Creating DLL... need some assistance

I'm working on creating a DLL file with C++, and I need to pass it 2 date values. What it needs to do from there is determine which days are working days in between the 2 dates that were passed.

We have a text file which maintains days that are holidays and other days when the office is closed. So this we'll use to filter some things out.

Anyone know where I can read up on this? Any examples of date related DLL files?

Thanks in advance,
- Cam

it is you pass in 2 date variable and let the dll determine which is the current day? if neither one is the current day, what the return value?