The com_interface attribute is not needed on derived classes.

dlls/ole32/ole16.c

@@ -139,7 +139,7 @@ VOID WINAPI IMalloc16_fnFree(IMalloc16* iface,SEGPTR pv)
  */
 DWORD WINAPI IMalloc16_fnGetSize(const IMalloc16* iface,SEGPTR pv)
 {
-	ICOM_CTHIS(IMalloc16Impl,iface);
+	ICOM_THIS(IMalloc16Impl,iface);
         TRACE("(%p)->GetSize(%08lx)\n",This,pv);
         return HeapSize( GetProcessHeap(), 0, MapSL(pv) );
 }
@@ -148,7 +148,7 @@ DWORD WINAPI IMalloc16_fnGetSize(const IMalloc16* iface,SEGPTR pv)
  * IMalloc16_DidAlloc [COMPOBJ.507]
  */
 INT16 WINAPI IMalloc16_fnDidAlloc(const IMalloc16* iface,LPVOID pv) {
-        ICOM_CTHIS(IMalloc16,iface);
+        ICOM_THIS(IMalloc16,iface);
 	TRACE("(%p)->DidAlloc(%p)\n",This,pv);
 	return (INT16)-1;
 }

include/objbase.h

@@ -246,7 +246,11 @@
 #define THIS   void
 
 #define interface struct
+#ifdef ICOM_USE_COM_INTERFACE_ATTRIBUTE
+#define DECLARE_INTERFACE(iface)        interface __attribute__((com_interface)) iface
+#else
 #define DECLARE_INTERFACE(iface)        interface iface
+#endif
 #define DECLARE_INTERFACE_(iface,ibase) interface iface : public ibase
 
 #define BEGIN_INTERFACE
@@ -293,17 +297,11 @@
 
 /* Wine-specific macros */
 
-#define ICOM_DEFINE(iface,ibase) \
-    DECLARE_INTERFACE_(iface,ibase) { iface##_METHODS } ICOM_COM_INTERFACE_ATTRIBUTE;
-
+#define ICOM_DEFINE(iface,ibase) DECLARE_INTERFACE_(iface,ibase) { iface##_METHODS };
 #define ICOM_VTABLE(iface)       iface##Vtbl
 #define ICOM_VFIELD(iface)       ICOM_VTABLE(iface)* lpVtbl
-
-#define ICOM_THIS(impl,iface)          impl* const This=(impl*)(iface)
-#define ICOM_CTHIS(impl,iface)         const impl* const This=(const impl*)(iface)
-
+#define ICOM_THIS(impl,iface)    impl* const This=(impl*)(iface)
 #define ICOM_THIS_MULTI(impl,field,iface)  impl* const This=(impl*)((char*)(iface) - offsetof(impl,field))
-#define ICOM_CTHIS_MULTI(impl,field,iface) const impl* const This=(const impl*)((char*)(iface) - offsetof(impl,field))
 
 #include "objidl.h"
 

include/unknwn.h

@@ -8,11 +8,6 @@
 extern "C" {
 #endif
 #include "wtypes.h"
-#if defined(ICOM_USE_COM_INTERFACE_ATTRIBUTE) && defined(__cplusplus) && !defined(CINTERFACE)
-# define ICOM_COM_INTERFACE_ATTRIBUTE __attribute__((com_interface))
-#else
-# define ICOM_COM_INTERFACE_ATTRIBUTE
-#endif
 #if defined(ICOM_MSVTABLE_COMPAT) && (!defined(__cplusplus) || defined(CINTERFACE))
 # define ICOM_MSVTABLE_COMPAT_FIELDS long dummyRTTI1,dummyRTTI2;
 # define ICOM_MSVTABLE_COMPAT_DummyRTTIVALUE 0,0,
@@ -28,8 +23,12 @@ typedef IUnknown *LPUNKNOWN;
  */
 DEFINE_GUID(IID_IUnknown, 0x00000000, 0x0000, 0x0000, 0xc0,0x00, 0x00,0x00,0x00,0x00,0x00,0x46);
 #if defined(__cplusplus) && !defined(CINTERFACE)
-struct IUnknown {
-
+#ifdef ICOM_USE_COM_INTERFACE_ATTRIBUTE
+struct __attribute__((com_interface)) IUnknown
+#else
+struct IUnknown
+#endif
+{
     virtual HRESULT STDMETHODCALLTYPE QueryInterface(
         REFIID riid,
         void** ppvObject) = 0;
@@ -40,7 +39,7 @@ struct IUnknown {
     virtual ULONG STDMETHODCALLTYPE Release(
         ) = 0;
 
