It works if I replace the 'bool' return type of 'finished' with int and CInt on the C++ and Haskell side, respectively, and test for (/= 0). On Mon, May 2, 2011 at 9:35 PM, Huynh Huu Long wrote:

Hi, I tried to access C++ iterators from Haskell via the FFI. There are two example programs attached, in Haskell as well as in C++. Both utilise the same iterator wrapper example.cpp, but when running the Haskell program it prints an empty list, where it should print the contents of some vector. The C++ program meanwhile runs fine though. What does not seem to work is this part: bool finished (std::vector<int>::iterator *begin, std::vector<int>::iterator *end) {     return *begin == *end; } In Haskellland, "finished :: Ptr Iterator -> Ptr Iterator -> IO Bool" always returns IO True. Is this a bug lurking in my program or is it a GHC issue? Long _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

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