Monitoring amount of allocated memory

Question

I have been trying to get the amount of memory allocated by my C++ program. For testing purposes I created a structure:

struct player {
    string name;
    int id;
    player(string _name, int _id) : name(_name), id(_id) {}
    player(){};
    void set(string _name, int _id){
        name = _name;
        id = _id;
    }
    string tostring() {
        return ("{name: " + name + ", id: " + to_string(id) + "}");
    }
};

And this is what I am doing in my main function:

player* players;
players = new player[4]();

players[0].set("a", 1);
players[1].set("b", 2);
players[2].set("c", 3);
players[3].set("d", 4);

for(int i = 0; i < 4; i ++) {
    cout << players[i].tostring() << endl;
}

delete [] players;

So i want to print the amount of allocated memory before and after the "delete" operator. I have tried to do it in two ways, suggested by this thread. 1)

size_t getMemoryUsage() {
    PROCESS_MEMORY_COUNTERS memCounter;
    BOOL result = GetProcessMemoryInfo(GetCurrentProcess(), &memCounter, sizeof( memCounter ));

    SIZE_T physMemUsedByMe = memCounter.WorkingSetSize;
    return physMemUsedByMe;
}

Assuming this gives the memory, mapped to my process in bytes, the result I get is always something around 18.7 Mbytes. But every time I run it, I get slightly different result. Also, after I call the delete operator, I get 18.8 Mbytes. So after I free memory, the memory I use raises???

2)

void printMemoryStatus()
{
    MEMORYSTATUSEX statex;
    statex.dwLength = sizeof (statex);
    GlobalMemoryStatusEx (&statex);
    cout << (statex.ullTotalVirtual - statex.ullAvailVirtual) << endl;
}

Also assuming this result is in bytes, I get 145.273 Mbytes in the output.

The size of my structure is 28 bytes, so my program should use something at least close to 112 bytes. so neither of those two methods are what i need. How can I get the amount of memory my program uses without any external tools.

My headers are:

#include <stdlib.h>
#include <iostream>
#include <fstream>
#include <windows.h>
#include <psapi.h>
#include <tchar.h>

I am compiling with MinGW in codeblocks, with the psapi library as a linked library. My g++ version is 9.2.0 on Windows 10.

You are actually not releasing correctly the memory. This question is strongly related to https://stackoverflow.com/questions/2814188/c-array-of-pointers-delete-or-delete. — afkid, Jun 20 '20 at 12:03
To correctly release the memory, you need to delete each element of the array and then delete the array itself. — afkid, Jun 20 '20 at 12:03
OP is not allocating an array of pointers. The delete is correct — stark, Jun 20 '20 at 14:38
@afkid this is a mistake I did a few hours ago. I tried to just delete the 2nd element of the array, which leads to a crash. As stark said, this is not an array of pointers, but a pointer that leads to an array. — Boris Vassilev, Jun 20 '20 at 19:59
You have to take padding for memory alignment into account. Basically, runtime of C allocates over-sized than you need to align. — Y.Z, Jun 21 '20 at 02:57

Monitoring amount of allocated memory

0 Answers0