diff --git a/src/proto/if_ruby.pro b/src/proto/if_ruby.pro
index 496859c..cc7c7e6 100644
--- a/src/proto/if_ruby.pro
+++ b/src/proto/if_ruby.pro
@@ -7,4 +7,5 @@
 void ruby_buffer_free(buf_T *buf);
 void ruby_window_free(win_T *win);
 void vim_ruby_init(void *stack_start);
+void do_rubyeval(char_u *str, typval_T *rettv);
 /* vim: set ft=c : */