send(3N)                NETWORK FUNCTIONS                send(3N)



NAME
     send, sendto, sendmsg - send a message from a socket

SYNOPSIS
     #include <sys/types.h>
     #include <sys/socket.h>

     int send(s, msg, len, flags)
     int s;
     char *msg;
     int len, flags;

     int sendto(s, msg, len, flags, to, tolen)
     int s;
     char *msg;
     int len, flags;
     struct sockaddr *to;
     int tolen;

     int sendmsg(s, msg, flags)
     int s;
     struct msghdr *msg;
     int flags;

DESCRIPTION
     s is a socket created with  socket(3N).   send(),  sendto(),
     and  sendmsg()  are  used  to  transmit a message to another
     socket.  send() may be used only when the  socket  is  in  a
     connected state, while sendto() and sendmsg() may be used at
     any time.

     The address of the target is given by to with tolen specify-
     ing  its  size.   The length of the message is given by len.
     If the message is too long to pass  atomically  through  the
     underlying  protocol,  then  the error EMSGSIZE is returned,
     and the message is not transmitted.

     No indication of failure to deliver is implicit in a send().
     Return values of -1 indicate some locally detected errors.

     If no buffer space is available at the socket  to  hold  the
     message  to  be  transmitted,  then  send() normally blocks,
     unless the socket has been placed in non-blocking  I/O  mode
     (see  fcntl(2)).  The select() call may be used to determine
     when it is possible to send more data.

     The flags parameter is formed by ORing one or  more  of  the
     following:

     MSGOOB   Send out-of-band data on sockets that support this
               notion.  The underlying protocol must also support
               out-of-band  data.   Currently,  only  SOCKSTREAM



                          Last change:                          1

send(3N)                NETWORK FUNCTIONS                send(3N)



               sockets created in the AFINET address family sup-
               port out-of-band data.

     MSGDONTROUTE
               The SODONTROUTE option is turned on for the dura-
               tion  of  the operation.  It is used only by diag-
               nostic or routing programs.

     See recv(3N) for a description of the msghdr structure.

RETURN VALUE
     These calls return the number of bytes sent,  or  -1  if  an
     error occurred.

ERRORS
     The calls fail if:

     EBADF               s is an invalid descriptor.

     ENOTSOCK            s is a descriptor  for  a  file,  not  a
                         socket.

     EINVAL              tolen is not the size of a valid address
                         for the specified address family.

     EINTR               The   operation   was   interrupted   by
                         delivery  of  a  signal  before any data
                         could be buffered to be sent.

     EMSGSIZE            The socket requires that message be sent
                         atomically,  and  the  message  was  too
                         long.

     EWOULDBLOCK         The socket is  marked  non-blocking  and
                         the requested operation would block.

     ENOMEM              There  was  insufficient   user   memory
                         available for the operation to complete.

     ENOSR               There    were    insufficient    STREAMS
                         resources available for the operation to
                         complete.

SEE ALSO
     connect(3N), fcntl(2), getsockopt(3N), recv(3N), socket(3N),
     write(2).









                          Last change:                          2