On Jul 17, 2008, at 5:36 PM, Max Taylor wrote: > > What if I wanted to send a 'short' or a 'pointer' or a 'single', or > a 'double' to the above example once it has been DEF'd? > To quote the reference manual: "The number, order, and data types of the parameters in the Def Fn Using <Fn address> list must match the number, order, and data types in the parameter list of the referenced function" Good try but Def FN using is not the answer for what you seek( but keep reading ). > Could the number and type of the parameters be totally dynamic? > > Is it possible to build such a FN? The question's timing is good. Recently, the FBtoC team ( mostly Bernie ) pondered how to use a Core Foundation call that accepts a variable number of parameters ( CFStringCreateWithFormat ) without interfering with the possible use of the same call by the FBer's code. A PASSTHROUGH solution is possible but ugly. Bernie did some research and came up with the va_start and va_list C macros. The work is still in progress ( and experimental ---so no promises ) and hasn't been submitted to the team yet, but initial work is promising. So, yes there is a possibility that calling user FNs with multiple parms is possible. However, when/if implemented it will be FBtoC-only. Brian S.