Re: C++ ABI testing issues, gcc-3.3 <-> gcc-3.2 compatibility

["H. J. Lu" <hjl at lucon dot org>]

On Sat, Aug 03, 2002 at 06:41:48PM +0200, Jakub Jelinek wrote:
> On Sat, Aug 03, 2002 at 01:05:06PM +0200, Jakub Jelinek wrote:
> > On Sat, Aug 03, 2002 at 12:36:07PM +0200, Jakub Jelinek wrote:
> > > The last step was to make clean in libstdc++-v3 and exchange gcc subdirectories
> > > in the two trees (so that 3.2 build tree ended up with gcc 3.3 compiler and
> > > vice versa), then run make in libstdc++-v3 followed by make check (ie.
> > > basically built 3.2 libstdc++-v3 using g++ 3.3 and 3.3 libstdc++-v3 using
> > > g++ 3.2. This resulted in just those 25 XPASSes and 1 26_numeric FAIL.
> > 
> > Which is an obvious thinko in this last step, because make check was run
> > with the same g++ as libstdc++.so.5.0.0.
> > I've rerun the tests after swapping back gcc directories, ie.
> > 3.2 libstdc++ source + built with g++ 3.3 + make check run against it with g++ 3.2
> > 3.3 libstdc++ source + built with g++ 3.2 + make check run against it with g++ 3.3
> > but the results were the same, ie. 25 XPASSes, 1 FAIL.
> 
> I've redone all the tests with vanilla gcc-3_2-branch and vanilla HEAD both
> configured by plain configure, and in this case all 6 different make check
> runs gave the same result.
> This begs for the question whether if libstdc++ configured with
> --enable-threads=posix and configured without this are not
> binary compatible, we shouldn't default to
			^^^^^^^^^^^^^^^^^
Are you suggesting the current default for Linux is a good thing and
all Linux distributions should do same?

I have been suggesting Linux should be default to --enable-threads=posix
and --enable-shared for a long time.

> --enable-threads=posix --enable-__cxa_atexit
> for linux native builds, so that
> a) all linux distributions out there create binary compatible libstdc++
> b) people who build gcc themselves and forget about --enable-threads=posix
>    would be binary incompatible with vendor compilers
> 


H.J.