You can get useful memory usage information out of the Delphi runtime without using any direct Win32 calls:
unit X;
uses FastMM4; //include this or method will return 0.
....
function GetMemoryUsed: UInt64;
var
st: TMemoryManagerState;
sb: TSmallBlockTypeState;
begin
GetMemoryManagerState(st);
result := st.TotalAllocatedMediumBlockSize
+ st.TotalAllocatedLargeBlockSize;
for sb in st.SmallBlockTypeStates do begin
result := result + sb.UseableBlockSize * sb.AllocatedBlockCount;
end;
end;
The best thing about this method is that it’s strictly tracked: when you allocate memory, it goes up, and when you deallocate memory, it goes down by the same amount right away. I use this before and after running each of my unit tests, so I can tell which test is leaking memory (for example).