1 files changed, 1 insertions, 1 deletions
diff --git a/embed.fnc b/embed.fnc
index deff9ad39f..54389d5b0c 100644
--- a/embed.fnc
+++ b/embed.fnc
@@ -341,7 +341,7 @@ Ap	|void	|gp_free	|NULLOK GV* gv
 Ap	|GP*	|gp_ref		|NULLOK GP* gp
 Ap	|GV*	|gv_AVadd	|NN GV* gv
 Ap	|GV*	|gv_HVadd	|NN GV* gv
-Ap	|GV*	|gv_IOadd	|NN GV* gv
+Ap	|GV*	|gv_IOadd	|NULLOK GV* gv
 ApR	|GV*	|gv_autoload4	|NULLOK HV* stash|NN const char* name|STRLEN len|I32 method
 Ap	|void	|gv_check	|NN const HV* stash
 Ap	|void	|gv_efullname	|NN SV* sv|NN const GV* gv