1 files changed, 2 insertions, 1 deletions
diff --git a/byterun/extern.c b/byterun/extern.c
index b01a5f89e..4d5888002 100644
--- a/byterun/extern.c
+++ b/byterun/extern.c
@@ -338,7 +338,8 @@ static void extern_rec(value v)
       void (*serialize)(value v, unsigned long * wsize_32,
                         unsigned long * wsize_64)
         = Custom_ops_val(v)->serialize;
-      if (serialize == NULL) failwith("output_value: abstract value");
+      if (serialize == NULL) 
+        extern_invalid_argument("output_value: abstract value");
       Write(CODE_CUSTOM);
       writeblock(ident, strlen(ident) + 1);
       Custom_ops_val(v)->serialize(v, &sz_32, &sz_64);