FD_ISSET (socket number, socket vector queue) returns true, if Socket Number in the queue “became readyâ€ (i.e. has value 1 in queue)
FD_ISSET (tundu posta, tundu vector foleni) anarudi kweli, kama soketi Idadi katika foleni â € œbecame readyâ € (k.v. ina thamani 1 katika foleni)