Release Resources / "Free Up Spare Memory"

What do you put in this section to get the plug-in to “free up spare memory”?

void DemoAudioProcessor::releaseResources()
{
// When playback stops, you can use this as an opportunity to free up any
// spare memory, etc.
}

Thanks!

Free up any memory you may have allocated in prepareToPlay(), numChannelsChanged(), etc.

For example, I often use vectors to hold DSP processes like filters. I allocate the memory in numChannelsChanged() so I can have one processor for each channel and then I call .clear() on them in releaseResources().