Re: Exceptions, Optimizations and AIX

["Michael Veksler" <VEKSLER at il dot ibm dot com>]

> A little supplement:
>
> I just tried building all my objects/libraries with -O1 and it works.
> 
> So mixing different objects/libraries with different optimization levels
> doesn't work.
> This is not what i would expect. Can you please confirm that this should
> work?

I found that on some circumstances it may look it is a matter of
optimization flags when in fact one of the following happens:
1. You forgot to add a link flag: -Wl,-brtl
   This will break many things, including static variables
   of template classes. 
2. When you created two different shared objects, you created
   them in the following way:
      gcc -shared first.o -o tmp.so && mv tmp.so first.so
      gcc -shared second.o -o tmp.so && mv tmp.so second.so
   This will break your global variable construction.

In all cases, when global variables get broken, it is possible 
to have exceptions broken as well.

One annoying thing that I have noticed for AIX-4.3.3 and at least 
gcc-3.2, is that exception handling information gets constructed
after global variables are. This means that 'catch' does not
work in constructors of global variable.
I have not checked that for newer gcc's yet.