set_sound_input_source - Selects the audio input source. Allegro game
programming library.
#include <allegro.h>
int set_sound_input_source(int source);
Selects the audio input source. The parameter should be one of the
values:
SOUND_INPUT_MIC
SOUND_INPUT_LINE
SOUND_INPUT_CD
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).
start_sound_input(3alleg)