diff --git a/src/proto/eval.pro b/src/proto/eval.pro
index e81669b..6d11447 100644
--- a/src/proto/eval.pro
+++ b/src/proto/eval.pro
@@ -94,6 +94,7 @@
 float_T vim_round(float_T f);
 long do_searchpair(char_u *spat, char_u *mpat, char_u *epat, int dir, char_u *skip, int flags, pos_T *match_pos, linenr_T lnum_stop, long time_limit);
 char_u *get_callback(typval_T *arg, partial_T **pp);
+void free_callback(char_u *callback, partial_T *partial);
 void set_vim_var_nr(int idx, varnumber_T val);
 varnumber_T get_vim_var_nr(int idx);
 char_u *get_vim_var_str(int idx);