FPC's Memory Manager is similar to Borlands in the way you define it, but there are extra fields in the TMemoryManager record that you need to define for it to work.

I think the HeapStatus and FPCHeapStatus functions need to be assigned as well.

I have not tried to use a FPC dll memory manager with Delphi, I always compile all the binaries in the same app. Not sure if it will work, but in theory if your delphi app, implements all the things the FPC memory manager requires there should not be a problem.

Another thing, rather than trying to change the dll memory manager to be the same as the applications, I do it the other way around. I have a core memory management dll whcih all the other dll's and exe's use. It made things allot easier to implement.