listen(2)                  DG/UX 4.30                   listen(2)



     NAME
          listen - Listen for connections on a socket.

     SYNOPSIS
          int   listen  (s, backlog)
          int             s;
          int             backlog;

     PARAMETERS
          s              File descriptor of socket to listen on.


          backlog        Maximum number of waiting connections.

     DESCRIPTION
          To accept connections, a socket is first created with
          socket(), a backlog for incoming connections is specified
          with listen(), and then the connections are accepted with
          accept().  The listen call applies only to sockets of type
          SOCK_STREAM or SOCK_PKTSTREAM.

          The <backlog> parameter defines the maximum length to which
          the queue of pending connections may grow.  If a connection
          request arrives with the queue full, the client will receive
          the error [ECONNREFUSED].

          In DG/UX the backlog is currently limited to SOMAXCONN.  If
          a backlog greater than SOMAXCONN is specified, the backlog
          will be set SOMAXCONN; however no error notification will be
          returned.  SOMAXCONN is defined in <sys/socket.h>.

     ACCESS CONTROL
          None.  (See domain-specific restrictions in related
          documentation.)

     RETURN VALUE
          0              Completed successfully.


          -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.




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

     listen(2)                  DG/UX 4.30                   listen(2)



          EOPNOTSUPP     The socket is not of a type that supports the
                         operation listen.


          EINVAL         Invalid argument.

     SEE ALSO
          The related manual sections:  inet(3N), inet(6F),
          unix_ipc(6F), accept(2), connect(2), socket(2).














































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