man voice_sweep_frequency () - Starts a frequency sweep for a voice. Allegro game programming library.
NAME
voice_sweep_frequency - Starts a frequency sweep for a voice. Allegro game programming library.
SYNOPSIS
#include <allegro.h>
void voice_sweep_frequency(int voice, int time, int endfreq);
DESCRIPTION
Starts a frequency sweep (glissando) from the current pitch to the specified ending pitch, lasting for time milliseconds.