title: Simple sound wave generator with SDL in c++
body: <p>i am having problems understanding how the audio part of the sdl library works
  now, i know that when you initialize it, you have to specify the frequency and a >>callback&lt;&lt; function, which i think is then called automatically at the given frequency.
  can anyone who worked with the sdl library write a simple example that would use sdl_audio to generate a 440 hz square wave (since it is the simplest waveform) at a sampling frequency of 44000 hz?</p>