FAQ: What's the difference between a functionoid and a functor? ←(in the new Super-FAQ)
It's in Section: Pointers to member functions:
- FAQ: Is the type of "pointer-to-member-function" different from "pointer-to-function"?
 - FAQ: How do I pass a pointer-to-member-function to a signal handler, X event callback, system call that starts a thread/task, etc?
 - FAQ: Why do I keep getting compile errors (type mismatch) when I try to use a member function as an interrupt service routine?
 - FAQ: Why am I having trouble taking the address of a C++ function?
 - FAQ: How can I avoid syntax errors when creating pointers to members?
 - FAQ: How can I avoid syntax errors when calling a member function using a pointer-to-member-function?
 - FAQ: How do I create and use an array of pointer-to-member-function?
 - FAQ: How do I declare a pointer-to-member-function that points to a const member function?
 - FAQ: What is the difference between the .* and ->* operators?
 - FAQ: Can I convert a pointer-to-member-function to a void*?
 - FAQ: Can I convert a pointer-to-function to a void*?
 - FAQ: I need something like function-pointers, but with more flexibility and/or thread-safety; is there another way?
 - FAQ: What the heck is a functionoid, and why would I use one?
 - FAQ: Can you make functionoids faster than normal function calls?
 - FAQ: What's the difference between a functionoid and a functor? (this FAQ)