"David R. Doucette" <ddoucette@xxxxxxxxxxxxxxxx> writes: > We just installed Lucid Lynx a few days ago, and have hit a fatal flaw > with g++ that has forced us to stop the deployment and roll back the > systems we could. > > Structures in Lucid are now mapping differently than in the past, so > we can no longer read our own files! Further, if any files are written > by code produced by the new g++, they are corrupted. > > The problem is that doubles are now being mapped onto a boundary > divisible by 8 rather than a boundary divisible by 4, meaning that > offsets change and structs get bigger. > > I've attached a tar file showing the mapping on Jaunty, Karmic, and > Lucid to show the change. This is a greatly simplified program that > shows the problem, but it's happening in all of our C++ programs. What are the old and new versions of gcc? Did you build gcc yourself? How were the versions of gcc configured? You didn't say what processor you are using, but I assume it is x86. Normally on 64-bit x86 doubles are always aligned on an 8-byte boundary. On 32-bit x86 they are normally aligned on a 4-byte boundary, though this can be changed with the -malign-double option. gcc works pretty hard to keep the same ABI across releases, so I suspect that something else must have changed. Ian
