cd _build

ocamlfind ocamlopt -thread -package "$PACKS" -c ../c_callbacks.ml -o c_callbacks.cmx

ocamlfind ocamlopt -thread -linkpkg -package "$PACKS" -output-obj -o camlcode.o c_callbacks.cmx

gcc -I ${WHERE} -g -Wall -Wextra  -c ../c_shim.c -o c_shim.o

gcc -shared camlcode.o c_shim.o -ldl -lm -L ${WHERE} \

        $(ocamlfind query cstruct)/cstruct.a \

        $(ocamlfind query cstruct)/libcstruct_stubs.a \

        $(ocamlfind query io-page)/io_page.a \

        $(ocamlfind query io-page)/io_page_unix.a \

        $(ocamlfind query io-page)/libio_page_unix_stubs.a \

        $(ocamlfind query lwt.unix)/liblwt-unix_stubs.a \

        $(ocamlfind query lwt.unix)/lwt-unix.a \

        $(ocamlfind query lwt.unix)/lwt.a \

        $(ocamlfind query threads)/libthreadsnat.a \

        -lasmrun -lbigarray -lunix -o my_shared_library.so

```

I tried following Jeremy's inverted ctypes example here:

This looks good because it relies on ocamlfind + ocamlopt to do the right thing but unfortunately it fails on my OSX box because it produces a "bundle" (with "-bundle" linker option) rather than a shared library (with a "-shared" linker option):

When ocamlopt builds the ctypes-inverted-stubs-example .so it's one of these:

```

```

which then causes failures which look like

```

ld: can't link with bundle (MH_BUNDLE) only dylibs (MH_DYLIB) file '../_build/test/../libxmlm.so' for architecture x86_64

```

When I do it by hand, I can replace "-bundle" with "-shared" which results in:

```

$ file _build/libxmlm.so 

_build/libxmlm.so: Mach-O 64-bit dynamically linked shared library x86_64

```

which then links ok.

Any tips greatly appreciated!

Thanks,