如何让线程直接执行std::sort()，而不创建中间函数？
比如：
std::thread t1(std::sort, data.begin(), data.end());我的想法是让每个线程对向量的一半进行排序，然后合并它：
#include <vector>
#include <thread>
#include <iostream>
#include <algorithm>
// Type your code here, or load an example.
void myfunc(std::vector<int>& data) {
std::sort(data.begin(), data.begin() + data.size() / 2);
return;
}
int main()
{
std::vector<int> data = { 1, 8, 123, 10, -3, 15, 2, 7 };
std::thread t1(myfunc, std::ref(data)); // works
//std::thread t1(std::sort, data.begin(), data.begin() + data.size() / 2); // doesn't
std::sort(data.begin() + data.size() / 2, data.end());
t1.join();
std::inplace_merge(data.begin(), data.begin() + data.size() / 2, data.end());
for (auto x : data)
std::cout << x << "\n";
}编译器错误，当使用注解行而不是上面的行时（我使用了在线代码编辑器）：
error: no matching function for call to 'std::thread::thread(<unresolved overloaded function type>, std::vector<int>::iterator, __gnu_cxx::__normal_iterator<int*, std::vector<int> >)'
16 | d t1(std::sort, data.begin(), data.begin() + data.size() / 2); // doesn't
| ^
In file included from /usr/include/c++/11/thread:43,
from /tmp/bBJEjs0nrj.cpp:2:
/usr/include/c++/11/bits/std_thread.h:127:7: note: candidate: 'template<class _Callable, class ... _Args, class> std::thread::thread(_Callable&&, _Args&& ...)'
127 | thread(_Callable&& __f, _Args&&... __args)
| ^~~~~~
/usr/include/c++/11/bits/std_thread.h:127:7: note: template argument deduction/substitution failed:
/tmp/bBJEjs0nrj.cpp:16:75: note: couldn't deduce template parameter '_Callable'
16 | d t1(std::sort, data.begin(), data.begin() + data.size() / 2); // doesn't
| ^
In file included from /usr/include/c++/11/thread:43,
from /tmp/bBJEjs0nrj.cpp:2:
/usr/include/c++/11/bits/std_thread.h:157:5: note: candidate: 'std::thread::thread(std::thread&&)'
157 | thread(thread&& __t) noexcept
| ^~~~~~
/usr/include/c++/11/bits/std_thread.h:157:5: note: candidate expects 1 argument, 3 provided
/usr/include/c++/11/bits/std_thread.h:121:5: note: candidate: 'std::thread::thread()'
121 | thread() noexcept = default;
| ^~~~~~
/usr/include/c++/11/bits/std_thread.h:121:5: note: candidate expects 0 arguments, 3 provided预期输出：
-3,1,27,8,10,15,123
3条答案
按热度按时间9lowa7mx1#
原始代码的最直接翻译使用模板示例化：
j2cgzkjk2#
std::sort()是一个函数模板，因此不能按原样传递给需要具体函子（行为类似函数的类型）的函数。您需要将std::sort强制转换为正确的函数指针类型，或者以某种方式将其 Package ，以便编译器确定您试图调用的std::sort()的版本。最简单的处理方法是使用lambda表达式来 Package 对
std::sort()的调用，这样编译器就可以为您进行模板推导，如下所示：5vf7fwbs3#
您可以使用lambda：