Re: [Caml-list] Compiling the ocaml distribution under multiarched Debian/Ubuntu

[Gerd Stolpmann <info@gerd-stolpmann.de>]

Am Freitag, den 13.01.2012, 15:17 +0100 schrieb Philippe Veber:
> 
> 
> 2012/1/13 Gerd Stolpmann <info@gerd-stolpmann.de>
>         Am Freitag, den 13.01.2012, 14:18 +0100 schrieb Stéphane
>         Glondu:
>         > Le 13/01/2012 12:59, Philippe Veber a écrit :
>         > > Debian and Ubuntu have not so recently switched to
>         multiarch binaries
>         > > (including libs, see
>         http://wiki.debian.org/Multiarch/Implementation).
>         > > This is an important change for ocaml C bindings since the
>         libraries are
>         > > now to be found in /usr/lib/<arch description> instead
>         of /usr/lib. I
>         > > was just bitten by this, when realizing that the ocaml
>         configure script
>         > > couldn't find libX11.so and wouldn't install graphics. A
>         similar problem
>         > > was handled by the people in charge of debian ocaml
>         packages
>         > > (http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=619344).
>         Now my
>         > > question is the following: will this evolution be a
>         problem for GODI/odb
>         > > packages (and more generally source distribution), and
>         what is the
>         > > advised fix for it?
>         >
>         > My advice would be to rely on pkg-config (a kind of
>         ocamlfind for C
>         > libraries), or similar scripts (pcre-config, etc.) provided
>         by the
>         > libraries. Otherwise, there is no good, portable (I mean,
>         not
>         > Debian-specific) way to guess where a library is, and the
>         packager will
>         > give an explicit path in his call to the configure script in
>         > debian/rules. By the way, this is what we did for ocaml [1].
>         >
>         > [1]
>         >
>         http://anonscm.debian.org/gitweb/?p=pkg-ocaml-maint/packages/ocaml.git;a=commitdiff;h=1db9b654b7d8b702cddb44df5aea1982f3120883
>         
>         
>         In GODI there is a library searcher for libs that do not
>         support
>         pkg-config et al. It just tries a list of typical paths used
>         by various
>         OS. The method works well if the library is not dependent on
>         other
>         libraries, and is quite portable. Of course, you cannot be
>         sure to find
>         the right library if several versions are installed (which is
>         quite
>         common on non-open-source OS where the developer has to do it
>         on its
>         own), but otherwise it is good enough for setting a default if
>         the user
>         does not have special wishes.
>         
>         So, e.g. for X11, there is no pkg-config, and GODI falls back
>         to
>         searching. Btw, we don't rely here on what the Ocaml configure
>         script
>         finds out, but have our own searcher, simply because this
>         makes it
>         easier to respect users' wishes.
> 'seems like pkg-config was updated:
> 
> pveber@gesundheit:~/usr/src/ocaml-3.12.1$ pkg-config --libs x11
> -lX11  

Traditionally, X11 came with its own system called imake, which is a
preprocessor for makefiles. If there is now pkg-config support, this is
very new, or an extension by the distributor.

Gerd

-- 
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Gerd Stolpmann, Darmstadt, Germany    gerd@gerd-stolpmann.de
Creator of GODI and camlcity.org.
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Company homepage:       http://www.gerd-stolpmann.de
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