How to free memory by pointer a (placement new)?

Question

I can't understand how to properly free the memory by pointer a

MemoryManager mm;
char* a = new(mm) char[len];

Answer 1

You just call the destructor (if needed) and deallocate with your memory manager

// Deallocate memory
MemoryManager.free(a);

Or, you could define a delete operator for your custom allocator:

void operator delete(void *ptr, const MemoryManager &m) {...}
...
operator delete(a, mm);