Well, the problem is not to use the pointer type as such, but compatibility issue. I have this function behaving like malloc, and other functions which take pointers to - let's say - float. Since malloc returns void* I suspect the problems I experience are due to this mismatch. Justin Collins schrieb: > Thorsten Hater wrote: >> Hello, >> >> I'm playing around with FFI and encountered a problem, I could not solve >> till now. >> Let's assume I use standard C's malloc in my wrapper: >> >> attach_function :malloc, [:int], :pointer >> >> so far no problem. But what now? The pointer returned is of type void*, >> which is of no help, since I need double*, int* and float* ... >> Is there a type cast mechanism in FFI (or anything similar) or do I >> have to wrap >> the original library in another layer of C (alternatively write a >> helper lib...) >> Or can I import C's typecasts using FFI itself? >> >> Best regards, >> Thorsten >> >> > > If nothing else, you can use the read_* and write_* methods (like > read_int) to interact with it. > > -Justin >