Hi all! Not long ago, I faced with problem building library with Cabal. I'm trying to build simple Haskell project as a shared library for use in MS Visual Studio (yes, I use FFI for this). And I created simple test project: / {-# LANGUAGE ForeignFunctionInterface #-} module GrepWrap where import Foreign import Foreign.C.String import Data.Char printCString :: CString -> IO () printCString s = do ss <- peekCString s putStrLn ss getCStringFromKey :: IO CString getCStringFromKey = do guess <- getLine newCString guess hello :: IO() hello = do putStrLn "Hi there!" foreign export stdcall В В В В hello :: IO () foreign export stdcallВ В printCString :: CString -> IO () foreign export stdcallВ В getCStringFromKey :: IO CString/ Also, I created file for safe initialization with wrappers for hs_init() and hs_exit() calls: /// StartEnd.c #include <Rts.h> extern void __stginit_GrepWrap(void); void HsStart() { int argc = 1; char* argv[] = {"ghcDll", NULL}; // argv must end with NULL // Initialize Haskell runtime char** args = argv; hs_init(&argc, &args); } void HsEnd() { hs_exit(); }/ I compile these files with the next commands: /*> ghc -c GrepWrap.c*//* *//*> ghc -c StartEnd.c*//* *//*> ghc -shared -o grepWrap.dll grepWrap.hs StartEnd.o*/ /Linking grepWrap.dll ...// //Creating library file: grepWrap.dll.a// /// After it, I've got grepWrap.dll and grepWrap.dll.a files. I successfully linked that library with my simple C++ test app, that uses these functions. And I was able to use my Haskell functions in my simple C++ app. Further, I'd like to use Cabal build system for building the same Haskell library filles. My cabal file looks like this: /*name: GrepWrap version: 1.0 synopsis: example shared library for C use build-type: Simple cabal-version: >=1.10 library default-language: Haskell2010 exposed-modules: GrepWrap extra-libraries: HSbase-4.6.0.1, wsock32, user32, shell32, HSinteger-gmp-0.5.0.0, HSghc-prim-0.3.0.0, HSrts, gdi32, winmm c-sources: StartEnd.c extensions: ForeignFunctionInterface build-depends: base >= 4 --ghc-options: "-v"*/ After build, in directory dist/build I got a set of files and among them there are: _/libHSGrepWrap-1.0-ghc7.6.3.dll/_ , ___/libHSGrepWrap-1.0-ghc7.6.3.dll.a/_ and /_GrepWrap_stub.h_/ . I use these files in the same Visual Studio project (of course, I changed names of dependent libraries in dependencies configuration in Visual Studio). Application successfully builds, but after run this app, I've got the next exception: Unhandled exception at 0x6D7905FB (libHSrts-ghc7.6.3.dll) in GrepWrapCabalUseDll.exe: 0xC0000005: Access violation reading location 0x00000000 It occurs, when I call functions from library (but when HsStart() already called). When I use "-v" flag with compilation (using ghc) I saw such linker message log: /*** Linker:// //"C:\Program Files (x86)\Haskell Platform\2013.2.0.0\lib/../mingw/bin/gcc.exe" "-fno-stack-protector" "-Wl,--hash-size=31" "-Wl,--reduce-memory-overheads" "-o" "grepWrap.dll" "-shared" "-Wl,--out-implib=grepWrap.dll.a" "grepWrap.o" "-Wl,--enable-auto-import" "StartEnd.o" "-LC:\Program Files (x86)\Haskell Platform\2013.2.0.0\lib\base-4.6.0.1" "-LC:\Program Files (x86)\Haskell