diff --git a/dlls/dswave/dswave_private.h b/dlls/dswave/dswave_private.h
index c2c1f4b2e1..6f402d768d 100644
--- a/dlls/dswave/dswave_private.h
+++ b/dlls/dswave/dswave_private.h
@@ -48,7 +48,7 @@ typedef struct IDirectMusicWaveImpl IDirectMusicWaveImpl;
 /*****************************************************************************
  * ClassFactory
  */
-extern HRESULT WINAPI DMUSIC_CreateDirectMusicWaveImpl (LPCGUID lpcGUID, LPVOID* ppobj, LPUNKNOWN pUnkOuter);
+extern HRESULT WINAPI DMUSIC_CreateDirectMusicWaveImpl (LPCGUID lpcGUID, LPVOID* ppobj, LPUNKNOWN pUnkOuter) DECLSPEC_HIDDEN;
 
 
 /*****************************************************************************
@@ -70,7 +70,7 @@ struct IDirectMusicWaveImpl {
 /**********************************************************************
  * Dll lifetime tracking declaration for dswave.dll
  */
-extern LONG DSWAVE_refCount;
+extern LONG DSWAVE_refCount DECLSPEC_HIDDEN;
 static inline void DSWAVE_LockModule(void) { InterlockedIncrement( &DSWAVE_refCount ); }
 static inline void DSWAVE_UnlockModule(void) { InterlockedDecrement( &DSWAVE_refCount ); }
 
@@ -107,10 +107,10 @@ typedef struct {
 #define ICOM_THIS_MULTI(impl,field,iface) impl* const This=(impl*)((char*)(iface) - offsetof(impl,field))
 
 /* FOURCC to string conversion for debug messages */
-extern const char *debugstr_fourcc (DWORD fourcc);
+extern const char *debugstr_fourcc (DWORD fourcc) DECLSPEC_HIDDEN;
 /* returns name of given GUID */
-extern const char *debugstr_dmguid (const GUID *id);
+extern const char *debugstr_dmguid (const GUID *id) DECLSPEC_HIDDEN;
 /* dump whole DMUS_OBJECTDESC struct */
-extern const char *debugstr_DMUS_OBJECTDESC (LPDMUS_OBJECTDESC pDesc);
+extern const char *debugstr_DMUS_OBJECTDESC (LPDMUS_OBJECTDESC pDesc) DECLSPEC_HIDDEN;
 
 #endif	/* __WINE_DSWAVE_PRIVATE_H */