diff --git a/daemon/remote.h b/daemon/remote.h
index fd8d3814a87142a315aa04a6e85961293f1ca851..1eb83865cb8da8e1ab4093104238be2c81e0eb09 100644
--- a/daemon/remote.h
+++ b/daemon/remote.h
@@ -30,18 +30,22 @@
 typedef union {
 # include "remote_dispatch_args.h"
 } dispatch_args;
+verify(sizeof(dispatch_args) > 0);
 
 typedef union {
 # include "remote_dispatch_ret.h"
 } dispatch_ret;
+verify(sizeof(dispatch_ret) > 0);
 
 typedef union {
 # include "qemu_dispatch_args.h"
 } qemu_dispatch_args;
+verify(sizeof(qemu_dispatch_args) > 0);
 
 typedef union {
 # include "qemu_dispatch_ret.h"
 } qemu_dispatch_ret;
+verify(sizeof(qemu_dispatch_ret) > 0);