Repeating key events blocking - events

Question

I wrote a simple program with SFML and OpenGL which draws a spinning square that can be moved around the screen with the arrow keys.
It works fine on all the Linux and Mac computers I've tested it on, but when I try to move the square on Windows (by holding down an arrow key) it moves a small distance and then stops moving and spinning. I'm pretty sure the program is getting stuck in the GetEvent method - my guess is that when I've held the key down long enough for it to start repeating, the event stack keeps getting new events added to it before I can pop everything off it (and if I turn the key repeat rate on Windows right down to the minimum then the problem goes away - I don't really like this as a solution though).
I found that pressing and holding Alt, Ctrl, Delete, Page up, Page down, Home, End etc all cause this behavior too (even though I don't specifically detect any of these keys in the program), but all the letter keys, as well as space, enter, backspace and the keypad arrow keys work fine (i.e. they don't cause the program to pause if I hold them down for too long).
I don't have the exact code (I just turned my laptop off), but it looks like:
while(running) {
while(app.GetEvent(event))
if(event.Type==sf::Event::Closed) running=false;
if(input.IsKeyDown(sf::Key::Right)); // move right
// etc etc
// update rotation
// draw everything
}
Any ideas as to what the exact problem might be, and how I could fix it?

Answer 1

I know this is an old question but I would like to answer it in the interest of helping others who may find themselves here experiencing similiar problems.
SFML 1.6 has two ways you can get input from the user. One is event-based where you process each event sent to you via sf::Window::GetEvent(). The other is query-based where you check the sf::Input class of your window directly.
You have used the query-based method here but put it inside an event loop which isn't really the way it was intended to be used. It was meant to be used like this. This is a nice feature because SFML essentially keeps a boolean table of keys automatically for you so you don't need to manage key states yourself. IMHO for using repeating input this is more elegant since you won't be spamming your event queue, just checking a boolean value.
while(app.GetEvent(event))
if(event.Type == sf::Event::Closed) running=false;
if(event.Type == sf::Event::KeyPressed && event.Key.Code == sf::Key::Right)
{
// move right
}
}
If you wanted to just query sf::Input directly then you use the same code as above, but you put it outside the event loop.
while(app.GetEvent(event)
{
}
if (myWindow.GetInput().IsKeyDown(sf::Key::Right))
{
}
By default automatic key repeat should be enabled for sf::Windows but you can make sure by using sf::Window::EnableKeyRepeat(true). This means it will send a KeyPressed event repeatedly while a key is held down.
Try using the query-based method outside the main event loop and see if that works for you.