diff --git a/src/structs.h b/src/structs.h
index 550e53a..7bcbc38 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -642,6 +642,7 @@
 #define CMOD_LOCKMARKS	    0x0800	// ":lockmarks"
 #define CMOD_KEEPPATTERNS   0x1000	// ":keeppatterns"
 #define CMOD_NOSWAPFILE	    0x2000	// ":noswapfile"
+#define CMOD_VIM9CMD	    0x4000	// ":vim9cmd"
 
     int		cmod_split;		// flags for win_split()
     int		cmod_tab;		// > 0 when ":tab" was used