RE: [Caml-list] Specifying a framework to link with using ocamlopt?

[David Allsopp <dra-news@metastack.com>]

Alan Schmitt wrote:
> On 23 févr. 2011, at 16:48, David Allsopp wrote:
> 
> > Yes and no. I think there's a warning missing in ocamlmklib.
> Essentially, you're meant to pass some C object files (the stubs)
> whenever you use ocamlmklib - I think that what's going on is that
> because there are no .o files passed, it's not compiling libGL.a and so
> the linking instruction included is failing. ocamlmklib probably should
> warn that you passed no c objects and libGL.a doesn't seem to exist
> either.
> >
> > That said, I think it's that you're using ocamlmklib in a weird way by
> compiling the stubs separately and renaming the library that's causing
> the problems. The -lGL is added because of the -o GL. Try passing -oc
> gl_stubs to your second ocamlmklib call as well or alternatively do it as
> one:
> >
> > ocamlmklib -verbose -o GL -oc gl_stubs GL.cmx -framework OpenGL GL.cmx
> gl.wrap.o
> >
> > but you can safely omit the -oc gl_stubs if you're happy for the stub
> library to be libGL.a instead. Does that work?
> 
> It seems that using the gl_stubs bit is necessary. Otherwise I get:
> [:)][top] % ocamlmklib -verbose -o GL -framework OpenGL GL.cmx gl.wrap.o
> + gcc -bundle -flat_namespace -undefined suppress -o ./dllGL.so gl.wrap.o
> -L/Users/schmitta/godi/lib -framework OpenGL
> + ar rc ./libGL.a  gl.wrap.o; ranlib ./libGL.a
> + /Users/schmitta/godi/bin/ocamlopt -a -o GL.cmxa  GL.cmx -cclib -lGL -
> ccopt -L/Users/schmitta/godi/lib -ccopt -framework -ccopt OpenGL
> 
> where the -lGL is still there.

No - it's now correct that the -lGL is there now. You should also have libGL.a as a result of that command - note those extra calls to ar and ranlib which I don't think you were getting before. Of course, if you want it to be called libgl_stubs.a then that's another matter but the library GL.cmxa built from this command should work (where you previous one did not).

> With you other command line (removing the duplicated instance of
> "GL.cmx"),

Oops!

> it works much better:
> 
> [:)][top] % ocamlmklib -verbose -o GL -oc gl_stubs GL.cmx -framework
> OpenGL gl.wrap.o
> + gcc -bundle -flat_namespace -undefined suppress -o ./dllgl_stubs.so
> gl.wrap.o -L/Users/schmitta/godi/lib -framework OpenGL
> + ar rc ./libgl_stubs.a  gl.wrap.o; ranlib ./libgl_stubs.a
> + /Users/schmitta/godi/bin/ocamlopt -a -o GL.cmxa  GL.cmx -cclib -
> lgl_stubs -ccopt -L/Users/schmitta/godi/lib -ccopt -framework -ccopt
> OpenGL
> 
> Applying the same recipe to the other libraries solved the issue. Thanks
> a bunch!

No probs.


David