thread_local C++11，VS2015 中的错误 C2492 [英] thread_local C++11, Error C2492 in VS2015

问题描述

我有这样的课程:

在 CustomAllocator.h 文件中:

in CustomAllocator.h file:

namespace MemoryMgmt
{
  class PoolMemory 
  {
   ....
  }
}
class CustomAllocator
  {
  public:
    void * operator new(size_t i_size);
    void operator delete(void*, void*);
    virtual ~CustomAllocator(){}; 


#pragma warning(suppress: 4251)
    static thread_local MemoryMgmt::PoolMemory memory_manager_current;
  };
inline void * CustomAllocator::operator new(size_t i_size)
  {
  return memory_manager_current.AllocateChars(i_size);
  }
inline void CustomAllocator::operator delete(void * , void*)
  {
  //Should not be used
  ASSERT(!"Placement delete should not be used for memory objects");
  }

在 CustomAllocator.cpp 文件中:

in CustomAllocator.cpp file:

#include <CustomAllocator.h>

thread_local MemoryMgmt::PoolMemory CustomAllocator::memory_manager_current;

我在许多不同的库中使用了 CustomAllocator 类.我会收到以下错误(许多错误与此相同):

I used CustomAllocator class in many different libraries. and I will get the following error (many errors same as):

error C2492: 'public: static MemoryMgmt::PoolMemory CustomAllocator::memory_manager_current': data with thread storage duration may not have dll interface (compiling source file D:\*******.cpp)

我使用的是 Visual Studio 2015，我想这个版本完全支持它.

I use visual studio 2015 and I guess it is fully supported in this version.

推荐答案

同时使用 __declspec(dllexport) 和 __declspec(thread) 时会出现此错误.在您的情况下， memory_manager_current 是用作线程本地存储的 static 类成员.但是，我强烈怀疑该类可能已使用属性 __declspec(dllexport) 声明(尽管在您帖子的代码中未看到).

This error occurs when you use __declspec(dllexport) and __declspec(thread) together. In your case memory_manager_current is static class member used as thread local storage. However, I strongly suspect the class might have declared with attribute __declspec(dllexport) (Although not seen in the code in your post).

您可以安全地将memory_manager_current移出类，并将其作为class CustomAllocator的实现文件中的全局变量.

You can safely move memory_manager_current out of class and make it as global variable in the implementation file of class CustomAllocator.

希望这会有所帮助.

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