Compiler does not know, which overload of cb to chose.2) Even if it did know, it would not convert from void* to, say void(*)(int), without any explicit conversion. However, it can deduce it if you give compiler enough information:
Problem #1: The name of the second argument and the type of the second argument are swapped somehow. It should be: Instead of: Which is what you have. Problem #2: You need to add a couple of parentheses to get the function correctly dereferenced: Eventually, this is what you get: And here is a live example of your program … Read more
so your answer is But naturally, this is a bad practice, just use typedefs 🙂 Extra: Wonder how to declare an array of 3 pointers to functions taking int and returning a pointer to an array of 4 pointers to functions taking double and returning char? (how cool is that, huh? :)) :))
How should I use array of function pointers in C? How can I initialize them?
Unlike static member functions or free functions, non-static member functions won’t implicitly convert to member function pointers. (emphasis mine) An lvalue of function type T can be implicitly converted to a prvalue pointer to that function. This does not apply to non-static member functions because lvalues that refer to non-static member functions do not exist. So you need to use & explicitly to … Read more
Note: Most of the answers cover function pointers which is one possibility to achieve “callback” logic in C++, but as of today not the most favourable one I think. What are callbacks(?) and why to use them(!) A callback is a callable (see further down) accepted by a class or function, used to customize the current logic … Read more
I am trying to write a program which implements the Pop and Push functions. The problem is, I am trying to pass the pointer that points to integer Top to the function, so that this integer keeps changing, but when I try to compile I always get this line: **error: called object is not a … Read more
Function pointers in C Let’s start with a basic function which we will be pointing to: First thing, let’s define a pointer to a function which receives 2 ints and returns an int: Now we can safely point to our function: Now that we have a pointer to the function, let’s use it: Passing the … Read more
std::function is a type erasure object. That means it erases the details of how some operations happen, and provides a uniform run time interface to them. For std::function, the primary1 operations are copy/move, destruction, and ‘invocation’ with operator() — the ‘function like call operator’. In less abstruse English, it means that std::function can contain almost any object that acts like a function … Read more