Is it possible to load a function into some allocated memory and run it from there?

Question

I'm messing around with some interprocess communication stuff and I am curious if it's possible to copy a function into some shared memory and run it from there from either process.

Something like:

memcpy(shared_memory_address, &func, &func + sizeof(func));

I realize you can't take the size of the function but that was what popped into my head.

Answer 1

Theoretically, as functions are just sequence of byte code somewhere in the memory, you could copy the memory block of the function and call (jump into) it. Though c++ Abstracts that possibility away, as you noticed, we cannot actually know the size of function (although we can get pointer to it).

Still, there's libraries. For example, you could tell remote executable to load specific function from dynamic library and execute it. Check wikipedia-article for the references.