diff --git a/src/structs.h b/src/structs.h
index 670e0d2..05ea6fc 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -662,7 +662,8 @@
     regmatch_T	cmod_filter_regmatch;	// set by :filter /pat/
     int		cmod_filter_force;	// set for :filter!
 
-    int		cmod_verbose;		// non-zero to set 'verbose'
+    int		cmod_verbose;		// non-zero to set 'verbose', -1 is
+					// used for zero override
 
     // values for undo_cmdmod()
     char_u	*cmod_save_ei;		// saved value of 'eventignore'