Date 4GL incompatibility

SOLVED

Hi, 

How do I write this 4gl statement for a Date Datatype?

Subprog C_DAT(VALEUR)
Variable Date VALEUR

If VALEUR = ""
mkstat=2
GMESSAGE = "Date is Mandatory"
Endif
End

This is throwing an incompatibility error because I think you cant write "" to represent a blank field in 4gl. How can I write this if the field is left blank?

Thank you!