MSVC不会一直发出C2893吗？错误？ [英] MSVC Doesn't issue C2893 consistently ? Bug?

问题描述

start_thread2和start_thread3线程中的代码是否应该调用？ 

http://stackoverflow.com/questions/42236085/msvc-inconsistent-c293-failed-to-specialize- function-template

解决方案

嗨obidan2，

感谢您在此处发帖。

>> 我知道您应该使用std :: ref来获取  reference_wrapper并按值传递，但我不明白为什么代码在一种情况下编译而不是另一种情况。有人可以解释为什么它使用bind编译好但是
不是线程，为什么它不能用start_thread1编译？

仅限功能b 对可调用函数对象的inds参数。如果你不使用std：ref，也可以编译代码，但它将是函数参数对象，而不是
的实例

希望这对您有所帮助。

最诚挚的问候，

Sera Yu 的

Should the code in the start_thread2 and start_thread3 thread calls not compile ? 
http://stackoverflow.com/questions/42236085/msvc-inconsistent-c293-failed-to-specialize-function-template

解决方案

Hi obidan2,

thanks for posting here.

>>I know you should use std::ref in order to get a  reference_wrapper and pass it by value,but I don't understand why code compiles in one case and not the other. Can someone explain why it compiles fine with bind but not thread, and why it doesn't compile with start_thread1 ?

The std::thread(Fn&& F, Args&&... A) constructs an object that's associated with a new thread of execution and executes the pseudo-function INVOKE that's defined in <functional>. The std::reference_wrapper is a class template that wraps a reference in a copyable, assignable object. It is frequently used as a mechanism to store references inside standard containers. That's why we should use helper function like std::ref to construct a reference_wrapper from an argument. For example:

And the std::bind Function only binds arguments to a callable function object. The code could also be compiled if you don't use std:ref, but it will be the function parameter object, not the instance of std::reference_wrapper. For example:

For more information, please refer to this document below.

https://msdn.microsoft.com/en-us/library/mt771480.aspx

Hope this could be help of you.

Best Regards,
Sera Yu

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