set_sound_input_source - Selects the audio input source. Allegro game programming library.

       Selects the audio input source. The parameter should be one of the values:

          SOUND_INPUT_MIC
          SOUND_INPUT_LINE
          SOUND_INPUT_CD

       set_sound_input_source - Selects the audio input source. Allegro game programming library.

       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(3alleg4)

Allegro                                           version 4.4.3                  set_sound_input_source(3alleg4)

#include<allegro.h>intset_sound_input_source(intsource);