This function is a legacy means of locking the audio device.
Defined in SDL_audio.h
void SDL_LockAudio(void);New programs might want to use SDL_LockAudioDevice() instead. This function is equivalent to calling...
SDL_LockAudioDevice(1);...and is only useful if you used the legacy SDL_OpenAudio() function.
This function is available since SDL 2.0.0.