Pointers can be declared as pointing to mutable (non-const) data or pointer to constant data.
Pointers can be defined to point to a function.
My coworkers and I were discussing the use of "const" with pointers and the question came up regarding the use of const
with function pointers.
Here are some questions:
- What is the meaning of a pointer to a constant function versus a pointer to a non-constant function?
- Can a function be const?
- Can a function be non-const (mutable)?
- What is the proper (safe) syntax for passing a function pointer?
Edit 1: Function pointer syntax
typedef void (*Function_Pointer)(void); // Pointer to void function returning void.
void function_a(Function_Pointer p_func); // Example 1.
void function_b(const Function_Pointer p_func); // Example 2.
void function_c(Function_Pointer const p_func); // Example 3.
void function_d(const Function_Pointer const p_func); // Example 4.
The above declarations are examples of treating a function pointer like a pointer to an intrinsic type.
A data, variable or memory pointer allows for the above combinations.
So the questions are: can a function pointer have the same combinations and what is meant by a pointer to a const function (such as Example 2)?