{
{   The purpose of this request is to determine why a command or function
{ processor was called.  Normally, of course, the command or function is to be
{ processed; but a command or function processor may also be called as a
{ result of a call to the display_command/function_information command or its
{ equivalent.  In the latter case it is the responsibility of the command or
{ function processor to display the appropriate information.
{
{   Most command and function processors need not concern themselves with this
{ aspect of interfacing with SCL since they call clp$evaluate_parameters and
{ that request takes care of it for them.  This request is provided for those
{ command and function processors that, for whatever reason, don't use
{ clp$evaluate_parameters.
{
{       CLP$GET_REASON_FOR_CALL (INFORMATION_REQUEST, DISPLAY_FILE,
{         PROMPTING_ACTIVATED, STATUS)
{
{ INFORMATION_REQUEST: (output)  This parameter specifies whether the current
{       command or function processor was called to just provide information
{       (TRUE) or actually process the command or function (FALSE).
{
{ DISPLAY_FILE: (output)  This parameter specifies the file to which
{       information about the command or function is to be displayed.  This
{       parameter is meaningless (and set to all blanks) when FALSE is
{       returned for INFORMATION_REQUEST.
{
{ PROMPTING_ACTIVATED: (output)  This parameter specifies whether the command
{       or function processor should prompt for missing or erroneous
{       parameters (TRUE) or not (FALSE).  This parameter is meaningless (and
{       set to FALSE) when TRUE is returned for INFORMATION_REQUEST.
{
{ STATUS: (output)  This parameter specifies the request status.
{
