diff --git a/src/dummy/i_system.c b/src/dummy/i_system.c
index 00550c410..8556c0248 100644
--- a/src/dummy/i_system.c
+++ b/src/dummy/i_system.c
@@ -8,7 +8,7 @@ UINT8 graphics_started = 0;
 
 UINT8 keyboard_started = 0;
 
-size_t I_GetFreeMem(UINT32 *total)
+size_t I_GetFreeMem(size_t *total)
 {
 	*total = 0;
 	return 0;