<< Click to Display Table of Contents >> Navigation:  WinLicense > FAQ > Registration > Common > How do I check to see if a license has a resistration date set? When I use the function WLRegExpirationDate(addr(TrialDate)) with no expiration date set then I receive an error "invalid argument to encode date"

If you don’t insert Expiration date in the license, the return value for WLRegExpirationDate is -1

 

You should not display the date if you get -1 as the SYSTEMTIME structure is filled with 0,0,0

 

If you are generating license keys with different expiration restrictions (by days, executions, date...) You can first call the function WLRegGetLicenseRestrictions to know the restrictions in the current license.