SYNTAX        VHA_INTRPT(P1)

PURPOSE       Detects key presure

ARGUMENTS     P1 - CHARACTER of ARRAY (numeric)
                 - OPTIONAL
                 - key(s) to be detected

RETURNS       LOGICAL
               .T. if key is pressed
               .F. if key not pressed

              Example:

                 DO WHILE .NOT. VHA_INTRPT()
                    ....
                    ....
                    ....
                 ENDDO