diff --git a/gdbus/gdbus.h b/gdbus/gdbus.h
index a0583e64..e5e7938d 100644
--- a/gdbus/gdbus.h
+++ b/gdbus/gdbus.h
@@ -82,6 +82,11 @@ typedef enum {
 	G_DBUS_SECURITY_FLAG_ALLOW_INTERACTION = (1 << 2),
 } GDBusSecurityFlags;
 
+typedef struct {
+	const char *name;
+	const char *signature;
+} GDBusArgInfo;
+
 typedef struct {
 	const char *name;
 	const char *signature;
@@ -89,12 +94,15 @@ typedef struct {
 	GDBusMethodFunction function;
 	GDBusMethodFlags flags;
 	unsigned int privilege;
+	const GDBusArgInfo *in_args;
+	const GDBusArgInfo *out_args;
 } GDBusMethodTable;
 
 typedef struct {
 	const char *name;
 	const char *signature;
 	GDBusSignalFlags flags;
+	const GDBusArgInfo *args;
 } GDBusSignalTable;
 
 typedef struct {