.cpp
@@ -35,8 +35,9 @@ using Jack::JackWinMMEInputPort;
 
 void CALLBACK
 JackWinMMEInputPort::HandleMidiInputEvent(HMIDIIN handle, UINT message,
-                                          DWORD port, DWORD param1,
-                                          DWORD param2)
+                                          DWORD_PTR port,
+                                          DWORD_PTR param1,
+                                          DWORD_PTR param2)
 {
     ((JackWinMMEInputPort *) port)->ProcessWinMME(message, param1, param2);
 }
@@ -201,7 +202,7 @@ JackWinMMEInputPort::ProcessJack(JackMidiBuffer *port_buffer,
 }
 
 void
-JackWinMMEInputPort::ProcessWinMME(UINT message, DWORD param1, DWORD param2)
+JackWinMMEInputPort::ProcessWinMME(UINT message, DWORD_PTR param1, DWORD_PTR param2)
 {
     set_threaded_log_function();
     switch (message) {
diff --git a/windows/winmme/JackWinMMEInputPort.h b/windows/winmme/JackWinMMEInputPort.h
index 74571068..98f8a18a 100644
--- a/windows/winmme/JackWinMMEInputPort.h
+++ b/windows/winmme/JackWinMMEInputPort.h
@@ -33,8 +33,10 @@ namespace Jack {
     private:
 
         static void CALLBACK
-        HandleMidiInputEvent(HMIDIIN handle, UINT message, DWORD port,
-                             DWORD param1, DWORD param2);
+        HandleMidiInputEvent(HMIDIIN handle, UINT message,
+                             DWORD_PTR port,
+                             DWORD_PTR param1,
+                             DWORD_PTR param2);
 
         void
         EnqueueMessage(DWORD timestamp, size_t length, jack_midi_data_t *data);
@@ -43,7 +45,7 @@ namespace Jack {
         GetInErrorString(MMRESULT error, LPTSTR text);
 
         void
-        ProcessWinMME(UINT message, DWORD param1, DWORD param2);
+        ProcessWinMME(UINT message, DWORD_PTR param1, DWORD_PTR param2);
 
         void
         WriteInError(const char *jack_func, const char *mm_func,
diff --git a/windows/winmme/JackWinMMEPort.cpp b/windows/winmme/JackWinMMEPort.cpp
index 1fb233fd..39f33864 100644
--- a/windows/winmme/JackWinMMEPort.cpp
+++ b/windows/winmme/JackWinMMEPort.cpp
@@ -31,7 +31,11 @@ using Jack::JackWinMMEPort;
 ///////////////////////////////////////////////////////////////////////////////
 
 JackWinMMEPort::JackWinMMEPort()
-{}
+{
+     memset(alias, 0, sizeof(alias));
+     memset(name, 0, sizeof(name));
+     memset(device_name, 0, sizeof(device_name));
+}
 
 JackWinMMEPort::~JackWinMMEPort()
 {}