Hello Ian, I'm using GCC 4.2, which is the one shipped with all the versions of OSX from 2008 onwards. I wanted to make my application work with this version of GCC for two reasons: 1) It's the default version shipped with OSX, and if the en user can get my program to work out of the box, that would be the best. Installing another version of GCC on OSX takes approximately a gigabyte, unless it is possible to narrow the installation down to those components that are absolutely necessary, which most probably requires some advanced knowledge. 2) Apple is not going to switch to later versions of GCC, since the later ones are under the GPLv3 license, which conflicts with Apple's licensing policies. That's probably one of the reasons why Apple decided to ditch GCC altogether and use LLVM for the upcoming Xcode 4. I'll give a try with a newer version of GCC and try LLVM as well. Thanks for the information! Cheers, Nicolas Ian Lance Taylor-3 wrote: > > nchaumont <nicolas.chaumont@xxxxxxxxx> writes: > >> Here is my understanding of the problem: dynamic_cast can only succeeds >> in >> GCC if both object's typeinfo have the same address. > > Which version of gcc are you using? That was changed in gcc 4.3 to > avoid the kinds of problems you are encountering. > > Ian > > -- View this message in context: http://old.nabble.com/Question-about-Darwin-GCC-and-weak-symbol-tagging-policy----second-attempt-tp30654360p30662867.html Sent from the gcc - Help mailing list archive at Nabble.com.