Here are 3 examples of the kind of DECLAREs I'm dealing with.

Declare Function Dur1& LIB "dur.dll" ()
Declare Function Dur2% LIB "dur.dll" (ByVal Indx&, ByVal Item$, ErrorStat%)
Declare Sub Dur3 LIB "dur.dll" (ByVal Indx&, ByVal Item$, ErrorStat%)

If it just requires trial and error, I'll manage.