diff --git a/src/harfbuzz-impl.c b/src/harfbuzz-impl.c
index 79b837deb..4ba70ed47 100644
--- a/src/harfbuzz-impl.c
+++ b/src/harfbuzz-impl.c
@@ -65,5 +65,7 @@ _hb_free( HB_Pointer  block )
 HB_INTERNAL HB_Error
 _hb_err (HB_Error code)
 {
+  static int numerr = 0;
+  numerr++;
   return code;
 }