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Why are my changes to the registry not being saved in C ++?

I am trying to edit the registry using C ++ and this is my first attempt at this and I am failing. I don't get an error code, everything says it completed successfully, but it doesn't actually change the registry key.

Here is the code I'm using:

HKEY hkey;
DWORD dwDisposition, dwType, dwSize;
int autorun = 0x00;
int CD_AUTORUN_DISABLED = 0x20;
long errorCode;
errorCode = RegOpenKeyEx(HKEY_CURRENT_USER, TEXT("Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\Explorer"), 0, KEY_ALL_ACCESS, &hkey);

if(errorCode == ERROR_SUCCESS) {
        dwType = REG_DWORD;
        dwSize = sizeof(dwType);
        errorCode = RegQueryValueEx(hkey, TEXT("NoDriveTypeAutoRun"), NULL, &dwType, 
(PBYTE)&autorun, &dwSize);

cout << "Autorun value: " << autorun << endl;
if((autorun & CD_AUTORUN_DISABLED) == 0x20){
        int newAutorun = (autorun - CD_AUTORUN_DISABLED);
        cout << "New value: " << newAutorun  << endl;
        errorCode = RegSetValueEx(hkey, TEXT("NoDriveTypeAutoRun"), 0, dwType, (PBYTE) &autorun, dwSize);
        if(errorCode == ERROR_SUCCESS){
            errorCode = RegCloseKey(hkey);              
            if(errorCode == ERROR_SUCCESS){
                cout << "Value changed." << endl;
            }
        }else{
            cout << "Value change failed, error code: " << errorCode << endl;
        }
    }else{
        cout << "Keep current value." << endl;
    }

}else{
    if(errorCode == ERROR_ACCESS_DENIED){
        cout << "Access denied." << endl;
    }else{
        cout << "Error! " << errorCode << " : " << ERROR_SUCCESS << endl;
    }
}

What am I doing wrong?

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3 answers


You seem to be setting the registry key to the same value that you read it.

int newAutorun = (autorun - CD_AUTORUN_DISABLED);
                cout << "New value: " << newAutorun  << endl;
                errorCode = RegSetValueEx(hkey, TEXT("NoDriveTypeAutoRun"), 0, dwType, (PBYTE) **&autorun**, dwSize);


Should be

int newAutorun = (autorun - CD_AUTORUN_DISABLED);
                cout << "New value: " << newAutorun  << endl;
                errorCode = RegSetValueEx(hkey, TEXT("NoDriveTypeAutoRun"), 0, dwType, (PBYTE) &newAutorun, dwSize);
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I think:

errorCode = RegSetValueEx(hkey, TEXT("NoDriveTypeAutoRun"), 0, dwType, (PBYTE) &autorun, dwSize);

should be as follows:



errorCode = RegSetValueEx(hkey, TEXT("NoDriveTypeAutoRun"), 0, dwType, (PBYTE) &newAutorun, dwSize);

(take a close look at the second-last parameter)

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Try to change this:

errorCode = RegSetValueEx (hkey, TEXT ("NoDriveTypeAutoRun"), 0, dwType, (PBYTE) and autorun, dwSize);

:

errorCode = RegSetValueEx (hkey, TEXT ("NoDriveTypeAutoRun"), 0, dwType, (PBYTE) and newAutorun, dwSize);

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