send(2) 							System Calls Manual							   send(2)

NAME

       send - Sends messages on a socket

SYNOPSIS

       #include <sys/socket.h>
       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
       compatibility (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 industry standards and associated tags.

PARAMETERS

       Specifies the unique name for the socket.  Points to the buffer containing the message to send.	Specifies the length  of  the  message	in
       bytes.	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: Sends out-of-band data on  sockets	that  support  out-of-band
       communication.  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 connect() call).	The sendto() and sendmsg() functions can be used with unconnected or connected sockets.

       Specify the length of the message with the length parameter.  If the message is too long to pass through the underlying protocol, the  sys-
       tem 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 appropriate 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 characters 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: The calling proces does not have the appropriate privileges.
       The socket parameter is not valid.  A connection was forcibly closed by a peer.	The socket is not connection-oriented and no peer  address
       is set.	The buffer parameter cannot be accessed.

	      [Tru64  UNIX]  The  message  parameter  is  not in a readable or writable part of the user address space.  A signal interrupted send
	      before any data was transmitted.	An I/O error occurred while reading from or writing to the file system.  The message is too  large
	      to  be  sent  all  at  once,  as	the socket requires.  The local network connection is not operational.	The destination network is
	      unreachable.  Insufficient resources were available in the system to complete the call.  The available STREAMS resources were insuf-
	      ficient  for  the  operation  to	complete.  The socket is not connected or otherwise has not had the peer prespecified.	The socket
	      parameter refers to a file, not a socket.  The socket argument is associated with a socket that does not support one or more of  the
	      values  set in flags.  The socket is shut down for writing, or the socket is connection-oriented and the peer is closed or shut down
	      for reading. In the latter case, and if the socket is of type SOCK_STREAM, the SIGPIPE signal is generated to the  calling  process.
	      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), shut-
       down(2), socket(2),

       Standards: standards(5) delim off

																	   send(2)