{
{    The purpose of this procedure is to access the channel connection for
{ which the given message is destined.  The channel connection is accessed via
{ a non exclusive to the root.  The given reference number is used to find the
{ channel connection and the message is validated as belonging to the
{ referenced channel connection.  If the channel connection has the 'queue on
{ connection' attribute set and the message is other than a connect or a
{ disconnect PDU, it is queued on the channel connection and the cooresponding
{ receiver task is readied.  If the 'queue on connection' attribute is not set,
{ the requested information is returned from the channel connection.
{
{       NLP$CL_VALIDATE_AND_OPTIONAL_Q (MESSAGE_DESCRIPTOR, CC_PDU_KIND,
{             REFERENCE_NUMBER, CONSUME_SEQUENCE_NUMBER, VALIDATION_COMPLETE,
{             REFERENCE_NUMBER_VALID, MESSAGE_QUEUED, RECEIVER, SENDER)
{
{ MESSAGE_DESCRIPTOR: (input, output)  This parameter contains the pointer to
{       the message.
{
{ CC_PDU_KIND: (input) This parameter specifies the kind of the received
{       channel connection event.
{
{ RERERENCE_NUMBER: (input)  This parameter contains the reference number of
{       the channel connection for which the message is destined.
{
{ CONSUME_SEQUENCE_NUMBER: (input)  This parameter specifies whether or not a
{        Channel Connection sequence number should be consumed (i.e., whether
{        or not a unique sequence number should be assigned).  Note that only
{        data PDUs consume sequence numbers.  A disconnect or disconnect PDU
{        will not consume sequence numbers.
{
{ VALIDATION_COMPLETE: (output)  This parameter specifies whether validation
{        of the reference number was possible.  If the procedure was unable to
{        obtain access to the connection list, validation is not possible and
{        this parameter will be set to FALSE.
{
{ REFERENCE_NUMBER_VALID: (output)  This parameter specifies whether the
{        reference number is valid (i.e., whether the connection exists).  This
{        parameter is valid only if the value of the VALIDATION_COMPLETE
{        parameter is TRUE.
{
{ MESSAGE_QUEUED: (output)  This parameter is set to TRUE if the given message
{       was queued on the channel connection.  Note that if the message is not
{       going to consume sequence number it is not queued on the channel
{       connection.
{
{ RECEIVER: (output)  This parameter specifies the last task recorded as a
{        receiver.
{
{ SENDER: (output)  This parameter specifies the last task recorded as a
{        sender.
{
