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기능 :바인딩 기능을 수 std :: 나는 다음과 같은 코드가 작동하게하기 위해 노력하고있어 <void()>
#include <cstdio>
#include <functional>
#include <string>
#include <memory>
using namespace std;
class Foo {
public:
Foo(): m_str("foo") { }
void f1(string s1, string s2, unique_ptr<Foo> p)
{
printf("1: %s %s %s\n", s1.c_str(), s2.c_str(), p->str());
}
void f2(string s1, string s2, Foo* p)
{
printf("2: %s %s %s\n", s1.c_str(), s2.c_str(), p->str());
}
const char* str() const { return m_str.c_str(); }
private:
string m_str;
};
int main()
{
string arg1 = "arg1";
string arg2 = "arg2";
Foo s;
unique_ptr<Foo> ptr(new Foo);
//function<void()> f(bind(&Foo::f1, &s, arg1, arg2, std::move(ptr)));
function<void()> f(bind(&Foo::f2, &s, arg1, arg2, ptr.release()));
f();
}
호출 F() 푸에 바인딩을 :: F2는 (마지막 매개 변수는 원시 포인터) 잘 작동하지만 Foo :: f1에 바인딩하면 컴파일 오류가 발생합니다.
test.cpp: In function ‘int main()’:
test.cpp:36:70: error: no matching function for call to ‘std::function<void()>::function(std::_Bind_helper<false, void (Foo::*)(std::basic_string<char>, std::basic_string<char>, std::unique_ptr<Foo>), Foo*, std::basic_string<char, std::char_traits<char>, std::allocator<char> >&, std::basic_string<char, std::char_traits<char>, std::allocator<char> >&, std::unique_ptr<Foo, std::default_delete<Foo> > >::type)’
function<void()> f(bind(&Foo::f1, &s, arg1, arg2, std::move(ptr)));
^
test.cpp:36:70: note: candidates are:
In file included from test.cpp:2:0:
/usr/include/c++/4.8.2/functional:2251:2: note: template<class _Functor, class> std::function<_Res(_ArgTypes ...)>::function(_Functor)
function(_Functor);
^
/usr/include/c++/4.8.2/functional:2251:2: note: template argument deduction/substitution failed:
/usr/include/c++/4.8.2/functional:2226:7: note: std::function<_Res(_ArgTypes ...)>::function(std::function<_Res(_ArgTypes ...)>&&) [with _Res = void; _ArgTypes = {}]
function(function&& __x) : _Function_base()
^
/usr/include/c++/4.8.2/functional:2226:7: note: no known conversion for argument 1 from ‘std::_Bind_helper<false, void (Foo::*)(std::basic_string<char>, std::basic_string<char>, std::unique_ptr<Foo>), Foo*, std::basic_string<char, std::char_traits<char>, std::allocator<char> >&, std::basic_string<char, std::char_traits<char>, std::allocator<char> >&, std::unique_ptr<Foo, std::default_delete<Foo> > >::type {aka std::_Bind<std::_Mem_fn<void (Foo::*)(std::basic_string<char>, std::basic_string<char>, std::unique_ptr<Foo>)>(Foo*, std::basic_string<char>, std::basic_string<char>, std::unique_ptr<Foo>)>}’ to ‘std::function<void()>&&’
/usr/include/c++/4.8.2/functional:2429:5: note: std::function<_Res(_ArgTypes ...)>::function(const std::function<_Res(_ArgTypes ...)>&) [with _Res = void; _ArgTypes = {}]
function<_Res(_ArgTypes...)>::
^
/usr/include/c++/4.8.2/functional:2429:5: note: no known conversion for argument 1 from ‘std::_Bind_helper<false, void (Foo::*)(std::basic_string<char>, std::basic_string<char>, std::unique_ptr<Foo>), Foo*, std::basic_string<char, std::char_traits<char>, std::allocator<char> >&, std::basic_string<char, std::char_traits<char>, std::allocator<char> >&, std::unique_ptr<Foo, std::default_delete<Foo> > >::type {aka std::_Bind<std::_Mem_fn<void (Foo::*)(std::basic_string<char>, std::basic_string<char>, std::unique_ptr<Foo>)>(Foo*, std::basic_string<char>, std::basic_string<char>, std::unique_ptr<Foo>)>}’ to ‘const std::function<void()>&’
/usr/include/c++/4.8.2/functional:2206:7: note: std::function<_Res(_ArgTypes ...)>::function(std::nullptr_t) [with _Res = void; _ArgTypes = {}; std::nullptr_t = std::nullptr_t]
function(nullptr_t) noexcept
^
/usr/include/c++/4.8.2/functional:2206:7: note: no known conversion for argument 1 from ‘std::_Bind_helper<false, void (Foo::*)(std::basic_string<char>, std::basic_string<char>, std::unique_ptr<Foo>), Foo*, std::basic_string<char, std::char_traits<char>, std::allocator<char> >&, std::basic_string<char, std::char_traits<char>, std::allocator<char> >&, std::unique_ptr<Foo, std::default_delete<Foo> > >::type {aka std::_Bind<std::_Mem_fn<void (Foo::*)(std::basic_string<char>, std::basic_string<char>, std::unique_ptr<Foo>)>(Foo*, std::basic_string<char>, std::basic_string<char>, std::unique_ptr<Foo>)>}’ to ‘std::nullptr_t’
/usr/include/c++/4.8.2/functional:2199:7: note: std::function<_Res(_ArgTypes ...)>::function() [with _Res = void; _ArgTypes = {}]
function() noexcept
^
/usr/include/c++/4.8.2/functional:2199:7: note: candidate expects 0 arguments, 1 provided
무엇이 잘못 되었나요?
gcc 4.8.2 및 -std = C++ 0x (-std = C++ 11 역시 실패 함) 플래그를 사용하고 있습니다.
감사
std :: bind에 rvalues를 전달하는 데 문제가 있습니다. http://stackoverflow.com/questions/4871273/passing-rvalues-through-stdbind를 참조하십시오. f1이 포인터의 소유권을 실제로 획득해야합니까? f1은 const ref를 통해 포인터를 취할 수 있고 std :: ref를 사용하여 std :: bind에 포인터를 전달할 수 있습니다. http://coliru.stacked-crooked.com/a/5ebe39ccca544bea – countfromzero
참조 http://stackoverflow.com/ 질문/9955714/do-stdbind-work-with-move-only-types-in-general-and-stdunique-ptr-in-part – zch
@justinls 그래, 소유권을 가져야하지만, 예를 들어 주셔서 감사합니다. std :: move를 사용하여 작동하게하는 방법을 찾지 못하면 제안을 사용하여 해결 방법을 제안합니다. – rogerzanoni