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Guillaume Laurent wrote:
>On Sunday 19 September 2004 15:24, Thiago Macieira wrote:
>> - a constructor for one of the classes inheriting the virtual base calls
>> one function which in turn calls an overridden virtual function
>
>Virtual functions do not work in ctors in general.

They work fine in g++ 3.3/3.4 and there's nothing in the standard that=20
prevents us from doing that.

The problem you're alluding to is that people expect constructors to call=20
the overriden functions in more-derived classes. That isn't supported by=20
the standard: both g++ 2.95 and the 3.x series work correctly. Calls to=20
virtual functions inside a constructor are not virtual at all.

The problem in this case is that a virtual function is called *indirectly*=
=20
from inside the constructor: the constructor calls a function which in turn=
=20
calls the virtual function.

Leo Savernik wrote:
>Why discouraged? This is the very first gross bug that I've ever
>encountered with 2.95=20

Exactly. So there's a major bug. Therefore, it's people using it that shoul=
d=20
properly fix their compilers, not us working around the bugs.

g++ 2.95.4 on Linux is known now to produce invalid code. It should no=20
longer be used. As a compromise till people upgrade their compilers (to a=20
2.95.5, for instance, if that ever comes along), we should provide code=20
that doesn't trigger the bug for a while, but not for long.

As for its use on other platforms, I said "not supported" meaning that the=
=20
user's problem of making it work, not ours.

=2D-=20
  Thiago Macieira  -  Registered Linux user #65028
   thiago (AT) macieira (DOT) info
    ICQ UIN: 1967141   PGP/GPG: 0x6EF45358; fingerprint:
    E067 918B B660 DBD1 105C  966C 33F5 F005 6EF4 5358

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