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VC 6.0 to VC 8.0 Conversion Guide

error C2152: '=' : pointers to functions with different attributes db​

#include<windows.h>
HANDLE h;
void (*f)(int, int);
int _stdcall WinMain( HINSTANCE i, HINSTANCE j, char *k, int l )
{
h = LoadLibrary("z1.dll");
f = GetProcAddress(h,"abc");
}

Solution

#include<windows.h>
HANDLE h;
void (_stdcall *f)(int, int);
int _stdcall WinMain( HINSTANCE i, HINSTANCE j, char *k, int l )
{
h = LoadLibrary("z1.dll");
f = GetProcAddress(h,"abc");
}

error C2228: left of '.length' must have class/struct/union type​

string GetNewPin(string) {
do {
cout << "Enter new PIN number: ";
cin >> newPin;
} while(int(newPin.length) != 4); //error C2228
return newPin;
}

Solution

while( newPin.length() != 4); // length() is a memberfunction of string

error C2259: 'CException' : cannot instantiate abstract class​

Catch(CEXception e)

Reason

As MFC throws Exceptions as pointers to exception as there was no such pointer to exception it is resolved by including pointer to exception

solution

Catch(CEXception *e)

error C2440​

Error 1 - 'static_cast' : cannot convert from 'BOOL (__thiscall CSystemSetupDlg::* )(void)' to 'AFX_PMSG'​

Reason: As the ON Message handler expects the return type as Void as the return type was BOOL it was converted to void using pointer to member funtion. error C2440: 'static_cast' : cannot convert from 'BOOL (__thiscall CUniOLDoc::* )(void)' to 'AFX_PMSG' ON_COMMAND(ID_RUN_ENDRUN, OnEndRun)

Solution

typedef void (CUniOLDoc::*ptrHandler)();
ON_COMMAND(ID_RUN_ENDRUN, (ptrHandler)OnEndRun)
Error 2 - error C2440: 'static_cast' : cannot convert from 'BOOL (**thiscall CUniOLApp::* )(UINT)' to 'void (**thiscall CCmdTarget::* )(UINT)'​

Reason:

ON_COMMAND_RANGE(ID_FILE_MRU_FILE1,ID_FILE_MRU_FILE4,OnOpenRecentFile)
ON_COMMAND_RANGE always expect to be return type of void.

Solution

ON_COMMAND_RANGE(ID_FILE_MRU_FILE1,ID_FILE_MRU_FILE4,(void (__thiscall CCmdTarget::* )(UINT))OnOpenRecentFile)

error C2664​

Error 1 - error C2664: 'DDV_MaxChars' : cannot convert parameter 2 from 'double' to 'const CString &'​

Reason : As the Second Parameter in DDV_MAxChars takes strictly of string variables as there was of double type

Solution: The double varaiables are formated to string type.

Error 2 - error C2664: 'sprintf' : cannot convert parameter 1 from 'TCHAR [250]' to 'char *'​
sprintf(szQuery,"INSERT INTO tSupportUnitInfo(txtSUName,txtProductSetup,txtSystemSetup,txtCOMPort) VALUES('%s','%s','%s','%s')",CString(bstrSU),CString(bstrPS),CString(bstrSS),CString(bstrPort));

Solution:

CString szQuery;szQuery.Format("INSERT INTO tSupportUnitInfo(txtSUName,txtProductSetup,txtSystemSetup,txtCOMPort) VALUES('%s','%s','%s','%s')",CString(bstrSU),CString(bstrPS),CString(bstrSS),CString(bstrPort));

Note: User Manager does not use MFC .Since ATL and Mfc have shared libraries include <atlstr.h>​

so that the error "CString :Undeclared identifier" is eliminated.

Error 4 - error C2664: 'ATL::CRegKey::Create' : cannot convert parameter 2 from 'const char [27]' to 'LPCTSTR'​
if( objReg.Create(HKEY_LOCAL_MACHINE,"SOFTWARE\\EClient\\") == ERROR_SUCCESS )

Solution:

if( objReg.Create(HKEY_LOCAL_MACHINE,_T("SOFTWARE\\ EClient \\")) == ERROR_SUCCESS )
Error 5 - error C2664: 'MessageBoxW' : cannot convert parameter 2 from 'const char [8]' to 'LPCWSTR'​

MessageBox(NULL,"success","Job Transfer",MB_OK);

Solution:

MessageBox(NULL,_T("success"),_T("Job Transfer"),MB_OK);

Error 7 - error C2664: void ATL::CStringT<BaseType,StringTraits>::Format(const wchar_t_,...) : cannot convert parameter 1 from 'const char [4]' to 'const wchar_t_'​

CString str ; str.Format("%ld",lngError) ;

Solution:

CString str ; str.Format(_T("%ld"),lngError) ;

Error 8 - error C2664: 'atof' : cannot convert parameter 1 from 'class CString' to 'const char *'​

*fltUVTarget=(float)atof(CString(bstrValue));

Solution:

USES_CONVERSION ;
LPCSTR strval = W2A(bstrValue);
*fltUVTarget=(float)atof(strval);

error code 3867​

class A
{
public:
 int Test(void);
};

void fun(int (A::*test) (void));

int main()
{
 fun(A::Test);//C3867 error in VC
 return 0;
}

Reason: To create a pointer to a member function, the address of operator (&) must be used with the fully qualified name of the method. Not having to use the & operator and the fully qualified name of the method lead to logic bugs in code due missing parenthesis in function calls.

Solution: Add &. fun(&A::Test);

error 2039 'ReadHuge' : is not a member of 'CFile'​

objJobFile.ReadHuge(pData,dwFileLength) ;

Solution objJobFile.Read(pData,dwFileLength) ;

error C2065: 'i' : undeclared identifier​

Reason: As the variable was not declared in the for loop.

for(i = 0; i<10; i++)
{
}

Solution

for(int i = 0; i<10; i++)
{
}