'WinMain' : function cannot be overloaded

 Create a MFC Application (UNICODE), paste following code in one of your cpp file.

int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow)

{ return TRUE }

 Build project and following error occurred:

Error	1	error C2731: 'WinMain' : function cannot be overloaded	D:TestCopyFilesCopyFiles.cpp	37	1	CopyFiles

Solution:

Change the third parameter type "LPTSTR" to LPSTR.

Or, include  Windows.h and tchar.h

Reference: http://www.cplusplus.com/forum/windows/79761/