os::Posix::is_valid_signal() uses sigaddset() to validate the signal (because the range of valid signals depends on if and how many real time signals the system supports, which is a runtime setting).
It uses sigaddset() but does not initialize the signal set beforehand. This is invalid and the behaviour is undefined, even if it seemed to work in the practice.
It uses sigaddset() but does not initialize the signal set beforehand. This is invalid and the behaviour is undefined, even if it seemed to work in the practice.