al_destroy_sample man page
al_destroy_sample — Allegro 5 API
#include <allegro5/allegro_audio.h> void al_destroy_sample(ALLEGRO_SAMPLE *spl)
Free the sample data structure. If it was created with the
free_buf parameter set to true, then the buffer will be freed with al_free(3).
This function will stop any sample instances which may be playing the buffer referenced by the ALLEGRO_SAMPLE(3).
al_destroy_sample_instance(3), al_stop_sample(3), al_stop_samples(3)