Sherwin questions

• why bf1 and bf2 share a memory location, whereas bf3 and bf4 have its own memory location?
• what's the difference between following code, why one works and the other doesn't?
• Why do I have two users with uid 0 on my Mac?
• why compiler said: 'enable_if' cannot be used to disable this declaration
• How can openat avoid TOCTTOU errors?
• what's the difference between the function pointer getting from std::function::target<>() and normal function pointer?
• Why does compiler complain that f() is not visible?
• How to do multi-inheritance in swift?

Sherwin answers