It’s possible in GCC, but the way it’s documented in C++ language extensions section suggests there’s no portable way to do it. You can do two things: If you control the class, create a non-virtual function and a virtual wrapper for it and when you know you don’t need virtual dispatch, just take address of … Read more
The quoted statements in question seems to be validated by the following statements from the standard. From dcl.mptr#3’s note: [ Note: See also [expr.unary] and [expr.mptr.oper]. The type “pointer to member” is distinct from the type “pointer”, that is, a pointer to member is declared only by the pointer to member declarator syntax, and never by … Read more
p->pfn is a pointer of pointer-to-member-function type. In order to call a function through such a pointer you need to use either operator ->* or operator .* and supply an object of type C as the left operand. You didn’t. I don’t know which object of type C is supposed to be used here – … Read more
I don’t believe that there are any facilities provided by the language for doing this. There are overloads for operator << for streams to print out normal void* pointers, but member function pointers are not convertible to void*s. This is all implementation-specific, but typically member function pointers are implemented as a pair of values – … Read more
It works because the Standard says that’s how it should happen. I did some tests with GCC, and it turns out for virtual functions, GCC stores the virtual table offset of the function in question, in bytes. struct A { virtual void f() { } virtual void g() { } }; int main() { union … Read more
C++03 std, §4.11 2 Pointer to member conversions: An rvalue of type “pointer to member of B of type cv T,” where B is a class type, can be converted to an rvalue of type “pointer to member of D of type cv T,” where D is a derived class (clause 10) of B. If … Read more
You can’t. You either pass a pointer to a static method or Parent has to accept also a pointer to the object. You might want to look at boost::bind and boost::function for that: #include <boost/bind.hpp> #include <boost/function.hpp> struct Y { void say(void) { std::cout << “hallo!”;} boost::function<void()> getFunc() { return boost::bind(&Y::say, this); } }; struct … Read more
In the most normal situation, you can pretty much think of struct A { int i; int foo() { return i; } }; A a; a.foo(); as struct A { int i; }; int A_foo( A* this ) { return this->i; }; A a; A_foo(&a); (Starting to look like C, right?) So you would think … Read more
Currently there is no standard way of doing this in C++ although the information must be available somewhere. Otherwise, how could the program call the function? However, GCC provides an extension that allows us to retrieve the address of a virtual function: void (A::*mfp)() = &A::func; printf(“address: %p”, (void*)(b->*mfp)); …assuming the member function has the … Read more
In the standard (e.g. N3337 – not the latest but fine for this) there is a note at the end of section 8.3.3.3 that reads: [ Note: See also 5.3 and 5.5. The type “pointer to member” is distinct from the type “pointer”, that is, a pointer to member is declared only by the pointer … Read more