diff --git a/src/proto/optionstr.pro b/src/proto/optionstr.pro
index 340ffc4..39c40f3 100644
--- a/src/proto/optionstr.pro
+++ b/src/proto/optionstr.pro
@@ -156,6 +156,7 @@
 int expand_set_swapsync(optexpand_T *args, int *numMatches, char_u ***matches);
 char *did_set_switchbuf(optset_T *args);
 int expand_set_switchbuf(optexpand_T *args, int *numMatches, char_u ***matches);
+int expand_set_tabclose(optexpand_T *args, int *numMatches, char_u ***matches);
 char *did_set_tabline(optset_T *args);
 char *did_set_tagcase(optset_T *args);
 int expand_set_tagcase(optexpand_T *args, int *numMatches, char_u ***matches);