pointer to const member function typedef

c++ pointer to member function
c++ pointer to const member function
c++ call member function pointer
c++ pass member function as argument
c++ pointer to member function inside class
c++ member function type
c++ const member function
iso c++ forbids taking the address of a bound member function to form a pointer to member function

I know it's possible to separate to create a pointer to member function like this

struct K { void func() {} };
typedef void FuncType();
typedef FuncType K::* MemFuncType;
MemFuncType pF = &K::func;

Is there similar way to construct a pointer to a const function? I've tried adding const in various places with no success. I've played around with gcc some and if you do template deduction on something like

template <typename Sig, typename Klass>
void deduce(Sig Klass::*);

It will show Sig with as a function signature with const just tacked on the end. If to do this in code it will complain that you can't have qualifiers on a function type. Seems like it should be possible somehow because the deduction works.


You want this:

typedef void (K::*MemFuncType)() const;

If you want to still base MemFuncType on FuncType, you need to change FuncType:

typedef void FuncType() const;
typedef FuncType K::* MemFuncType;

How do I declare a pointer-to-member-function that points to a const , [33.8] How do I declare a pointer-to-member-function that points to a const member function? Short answer: add a const to the right of the ) when you use a typedef  Normal C functions can be thought of as having a different calling convention from member functions, so the types of their pointers (pointer-to-member-function vs pointer-to-function) are different and incompatible. C++ introduces a new type of pointer, called a pointer-to-member, which can be invoked only by providing an object.


A slight refinement showing how to do it without a typedef. In a deduced context like the following, you can't use a typedef.

template <typename Class, typename Field>
Field extract_field(const Class& obj, Field (Class::*getter)() const)
{
   return (obj.*getter)();
}

applied to some class with a const getter:

class Foo {
 public:
  int get_int() const;
};

Foo obj;
int sz = extract_field(obj, &Foo::get_int);

Pointers to Member Functions, C++ FAQ, Types. typedef declaration Declares a variable of a pointer or pointer-to-​member type. int * const *(*g)(float), g is pointer to a function with prototype int * const * func(float) where its return value int * const * is a pointer to a  We could come up with a name for the pointer-to-member function as fptr, then we have: Return_Type: int Class_Name: Foo Argument_List: string declaration of a pointer-to-member function named "fptr": int (Foo::*fptr) (string); To assign a member function to the pointer, the grammar is: fptr= &Foo::f;


Another more direct way to do it (avoiding using and typedefs) is this:

#include <iostream>

class Object
{
    int i_;
public:
    int j_;
    Object()
        : Object(0,0)
    {}
    Object(int i, int j)
        : i_(i),
        j_(j)
    {}

    void printIplusJplusArgConst(int arg) const
    {
        std::cout << i_ + j_ + arg << '\n';
    }
};

int main(void)
{
    void (Object::*mpc)(int) const = &Object::printIplusJplusArgConst;

    Object o{1,2};
    (o.*mpc)(3);    // prints 6

    return 0;
}

mpc is a const method pointer to Object.

Pointer declaration, [C++] Getting a pointer to a const member-function <class R, class T>struct use_const_overload{ typedef R (T::*MemFuncPtr)() const; static  Now we can use a typedef to create a named function pointer type called printer: typedef void (*printer_t) (int); This creates a type, named printer_t for a pointer to a function that takes a single int argument and returns nothing, which matches the signature of the functions we have above.


[C++] Getting a pointer to a const member-function, I discuss what member function pointers are, how to declare and use them, and private: long mVal; }; typedef long (Test::*Multiplier)() const; int main( int argc,  Pointers to Members and Virtual Functions. Invoking a virtual function through a pointer-to-member function works as if the function had been called directly. The correct function is looked up in the v-table and invoked. The key to virtual functions working, as always, is invoking them through a pointer to a base class. (For more information


Pointers to C++ Member Functions, Learn more about const keyword in C++. Learn about const function, const pointer, const data member, etc. Start with basics and ask your doubts. Class member functions know where their data is because they are passed a pointer to it (as a "hidden" first argument) when the function is called. A static member function does NOT receive that pointer, because there is no way to know which data to pass, since no class instance is referenced when calling a static function.


C++ const keyword : CodesDope, In C and C++ we use the keyword const to make program elements constant. sizeof and typedef in C++ · Decision Making · Loop types · Storage Classes · Functions Variables; Pointers; Function arguments and return types; Class Data members A const member function never modifies data members in an object. z/OS® XL C++ allows the __cdecl keyword on member functions and nonmember functions. These functions can be static or nonstatic. It also allows the keyword on pointer-to-member function types and the typedef specifier.