more OSystem docs & cleanup

svn-id: r8118

1 files changed, 1 insertions, 1 deletions

diff --git a/backends/null/null.cpp b/backends/null/null.cpp
index 4878ebeffa..8098445a89 100644
--- a/backends/null/null.cpp
+++ b/backends/null/null.cpp
@@ -42,7 +42,7 @@ public:
 	void delay_msecs(uint msecs);
 	void create_thread(ThreadProc *proc, void *param) { }
 	bool poll_event(Event *event) { return false; }
-	bool set_sound_proc(void *param, SoundProc *proc, byte sound) {}
+	bool set_sound_proc(SoundProc *proc, void *param, SoundFormat format) {}
 	void quit() { exit(1); }
 	uint32 property(int param, Property *value) { return 0; }
 	static OSystem *create(int gfx_mode, bool full_screen);