diff --git a/src/proto/filepath.pro b/src/proto/filepath.pro
index bf3d516..2970e50 100644
--- a/src/proto/filepath.pro
+++ b/src/proto/filepath.pro
@@ -22,6 +22,7 @@
 void f_glob2regpat(typval_T *argvars, typval_T *rettv);
 void f_globpath(typval_T *argvars, typval_T *rettv);
 void f_isdirectory(typval_T *argvars, typval_T *rettv);
+void f_isabsolutepath(typval_T *argvars, typval_T *rettv);
 void f_mkdir(typval_T *argvars, typval_T *rettv);
 void f_pathshorten(typval_T *argvars, typval_T *rettv);
 void f_readdir(typval_T *argvars, typval_T *rettv);