{   The purpose of this request is to allow an application to identify
{ itself to MLI so that other applications can send messages to it.
{ MLI records the name of the application and initializes internal
{ tables which are used for MLI communication.
{
{        MLP$SIGN_ON (APPLICATION_NAME, MAX_MESSAGES, UNIQUE_APPLICATION_NAME,
{          STATUS)
{
{ APPLICATION_NAME: (input) This parameter specifies the application
{        name by which the calling program wishes to be identified to
{        MLI and other applications.  If a NULL value is given for this
{        parameter, a unique name will be generated by MLI and returned
{        in the unique_application_name parameter.
{
{ MAX_MESSAGES: (input) This parameter specifies the maximum number of
{        messages that can be sent to the application at one time (i.e.,
{        the maximum number of unreceived messages that can be queued
{        for the application). If the value of this parameter is zero then
{        a maximum of mlc$max_in_transit messages will be queued from the
{        same or different senders.  This is the only condition where a
{        sender can have more than one message outstanding to the same
{        receiver.  The maximum value for this parameter is mlc$max_queued_messages.
{
{ UNIQUE_APPLICATION_NAME: (output) If the value of the application_name parameter
{        is mlc$unique_name then this parameter will contain a unique application
{        name which must be used on all other mlp$ requests when referencing this
{        "instance" of sign on.  If the value of the application_name parameter
{        is not mlc$unique_name then this parameter will contain a copy of the
{        application_name parameter.
{
{ STATUS: (output) This parameter specifies the request status.
{        The following status values may be returned by this request:
{           mlc$ant_full
{           mlc$busy_interlock
{           mlc$max_msgs_too_large
{           mlc$max_signons_this_appl
{           mlc$max_signons_this_task
{           mlc$mli_internal_error
{           mlc$ok
{           mlc$pool_buffer_not_avail
{           mlc$receiver_name_syntax_error
{           mlc$system_name_no_match
{

