如何將void（__thiscall MyClass :: *）（void *）轉換為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”方法並使其自動調用，如下所示：

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);
}

我四處搜尋，無法弄明白。 有沒有人做過這樣的事情？ 或者我走錯了路？ 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));
}