set_sound_input_source (3) - Linux Manuals
set_sound_input_source: Selects the audio input source. Allegro game programming library.
NAME
set_sound_input_source - Selects the audio input source. Allegro game programming library.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