etween these types is that record boundaries are
+maintained using the
+.Dv SOCK_SEQPACKET
+type.
+A record can be sent using one or more output operations and received using one
+or more input operations, but a single operation never transfers parts of more
+than one record.
+Record boundaries are set by the sender with the
+.Dv MSG_EOR
+flag of
 .Xr send 2
-calls.
-Datagrams are generally received with
+or
+.Xr sendmsg 2
+functions.
+There is no possibility to set a record boundary with
+.Xr write 2 .
+Record boundaries are visible to the receiver via the
+.Dv MSG_EOR
+flag in the received message flags returned by the
+.Xr recvmsg 2
+function.
+It is protocol-specific whether a maximum record size is imposed.
+.Pp
+The
+.Dv SOCK_SEQPACKET
+socket is supported by the following protocol families:
+.Dv PF_INET ,
+.Dv PF_INET6 ,
+and
+.Dv PF_UNIX .
+.Pp
+.Sh RAW SOCKET TYPE
+The
+.Dv SOCK_RAW
+socket type provides access to internal network protocols and interfaces.
+It is a datagram socket in its nature, thus has the same semantics of
+read and write operations.
+The
+.Dv SOCK_RAW
+type is available only to the super-user and is described in
+.Xr ip 4
+and
+.Xr ip6 4 .
+.Sh NON-BLOCKING MODE
+A socket can be created in
+.Em non-blocking mode
+with the help of
+.Dv SOCK_NONBLOCK
+flag.
+Alternatively, the non-blocking mode on a socket can be turned on and off with
+the help of the
+.Dv O_NONBLOCK
+flag of the
+.Xr fcntl 2
+system call.
+.Pp
+When a non-blocking socket has not enough data in its receive buffer to fulfil
+the application supplied buffer, then data receiving system calls like
+.Xr recv 2 ,
 .Xr recvfrom 2 ,
-which returns the next datagram with its return address.
+.Xr recvmsg 2
+and
+.Xr read 2
+will not block waiting for the data but immediately return.
+Return value will indicate amount of bytes read into the supplied buffer.
+The
+.Va errno
+will be set to
+.Dv EAGAIN
+.Po
+has same value as
+.Dv EWOULDBLOCK
+.Pc .
+.Pp
+If application tries to send more data on a non-blocking socket than the socket
+send buffer can accomodate with
+.Xr send 2 ,
+.Xr sendto 2 ,
+.Xr sendmsg 2
+or
+.Xr write 2
+system calls partial data will be sent.
+Return value will indicate amount of bytes sent.
+The
+.Va errno
+will be set to
+.Dv EAGAIN .
+Note that sockets of
+.Dv SOCK_DGRAM
+type are unreliable, thus for these sockets sending operations will never fail
+with
+.Dv EAGAIN
+in non-blocking mode neither will block in blocking mode.
+.Sh OTHER OPERATIONS ON SOCKETS
+Since socket descriptors are file descriptors, many generic file operations
+performed by
+.Xr fcntl 2 ,
+apply.
+Socket descriptors can be used with all event engines, such as
+.Xr kevent 2 ,
+.Xr select 2
+and
+.Xr poll 2 .
 .Pp
 An
 .Xr fcntl 2
@@ -250,6 +363,12 @@ The
 and
 .Xr getsockopt 2
 system calls are used to set and get options, respectively.
+.Pp
+Connection associated with a socket can be terminated by
+.Xr close 2
+system call.
+One direction of communication can be disabled with
+.Xr shutdown 2 .
 .Sh RETURN VALUES
 A -1 is returned if an error occurs, otherwise the return
 value is a descriptor referencing the socket.
@@ -282,16 +401,23 @@ The socket type is not supported by the protocol.
 .Sh SEE ALSO
 .Xr accept 2 ,
 .Xr bind 2 ,
+.Xr close 2 ,
 .Xr connect 2 ,
+.Xr fcntl 2 ,
 .Xr getpeername 2 ,
 .Xr getsockname 2 ,
 .Xr getsockopt 2 ,
 .Xr ioctl 2 ,
+.Xr kevent 2 ,
 .Xr listen 2 ,
+.Xr poll 2 ,
 .Xr read 2 ,
 .Xr recv 2 ,
 .Xr select 2 ,
 .Xr send 2 ,
+.Xr sendmsg 2 ,
+.Xr sendto 2 ,
+.Xr signal 3 ,
 .Xr shutdown 2 ,
 .Xr socketpair 2 ,
 .Xr write 2 ,