Valgrind shows definitely lost memory from official code example

SDL Development
1

Hello,

Why does Valgrind show definite lost memory from an official SDL Code example? ( After I close the window )

Code:

#include <SDL2/SDL.h>
int main(int argc, char* argv[])
{
        SDL_Window* window;
        SDL_Renderer* renderer;

        /* Initialize SDL. */
        if (SDL_Init(SDL_INIT_VIDEO) < 0)
                return 1;

        /* Create the window where we will draw. */
        window = SDL_CreateWindow("SDL_RenderClear",
                        SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
                        512, 512,
                        0);

        /* We must call SDL_CreateRenderer in order for draw calls to affect this window. */
        renderer = SDL_CreateRenderer(window, -1, 0);

        /* Select the color for drawing. It is set to red here. */
        SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);

        /* Clear the entire screen to our selected color. */
        SDL_RenderClear(renderer);

        /* Up until now everything was drawn behind the scenes.
           This will show the new, red contents of the window. */
        SDL_RenderPresent(renderer);

        /* Give us time to see the window. */
        SDL_Delay(5000);

        /* Always be sure to clean up */
        SDL_Quit();
        return 0;
}

After I close the window it shows a definite lost of: definitely lost: 68,536 bytes in 28 blocks

2

After I close the window it shows a definite lost of: definitely lost: 68,536 bytes in 28 blocks

Xlib leaks about this much, and it can’t be avoided by SDL. It’s been this way for years; it’s not clear to me if it can be fixed in Xlib, or if it’s even a bug or just some stuff they allocate at startup and keep around in case you need it again.

You can see the culprits, down in libx11, if you run Valgrind with --leak-check=full .

–ryan.

3

Ok, thank you for your answer.

1 Like