Technical Q&AsOV 01 - Test What You Ship (02-Nov-98)
If a fat WDEF requests the current ISA on a system whose Window Manager is 68K code, the WDEF's 68K code is called. Until Mac OS 8.5, requesting the current ISA would never result in the WDEF's PowerPC code being called, because Window Manager was 68K code. However, since the Window Manager is PowerPC code in Mac OS 8.5, the PowerPC half of a fat WDEF requesting the current ISA is always called. The PowerPC half of the WDEFs in the crashing applications proved to be catastrophically faulty in some small way or other. Generally, this turned out to be incorrect We theorize that some developers built fat WDEFs without testing them fully. This is somewhat understandable, because it was impossible to test a fat WDEF which requested the current ISA when that ISA was PowerPC until Mac OS 8.5. Given a fat WDEF which requests the current ISA, Window Manager now goes out of its way to call the 68K code, which is more likely to have been tested. There is a larger lesson to be learned here: be careful not to ship code you haven't tested. In other words, code only what you can test now. Worldwide Developer Technical Support Technical Q&As Contents To contact us, please use the Contact Us page. |