Hi I'm attempting to call a function in a shared library from a VBA macro in Mac excel. This is a typical c function: extern "C" bool SetBootstraps(int nBootstraps) In VBA I have it declared as: declare function SetBootstraps lib "mylib" (nBootstraps as long) as Boolean When I attempt to run this via the c debugger I don't get the value passed down to excel that I would expect. What do I have to do to pass variables down correctly. Do I need to use CDecl in the VBA or do I need to use pascal in the C. Which is correct. Also am I correct in thinking that the following is correct VBA C Integer short Long int Double double Boolean bool Thanks Ian