Question

I have application which reads key in registry entry.

Its working good on Multi-Byte Character Set

But On Unicode character set it cannot open key

This is my code:

HKEY hkey = 0;
    char buf[255] = {0};
    DWORD dwType = 0;
    DWORD dwBufSize = sizeof(buf);
    const char* subkey_x64 = "SOFTWARE\\Wow6432Node\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\UCP";
    const char* subkey_x86 = "SOWTWARE\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\UCP";

    if (RegOpenKey(HKEY_LOCAL_MACHINE, (LPCWSTR)subkey_x64, &hkey) == ERROR_SUCCESS)
    {
        dwType = REG_SZ;
        if (RegQueryValueEx(hkey, (LPCWSTR)"DisplayIcon", 0, &dwType, (BYTE*)buf, &dwBufSize) == ERROR_SUCCESS)
        {
            cout << "Key Value IS: " << buf << endl;
        }
        else
        {
            cout << "Cannot get key value..." << endl << endl;
        }
    }
    else
    {
        cout << "Cannot open key\n" << endl << endl;
        RegCloseKey(HKEY_PERFORMANCE_DATA);
    }

Does anybody have an idea why it cannot open key?

(LPCWSTR) is not good approach?

Im using visual studio 2010

Answer 1

const char* is not an Unicode string. Change to const wchar_t* and you won’t need a cast.

With the cast you say the compiler to interpret that address as a pointer to an Unicode string but it’s not.

Moreover when you declare an Unicode string literal you should use L prefix: L"DisplayIcon" (again no need for a cast). If your code may run both on Unicode and multi-byte you may use the TEXT() macro to do the trick for you (or its short version _T()): _T("DisplayIcon").