Using C-Predicates in Eclipse

Hiho,
I want to use some C-methods in Eclipse. I use Windows, so I have a compiled
file ("main.exe"), which I can load with "load("main.exe").". This call
worked, but the next call "external(myFunc/2, p_myFunc)." failed with this
error :
External function does not exist in external_(myFunc/ 2, p_myFunc, eclipse)
There is a function with the interface "int myFunc()" in my C-program, so I
do not know, what I did wrong. Could anybody help me ?

Georg