将C++builder中的类成员函数当作windows回调函数

来源：互联网发布：php 日期格式转时间戳编辑：程序博客网时间：2024/06/05 11:31

VCL的成员函数通常情况下，不能作为winodws的回函数，因为成员函数隐式包含一个this指针参数。回调函数中，最先运行机器码（windows自动执行）。

//16个字节汇编指令#pragma pack(push) //保存对齐状态#pragma pack(1)struct TInstruction{     byte Code1[7];     void *Self;     byte Code2;     void *Method;};#pragma pack(pop) //恢复对齐状态typedef TInstruction * PInstruction ;//改造回调函数PInstruction MakeInstruction(TMethod &Method){   //机器码使参数符合回调要求，然后又使之复合成员函数的调用要求   byte Code[16] ={0xFF,0x34,0x24,0xC7,0x44,0x24,0x04,0x00,0x00,0x00,0x00,0xE9,0x00,0x00,0x00,0x00};   PInstruction P;   P = (PInstruction)malloc(sizeof(struct TInstruction));   memmove(P,Code, 16);   P->Self    = Method.Data;   P->Method  = (void *)((long)(Method.Code)-(long(P)+sizeof(Code)));   return P;}//类销毁时使用void FreeInstruction(void *P){   free(P);}//---------------------------------------------------------------------------//定时器回调函数TIMERPROC __stdcall TForm1::TimerProc(  HWND hwnd,         // handle to window  UINT uMsg,         // WM_TIMER message  UINT_PTR idEvent,  // timer identifier  DWORD dwTime       // current system time){   this->Caption = Now();   KillTimer(hwnd,0);}void __fastcall TForm1::Button3Click(TObject *Sender){    TMethod M;    ShortString ProcName = "TimerProc";    M.Code = MethodAddress(ProcName);    M.Data = this;    P1 = MakeInstruction(M);//P1是在TForm1中定义的成员变量void * P1    SetTimer(this->Handle,0,1000,(TIMERPROC)(P1));//定时器函数}

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