-} ICOM_COM_INTERFACE_ATTRIBUTE;
+};
 #else
 typedef struct IUnknownVtbl IUnknownVtbl;
 struct IUnknown {
@@ -109,8 +108,8 @@ typedef IClassFactory *LPCLASSFACTORY;
  */
 DEFINE_GUID(IID_IClassFactory, 0x00000001, 0x0000, 0x0000, 0xc0,0x00, 0x00,0x00,0x00,0x00,0x00,0x46);
 #if defined(__cplusplus) && !defined(CINTERFACE)
-struct IClassFactory: IUnknown {
-
+struct IClassFactory : public IUnknown
+{
     virtual HRESULT STDMETHODCALLTYPE CreateInstance(
         IUnknown* pUnkOuter,
         REFIID riid,
@@ -119,7 +118,7 @@ struct IClassFactory: IUnknown {
     virtual HRESULT STDMETHODCALLTYPE LockServer(
         BOOL fLock) = 0;
 
-} ICOM_COM_INTERFACE_ATTRIBUTE;
+};
 #else
 typedef struct IClassFactoryVtbl IClassFactoryVtbl;
 struct IClassFactory {

include/unknwn.idl

@@ -21,11 +21,6 @@ import "wtypes.idl";
 /* COM vtable compatibility macros for g++ */
 /* Included here because the generated header needs them */
 
-cpp_quote("#if defined(ICOM_USE_COM_INTERFACE_ATTRIBUTE) && defined(__cplusplus) && !defined(CINTERFACE)")
-cpp_quote("# define ICOM_COM_INTERFACE_ATTRIBUTE __attribute__((com_interface))")
-cpp_quote("#else")
-cpp_quote("# define ICOM_COM_INTERFACE_ATTRIBUTE")
-cpp_quote("#endif")
 cpp_quote("#if defined(ICOM_MSVTABLE_COMPAT) && (!defined(__cplusplus) || defined(CINTERFACE))")
 cpp_quote("# define ICOM_MSVTABLE_COMPAT_FIELDS long dummyRTTI1,dummyRTTI2;")
 cpp_quote("# define ICOM_MSVTABLE_COMPAT_DummyRTTIVALUE 0,0,")

tools/widl/header.c

@@ -688,15 +688,21 @@ void write_com_interface(type_t *iface)
   write_forward(iface);
   /* C++ interface */
   fprintf(header, "#if defined(__cplusplus) && !defined(CINTERFACE)\n");
-  fprintf(header, "struct %s", iface->name);
   if (iface->ref)
-      fprintf(header, ": %s", iface->ref->name);
-  fprintf(header, " {\n");
+      fprintf(header, "struct %s : public %s\n", iface->name, iface->ref->name);
+  else
+  {
+      fprintf(header, "#ifdef ICOM_USE_COM_INTERFACE_ATTRIBUTE\n");
+      fprintf(header, "struct __attribute__((com_interface)) %s\n", iface->name);
+      fprintf(header, "#else\n");
+      fprintf(header, "struct %s\n", iface->name);
+      fprintf(header, "#endif\n");
+  }
+  fprintf(header, "{\n");
   indentation++;
-  fprintf(header, "\n");
   write_cpp_method_def(iface);
   indentation--;
-  fprintf(header, "} ICOM_COM_INTERFACE_ATTRIBUTE;\n");
+  fprintf(header, "};\n");
   fprintf(header, "#else\n");
   /* C interface */
   fprintf(header, "typedef struct %sVtbl %sVtbl;\n", iface->name, iface->name);