Benjamin Grange writes: > For those interested, I have found an excellent article about my problem: > http://www.cellperformance.com/mike_acton/2006/06/understanding_strict_aliasing.html Hmm. It's certainly a very long article. One thing that may be misleading: it suggests that this issue is something to do with C99 conformance. C89 has the same restrictions on pointer conversion. Andrew.