Some given C functions receive pointers and manipulate the memory where the pointers are pointing to. How should my c-lamda expression look like to mach that requirement? Here's a simple example (not real, but to show my problem). If the given C Funktion looks like that: void inc_int(int *pI) { (*pI)++; } Is it then Ok to use it from Gambit 4.0 beta 11 like follows? (define inc-int (c-lambda ((pointer int)) void "inc_int")) If yes: what can I pass to inc-int? How to express the Scheme equivalent to the C pointer? Otherwise: how should my Scheme procedure definition look like? Of course the example above is a very simple one. A good solution should also work with more complicated C functions, e.g. of type int () (int *, char **). Regards Thomas Hafner