[Couenne] Dependencies and library build order

[Pietro Belotti]

Apologies for the late (13+ months...) reply. I think option A is the
best, since libCouenne and libBonCouenne are built using the same
exact files. I'm trying it in trunk now, but it should be easy to
extend this to stable/0.5 and others. The only entity to be built in
src/main should be the executable.

Pietro

On Thu, Nov 21, 2013 at 5:55 AM, Tony Kelman <kelman at berkeley.edu> wrote:
> Pietro,
> (and anyone else who may have an opinion about this)
>
> There’s been discussion here
> https://projects.coin-or.org/BuildTools/ticket/105 about explicitly linking
> dependencies into shared libraries (at least optionally), which is needed
> for using COIN solvers in Python/Julia, packaging for Debian, building
> Windows DLL’s via autotools in Cygwin/MinGW, and it can fix some occasional
> linking errors. For most projects this is doable with a few extra lines in
> automake. Couenne, on the other hand, appears to have a sort-of-circular
> dependency in the order it builds its libraries.
>
> If you build with LDFLAGS=”-Wl,--no-undefined”, you can see that
> Couenne/src/libCouenne depends on Couenne/src/main/libBonCouenne, but the
> couenne AMPL executable also gets built in Couenne/src/main. The couenne
> executable depends on Couenne/src/readnl/libCouenneReadnl, which depends on
> Couenne/src/libCouenne. I can think of a few ways in which this could be
> rearranged in order to resolve the problem and make building Couenne with
> --no-undefined possible:
>
> A) Remove Couenne/src/main/libBonCouenne, and compile its three source files
> into Couenne/src/libCouenne instead.
>
> B) Move one or more of the existing libraries and/or executables into a
> different folder, so the dependency order of libBonCouenne, then libCouenne,
> then libCouenneReadnl, then couenne executable can be respected without ever
> having to leave and re-enter a directory (which would be rather difficult to
> express in terms of Makefile dependencies).
>
> C) Leave Couenne/src/main/libBonCouenne where it is, but also compile its
> three source files into Couenne/src/libCouenne, possibly only when the
> --enable-dependency-linking option (which was recently created for this
> purpose) is provided to configure.
>
> I went with approach C in my patch at the above link because it required the
> fewest changes, however I don’t know if it is safe to duplicate code like
> that in both libCouenne and libBonCouenne. Which one of these approaches do
> you think would be the safest, most maintainable and least disruptive option
> to consider?
>
> Thanks,
> Tony
>
>
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