diff --git a/reactos/win32ss/gdi/gdi32/objects/font.c b/reactos/win32ss/gdi/gdi32/objects/font.c
index 6a9a90698cf..56998ab84bc 100644
--- a/reactos/win32ss/gdi/gdi32/objects/font.c
+++ b/reactos/win32ss/gdi/gdi32/objects/font.c
@@ -385,7 +385,7 @@ GetCharacterPlacementA(
     DWORD ret;
     UINT font_cp;
 
-    if ( !lpString || uCount <= 0 || (nMaxExtent < 0 && nMaxExtent != -1 ) )
+    if ( !lpString || uCount <= 0 || !lpResults || (nMaxExtent < 0 && nMaxExtent != -1 ) )
     {
         SetLastError(ERROR_INVALID_PARAMETER);
         return 0;