Question

std::map<int, int> * mp = new std::map<int, int>;
for(int i = 0; i < 999999; i++){
  mp->insert(std::pair<int, int>(i, 999999-i )); 
}
p("created");
//mp->clear();     -     doesn't help either
delete mp;
p("freed");

The problem is: “delete mp” doesn’t do anything. To compare:

std::vector<int> * vc = new std::vector<int>;
for(int i = 0; i < 9999999; i++){
  vc->push_back(i); 
}
p("created");
delete vc;
p("freed");

releases memory. How to release memory from map?
PS: p(“string”) just pauses program and waits for input.

Answer 1

The RAM used by the application is not a precise way to tell if the memory has been semantically freed.

Freed memory is memory that you can reuse. Sometimes though, you don’t observe this freed memory directly in what the OS reports as memory used by our app.

You know that the memory is freed because the semantics of the language say so.