diff --git a/src/proto/ops.pro b/src/proto/ops.pro
index 85fb983..a8c144e 100644
--- a/src/proto/ops.pro
+++ b/src/proto/ops.pro
@@ -15,6 +15,7 @@
 int may_get_selection __ARGS((int regname));
 void *get_register __ARGS((int name, int copy));
 void put_register __ARGS((int name, void *reg));
+void free_register __ARGS((void *reg));
 int yank_register_mline __ARGS((int regname));
 int do_record __ARGS((int c));
 int do_execreg __ARGS((int regname, int colon, int addcr, int silent));