Re: [SQL] dynamically loaded functions

On Wed, 2005-07-13 at 10:24 -0700, TJ O'Donnell wrote:
> >
> > It sounds like you need to link gnova.so against the other shared
> > objects so the runtime linker can find them. For examples, see the
> > Makefiles used by contributed modules like dblink, xml2, and a few
> > others that link against external libraries.
> >
> That approach is working, but only after much troubles.
> I have several 3rd party libraries, some of which call each other.
> It appears I need to carefully order the libraries in the
> link step, or some needed functions do not get included in the
> final .so.
>
> This problem used to crop up all the time way back 20 years ago
> with linkers. I thought all this name resolution stuff was all worked
> out with modern linkers. I'm "linking" with (linux redhat)
> gcc -shared -o my.so my.o my2.o their.a their2.a their3.a
> When function x() in their2.a calls something in their.a
> (or is it the other way around?)
> I get an error from postmaster that my.so cannot be loaded because
> function x cannot be found.
> If I reverse their.a their2.a in the link command, all is well.
> Note: I never use, nor even knew about the exitence of function x() - "they" do.
>
> Any help on how to make this more pain-free?
>
> TJ
>

I don't know much about pgsql but I do know that when linking if module1
needs something in module2 and module2 needs something in module1 then
you can put the the same module in the library link (i.e. '-l') list
more than once.

>
> Michael Fuhr wrote:
> > On Mon, Jul 11, 2005 at 08:16:17PM -0700, TJ O'Donnell wrote:
> >
> >>CREATE or REPLACE FUNCTION cansmiles(varchar) RETURNS varchar
> >> AS 'gnova', 'oe_cansmiles' LANGUAGE 'c' IMMUTABLE STRICT;
> >>requires preloading of oe_chem.so to work.
> >>
> >>Is there any way I can associate oe_cansmiles with 2 .so's without
> >>preloading?
> >
> >
> > It sounds like you need to link gnova.so against the other shared
> > objects so the runtime linker can find them. For examples, see the
> > Makefiles used by contributed modules like dblink, xml2, and a few
> > others that link against external libraries.
> >
>