Force garbage collection/compaction with malloc()

Question

I have a C++ program that benchmarks various algorithms on input arrays of different length. It looks more or less like this:

# (1)
for k in range(4..20):
  # (2)
  input = generate 2**k random points
  for variant in variants:
    benchmark the following call
    run variant on input array
  # (3)

Is it possible to reset the whole heap management at (2) to the state it had at (1)? All memory allocated on the heap that was allocated during the program is guaranteed to be freed at (3).

I am using g++ 4.3 on Linux.

Edit: I understand that there is no real garbage collection in C/C++. I want to force the memory allocation to join adjacent empty chunks of memory it has in its free list at (2).

Answer 1

If you want the test runs to start in the same heap states, you can run them in their own processes created by fork().