al_get_native_file_dialog_count - Man Page

#include <allegro5/allegro_native_dialog.h>

int al_get_native_file_dialog_count(const ALLEGRO_FILECHOOSER *dialog)

Returns the number of files selected, or 0 if the dialog was cancelled.

al_create_native_file_dialog(3), al_get_native_file_dialog_path(3).