I have a class:
<template class F>
class test
{
public:
test(F fn) : fn_(fn)
{
}
private:
F fn_;
};
I want to specify F as std::function, for example F can be std::function < void () >. But there can be many kinds of std::function, such as std::function < int () >. I just want to limit F to std::function. How do I write it without further specific restrictions?
template<typename F>
class Test
{
public:
typedef std::function<F> func_type;
Test(const func_type& fn)
: _fn(fn)
{}
template<typename ...Args>
auto operator ()(Args&& ...args)
{
return _fn(std::forward<Args>(args)...);
}
private:
func_type _fn;
};
int main() {
std::function<void(const std::string&)> print = [](const std::string& name) {
std::cout << "Hello " << name << " !" << std::endl;
};
Test<void(const std::string&)> t(print);
t("Jason");
return 0;
}take a look, isn't it?
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