diff --git a/gdbus/gdbus.h b/gdbus/gdbus.h
index a0583e6..e5e7938 100644
--- a/gdbus/gdbus.h
+++ b/gdbus/gdbus.h
@@ -85,16 +85,24 @@ typedef enum {
 typedef struct {
 	const char *name;
 	const char *signature;
+} GDBusArgInfo;
+
+typedef struct {
+	const char *name;
+	const char *signature;
 	const char *reply;
 	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 {