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send(2)								      send(2)



NAME
  send - Sends messages	on a socket

SYNOPSIS

  #include <&lt;sys/socket.h>&gt;
  ssize_t send (
	  int socket,
	  const	void *buffer,
	  size_t length,
	  int flags );

   [Tru64 UNIX]	 The following definition of the send()	function  does not
  conform to current standards and is supported	only for backward compatibil-
  ity (see standards(5)):

  int send (
	  int socket,
	  char *message,
	  int length,
	  int flags );

STANDARDS

  Interfaces documented	on this	reference page conform to industry standards
  as follows:

  send():  XNS5.0

  Refer	to the standards(5) reference page for more information	about indus-
  try standards	and associated tags.

PARAMETERS

  socket    Specifies the unique name for the socket.

  buffer    Points to the buffer containing the	message	to send.

  length    Specifies the length of the	message	in bytes.

  flags	    Allows the sender to control the transmission of the message.
	    The	flags parameter	to send	a call is formed by logically ORing
	    the	values shown in	the following list, defined in the
	    sys/socket.h header	file:

	    MSG_OOB   Sends out-of-band	data on	sockets	that support out-of-
		      band communication.

	    MSG_DONTROUTE
		      Sends without using routing tables.  (Not	recommended,
		      for debugging purposes only.)


DESCRIPTION

  The send() function sends a message only when	the socket is connected	(this
  includes when	the peer of a connectionless socket has	been set with a	con-
  nect() call).	 The sendto() and sendmsg() functions can be used with uncon-
  nected or connected sockets.

  Specify the length of	the message with the length parameter.	If the mes-
  sage is too long to pass through the underlying protocol, the	system
  returns an error and does not	transmit the message.

  No indication	of failure to deliver is implied in a send() function.	A
  return value of -1 indicates only locally detected errors.

  If no	space for messages is available	at the sending socket to hold the
  message to be	transmitted, the send()	function blocks	unless the socket is
  in a nonblocking I/O mode.  Use the select() function	to determine when it
  is possible to send more data.

  The socket in	use may	also require that the calling process have appropri-
  ate privileges.

NOTES

  [Tru64 UNIX]	 The send() function is	identical to the sendto() function
  with a zero-valued dest_len parameter, and to	the write() function if	no
  flags	are used.  For that reason, the	send() function	is disabled when
  4.4BSD behavior is enabled (that is, when the	_SOCKADDR_LEN compile-time
  option is defined).

RETURN VALUES

  Upon successful completion, the send() function returns the number of	char-
  acters sent.	Otherwise, a value of -1 is returned and errno is set to
  indicate the error.

ERRORS

  If the send()	function fails,	errno may be set to one	of the following
  values:

  [EACCES]  The	calling	proces does not	have the appropriate privileges.

  [EBADF]   The	socket parameter is not	valid.

  [ECONNRESET]
	    A connection was forcibly closed by	a peer.

  [EDESTADDRREQ]
	    The	socket is not connection-oriented and no peer address is set.

  [EFAULT]  The	buffer parameter cannot	be accessed.

	    [Tru64 UNIX]  The message parameter	is not in a readable or	writ-
	    able part of the user address space.

  [EINTR]   A signal interrupted send before any data was transmitted.

  [EIO]	    An I/O error occurred while	reading	from or	writing	to the file
	    system.

  [EMSGSIZE]
	    The	message	is too large to	be sent	all at once, as	the socket
	    requires.

  [ENETDOWN]
	    The	local network connection is not	operational.

  [ENETUNREACH]
	    The	destination network is unreachable.

  [ENOBUFS] Insufficient resources were	available in the system	to complete
	    the	call.

  [ENOSR]   The	available STREAMS resources were insufficient for the opera-
	    tion to complete.

  [ENOTCONN]
	    The	socket is not connected	or otherwise has not had the peer
	    prespecified.

  [ENOTSOCK]
	    The	socket parameter refers	to a file, not a socket.

  [EOPNOTSUPP]
	    The	socket argument	is associated with a socket that does not
	    support one	or more	of the values set in flags.

  [EPIPE]   The	socket is shut down for	writing, or the	socket is
	    connection-oriented	and the	peer is	closed or shut down for	read-
	    ing. In the	latter case, and if the	socket is of type
	    SOCK_STREAM, the SIGPIPE signal is generated to the	calling	pro-
	    cess.

  [EWOULDBLOCK]
	    The	socket is marked nonblocking, and no space is available	for
	    the	send() function.

RELATED	INFORMATION

  Functions: connect(2), getsockopt(2),	poll(2), recv(2), recvfrom(2),
  recvmsg(2), select(2), sendmsg(2), sendto(2),	setsockopt(2), shutdown(2),
  socket(2),

  Standards: standards(5)