Function Pointer

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. A function pointer is a type of pointer in C, C++, D, and other C-like programming languages, and Fortran 2003. When dereferenced, a function pointer can be used to invoke a function and pass it arguments just like a normal function. In programming languages like C, function pointers can be used to simplify code by providing a simple way to select a function to execute based on run-time values. Function pointers do always point to a function having a specific signature. Thus, all functions used with the same function pointer must have the same parameters and return type. Functors, or function objects, are similar to function pointers, and can be used in similar ways. A functor is an object of a class type that implements the function-call operator, allowing the object to be used within expressions using the same syntax as a function call. Functors are more powerful than simple function pointers, being able to contain their own data values, and allowing the programmer to emulate closures. They are also used as callback functions if it is necessary to use a member function as a callback function.