C++ std::vector 的独立 std::threads
我正在构建一个实时软件，其中我在 main() 和用于读取和处理数据的线程上有一个主要的无限循环.
I′m building a real time software where I have a main infinite loops on main() and threads used to read and process data.
其中一个问题是保持运行线程的 std::vector 以向它们发送信号并监视执行.所以我把这段代码放在一起:
One of the issues is keeping a std::vector of running threads to send signals to them and to monitor execution. So I put together this code:
#include <iostream>
#include <string>
#include <vector>
#include <thread>
#include <chrono>
namespace readerThread {
void start(int id)
{
while (1)
{
std::cout << "Reader " << id << " running..." << std::endl;
std::this_thread::sleep_for(std::chrono::milliseconds(1000));
}
}
}
int main()
{
int readers[] = { 1, 2, 3 };
std::vector<std::thread> readerThreads;
for (int &reader : readers)
{
std::thread th(readerThread::start, reader);
readerThreads.push_back(th);
}
while(true)
{
std::cout << "Waiting..." << std::endl;
std::this_thread::sleep_for(std::chrono::milliseconds(10000));
}
return 0;
}
它甚至没有编译，得到这个错误:
It doesn′t even compile, getting this error:
In file included from /usr/local/include/c++/5.1.0/x86_64-unknown-linux-gnu/bits/c++allocator.h:33:0,
from /usr/local/include/c++/5.1.0/bits/allocator.h:46,
from /usr/local/include/c++/5.1.0/string:41,
from /usr/local/include/c++/5.1.0/bits/locale_classes.h:40,
from /usr/local/include/c++/5.1.0/bits/ios_base.h:41,
from /usr/local/include/c++/5.1.0/ios:42,
from /usr/local/include/c++/5.1.0/ostream:38,
from /usr/local/include/c++/5.1.0/iostream:39,
from main.cpp:1:
/usr/local/include/c++/5.1.0/ext/new_allocator.h: In instantiation of 'void __gnu_cxx::new_allocator<_Tp>::construct(_Up*, _Args&& ...) [with _Up = std::thread; _Args = {const std::thread&}; _Tp = std::thread]':
/usr/local/include/c++/5.1.0/bits/alloc_traits.h:256:4: required from 'static std::_Require<std::allocator_traits<_Alloc>::__has_construct<_Tp, _Args ...> > std::allocator_traits<_Alloc>::_S_construct(_Alloc&, _Tp*, _Args&& ...) [with _Tp = std::thread; _Args = {const std::thread&}; _Alloc = std::allocator<std::thread>; std::_Require<std::allocator_traits<_Alloc>::__has_construct<_Tp, _Args ...> > = void]'
/usr/local/include/c++/5.1.0/bits/alloc_traits.h:402:16: required from 'static decltype (_S_construct(__a, __p, (forward<_Args>)(std::allocator_traits::construct::__args)...)) std::allocator_traits<_Alloc>::construct(_Alloc&, _Tp*, _Args&& ...) [with _Tp = std::thread; _Args = {const std::thread&}; _Alloc = std::allocator<std::thread>; decltype (_S_construct(__a, __p, (forward<_Args>)(std::allocator_traits::construct::__args)...)) = <type error>]'
/usr/local/include/c++/5.1.0/bits/stl_vector.h:917:30: required from 'void std::vector<_Tp, _Alloc>::push_back(const value_type&) [with _Tp = std::thread; _Alloc = std::allocator<std::thread>; std::vector<_Tp, _Alloc>::value_type = std::thread]'
main.cpp:37:30: required from here
/usr/local/include/c++/5.1.0/ext/new_allocator.h:120:4: error: use of deleted function 'std::thread::thread(const std::thread&)'
{ ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
^
In file included from main.cpp:4:0:
/usr/local/include/c++/5.1.0/thread:126:5: note: declared here
thread(const thread&) = delete;
^
线程是独立的，所以我不需要在主程序或任何线程上调用 join...
The threads areindependent, so I don′t need to call join on the main program nor on any thread...
所以，这是我的疑问:
为什么我的代码无法编译?
Why my code does not compile?
这是存储线程向量的正确方法吗?
Is that the correct way to store the vector of threads ?
感谢您的帮助...
PS:原代码:
推荐答案
你需要使用类似的东西
readerThreads.push_back(move(th));
这将使 th 成为右值，并导致调用移动构造函数.thread 的复制构造函数被设计为禁用(请参阅 Anthony Williams 的 C++ 并发实战).
This will make th an rvalue, and cause the move ctor to be called. The copy ctor of thread was disabled by design (see Anthony Williams' C++ Concurrency In Action).
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