diff --git a/dlls/dmusic/collection.c b/dlls/dmusic/collection.c
index 05f67d5578d..8473c0078ec 100644
--- a/dlls/dmusic/collection.c
+++ b/dlls/dmusic/collection.c
@@ -522,7 +522,7 @@ static const IPersistStreamVtbl persiststream_vtbl = {
 };
 
 
-HRESULT WINAPI DMUSIC_CreateDirectMusicCollectionImpl(LPCGUID lpcGUID, LPVOID* ppobj, LPUNKNOWN pUnkOuter)
+HRESULT DMUSIC_CreateDirectMusicCollectionImpl(REFIID lpcGUID, void **ppobj, IUnknown *pUnkOuter)
 {
 	IDirectMusicCollectionImpl* obj;
         HRESULT hr;
diff --git a/dlls/dmusic/dmusic.c b/dlls/dmusic/dmusic.c
index cb94497883e..3a1824143d7 100644
--- a/dlls/dmusic/dmusic.c
+++ b/dlls/dmusic/dmusic.c
@@ -588,7 +588,7 @@ static void create_system_ports_list(IDirectMusic8Impl* object)
 }
 
 /* For ClassFactory */
-HRESULT WINAPI DMUSIC_CreateDirectMusicImpl(LPCGUID riid, LPVOID* ret_iface, LPUNKNOWN unkouter)
+HRESULT DMUSIC_CreateDirectMusicImpl(REFIID riid, void **ret_iface, IUnknown *unkouter)
 {
     IDirectMusic8Impl *dmusic;
     HRESULT ret;
diff --git a/dlls/dmusic/dmusic_main.c b/dlls/dmusic/dmusic_main.c
index 6f69e48d607..5d4939937a9 100644
--- a/dlls/dmusic/dmusic_main.c
+++ b/dlls/dmusic/dmusic_main.c
@@ -43,7 +43,7 @@ LONG DMUSIC_refCount = 0;
 
 typedef struct {
         IClassFactory IClassFactory_iface;
-        HRESULT WINAPI (*fnCreateInstance)(REFIID riid, void **ppv, IUnknown *pUnkOuter);
+        HRESULT (*fnCreateInstance)(REFIID riid, void **ppv, IUnknown *pUnkOuter);
 } IClassFactoryImpl;
 
 /******************************************************************
diff --git a/dlls/dmusic/dmusic_private.h b/dlls/dmusic/dmusic_private.h
index ea6b7482f33..18d3e079b12 100644
--- a/dlls/dmusic/dmusic_private.h
+++ b/dlls/dmusic/dmusic_private.h
@@ -95,8 +95,8 @@ typedef struct instrument_articulation {
  */
 
 /* CLSID */
-extern HRESULT WINAPI DMUSIC_CreateDirectMusicImpl (LPCGUID lpcGUID, LPVOID* ppobj, LPUNKNOWN pUnkOuter) DECLSPEC_HIDDEN;
-extern HRESULT WINAPI DMUSIC_CreateDirectMusicCollectionImpl(LPCGUID lpcGUID, LPVOID* ppobj, LPUNKNOWN pUnkOuter) DECLSPEC_HIDDEN;
+extern HRESULT DMUSIC_CreateDirectMusicImpl(REFIID riid, void **ret_iface, IUnknown *pUnkOuter) DECLSPEC_HIDDEN;
+extern HRESULT DMUSIC_CreateDirectMusicCollectionImpl(REFIID riid, void **ppobj, IUnknown *pUnkOuter) DECLSPEC_HIDDEN;
 
 /* Internal */
 extern HRESULT DMUSIC_CreateDirectMusicBufferImpl(LPDMUS_BUFFERDESC desc, LPVOID* ret_iface) DECLSPEC_HIDDEN;