> is it possible to determine for opened socket when last time it was > used, > I need to do it by some system function I can't record the time of its > use.
AF_INET or AF_UNIX? Well, neither is topical here (it probably is in comp.unix.programmer), but for the later you might check it's timestamps with stat()/fstat() and st_atime it returns via it's 2nd argument (struct stat *)