user32: sizeof DDEPOKE and DDEDATA is six, which is probably not what is…

dlls/user32/dde_client.c

@@ -724,7 +724,7 @@ static WDML_XACT*	WDML_ClientQueuePoke(WDML_CONV* pConv, LPVOID pData, DWORD cbD
         GlobalUnlock(hglobal);
     }
 
-    pXAct->hMem = GlobalAlloc(GHND | GMEM_DDESHARE, sizeof(DDEPOKE) + cbData);
+    pXAct->hMem = GlobalAlloc(GHND | GMEM_DDESHARE, FIELD_OFFSET(DDEPOKE, Value[cbData]));
     ddePoke = GlobalLock(pXAct->hMem);
     if (!ddePoke)
     {

dlls/user32/dde_server.c

@@ -844,7 +844,7 @@ static	WDML_QUEUE_STATE WDML_ServerHandlePoke(WDML_CONV* pConv, WDML_XACT* pXAct
     if (!(pConv->instance->CBFflags & CBF_FAIL_POKES))
     {
 	hDdeData = DdeCreateDataHandle(pConv->instance->instanceID, pDdePoke->Value,
-				       GlobalSize(pXAct->hMem) - sizeof(DDEPOKE) + 1,
+				       GlobalSize(pXAct->hMem) - FIELD_OFFSET(DDEPOKE, Value),
 				       0, 0, pDdePoke->cfFormat, 0);
 	if (hDdeData)
 	{

dlls/user32/message.c

@@ -1456,8 +1456,8 @@ static BOOL post_dde_message( struct packed_message *data, const struct send_mes
         {
             size = GlobalSize( (HGLOBAL)uiLo ) ;
             if ((info->msg == WM_DDE_ADVISE && size < sizeof(DDEADVISE)) ||
-                (info->msg == WM_DDE_DATA   && size < sizeof(DDEDATA))   ||
-                (info->msg == WM_DDE_POKE   && size < sizeof(DDEPOKE))
+                (info->msg == WM_DDE_DATA   && size < FIELD_OFFSET(DDEDATA, Value)) ||
+                (info->msg == WM_DDE_POKE   && size < FIELD_OFFSET(DDEPOKE, Value))
                 )
             return FALSE;
         }

dlls/user32/tests/dde.c

@@ -699,10 +699,7 @@ static HDDEDATA CALLBACK server_ddeml_callback(UINT uType, UINT uFmt, HCONV hcon
 
         ptr = (LPSTR)DdeAccessData(hdata, &size);
         ok(!lstrcmpA(ptr, "poke data\r\n"), "Expected 'poke data\\r\\n', got %s\n", ptr);
-        todo_wine
-        {
-            ok(size == 14, "Expected 14, got %d\n", size);
-        }
+        ok(size == 12, "Expected 12, got %d\n", size);
         DdeUnaccessData(hdata);
 
         size = DdeQueryStringA(server_pid, hsz2, str, MAX_PATH, CP_WINANSI);
@@ -981,7 +978,7 @@ static HGLOBAL create_poke()
     DDEPOKE *poke;
     DWORD size;
 
-    size = sizeof(DDEPOKE) + lstrlenA("poke data\r\n") + 1;
+    size = FIELD_OFFSET(DDEPOKE, Value[sizeof("poke data\r\n")]);
     hglobal = GlobalAlloc(GMEM_DDESHARE, size);
     ok(hglobal != 0, "Expected non-NULL hglobal\n");