How can I perfectly manage my memory of my C project? - c

Question

I am working on an object of SDL Tetris. When I ran my code, it first worked fine. But it automatically stopped displaying my text a few minutes later. I guessed there must be some problem on the memory management and I proved that I was right via Task Manager.
I look over my source code but found nothing wrong. (at least I didn't find it) Every heap object I delcared was freed and textures were destroyed. So, what can be the problem?
Here's my source code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <time.h>
#include <stdbool.h>
#define SDL_MAIN_HANDLED
#include <SDL2/SDL.h>
#include <SDL2/SDL_ttf.h>
SDL_Window * window;
SDL_Renderer * renderer;
SDL_Surface * text;
TTF_Font* font;
bool running = true;
#define ScreenWidth 60
#define ScreenHeight 30
#define CharWidth 14
#define CharHeight 24
char screen[ScreenHeight][ScreenWidth + 1];
SDL_Color color = {192, 192, 192};
SDL_Rect rect;
int score = 0;
char shapes[7][17];
typedef struct Block {
int type;
char shape[17];
int x, y;
int width, height;
} Block;
Block * newBlock(int type) {
Block * block = malloc(sizeof(Block));
return block;
}
void CheckEvents() {
SDL_Event event;
while (SDL_PollEvent(&event)) {
if (event.type == SDL_QUIT) {
running = false;
} else if (event.type == SDL_KEYDOWN) {
switch (event.key.keysym.sym) {
case SDLK_w:
;
break;
case SDLK_a:
;
break;
case SDLK_d:
;
break;
case SDLK_s:
;
break;
case SDLK_SPACE:
;
break;
default:
break;
}
}
}
free(&event);
}
void UpdateBoard() {
for (int i = 0; i < ScreenHeight; ++i) {
for (int j = 0; j < ScreenWidth; ++j) {
screen[i][j] = ' ';
}
}
for (int i = 0; i != 20; ++i) {
screen[i + 2][1] = '#';
screen[i + 2][1 + 10 + 1] = '#';
}
for (int i = 0; i != 10 + 2; ++i) {
screen[22][i + 1] = '#';
}
sprintf(&(screen[0][1]), "Score: %d", score);
for (int i = 0; i != ScreenHeight; i++) {
for (int j = 0; j != ScreenWidth; j++) {
if (screen[i][j] == '\0') {
screen[i][j] = ' ';
}
}
}
}
void UpdateScreen() {
SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
SDL_RenderClear(renderer);
for (int i = 0; i < ScreenHeight; ++i) {
text = TTF_RenderText_Solid(font, screen[i], color);
SDL_Texture * texture;
texture = SDL_CreateTextureFromSurface(renderer, text);
rect.x = 0;
rect.y = i * CharHeight;
rect.w = strlen(screen[i]) * CharWidth;
rect.h = CharHeight;
SDL_RenderCopy(renderer, texture, NULL, &rect);
free(texture);
SDL_DestroyTexture(texture);
}
SDL_RenderPresent(renderer);
}
void Init() {
SDL_Init(SDL_INIT_EVERYTHING);
TTF_Init();
window = SDL_CreateWindow("Tetris", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
ScreenWidth * CharWidth, ScreenHeight * CharHeight, 0);
renderer = SDL_CreateRenderer(window, -1, 0);
font = TTF_OpenFont("s8514oem.fon", 0);
sprintf(shapes[0], "OOOO............");
sprintf(shapes[1], "OO...OO.........");
sprintf(shapes[2], ".OO.OO..........");
sprintf(shapes[3], "O...OOO.........");
sprintf(shapes[4], "..O.OOO.........");
sprintf(shapes[5], "OO..OO..........");
sprintf(shapes[6], "OOO..O..........");
}
int main(int argc, char ** argv) {
Init();
while (running) {
CheckEvents();
UpdateBoard();
UpdateScreen();
SDL_Delay(1000/16);
}
TTF_Quit();
SDL_Quit();
return 0;
}
My Makefile:
tetris:
gcc -std=c99 -Wall -Isrc/include -Lsrc/lib -o Tetris main.c -lSDL2main -lSDL2 -lSDL2_ttf

Answer 1

Several things:
Don't try to free() stack-allocated variables like event:
//free(&event);
text needs to be freed with SDL_FreeSurface() before replacing its pointer value with a new one from TTF_RenderText_Solid():
if(text) {
SDL_FreeSurface(text);
}
text = TTF_RenderText_Solid(font, screen[i], color);
Don't use free() on the textures returned by SDL_CreateTextureFromSurface(), only use SDL_DestroyTexture():
texture = SDL_CreateTextureFromSurface(renderer, text);
...
//free(texture);
SDL_DestroyTexture(texture);