diff --git a/src/proto/filepath.pro b/src/proto/filepath.pro
index 6261211..bf3d516 100644
--- a/src/proto/filepath.pro
+++ b/src/proto/filepath.pro
@@ -5,6 +5,7 @@
 void f_delete(typval_T *argvars, typval_T *rettv);
 void f_executable(typval_T *argvars, typval_T *rettv);
 void f_exepath(typval_T *argvars, typval_T *rettv);
+int file_is_readable(char_u *fname);
 void f_filereadable(typval_T *argvars, typval_T *rettv);
 void f_filewritable(typval_T *argvars, typval_T *rettv);
 void f_finddir(typval_T *argvars, typval_T *rettv);