[英]template function pointer parameter in a class method
I have a class method which takes in a function pointer of an object of any class but with a specific return and parameter list. 我有一个类方法,该方法接受任何类的对象的函数指针,但具有特定的返回和参数列表。
The problem is that the compiler returns that what I pass is not the same as the arguments of the method I'm using. 问题是编译器返回我传递的内容与我使用的方法的参数不同。
There are other things I'm have trouble with but I will point them out below and as always not every detail is here only whatever is important. 我还有其他麻烦的地方,但我会在下面指出,并且一如既往,并不是每个细节都只有重要的东西。
Class.h : Class.h :
template<typename Value, typename ...Args>
class thing <Value(Args...)>
{
/* moar code */
template<typename C>
void method(C* object, Value(C::*func)(Args...), Args... /*how do I pass all of the parameters from here*/)
{
(object->*fund)(/*then put the parameters in here*/);
/* Also would this work with or with out parameters being passed*/
/* this is then wrapped and stored to be used later */
}
}
In main func : 在主要功能中 :
thing<void(int)> thingObj;
AClass obj(/*initialise if needed*/);
thingObj.method(&obj, &AClass::func, /*Parameters*/);
Reason for not using boost/std::function is this is an experiment so I can lean how this works 不使用boost / std :: function的原因是这是一个实验,因此我可以了解其工作原理
Excuse the typos and lack of formatting on phone, will correct things and add detail wherever I feel necessary 请原谅电话上的错字和缺乏格式,在我认为有需要的地方,可以纠正问题并添加细节
You can use indices for it. 您可以为其使用索引。
template<std::size_t...> struct seq{};
template<std::size_t N, std::size_t... Is>
struct gen_seq : gen_seq<N-1, N-1, Is...>{};
template<std::size_t... Is>
struct gen_seq<0, Is...> : seq<Is...>{};
Then write overloading of your method like this 然后像这样编写方法的重载
template<typename C, size_t... indices>
void method(C* object, Value(C::*func)(Args...),
std::tuple<Args...>&& args, seq<indices...>)
{
(object->*func)(std::get<indices>(args)...);
}
And call it in your first method like 然后用第一个方法调用它
method(object, func, std::forward_as_tuple(args...), gen_seq<sizeof...(Args)>{});
This works for me: 这对我有用:
#include <iostream>
template <typename Signature>
class thing;
template <typename Value, typename... Args>
class thing <Value(Args...)>
{
public:
template<typename C>
void method(C* object, Value(C::*func)(Args...) const, Args&&... args)
{
(object->*func)(std::forward<Args>(args)...);
}
};
struct AClass
{
void func(int i) const
{
std::cout << "passed " << i << std::endl;
}
};
struct BClass
{
void add(double a, double b) const
{
std::cout << a << " + " << b << " = " << a + b << std::endl;
}
};
int main()
{
thing<void(int)> thingObj;
AClass obj;
thingObj.method(&obj, &AClass::func, 5);
BClass bobj;
thing<void(double, double)> anotherThing;
anotherThing.method(&bobj, &BClass::add, 10.2, 11);
}
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