To check the dates against the system dates in VuGen :
VuGen provides a date/time parameter
VuGen provides the lr_save_datetime() function to create a date or time parameter.
This function can be used to get date or time values in multiple formats. It also allows for offsets from the current system date/time. For more details and examples, see the Online Function Reference Guide.
Once the date has been saved into a parameter, you can convert to a string using the lr_eval_string function. Comparison or other operations can then be applied to it using standard ANSI C string functions.