Error: "Attempt to use a deleted function" when moving a promise
Error: "Attempt to use a deleted function" when moving a promise
我正在尝试编写一个包含 promise/future 的示例。在 this reference page 中的示例中，他们这样做了，并且在他们的在线编译器中工作得很好。当我在我的 Mac 上执行此操作（源代码在下面）时，它会抛出此错误，指示没有移动运算符。谁能告诉我哪里出了问题？
头文件：
#ifndef Demonstration9_hpp
#define Demonstration9_hpp
#include <iostream>
#include <thread>
#include <future>
using namespace std;
inline namespace demo9
{
class Demonstration9
{
private:
bool Job1();
void Job2();
public:
void Run();
};
}
#endif /* Demonstration9_hpp */
源文件：
#include "Demonstration9.hpp"
bool job1(string test_string)
{
this_thread::sleep_for(chrono::milliseconds(500));
return test_string == "test";
}
void job2()
{
this_thread::sleep_for(chrono::milliseconds(500));
}
bool Demonstration9::Run()
{
promise<bool> j1_promise;
future<bool> j1_future = j1_promise.get_future();
thread t1(job1, "test", move(j1_promise));
j1_future.wait(); // wait for result
cout << "result=" << j1_future.get() << '\n';
t1.join(); // wait for thread completion
// Demonstrate using promise<void> to signal state between threads.
promise<void> j2_promise;
future<void> j2_future = j2_promise.get_future();
thread t2(job2, move(j2_promise));
j2_future.wait();
t2.join();
}
构建日志：
In file included from
/Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.cpp:9: In
file included from
/Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.hpp:13:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/thread:342:5:
error: attempt to use a deleted function
__invoke(_VSTD::move(_VSTD::get<1>(__t)), _VSTD::move(_VSTD::get<_Indices>(__t))...);
^ /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/thread:352:5:
note: in instantiation of function template specialization
'std::__1::__thread_execute >, bool
(*)(std::__1::basic_string), const char *,
std::__1::promise , 2, 3>' requested here
__thread_execute(__p, _Index());
^ /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/thread:368:47:
note: in instantiation of function template specialization
'std::__1::__thread_proxy >, bool
(*)(std::__1::basic_string), const char *,
std::__1::promise > >' requested here
int __ec = __libcpp_thread_create(&__t_, &__thread_proxy<_Gp>, __p.get());
^ /Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.cpp:26:12:
note: in instantiation of function template specialization
'std::__1::thread::thread), char
const (&)[5], std::__1::promise , void>' requested here
thread t1(job1, "test", move(j1_promise));
^ In file included from /Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.cpp:9: In
file included from
/Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.hpp:12: In
file included from
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/iostream:38:
In file included from
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/ios:216:
In file included from
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/__locale:15:
In file included from
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/string:470:
In file included from
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/string_view:169:
In file included from
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/__string:56:
In file included from
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/algorithm:640:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/type_traits:1590:5:
note: '~__nat' has been explicitly marked deleted here
~__nat() = delete;
^ In file included from /Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.cpp:9: In
file included from
/Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.hpp:13:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/thread:342:5:
error: attempt to use a deleted function
__invoke(_VSTD::move(_VSTD::get<1>(__t)), _VSTD::move(_VSTD::get<_Indices>(__t))...);
^ /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/thread:352:5:
note: in instantiation of function template specialization
'std::__1::__thread_execute >, void (*)(),
std::__1::promise , 2>' requested here
__thread_execute(__p, _Index());
^ /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/thread:368:47:
note: in instantiation of function template specialization
'std::__1::__thread_proxy >, void (*)(),
std::__1::promise > >' requested here
int __ec = __libcpp_thread_create(&__t_, &__thread_proxy<_Gp>, __p.get());
^ /Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.cpp:34:12:
note: in instantiation of function template specialization
'std::__1::thread::thread , void>'
requested here
thread t2(job2, move(j2_promise));
^ In file included from /Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.cpp:9: In
file included from
/Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.hpp:12: In
file included from
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/iostream:38:
In file included from
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/ios:216:
In file included from
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/__locale:15:
In file included from
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/string:470:
In file included from
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/string_view:169:
In file included from
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/__string:56:
In file included from
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/algorithm:640:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/type_traits:1590:5:
note: '~__nat' has been explicitly marked deleted here
~__nat() = delete;
^ 2 errors generated.
