Can't change volume level

[kostosspb]

Hello, Anton!
Thanks for good project.
I want to add volume regulation, but it isn't work.
In loop section I'm write:

if(M5.BtnA.wasPressed())
  {
       volume_down();
       m5.update();
  }

Where I'm wrong?

[mpmarks]

The gain has an argument that is a float fraction. So try something like this:
void volume_up()
{
gain++;
if (gain >=100) gain = 100;
out->SetGain(gain/100.0);
}