Hello, I'm using the following cabal file to build a shared library with ghc: Build-Type: Simple Executable libmylibrary.dll If os(windows) CPP-Options: -DWIN32 Extensions: ForeignFunctionInterface Build-Depends: ... Main-Is: libmylibrary.hs Ghc-Options: -W --make -no-hs-main -optl-shared -optl-s -O2 The resulting library is called from a C++ graphical user interface (using Qt), which worked great so far on Windows and Linux. However, the compilation fails on MacOS X: Undefined symbols: "_ZCMain_main_closure", referenced from: _ZCMain_main_closure$non_lazy_ptr in libHSrts.a(Main.o) "___stginit_ZCMain", referenced from: ___stginit_ZCMain$non_lazy_ptr in libHSrts.a(Main.o) ld: symbol(s) not found collect2: ld returned 1 exit status I don't know much about shared libraries, even less about them on MacOS X :( Any idea ? Jean-Denis Koeck