Platform\2013.2.0.0\lib\integer-gmp-0.5.0.0" "-LC:\Program Files (x86)\Haskell Platform\2013.2.0.0\lib\ghc-prim-0.3.0.0" "-LC:\Program Files (x86)\Haskell Platform\2013.2.0.0\lib" "-lHSbase-4.6.0.1" "-lwsock32" "-luser32" "-lshell32" "-lHSinteger-gmp-0.5.0.0" "-lHSghc-prim-0.3.0.0" "-lHSrts" "-lm" "-lwsock32" "-lgdi32" "-lwinmm" "-u" "_ghczmprim_GHCziTypes_Izh_static_info" "-u" "_ghczmprim_GHCziTypes_Czh_static_info" "-u" "_ghczmprim_GHCziTypes_Fzh_static_info" "-u" "_ghczmprim_GHCziTypes_Dzh_static_info" "-u" "_base_GHCziPtr_Ptr_static_info" "-u" "_ghczmprim_GHCziTypes_Wzh_static_info" "-u" "_base_GHCziInt_I8zh_static_info" "-u" "_base_GHCziInt_I16zh_static_info" "-u" "_base_GHCziInt_I32zh_static_info" "-u" "_base_GHCziInt_I64zh_static_info" "-u" "_base_GHCziWord_W8zh_static_info" "-u" "_base_GHCziWord_W16zh_static_info" "-u" "_base_GHCziWord_W32zh_static_info" "-u" "_base_GHCziWord_W64zh_static_info" "-u" "_base_GHCziStable_StablePtr_static_info" "-u" "_ghczmprim_GHCziTypes_Izh_con_info" "-u" "_ghczmprim_GHCziTypes_Czh_con_info" "-u" "_ghczmprim_GHCziTypes_Fzh_con_info" "-u" "_ghczmprim_GHCziTypes_Dzh_con_info" "-u" "_base_GHCziPtr_Ptr_con_info" "-u" "_base_GHCziPtr_FunPtr_con_info" "-u" "_base_GHCziStable_StablePtr_con_info" "-u" "_ghczmprim_GHCziTypes_False_closure" "-u" "_ghczmprim_GHCziTypes_True_closure" "-u" "_base_GHCziPack_unpackCString_closure" "-u" "_base_GHCziIOziException_stackOverflow_closure" "-u" "_base_GHCziIOziException_heapOverflow_closure" "-u" "_base_ControlziExceptionziBase_nonTermination_closure" "-u" "_base_GHCziIOziException_blockedIndefinitelyOnMVar_closure" "-u" "_base_GHCziIOziException_blockedIndefinitelyOnSTM_closure" "-u" "_base_ControlziExceptionziBase_nestedAtomically_closure" "-u" "_base_GHCziWeak_runFinalizzerBatch_closure" "-u" "_base_GHCziTopHandler_flushStdHandles_closure" "-u" "_base_GHCziTopHandler_runIO_closure" "-u" "_base_GHCziTopHandler_runNonIO_closure" "-u" "_base_GHCziConcziIO_ensureIOManagerIsRunning_closure" "-u" "_base_GHCziConcziSync_runSparks_closure" "-u" "_base_GHCziConcziSignal_runHandlers_closure"// //Creating library file: grepWrap.dll.a// //link: done/ But, when I call cabal build with "-v2" option to get build log, I get the following: /> cabal build -v2 I've got the next log: creating dist\build creating dist\build\autogen Building GrepWrap-1.0... Preprocessing library GrepWrap-1.0... Building library... creating dist\build C:\Program Files (x86)\Haskell Platform\2013.2.0.0\bin\ghc.exe --make -fbuilding-cabal-package -O -odir dist\build -hidir dist\build -stubdir dist\build -i -idist\build -i. -idist\build\autogen -Idist\build\autogen -Idist\build -optP-include -optPdist\build\autogen\cabal_macros.h -package-name GrepWrap-1.0 -hide-all-packages -package-db dist\package.conf.inplace -package-id base-4.6.0.1-f0c2cc6dcf0e12bf75312a2e7f354095 -XHaskell2010 -XForeignFunctionInterface GrepWrap [1 of 1] Compiling GrepWrap ( GrepWrap.hs, dist\build\GrepWrap.o ) C:\Program Files (x86)\Haskell Platform\2013.2.0.0\bin\ghc.exe --make -fbuilding-cabal-package -O -prof -osuf p_o -hisuf p_hi -odir dist\build -hidir dist\build -stubdir dist\build -i -idist\build -i. -idist\build\autogen -Idist\build\autogen -Idist\build -optP-include -optPdist\build\autogen\cabal_macros.h -package-name GrepWrap-1.0 -hide-all-packages -package-db dist\package.conf.inplace -package-id base-4.6.0.1-f0c2cc6dcf0e12bf75312a2e7f354095 -XHaskell2010 -XForeignFunctionInterface GrepWrap [1 of 1] Compiling GrepWrap ( GrepWrap.hs, dist\build\GrepWrap.p_o ) C:\Program Files (x86)\Haskell Platform\2013.2.0.0\bin\ghc.exe --make -fbuilding-cabal-package -O -dynamic -fPIC -osuf dyn_o -hisuf dyn_hi -odir dist\build -hidir dist\build -stubdir dist\build -i -idist\build -i. -idist\build\autogen -Idist\build\autogen -Idist\build -optP-include -optPdist\build\autogen\cabal_macros.h -package-name GrepWrap-1.0 -hide-all-packages -package-db dist\package.conf.inplace -package-id base-4.6.0.1-f0c2cc6dcf0e12bf75312a2e7f354095 -XHaskell2010 -XForeignFunctionInterface GrepWrap [1 of 1] Compiling GrepWrap ( GrepWrap.hs, dist\build\GrepWrap.dyn_o ) Building C Sources... creating dist\build C:\Program Files (x86)\Haskell Platform\2013.2.0.0\bin\ghc.exe -c -prof -odir dist\build -Idist\build -optc-O2 -package-db dist\package.conf.inplace -package-id base-4.6.0.1-f0c2cc6dcf0e12bf75312a2e7f354095 StartEnd.c C:\Program Files (x86)\Haskell Platform\2013.2.0.0\bin\ghc.exe -c -prof -dynamic -fPIC -osuf dyn_o -odir dist\build -Idist\build -optc-O2 -package-db dist\package.conf.inplace -package-id base-4.6.0.1-f0c2cc6dcf0e12bf75312a2e7f354095 StartEnd.c Linking... C:\Program Files (x86)\Haskell Platform\2013.2.0.0\mingw\bin\ar.exe -r dist\build\libHSGrepWrap-1.0.a dist\build\GrepWrap.o dist\build\StartEnd.o C:\Program Files (x86)\Haskell Platform\2013.2.0.0\mingw\bin\ar.exe: creating dist\build\libHSGrepWrap-1.0.a C:\Program Files (x86)\Haskell Platform\2013.2.0.0\mingw\bin\ar.exe -r dist\build\libHSGrepWrap-1.0_p.a dist\build\GrepWrap.p_o dist\build\StartEnd.o C:\Program Files (x86)\Haskell Platform\2013.2.0.0\mingw\bin\ar.exe: creating dist\build\libHSGrepWrap-1.0_p.a C:\Program Files (x86)\Haskell Platform\2013.2.0.0\mingw\bin\ld.exe -x --hash-size=31 --reduce-memory-overheads -r -o dist\build\HSGrepWrap-1.0.o dist\build\GrepWrap.o dist\build\StartEnd.o C:\Program Files (x86)\Haskell Platform\2013.2.0.0\bin\ghc.exe -shared -dynamic -lHSbase-4.6.0.1 -lwsock32 -luser32 -lshell32 -lHSinteger-gmp-0.5.0.0 -lHSghc-prim-0.3.0.0 -lHSrts -lgdi32 -lwinmm -package-name GrepWrap-1.0 -no-auto-link-packages -package-db dist\package.conf.inplace -package-id base-4.6.0.1-f0c2cc6dcf0e12bf75312a2e7f354095 dist\build\GrepWrap.dyn_o dist\build\StartEnd.dyn_o -o dist\build\libHSGrepWrap-1.0-ghc7.6.3.dll Creating library file: dist\build\libHSGrepWrap-1.0-ghc7.6.3.dll.a In-place registering GrepWrap-1.0... C:\Program Files (x86)\Haskell Platform\2013.2.0.0\bin\ghc-pkg.exe update - --global --user --package-db=dist\package.conf.inplace/ I'm confused.. Cabal uses a batch of options, it adds multiple options that I can't control. I'd like to control this options. How can I build my Haskell library with Cabal build system as same as building it with simple ghc? I can call ghc manually, but it will be a hard task, when I'll compile library for multiple files. Best regards, Oleg Durandin