Hello. As this is my first post I will try to introduce myself as requested in the welcome email. If you aren't interested in my person, just continue reading at the next paragraph. I'm a student from Vienna/Austria. I attend what would match high school in the United States. I have been writing Python for about 3 years now and have just began to dig into the implementation of CPython. Now to my real question. I have noticed that PyThread_acquire_lock swallows all signals with pthread using sems. Looking at the source code it appears that this is intended, but I cannot see the reason for that. It seems the pthread sem implementation is the only one doing so. Can any of you tell me the reason why it swallows signals? I have already prepared a patch that introduces a new _noswallow function if sem are used and uses this in threadmodule.c. But if there isn't any real reason for it to swallow exceptions, I think it would be wisest to change that. Best regards, Florian Mayer