[Pkg-ace-devel] Bug#380739: boost compiles differently, if ACE header is included first

[Thomas Girard]

Hello Torsten,

please keep 380739 at bugs.debian.org in CC: list so that everything get
archived on the BTS.

On Thu, Aug 03, 2006 at 09:59:43AM +0200, Harling, Torsten wrote:
[...]
> > So, to recap, even though I agree that the order of #include should not
> > change your program behaviour, not defining _REENTRANT whenever you use
> > ACE will *not* work.  And defining _REENTRANT will make both programs
> > print 36.
> 
> That's correct, I've also found this.
> > 
> > Another way of enforcing correct flags would be to check whether symbol
> > _REENTRANT is defined, and if it is not, the header could abort
> > compilation with an #error stating _REENTRANT *must* be defined.
> > 
> > I am not convinced this is better.  What do you think?
> 
> We first used shared_ptr's about 3 or 4 years ago. That's when
> this bug hid itself undetected in our software. We only wondered,
> why using a shared_ptr would sometimes cause our software to hang.
> 
> The cause was, that mostly the shared_ptr ended up having no mutex.
> But, if a piece of code included the ace headers first, it might
> hang when using a shared_ptr, that was constructed in a different
> compilation unit.
> 
> An #error stating _REENTRANT *must* be defined, or even better,
> saying -pthread(s) *must* be used, would have prevented and fixed
> our bug a long time ago. I agree, that the latter would be more
> difficult, as you would have to figure out the correct option
> for different compilers and architectures.
> 
> So, I would recommend the #error.
> 
> The boost library also #error's out, if it requires multithreading
> support.

Okay, I'll try to write a patch for this and submit it upstream.

More on this issue soon.

Regards,

Thomas