class CMySocket { public: DWORD WINAPI WorkThread(LPVOID CompletetionPortID); ... };
有如上类,在类中某函数想以函数(WorkThread)
CreateThread(NULL, 0, WorkThread, ¶m, 0, &ThreadID))
编译会报错:cannot convert parameter 3 from 'unsigned long (void *)' to 'unsigned long (__stdcall *)(void *)' None of the functions with this name in scope match the target type
解决方法:
1.
这种情况,一般是将线程函数申明为静态,如:
class CRealtimeTask { public: static UINT taskmain(LPVOID param); BOOL StartTask(); };
在类中定义的成员函数,VC在编译时会强加一个this指针,所以才会出现上边的情况.将该成员函数声明为static类型,可以将this指针除去,但static成员函数只能访问static成员.
2.
以将线程函数申明成友员函数,这样可以传入该类的指针,访问类的成员;
class CRealtimeTask { public: friend UINT taskmain(LPVOID param); BOOL StartTask(); }; UINT taskmain(LPVOID param) { CRealtimeTask * pTaskMain = (CRealtimeTask *) param; //通过pTaskMain指针引用. return TRUE; } BOOL CRealtimeTask::StartTask() { AfxBeginThread(taskmain,this); }
3.
可以对成员函数实现回调,并访问非静态成员的,如下所示,这是为了实现线程函数访问类成员而实现的类.比MFC的实现方法好象要好一点.
class base; typedef int (base::*fnCallBack)(void *p); struct callback(void *param;fnCallBack *pfuc;base *pThis;}; class base { static int myThreadfuc(void *p) { struct callback *p1=(struct callback *)p; base *pthis=p1->base; fnCallBack *pfuc=p1->pfuc;void *param=p1->param; int i=(pthis->*pfuc)(param); delete p; return i; } public: void myCreateThread(fnCallBack pfuc,void *param) { struct callback *p=new struct callback; p.param=param; p.pThis=this; p.pfuc=pfuc; ::CreateThread(myThreadfuc,p); } virtual int myCallBack(void *p) { printf("It's base class./n"); return 0; } }; class derived: public base { int myCallBack(void *p){printf("It's derived class/n");} }; void myCreateThreadImitate(fnCallBack fuc,void *p) { (*fuc)(p); } void main() { base p;char *param; p.myCreateThread(&(base::myCallBack),param); derived p2;p2.myCreateThread(&(base::myCallBack),param); }