R devel - Nov 2011 - Including multiple third party libraries in an extension

Hi,

I've got a C extension structured roughly like:

package/
  src/
    Makevars
    foo.c
    some-lib/...
    some-other-lib/..

where foo.c and Makevars define dependencies on some-lib and
some-other-lib. Currently I'm having
Makevars configure;make install some-lib and some-other-lib into a local
build directory, which produces
shard libraries that ultimately I reference for foo.o in PKG_LIBS.

I'm concerned about distribution. I've setup the appropriate magic with
rpath for the packages .so (meaning
that when the final .so is produced the dynamic libraries dependencies on
some-lib and some-other-lib
will prefer the location built in src/some-lib/... and
src/some-other-lib/... But does this preclude me from
being able to distribute a binary package? If I do want to build a binary
distribution, is there a way I can
package up everything needed, not just the resulting .so?

Or, are there better ways to bundle extension-specific third party
dependencies? ;) I'd rather not have
my users have to install obscure libraries globally on their systems.


Thanks!


Tyler

	[[alternative HTML version deleted]]

Tyler,

On Nov 11, 2011, at 7:55 PM, Tyler Pirtle wrote:
> Hi,
> 
> I've got a C extension structured roughly like:
> 
> package/
>  src/
>    Makevars
>    foo.c
>    some-lib/...
>    some-other-lib/..
> 
> where foo.c and Makevars define dependencies on some-lib and
> some-other-lib. Currently I'm having
> Makevars configure;make install some-lib and some-other-lib into a local
> build directory, which produces
> shard libraries that ultimately I reference for foo.o in PKG_LIBS.
> 
> I'm concerned about distribution. I've setup the appropriate magic
with
> rpath for the packages .so
That is certainly non-portable and won't work for a vast majority of users.

> (meaning
> that when the final .so is produced the dynamic libraries dependencies on
> some-lib and some-other-lib
> will prefer the location built in src/some-lib/... and
> src/some-other-lib/... But does this preclude me from
> being able to distribute a binary package?
Yes. And I doubt the package will work the way you described it at all, because
the "deep" .so won't be even installed. Also there are potential
issues in multi-arch R (please consider testing that as well).

> If I do want to build a binary
> distribution, is there a way I can
> package up everything needed, not just the resulting .so?
> 
> Or, are there better ways to bundle extension-specific third party
> dependencies? ;) I'd rather not have
> my users have to install obscure libraries globally on their systems.
> 
Typically the best solution is to compile the dependencies as --disable-shared
--enable-static --with-pic (in autoconf speak - you don't need to actually
use autoconf). That way your .so has all its dependencies inside and you avoid
all run-time hassle. Note that it is very unlikely that you can take advantage
of the dynamic nature of the dependencies (since no one else knows about them
anyway) so there is not real point to build them dynamically.

Also note that typically you want to use the package-level configure to run
subconfigures, and *not* Makevars. (There may be reasons for an exception to
that convention, but you need to be aware of the differences in multi-arch
builds since Makevars builds all architectures at once from separate copies of
the src directories whereas the presence of configure allows you to treat your
package as one architecture at a time and you can pass-though parameters).

Cheers,
Simon