voidPrintNum(inti){std::cout<<"store a function pointer: "<<i<<std::endl;}classA{public:A(intnum):num_(num){}voidPrintNum(intn)const{std::cout<<"store a call to a member function: "<<num_<<std::endl;}private:int
std::cout<<'\n'; std::cout<<"bind to a pointer to member function:\n"; Foo foo; auto f3= std::bind(&Foo::print_sum, &foo,95, _1); f3(5); std::cout<<"bind to a pointer to data member:\n"; auto f4= std::bind(&Foo::data, _1); std::cout<< f4(foo) <<'\n';...
1//see file functional: class function<_Res(_ArgTypes...)>2template<typename T>3classfoo;45template<typename T1, typename T2>6classfoo<T1(T2)>{7public:8T1 i1;9T2 i2;10}; https://stackoverflow.com/questions/2402579/function-pointer-to-member-function https://stackoverflow.com/questions...
std::cout << "1) bind to a pointer to member function: "; Foo foo; // 这里的&foo就是为了补齐成员变量里面的默认参数this auto f3 = std::bind(&Foo::print_sum, &foo, 95, _1); f3(5); std::cout << "2) bind to a mem_fn that is a pointer to member function: "; } 执行...
std::cout << "bind to a pointer to member function:\n"; Foo foo; auto f3 = std::bind(&Foo::print_sum, &foo, 95, _1); f3(5); std::cout << "bind to a pointer to data member:\n"; auto f4 = std::bind(&Foo::data, _1); ...
官方说明: Class template std::function is a general-purpose polymorphic function wrapper. Instances of std::function can store, copy, and invoke any Callable target -- functions, lambda expressions, bind expressions, or other function objects, as well as pointers to member functions and pointers ...
发现从17开始有更直观简单的写法,就是看能不能static cast成想要的function pointer type,然后用SFINAE。针对文章最开始的问题可以这么写: using namespace std; struct Validator { template<typename T> static constexpr auto valid(T t) -> decltype((static_cast<void (*)(const double *)>(t), true))...
1.2 Member functions 1.3 基本使用#include<iostream> #include<functional> intfun(inta,intb,intc,intd) { std::cout<< a <<std::endl; std::cout<< b <<std::endl; std::cout<< c <<std::endl; std::cout<< d <<std::endl;
pointer to member object or to member function std::nullptr_t (since C++11) wrapper<f>() 中f是一个变量,它的值是运行期才能确定的。所以模板没办法编译通过,总不能等到运行时再Instantiate出一个wrapper<f>函数,让其中的i指向f吧? For pointers to functions, the valid arguments are pointers to func...
std::is_member_function_pointer::value C++ Copy 参数:模板std::is_member_function_pointer接受一个参数T(特征类),以检查T是否为非静态成员函数的指针。 返回值:此模板std::is_member_function_pointer返回一个布尔变量,如下所示: True:如果类型T是指向非静态成员函数类型的指针。