Ronald Guida wrote:
How do I create C-libraries that I can load into GHCi? I am trying to do some basic FFI, and it's not working.
So, after more searching on the internet and some RTFM, I think I found my answer, and it seems to work, but I don't know if it's the right answer to generalize from. 1. I can leave "test_foo.lhs" and "foo.cpp" as-is. 2. I need to change "foo.h" to the following: ------------------ // foo.h #if BUILD_DLL #define DECLSPEC __declspec(dllexport) #else #define DECLSPEC __declspec(dllimport) #endif extern "C" { DECLSPEC __stdcall int foo(int x); } ------------------ 3. I need to create a DEF file and list the functions to be exported in a DLL. ------------------ foo.def ------------------ LIBRARY foo DESCRIPTION "Foo Library" EXPORTS foo ------------------ Note: The library name on the first line must match the dll name. "LIBRARY foo" corresponds to "foo.dll" 4. The build process is as follows. (1) gcc -DBUILD_DLL -c foo.cpp (2) gcc -shared -o foo.dll foo.o foo.def \ -Wl,--enable-stdcall-fixup,--out-implib,libfoo.a 5. At this point, I'll have "foo.dll" and "libfoo.a". I can load my "foo" library, as a DLL, into GHCi with the command: $ ghci -lfoo In reality, I would use: $ ghci test_foo.lhs -lfoo 6. Once I'm satisfied and ready to compile: ghc --make test_foo.lhs -L. -lfoo Notes: (1) "-L." directs GHC to look in the current directory for libraries. GHCi seems to look there by default. (2) The resulting "test_foo.exe" will dynamicly load "foo.dll". 7. If I want a staticly linked executable instead: ar rcs libfoo_static.a foo.o ghc --make test_foo.lhs -L. -lfoo_static 8. Finally, I can put the build steps into a makefile. ------------------ # Makefile for foo test_foo.exe : test_foo.lhs libfoo.a foo.dll ghc --make test_foo.lhs -L. -lfoo test_foo_static.exe : test_foo.lhs libfoo_static.a ghc --make test_foo.lhs -L. -lfoo_static -o test_foo_static.exe libfoo.a : foo.dll foo.dll : foo.o foo.def gcc -shared -o foo.dll foo.o foo.def \ -Wl,--enable-stdcall-fixup,--out-implib,libfoo.a libfoo_static.a : foo.o ar rcs libfoo_static.a foo.o foo.o : foo.cpp foo.h gcc -DBUILD_DLL -c foo.cpp .PHONY: clean clean: rm -f *.[oa] rm -f *.dll rm -f *.hi rm -f *.exe ------------------ -- Ron