function-pointers

I've asked a question here about whether taking the address of a function forces the compilation of said function specifically with regard to Substitution-Failure-Is-Not-An-Error. The most direct answer to this can be found here : Informally, an object is odr-used if its address is taken, or a reference is bound to it, and a function is odr-used if a function call to it is made or its address is taken. If an object or a function is odr-used, its definition must exist somewhere in the program; a violation of that is a link-time error. But all the compilers I've tested show this as perfectly

#include<iostream> #include<conio.h> using namespace std; class Base; typedef void (Base::*function)(); class Base { public: function f; Base() { cout<<"Base Class constructor"<<endl; } virtual void g()=0; virtual void h()=0; }; class Der:public Base { public: Der():Base() { cout<<"Derived Class Constructor"<<endl; f=(function)(&Der::g); } void g() { cout<<endl; cout<<"Function g in Derived class"<<endl; } void h() { cout<<"Function h in Derived class"<<endl; } }; class Handler { Base *b; public: Handler(Base *base):b(base) { } void CallFunction() { cout<<"CallFunction in Handler"<<endl; (b->

I have a class EventMgr which has a template function to register a listener. But, when I register a listener, linker gives me a " error LNK2019: unresolved external symbol ". Appetizer code: class EventMgr { template< class T, class EvenT> void RegisterListener(T* listener, int EventType, void (T::*MemFunc)(EvenT*) ); } SoundMgr(which is a listener) tries to register for event: SoundMgr::SoundMgr(void) { EventManager::GetInstance()->RegisterListener(this, 1, (&SoundMgr::handleBulletFired)); } I'm not sure why it won't link. Why can it not find the reference types ? If you simply declared the

I was wondering if is possible to point a function of other structure into of a structure: Example: typedef struct { int func(int z) { return z * 2; } } sta; typedef struct { int(*this.func)(int); } stah; int main() { sta sa; stah sah; sah.func = &sa.func; return 0; } it's possible this in a struct? skypjack The declaration of func should look like this: int(sta::*func)(int); Or, alternatively: using my_type = int(sta::*)(int); my_type func; This is easier to read: my_type is an alias for the type pointer to a member function of sta that gets an int and returns an int . func is nothing more

I have a function pointer in a dll file (in implementation, not header). How can I call the function pointed to by this pointer in the exe source code? you can export a function returning the pointer. Header: typedef void ( *MyPtr ) (); __declspec( dllexport ) MyPtr GetMyPtr(); Source: MyPtr GetMyPtr() { //retunr the function pointer here } 来源： https://stackoverflow.com/questions/7764074/exporting-a-function-pointer-from-dll