SDL app quitting in event loop - c++

Question

int main( int argc, char* args[] )
{
if( SDL_Init(SDL_INIT_EVERYTHING) < 0 )
std::cout<<"unable to init sdl";
SDL_Surface *screen = SDL_SetVideoMode(800,600,32,SDL_DOUBLEBUF);
std::cout<<"before while\n";
SDL_Event event;
while(SDL_PollEvent(&event))
{
std::cout<<"in while\n";
if(event.type == SDL_QUIT)
std::cout<<"SDL_QUIT\n";
}
std::cout<<"after while\n";
SDL_Quit();
}
For some unknown reason this SDL app quits after running in the while loop 4 times without me killing/closing/etc it and without printing "SDL_QUIT" to stdout.
Is there a reason for this? How do I fix it?

Answer 1

You need to keep your application alive by creating a main loop for it. As of now, your application just quits after you poll all the initial events:
int main( int argc, char* args[] )
{
if( SDL_Init(SDL_INIT_EVERYTHING) < 0 )
std::cout<<"unable to init sdl";
SDL_Surface *screen = SDL_SetVideoMode(800,600,32,SDL_DOUBLEBUF);
SDL_Event event;
bool active = true;
while(active)
{
while(SDL_PollEvent(&event))
{
if(event.type == SDL_QUIT)
{
std::cout<<"SDL_QUIT\n";
active = false;
}
}
// TODO: add drawing to screen
SDL_Flip(screen);
}
SDL_Quit();
}

Answer 2

SDL_PollEvent will return false when there are no more events to handle, which is right after application startup in this case.
You need to nest the poll loop inside another loop that keeps the application alive:
int running = 1;
while (running)
{
while (SDL_PollEvent(&event))
{
if (event.type == SDL_QUIT)
running = 0;
}
// Update and draw here usually
}