dll3.cpp

vc中的DLL是个好东东

// DLL3.cpp : Defines the entry point for the DLL application.
//

#include "stdafx.h"
#define DLL3_EXPORTS
#include "DLL3.h"

BOOL APIENTRY DllMain( HANDLE /*hModule*/, 
                       DWORD  ul_reason_for_call, 
                       LPVOID /*lpReserved*/
					 )
{
    switch (ul_reason_for_call)
	{
		case DLL_PROCESS_ATTACH:
		case DLL_THREAD_ATTACH:
		case DLL_THREAD_DETACH:
		case DLL_PROCESS_DETACH:
			break;
    }
    return TRUE;
}


///////////////////////////////////////////////////////////////////////////////
// GetCycleCount - private function of DLL3.cpp.  The static keyword ensures
//                 that this function name is not visible outside DLL3.cpp.
static inline unsigned __int64 GetCycleCount()
{
	unsigned int timehi, timelo;

	// Use the assembly instruction rdtsc, which gets the current
	// cycle count (since the process started) and puts it in edx:eax.
	__asm
	{
		rdtsc
		mov timehi, edx;
		mov timelo, eax;
	}

	return ((unsigned __int64)timehi << 32) + (unsigned __int64)timelo;
}


///////////////////////////////////////////////////////////////////////////////
// Example of an exported class
///////////////////////////////////////////////////////////////////////////////
// This is the constructor of class CDLL3 that has been exported;
// see DLL3.h for the class definition
CDLL3::CDLL3()
{ 
}

int CDLL3::GetCpuSpeed()
{
	const unsigned __int64 ui64StartCycle = GetCycleCount();
	Sleep(1000);
	return static_cast<int>((GetCycleCount() - ui64StartCycle) / 1000000);
}

///////////////////////////////////////////////////////////////////////////////
// Class wrapper functions
///////////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////////
// CreateDLL3 - create an instance of the class CDLL3
void * __stdcall CreateDll3()
{
	return new CDLL3;
}

///////////////////////////////////////////////////////////////////////////////
// DestroyDLL3 - free the memory for the class instance 
void __stdcall DestroyDll3(void * objptr)
{
	CDLL3 *dll3 = (CDLL3 *) objptr;
	if (dll3)
		delete dll3;
}

///////////////////////////////////////////////////////////////////////////////
// GetCpuSpeed - returns CPU speed in MHz;  for example, ~2193 will be 
//               returned for a 2.2 GHz CPU.
int __stdcall GetCpuSpeedDll3(void * objptr)
{
	CDLL3 *dll3 = (CDLL3 *) objptr;
	if (dll3)
		return dll3->GetCpuSpeed();
	else
		return 0;
}