行
thread t1(job1, "test", move(j1_promise));
正在尝试调用
job1("test", move(j1_promise));
在一个单独的线程中。但是你的 job1 只接受一个参数。
我正在尝试编写一个包含 promise/future 的示例。在 this reference page 中的示例中，他们这样做了，并且在他们的在线编译器中工作得很好。当我在我的 Mac 上执行此操作（源代码在下面）时，它会抛出此错误，指示没有移动运算符。谁能告诉我哪里出了问题？
头文件：
#ifndef Demonstration9_hpp
#define Demonstration9_hpp
#include <iostream>
#include <thread>
#include <future>
using namespace std;
inline namespace demo9
{
class Demonstration9
{
private:
bool Job1();
void Job2();
public:
void Run();
};
}
#endif /* Demonstration9_hpp */
源文件：
#include "Demonstration9.hpp"
bool job1(string test_string)
{
this_thread::sleep_for(chrono::milliseconds(500));
return test_string == "test";
}
void job2()
{
this_thread::sleep_for(chrono::milliseconds(500));
}
bool Demonstration9::Run()
{
promise<bool> j1_promise;
future<bool> j1_future = j1_promise.get_future();
thread t1(job1, "test", move(j1_promise));
j1_future.wait(); // wait for result
cout << "result=" << j1_future.get() << '\n';
t1.join(); // wait for thread completion
// Demonstrate using promise<void> to signal state between threads.
promise<void> j2_promise;
future<void> j2_future = j2_promise.get_future();
thread t2(job2, move(j2_promise));
j2_future.wait();
t2.join();
}
构建日志：
In file included from /Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.cpp:9: In file included from /Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.hpp:13: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/thread:342:5: error: attempt to use a deleted function __invoke(_VSTD::move(_VSTD::get<1>(__t)), _VSTD::move(_VSTD::get<_Indices>(__t))...); ^ /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/thread:352:5: note: in instantiation of function template specialization 'std::__1::__thread_execute >, bool (*)(std::__1::basic_string), const char *, std::__1::promise , 2, 3>' requested here __thread_execute(__p, _Index()); ^ /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/thread:368:47: note: in instantiation of function template specialization 'std::__1::__thread_proxy >, bool (*)(std::__1::basic_string), const char *, std::__1::promise > >' requested here int __ec = __libcpp_thread_create(&__t_, &__thread_proxy<_Gp>, __p.get()); ^ /Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.cpp:26:12: note: in instantiation of function template specialization 'std::__1::thread::thread), char const (&)[5], std::__1::promise , void>' requested here thread t1(job1, "test", move(j1_promise)); ^ In file included from /Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.cpp:9: In file included from /Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.hpp:12: In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/iostream:38: In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/ios:216: In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/__locale:15: In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/string:470: In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/string_view:169: In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/__string:56: In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/algorithm:640: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/type_traits:1590:5: note: '~__nat' has been explicitly marked deleted here ~__nat() = delete; ^ In file included from /Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.cpp:9: In file included from /Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.hpp:13: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/thread:342:5: error: attempt to use a deleted function __invoke(_VSTD::move(_VSTD::get<1>(__t)), _VSTD::move(_VSTD::get<_Indices>(__t))...); ^ /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/thread:352:5: note: in instantiation of function template specialization 'std::__1::__thread_execute >, void (*)(), std::__1::promise , 2>' requested here __thread_execute(__p, _Index()); ^ /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/thread:368:47: note: in instantiation of function template specialization 'std::__1::__thread_proxy >, void (*)(), std::__1::promise > >' requested here int __ec = __libcpp_thread_create(&__t_, &__thread_proxy<_Gp>, __p.get()); ^ /Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.cpp:34:12: note: in instantiation of function template specialization 'std::__1::thread::thread , void>' requested here thread t2(job2, move(j2_promise)); ^ In file included from /Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.cpp:9: In file included from /Users/maurits/Github/CPP-Demonstrations/src/Demonstration9.hpp:12: In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/iostream:38: In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/ios:216: In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/__locale:15: In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/string:470: In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/string_view:169: In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/__string:56: In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/algorithm:640: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/type_traits:1590:5: note: '~__nat' has been explicitly marked deleted here ~__nat() = delete; ^ 2 errors generated.
行
thread t1(job1, "test", move(j1_promise));
正在尝试调用
job1("test", move(j1_promise));
在一个单独的线程中。但是你的 job1 只接受一个参数。