Re: Function pointer and functor problem

"" <>
Sat, 25 Oct 2008 14:36:38 CST

So the queue would be like:

typedef void (*ptr)( );
queue<ptr> timer_queue;

Can it be done somehow using wrapper static functions of classes A and
B ??
Please provide some hint or guidance.

I think the most straightforward solution is to change the callbacks
so they take a single void* pointer as an argument. Then you can have
member functions in classes A and B, which static_cast<> the void*
parameter to their own class type and call a non-static member
function on that pointer:

struct Callback {
    typedef void (*func_ptr)(void*);
    func_ptr f;
    void *param;
    explicit Callback(func_ptr f_ = 0, void *param_ = 0) : f(f_),
param(param_) {}
queue<Callback> timer_queue;

struct A {
    static void static_callback(void* self) {
    void callback() {

A a;
timer_queue.push_back(Callback(A::static_callback, &a));

This is not strictly type-safe, so you have to be careful, but for the
simple-sounding case you are describing it is perfectly reasonable.

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