DJGPP gpp 4.4.1 and 4.4.2 fail under dosemu 1.4.0+svn.1828-2ubuntu2

[zub]

Binary package hint: dosemu

Trying to compile a trivial hello world C++ program using DJGPP's gpp (g++) version 4.4.1 or 4.4.2 fails under dosemu 1.4.0+svn.1828-2ubuntu2.

The issue is not reproducible with svn r. 1998, so it was probably fixed upstream already.

Maybe it has to do with the CPU emu used by DOSEMU on x86_86?

Release: Ubuntu 9.10 karmic
Package: 1.4.0+svn.1828-2ubuntu2
CPU: Intel(R) Core(TM)2 Duo CPU T9300 @ 2.50GHz
kernel: Linux 2.6.31-17-generic #54-Ubuntu SMP Thu Dec 10 17:01:44 UTC 2009 x86_64 GNU/Linux

To trigger the bug: Install DJGPP with GPP 4.4.2 or 4.4.1 (you only need bnu219b.zip djdev203.zip gcc442b.zip gpp442b.zip), set up DJGPP environment as mentioned in DJGPP readme. Create a simple C++ source -- including iostream is enough:

#incluide <iostream>

Then try to compile it inside DOSEMU: gpp test.cc

You get a host of complaints about stdlib headers:

In file included from c:/djgpp/bin/../lib/gcc/djgpp/4.42/../../../../include/cxx/4.42/bits/ios_base.h:41,

                 from c:/djgpp/bin/../lib/gcc/djgpp/4.42/../../../../include/cxx/4.42/ios:43,

                 from c:/djgpp/bin/../lib/gcc/djgpp/4.42/../../../../include/cxx/4.42/ostream:40,

                 from c:/djgpp/bin/../lib/gcc/djgpp/4.42/../../../../include/cxx/4.42/iostream:40,

                 from c:/test/test2.cc:1:

c:/djgpp/bin/../lib/gcc/djgpp/4.42/../../../../include/cxx/4.42/ext/atomicity.h:54: error: expected constructor, destructor, or type conversion before '__exchange_and_add'

...

but the issue is not really caused by the headers, because:
1) it works with different versions of DOSEMU (e.g. DOSEMU svn rev. 1998) and the same version of DJGPP GPP
2) if you add an "#error blah" somewhere to the top of include/cxx/4.42/djgpp/bits/atomic_word.h, which is included by include/cxx/4.42/ext/atomicity.h and which defines _Atomic_word (the type that gpp complains about in the above excerpt), you see the file is included without the #error being triggered => gpp is just terribly confused

[zub (zub-linux)]

I tracked the issue down in the upstream svn. It was fixed in change 1897. The log entry says:

r1897 | bartoldeman | 2009-07-12 23:44:28 +0200 | 3 lines
Changed paths:
   M /trunk/src/dosext/mfs/mangle.c
   M /trunk/src/dosext/mfs/mangle.h

Use a base-43 instead of a base-36 hash, like Samba does since version 2.0.4.
This reduces the collision chance by a factor 1.43.

Not sure how is this change relevant, but I was able to reproduce the bug in revisions <= 1896, while the bug doesn't manifest in revisions >= 1897.

[zub (zub-linux)]

A bit more digging reveals the cause and sheds light on the commit log meaning:

Adding #warning "compiling bits/atomicfwd_c.h" at the top of djgpp/include/cxx/4.42/bits/atomicfwd_c.h and compiling a simple source that includes <iostream> leads to this interesting result:

c:/djgpp/bin/../lib/gcc/djgpp/4.42/../../../../include/cxx/4.42/bits/atomic_word.h:1:2: warning: #warning "compiling bits/atomicfwd_c.h"

So it seems gpp is looking for "atomic_word.h" (that is present in djgpp/include/cxx/4.42/djgpp/bits), but searching for it in more paths, it's told by DOSEMU that the file is present in djgpp/include/cxx/4.42/bits and it's given the contents of atomicfwd_c.h instead. This in turn breaks the compilation.

With dosemu r. 1999 I get instead:

c:/djgpp/bin/../lib/gcc/djgpp/4.42/../../../../include/cxx/4.42/djgpp/bits/atomic_word.h:1:2: warning: #warning "compiling djgpp/bits/atomic_word.h"

Anyway the bug would be resolved by bumping up the svn revision the dosemu package is based on.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[zub (zub-linux)]

The bug is now fixed in all non-obsolete Ubuntu releases with the exception of Hardy Heron, as the fix in upstream was made in svn revision 1897.