this xpp, is a list implementation with a null terminator, the '\0' character, many points in system use this, but depending on the situation it'll be tweaked in a different way. this message communication interface it's very probably to be replaced for a class with a dict of lists, where each entry of dict is a proc_id and each entry of list is a message for the owned process for that key in dict, this only can be solved when the code is almost finished, to realize what can be replaced or not, for justs # TODO and/or # FIXME