recv(2)                    DG/UX 4.30                     recv(2)



     NAME
          recv - Receive a message from a socket.

     SYNOPSIS
          #include <sys/socket.h>

          int   recv  (s, buf, len, user_flags)
          int             s;
          char *          buf;
          int             len;
          int             user_flags;

     PARAMETERS
          s              File descriptor of socket to receive data
                         from.


          buf            Buffer for data.


          len            Length of buffer for data (bytes).


          user_flags     Flags for transfer.

     DESCRIPTION
          This call can only be used with connected sockets.

          If the message is too long to fit in the supplied buffer,
          excess bytes may be discarded depending on the type of
          socket the message is received from; datagram sockets
          truncate messages, stream sockets don't preserve packet
          boundaries so only the amount of data requested is received
          with no loss of data.

          The user_flags argument is constructed by or-ing zero or
          more literals beginning with "MSG_".  See <sys/socket.h> for
          a description of what flags exist and what they do.

          If no messages are available at the socket, the call waits
          for a message to arrive, unless the socket is nonblocking
          (see ioctl).  In that case, an error EAGAIN will be
          returned.

          The select call may be used to determine when more data
          arrives.

     ACCESS CONTROL
          None.

     RETURN VALUE
          Recv() returns the number of bytes received.



     Licensed material--property of copyright holder(s)         Page 1

     recv(2)                    DG/UX 4.30                     recv(2)



          0..<len>       Number of bytes transferred.


          -1             An error occurred.  Errno is set to indicate
                         the error.

     EXCEPTIONS
          Errno may be set to one of the following error codes:


          EBADF          The argument <s> is not an active valid
                         descriptor.


          ENOTSOCK       The argument <s> is not a socket.


          EAGAIN         The socket is marked non-blocking and the
                         receive operation would block.


          EINTR          The receive was interrupted by delivery of a
                         signal before any data was available for the
                         receive.


          EFAULT         The data was specified to be received into a
                         non-existent or protected part of the process
                         address space.


          EINVAL         Invalid argument.


          ENOTCONN       The socket is not connected.  Use
                         recvfrom(2).


          EOPNOTSUPP     The <flags> argument included the MSG_OOB
                         flag applied to a UDP socket.

     SEE ALSO
          The related manual sections:  read(2), send(2), socket(2).












     Licensed material--property of copyright holder(s)         Page 2