Has any more come of this?
I've just started playing with LADSPA (The Linux Audio
Developer's Simple Plugin API http://www.ladspa.org) on my
FreeBSD 4-STABLE box, and run into a similar problem.
This is an entirely C API, and the demonstration applications
are all straight C, but some of the plugins themselves are
written in C++. Without doing anything extra, attempting to
dlopen() one of these C++ shared libraries produced an Undefined
symbol __get_eh_context.
In the spirit John's fix (I think):
On Wed, Sep 13, 2000 at 05:49:11PM -0700, John Polstra wrote:
> As a work-around, try adding this to your main program. (I am
> assuming it is a C++ program too.)
>
> extern void terminate(void);
> void (*kludge_city)(void) = terminate;
I didn't actually do that (took a while to find the message in
the archives), but did:
(a) Changed the source file names to .cc, so that they would be
compiled as C++ code, and
(b) added a gratuitous class definition and use to a common
file, so that __get_eh_context and friends would be included in
the executable.
Neither of these made the problem go away, which surprised me,
because nm on the resulting executable showed the symbol to be
defined. I guess the dynamic linker doesn't look in the
executable, only the shared libraries?
This suggestion:
> Another possibility would be to link explicitly with libgcc when
> creating your dynamic library:
>
> cc -shared -o libphptest.so ... -lgcc
Works, even when the applications are compiled as ordinary C
programs again. I haven't tried running a system with more
than one C++ plugin yet, so I worry a little that there will
be multiple definition name clashes. If the dynamic linker is
smart enough to not worry about that, then this does seem to
be the "right" way to go, in some sense, because the resulting
shared library seems to have "pure" C linkage.
Perhaps we could put something about this in the Handbook, or
(better) the gcc info pages?
Is there a central repository of information about FreeBSD's
binutil and compiler state? I noticed a few things in the gcc
info pages about ABI-affecting switches (thunks for vtables and
the like). There are obviously system defaults for these
switches, but I don't know where to find out what they are.
--
Andrew
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