socket(7)						 Miscellaneous Information Manual						 socket(7)

NAME

       socket - interprocess communications

DESCRIPTION

       Sockets are communication endpoints that allow processes to communicate either locally or remotely.  They are accessed by means of a set of
       system calls (see socket(2)).

       The following requests are defined in (see ioctl(2)):

       If the int with the address
		      arg is non-zero, the socket is put into non-blocking mode.  Otherwise, the socket is put into blocking mode.  Blocking  mode
		      is  the  default.   The request is equivalent to the request, although using is not recommended.	See accept(2), connect(2),
		      recv(2), and send(2) for an explanation of how non-blocking mode is used.

       For	      SOCK_STREAM sockets, the number of bytes currently readable from this socket is returned in the  integer	with  the  address
		      arg.  For SOCK_DGRAM sockets, the number of bytes currently readable, plus the size of the sockaddr structure (defined in is
		      returned in the integer with the address arg.

       For	      SOCK_STREAM TCP sockets, on return the integer with the address arg is non-zero if the inbound TCP stream has been  read	up
		      to  where the out-of-band data byte starts.  Otherwise, the inbound TCP stream has not yet been read up to where the out-of-
		      band data byte starts.  For sockets other than SOCK_STREAM TCP sockets, on return the integer with the address arg is always
		      zero.

       This request sets the process group or process
		      ID associated with the socket to be the value of the integer with the address arg.  A process group or process ID associated
		      with the socket in this manner is signaled when the state of the socket changes: is delivered upon the  receipt  of  out-of-
		      band  data; is delivered if the socket is asynchronous, as described in below.  If the value of the integer with the address
		      arg is positive, the signal is sent to the process whose process ID matches the value specified.	If the value is  negative,
		      the  signal  is  sent to all the processes that have a process group equal to the absolute value of the value specified.	If
		      the value is zero, no signal is sent to any process.  It is necessary to issue this request with a non-zero integer value to
		      enable the signal delivery mechanism described above.  The default for the process group or process ID value is zero.

       This request returns the process group or process
		      ID  associated  with  the socket in the integer with the address arg.  See the explanation for above for more details on the
		      meaning of the integer value returned.

       If the integer whose address is
		      arg is non-zero, this request sets the state of the socket as asynchronous.  Otherwise, the socket is put  into  synchronous
		      mode (the default).  Asynchronous mode enables the delivery of the signal when either of the following conditions is met.

			   o  New data arrives.

			   o  For  connection-oriented protocols, whenever additional outgoing buffer space becomes available or the connection is
			      established or broken.

		      The process group or process ID associated with the socket must be non-zero in order for signals to be sent. The	signal	is
		      delivered according to the semantics of described above.

       The fcntl(2) and flags (defined in are supported by sockets.  If the flag is set, the socket is put into POSIX-style non-blocking mode.	If
       the flag is set, the socket is put into non-blocking mode.  Otherwise, the socket is put into blocking mode.  Blocking mode is the default.
       See accept(2), connect(2), recv(2), and send(2) for an explanation of how these forms of non-blocking mode are used.

       Since  the  and flags and requests are supported, the following clarifies on how these features interact.  If the or flag has been set, and
       requests behave accordingly, regardless of any requests.  If neither the flag nor the flag has been set, requests control the the  behavior
       of and

DEPENDENCIES

   AF_CCITT Only
       Only the and requests are defined for sockets.

AUTHOR

       was developed by the University of California, Berkeley.

SEE ALSO

       fcntl(2), getsockopt(2), ioctl(2), socket(2).

																	 socket(7)