Re: gobject-introspection typelibs and shared libraries

[ludo@gnu.org (Ludovic Courtès)]

Federico Beffa <beffa@ieee.org> skribis:

> On Sun, Dec 7, 2014 at 9:48 PM, Ludovic Courtès <ludo@gnu.org> wrote:
>> Federico Beffa <beffa@ieee.org> skribis:
>>
>>> currently the typelib files used by gobject-introspection can't find
>>> shared libraries and require setting LD_LIBRARY_PATH.
>>
>> I don’t know much about all this; could you give some context?  What’s a
>> typelib files exactly?
>
> gobject-introspection is a tool to create bindings to C libraries for
> other languages. To make the system flexible it creates an
> intermediate object. typelib files are a binary store on disk of this
> intermediate object.
>
> https://developer.gnome.org/gi/stable/overview.html

OK.

> The problem I've found is that the typelib files include the name of
> required shared libraries (.so), but not the absolute path. Therefore
> I was forced to set the LD_LIBRARY_PATH.

Yes, I see in the diagram on the page above that libraries are actually
dlopened, with the name that appears in the typelib file.

Thus the patch you proposed is the right thing, I think.  Before
committing, could you add a comment a the top of the file explaining
that the file names contained in typelib files are meant to be dlopen’d,
hence this patch?  Also please credit the original author of the patch.

> I was actually googling to find out how to instruct an application
> where to look for the typelib files, when I saw this email
>
> http://lists.science.uu.nl/pipermail/nix-dev/2014-September/014309.html
>
> and thought that we could borrow the approach.

Definitely.

Do we also need to do something for GI_TYPELIB_PATH?  Perhaps this
should be in the ‘native-search-paths’ field of gobject-introspection?
(It would be good to push both changes at once, if appropriate, to
reduce rebuilds.)

Thanks for the explanations, and for addressing this!

Ludo’.