construct from fd number */

forbid copying FileDescriptor objects or assigning them */

parse a header line into a key and a value */

constructor for uninitialized optional */ missing_ field of union is necessary to get rid of "may be used uninitialized" warning */

Read in packet */

add given signals to the mask */

default constructor for socket of (subclassed) domain and type */

constructor used by accept() and SecureSocket() */

allow move constructor */

allow move constructor */