send(3N)                                                           send(3N)

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

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

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

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

     int sendmsg(int s, const 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 specifying 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() 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 sock-
                      ets created in the AFINET address family support
                      out-of-band data.

     MSGDONTROUTE    The SODONTROUTE option is turned on for the duration
                      of the operation. It is used only by diagnostic 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.





Page 1                       Reliant UNIX 5.44                Printed 11/98

send(3N)                                                           send(3N)

DIAGNOSTICS
     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           The user memory available was not sufficient to com-
                      plete the operation.

     ENOSR            The STREAMS resources available were not sufficient
                      to complete the operation.

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


























Page 2                       Reliant UNIX 5.44                Printed 11/98