

Sockets Library Functions                         accept(3SOCKET)


NAME
     accept - accept a connection on a socket

SYNOPSIS
     cc [ _f_l_a_g ... ] _f_i_l_e ... -lsocket -lnsl [ _l_i_b_r_a_r_y ... ]
     #include <sys/types.h>
     #include <sys/socket.h>

     int  accept(int  s,   struct   sockaddr   *addr,   socklen_t
     *addrlen);

DESCRIPTION
     The argument _s is  a  socket  that  has  been  created  with
     socket(3SOCKET)  and bound to an address with bind(3SOCKET),
     and that is  listening  for  connections  after  a  call  to
     listen(3SOCKET).  The  accept()  function extracts the first
     connection on the queue of pending  connections,  creates  a
     new  socket  with  the  properties of _s, and allocates a new
     file descriptor, _n_s, for the socket. If no  pending  connec-
     tions  are present on the queue and the socket is not marked
     as non-blocking, accept() blocks the caller until a  connec-
     tion is present. If the socket is marked as non-blocking and
     no pending connections are present on  the  queue,  accept()
     returns  an error as described below.  The accept() function
     uses the netconfig(4) file to determine the  STREAMS  device
     file name associated with _s.
      This is the device on which the connect indication will  be
     accepted. The accepted socket, _n_s, is used to read and write
     data to and from the socket that connected to _n_s; it is  not
     used  to  accept  more  connections. The original socket (_s)
     remains open for accepting further connections.

     The argument _a_d_d_r is a result parameter that  is  filled  in
     with  the address of the connecting entity as it is known to
     the communications layer.  The  exact  format  of  the  _a_d_d_r
     parameter  is determined by the domain in which the communi-
     cation occurs.

     The argument _a_d_d_r_l_e_n is a value-result parameter. Initially,
     it  contains  the  amount  of  space  pointed to by _a_d_d_r; on
     return it contains  the  length  in  bytes  of  the  address
     returned.

     The accept() function is used with  connection-based  socket
     types, currently with SOCK_STREAM.

     It is possible to select(3C) or poll(2)  a  socket  for  the
     purpose  of  an  accept()  by  selecting or polling it for a
     read. However, this will only indicate when a connect  indi-
     cation is pending; it is still necessary to call accept().


SunOS 5.8           Last change: 16 May 1997                    1


Sockets Library Functions                         accept(3SOCKET)


RETURN VALUES
     The accept() function returns -1 on error. If  it  succeeds,
     it  returns  a non-negative integer that is a descriptor for
     the accepted socket.

ERRORS
     accept() will fail if:

     EBADF The descriptor is invalid.

     EINTR The accept attempt was interrupted by the delivery  of
           a signal.

     EMFILE
           The per-process descriptor table is full.

     ENODEV
           The protocol family and type corresponding to  _s could
           not be found in the netconfig file.

     ENOMEM
           There was insufficient user memory available  to  com-
           plete the operation.

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

     ENOTSOCK
           The descriptor does not reference a socket.

     EOPNOTSUPP
           The referenced socket is not of type SOCK_STREAM.

     EPROTO
           A  protocol  error  has  occurred;  for  example,  the
           STREAMS protocol stack has not been initialized or the
           connection has already been released.

     EWOULDBLOCK
           The socket is marked as non-blocking  and  no  connec-
           tions are present to be accepted.

ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |______________________________|______________________________|
    | MT-Level                    | Safe                        |
    |______________________________|______________________________|


SunOS 5.8           Last change: 16 May 1997                    2


Sockets Library Functions                         accept(3SOCKET)


SEE ALSO
     poll(2), bind(3SOCKET),  connect(3SOCKET),  listen(3SOCKET),
     select(3C),  socket(3SOCKET),  netconfig(4),  attributes(5),
     socket(3HEAD)


SunOS 5.8           Last change: 16 May 1997                    3