set_sound_input_source - Man Page

#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(3)

start_sound_input(3).