diff --git a/dlls/msctf/tests/inputprocessor.c b/dlls/msctf/tests/inputprocessor.c
index c4be695dd27..90d698964b7 100644
--- a/dlls/msctf/tests/inputprocessor.c
+++ b/dlls/msctf/tests/inputprocessor.c
@@ -1479,10 +1479,11 @@ static const ITfEditSessionVtbl EditSession_EditSessionVtbl =
     EditSession_DoEditSession
 };
 
-HRESULT EditSession_Constructor(ITfEditSession **ppOut)
+static HRESULT EditSession_Constructor(ITfEditSession **ppOut)
 {
     EditSession *This;
 
+    *ppOut = NULL;
     This = HeapAlloc(GetProcessHeap(),HEAP_ZERO_MEMORY,sizeof(EditSession));
     if (This == NULL)
         return E_OUTOFMEMORY;