import socket
import select


def createSocketpair( nUsePortnumberToEmulateSocketpair ):
    # See if socketpair() is available.
    bSocketpairImplemented = True
    try:
        hIPCConnectionEnd0, hIPCConnectionEnd1 = socket.socketpair( socket.AF_INET, socket.SOCK_STREAM )
    except AttributeError:
        # If we get this exception, that means socketpair() is not implemented, so we need to emulate it.
        bSocketpairImplemented = False

    if bSocketpairImplemented == True:
        return hIPCConnectionEnd0, hIPCConnectionEnd1
    
    # Create an IPC socket and set it to nonblocking mode.
    hIPCConnectionEnd0 = socket.socket( socket.AF_INET, socket.SOCK_STREAM )
    hIPCConnectionEnd0.setblocking( 0 )

    # Create a temporary server socket and make it non-blocking. Bind it to the port number
    # we've been given and set it up to listen for incoming connections.
    hTempServerSocket = socket.socket( socket.AF_INET, socket.SOCK_STREAM )
    hTempServerSocket.setblocking( 0 )
    hTempServerSocket.bind( ( '', nUsePortnumberToEmulateSocketpair ) )
    hTempServerSocket.listen( 1 )

    try:
        hIPCConnectionEnd0.connect( ( '', nUsePortnumberToEmulateSocketpair ) )
    except socket.error, TheError:
        # Error 10035 (operation would block) is not an error, as we're doing this with a non-blocking socket.
        if TheError[ 0 ] != 10035:
           raise 
        
    # Use select to wait up to 4 seconds for the connect() to succeed.
    vMonitorReadable = [ hTempServerSocket ]

    vReadable, vWriteable, vInError = select.select( vMonitorReadable, [], [], 4.0 )

    # See if the connect worked.
    if not hTempServerSocket in vReadable:
        print "Damn, server socket not in set of readable sockets."
        #raise socket.timeout


    # If we reach this line, the connect() must have succeeded. We can now call accept().
    hhIPCConnectionEnd1, tAddress = hTempServerSocket.accept()

    return ( hIPCConnectionEnd0, hhIPCConnectionEnd1 )

    
# Just a little list.
createSocketpair( 20000 )