Question

I have a function in an external library that I cannot change with the following signature:

void registerResizeCallback(void (*)(int, int)) 

I want to pass in a member function as the callback, as my callback needs to modify instance variables.

Obviously this isn’t possible with a simple:

registerResizeCallback(&Window::Resize); 

so I’m not really sure how to solve the problem.

Answer 1

Check "[33.2] How do I pass a pointer-to-member-function to a signal handler, X event callback, system call that starts a thread/task, etc?" at the C++ FAQ Lite:

Don’t.

Because a member function is meaningless without an object to invoke it on, you can’t do this directly

…

As a patch for existing software, use a top-level (non-member) function as a wrapper which takes an object obtained through some other technique.