Dear all, maybe this is a piece of c2hs behaviour I missed to understand, but it appears happening with C++ style includes deep in the header call hierarchy – in case of a such backend C++ library, if one wishes to refer to by *.h's in c2hs (e.g. for access to types of it), one might have a problem. - 8< cSample.h --------------------------------------------- #include <iostream> ///////// here, with c2hs, leading to build abort #ifdef __cplusplus extern "C" { #endif void sampleFunction(); #ifdef __cplusplus } #endif - 8< cSample.cpp --------------------------------------------- #include "cSample.h" #include <iostream> ///////// here no problem void sampleFunction(){ std::cout << "OK" << std::endl; } - 8< ---------------------------------------------------------------- While 'old school' FFI (foreign import ccall) handles this effortlessly, c2hs uses to abort with an exception like C/cSample.h:3:20: fatal error: iostream: No such file or directory compilation terminated. I see that hsqml gets around this, but apparently by tweaking Setup.hs in a way not quite trivial – would this be necessary in any case, or are there simpler alternatives? Please excuse if I oversaw something, but I am afraid I didn't see this interesting issue covered elsewhere. Thank you a lot in advance & cheers, Nick