SDL_DestroyWindow doesn't free memory - c++

Question

Basically, in my program I have to create and destroy a window. I always use the same window pointer creating and destroying the contents (texture and render).
I notice a memory leak in this process so I wrote a simple program to verify this, here the code.
The problem has the higher impact on Windows, on Ubuntu at the end of the test the memory is increased only around 3MB (around 236MB on Windows).
#include <iostream>
#include "SDL.h"
int main(int argc, char *argv[])
{
SDL_Init(SDL_INIT_VIDEO);
SDL_Window* mainWindow;
SDL_Renderer* mainRenderer;
SDL_Texture* mainTexture;
for (int i = 0; i < 200; i++)
{
mainWindow = SDL_CreateWindow("Memory Leak Test v1.0", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 320, 240, SDL_WINDOW_SHOWN);
mainRenderer = SDL_CreateRenderer(mainWindow, -1, SDL_RENDERER_ACCELERATED);
mainTexture = SDL_CreateTexture(mainRenderer, SDL_PIXELFORMAT_ABGR8888, SDL_TEXTUREACCESS_STREAMING, 320, 240);
if (i == 0)
{
std::cout << "SDL Memory Leak Tester, please check the amount of memory\noccupied by the process, then press Enter\n";
getchar();
}
SDL_Delay(50);
if (i == 199)
{
std::cout << "SDL Memory Leak Tester, please check the amount of memory\noccupied by the process, then press Enter\n";
getchar();
}
SDL_DestroyTexture(mainTexture);
SDL_DestroyRenderer(mainRenderer);
SDL_DestroyWindow(mainWindow);
}
std::cout << "Test finished, press Enter to close\n";
getchar();
return 0;
}
Any idea?