recvmsg(2)                 DG/UX 4.30                  recvmsg(2)



     NAME
          recvmsg - Receive a message from a socket.

     SYNOPSIS
          #include <sys/socket.h>

          int   recvmsg  (s, msg, user_flags)
          int             s;
          struct msghdr * msg;
          int             user_flags;

     PARAMETERS
          s              File descriptor of socket to receive from.


          msg            Pointer to receive msg packet.


          user_flags     Flags for transfer.

     DESCRIPTION
          This call is identical to recv or recvfrom depending on
          whether or not the msg_namelen fields are greater than zero.
          If the <msg_namelen> field of the msghdr structure is non-
          zero, this call is identical to recvfrom, otherwise it is
          identical to recv.

          The added value of this call is that it allows an IOV to be
          supplied in the msg packet for use of non-contiguous buffers
          (see readv for more information about IOV structures).

     ACCESS CONTROL
          None.

     RETURN VALUE
          These calls return the number of bytes received.


          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.





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     recvmsg(2)                 DG/UX 4.30                  recvmsg(2)



          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.


          EMSGSIZE       Too many entries in the iovec array.

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

































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