[amgamg]

Dear experts, you help is necessary!
When trying to compile this code an error encounted.
I think that thread in class is good idea for c++, so if you know what`s wrong, please post your opinion!
(and sorry for my broken english ;)

Expand|Select|Wrap|Line Numbers

1. #include <windows.h>
2. #include <stdlib.h>
3. #include <malloc.h>
4. #include <memory.h>
5. #include <tchar.h>
6.  
7. template <class T> class Thread
8. {
9. public:
10.     Thread(){}
11.     Thread(T data){ this->data = data; }
12.     virtual ~Thread(){}
13.     virtual void Proc(T data);
14.  
15.     void Run() {
16.         Run(data);
17.     }
18.  
19.     void Run(T data) {
20.         this->data = data;
21.         handle = ::CreateThread(0, 0,(LPTHREAD_START_ROUTINE)ThreadFunc, (LPVOID)this, 0, 0);
22.     }
23.  
24.     void Join() {
25.         ::WaitForSingleObject(handle, INFINITE);
26.     }
27. private:
28.     HANDLE handle;
29.     T data;
30.     static DWORD WINAPI ThreadFunc(LPVOID param)
31.     {
32.         Thread* This = (Thread*)param;
33.         This->Proc(This->data);
34.         return 0;
35.     }
36. };
37.  
38.  
39.  
40. class MyTask : public Thread<wchar_t*>
41. {
42.     void Proc(wchar_t* data)
43.     {
44.         ::MessageBox(NULL, L"Message from thread", data, NULL);
45.     }
46. };
47.  
48.  
49. int __stdcall WinMain(HINSTANCE hInstance, HINSTANCE, char*, int iShowCmd)
50. {
51.     MyTask * t = new MyTask();
52.     t->Run(L"Hola!");
53.     t->Join();
54.     return 0;
55. }
56.  

Expand|Select|Wrap|Line Numbers

1. Visual C++ 2008, Express Edition:
2.  
3. 1>App.obj : error LNK2001: unresolved external symbol ""public: virtual void __thiscall Thread<wchar_t *>::Proc(wchar_t *)" (?Proc@?$Thread@PA_W@@UAEXPA_W@Z)"
4.  

Any ideas?

[newb16]

Because you haven't implemented Thread::Proc. You did it with MyTask::Proc, but not for parent template class. Either decalare it pure virtual or define with empty body.