Hi, I made a lib from a cpp project with one function: BOOL Foo(LPCSTR bar) In the stack project I added the .lib file's folder to the extra-lib-dirs/extra-include-dirs and then, in main: {-# LANGUAGE ForeignFunctionInterface #-} module Main where import System.Win32.Types import Foreign.C.String main :: IO () main = do withCString "bar" c_Foo putStrLn "success" foreign import ccall "bindings.lib Foo" c_Foo :: LPCSTR -> IO BOOL When building I get the following error Building all executables for `tape' once. After a successful build of all of them, only specified executables will be rebuilt. tape-0.1.0.0: build (lib + exe) Preprocessing library for tape-0.1.0.0.. Building library for tape-0.1.0.0.. ignoring (possibly broken) abi-depends field for packages Preprocessing executable 'tape-exe' for tape-0.1.0.0.. Building executable 'tape-exe' for tape-0.1.0.0.. Linking .stack-work\dist\7d103d30\build\tape-exe\tape-exe.exe ... .stack-work\dist\7d103d30\build\tape-exe\tape-exe-tmp\Main.o:fake:(.text+0x102): undefined reference to `CreateDebuggedProcess' collect2.exe: error: ld returned 1 exit status `gcc.exe' failed in phase `Linker'. (Exit code: 1) -- While building custom Setup.hs for package tape-0.1.0.0 using: C:\sr\setup-exe-cache\x86_64-windows\Cabal-simple_Z6RU0evB_2.2.0.1_ghc-8.4.3.exe --builddir=.stack-work\dist\7d103d30 build lib:tape exe:tape-exe --ghc-options " -ddump-hi -ddump-to-file -fdiagnostics-color=always" Process exited with code: ExitFailure What am I doing wrong? Yotam