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// Ex20c.cpp : Defines the initialization routines for the DLL. 
// 
 
#include "stdafx.h" 
#include "Ex20c.h" 
#include "math.h" 
 
#ifdef _DEBUG 
#define new DEBUG_NEW 
#endif 
 
// 
//	Note! 
// 
//		If this DLL is dynamically linked against the MFC 
//		DLLs, any functions exported from this DLL which 
//		call into MFC must have the AFX_MANAGE_STATE macro 
//		added at the very beginning of the function. 
// 
//		For example: 
// 
//		extern "C" BOOL PASCAL EXPORT ExportedFunction() 
//		{ 
//			AFX_MANAGE_STATE(AfxGetStaticModuleState()); 
//			// normal function body here 
//		} 
// 
//		It is very important that this macro appear in each 
//		function, prior to any calls into MFC.  This means that 
//		it must appear as the first statement within the  
//		function, even before any object variable declarations 
//		as their constructors may generate calls into the MFC 
//		DLL. 
// 
//		Please see MFC Technical Notes 33 and 58 for additional 
//		details. 
// 
 
// CEx20cApp 
 
BEGIN_MESSAGE_MAP(CEx20cApp, CWinApp) 
END_MESSAGE_MAP() 
 
 
// CEx20cApp construction 
 
CEx20cApp::CEx20cApp() 
{ 
	// TODO: add construction code here, 
	// Place all significant initialization in InitInstance 
} 
 
 
// The one and only CEx20cApp object 
 
CEx20cApp theApp; 
 
 
// CEx20cApp initialization 
 
BOOL CEx20cApp::InitInstance() 
{ 
	CWinApp::InitInstance(); 
 
	return TRUE; 
} 
 
extern "C" __declspec(dllexport) double Ex20cSquareRoot(double d) 
{ 
    AFX_MANAGE_STATE(AfxGetStaticModuleState()); 
    TRACE("Entering Ex20cSquareRoot\n"); 
    if (d >= 0.0) { 
        return sqrt(d); 
    } 
    AfxMessageBox("Can’t take square root of a negative number."); 
    return 0.0; 
}