[opam-devel] conf- libraries and stub cmas: time for ocaml-discover?

[Christophe TROESTLER]

On Mon, 26 Aug 2013 11:57:40 +0100, Anil Madhavapeddy wrote:
> 
> [...] Ideally, we would be able to query three types of information
> from a conf package installation:
> 
> - an ML file that has values exposing cflags/lflags as OCaml values.
>   This can be used by discover.ml scripts (as used in Core or Lwt)
> 
> - a CMA file that embeds the dynamic linking flags via cclib, including
>   adding -Wl,--no-as-needed on newer systems like Ubuntu.  This lets a
>   Ctypes using dynamic linking (Ctypes.Foreign) just add a CMA to the
>   link line and have the correct gcc/clang libraries work.
> 
> - The final thing is some way to pass the right CFLAGS/LDFLAGS to
>   compile up generated C stubs with the right include/library paths to
>   gcc (either from Ctypes, or via the traditional camlidl/swig outputs).
>   Presumably this would be a raw shell fragment in a file, as usually
>   output by autoconf.

Sounds good to me.  For the last point, it is also important that
these flags are available in a way that makes adding ocamlbuild rules
using these flags easy.  Maybe, the C compiler and CFLAGS/LDFLAGS can
be duplicated in the first ML file (and then the configure phase — say
in oasis — may generate the proper rules).

Best,
C.