如何將void（__thiscall MyClass :: *）（void *）轉換爲void（__cdecl *）（void *）指針

Question

我想構建一個可以隱藏線程創建的「IThread」類。子類實現「ThreadMain」方法，並自動調用它看起來像這樣：

class IThread 
{ 
public: 
    void BeginThread(); 
    virtual void ThreadMain(void *) PURE; 
}; 
void IThread::BeginThread() 
{ 
    //Error : cannot convert"std::binder1st<_Fn2>" to "void (__cdecl *)(void *)" 
    m_ThreadHandle = _beginthread(
        std::bind1st(std::mem_fun(&IThread::ThreadMain), this), 
        m_StackSize, NULL); 
    //Error : cannot convert void (__thiscall*)(void *) to void (__cdecl *)(void *) 
     m_ThreadHandle = _beginthread(&IThread::ThreadMain, m_StackSize, NULL); 
} 

我已經搜索周圍，無法弄清楚。有沒有人做過這樣的事情？或者我走錯路了？ TIA

Answer 1

你不能。

您應該使用靜態函數（不是靜態成員函數，而是自由函數）。

// IThread.h 
class IThread 
{ 
public: 
    void BeginThread(); 
    virtual void ThreadMain() = 0; 
}; 

// IThread.cpp 
extern "C" 
{ 
    static void __cdecl IThreadBeginThreadHelper(void* userdata) 
    { 
     IThread* ithread = reinterpret_cast< IThread* >(userdata); 
     ithread->ThreadMain(); 
    } 
} 
void IThread::BeginThread() 
{ 
    m_ThreadHandle = _beginthread(
        &IThreadBeginThreadHelper, 
        m_StackSize, reinterpret_cast< void* >(this)); 
}