SYNOPSIS
#include <allegro.h>
int set_sound_input_source(int source);
DESCRIPTION
Selects the audio input source. The parameter should be one of the values:
SOUND_INPUT_MIC SOUND_INPUT_LINE SOUND_INPUT_CD
RETURN VALUE
The function returns zero on success, or -1 if the hardware does not provide an input select register (ie. you have no control over the input source).