Compatibility between g++ 4.1 and 4.2

Compatibility between g++ 4.1 and 4.2

[Stuart Brooks]

I was wondering if anyone could tell me whether C++ libraries compiled 
with gcc 4.2 are compatible with gcc 4.1 and vice versa. From 
http://gcc.gnu.org/onlinedocs/gcc/Compatibility.html I see that:
  "Starting with GCC 3.2, GCC binary conventions for C++ are based on a 
written, vendor-neutral C++ ABI "
and:
  "We have tried hard to provide a stable ABI that will be compatible 
with future GCC releases, but it is possible that we will encounter 
problems that make this difficult"

Does this mean I should have no problems?

Thanks
 Stuart

Re: Compatibility between g++ 4.1 and 4.2

[Ian Lance Taylor]

Stuart Brooks <stuartb@cat.co.za> writes:

> I was wondering if anyone could tell me whether C++ libraries compiled
> with gcc 4.2 are compatible with gcc 4.1 and vice versa. From
> http://gcc.gnu.org/onlinedocs/gcc/Compatibility.html I see that:
>   "Starting with GCC 3.2, GCC binary conventions for C++ are based on
> a written, vendor-neutral C++ ABI "
> and:
>   "We have tried hard to provide a stable ABI that will be compatible
> with future GCC releases, but it is possible that we will encounter
> problems that make this difficult"
> 
> Does this mean I should have no problems?

In general, yes.  Assuming there are no bugs.  Also see the
-fabi-version option.

Be aware that there was a bug in gcc 4.2.1 which was not in gcc 4.2.0
or gcc 4.2.2: the virtual table layout of the std::type_info class was
accidentally reordered.

Ian