C++ RegSetValueEx is giving problems

Question

I'm using RegSetValueEx to set a Registry key. The problem is that it only writes the first 2 characters. I can get the RegSetValueExA (ANSI version) to work, but my Project is set to Unicode in properties so I would like to use either RegSetValueEx or RegSetValueExW.

#include <iostream>
#include <Windows.h>

HKEY hKey;

int main()
{
    RegCreateKeyEx(HKEY_CURRENT_USER, L"SOFTWARE\\stuff", 0, NULL, NULL, KEY_ALL_ACCESS, NULL, &hKey, NULL);
    RegSetValueEx(hKey, L"Test", 0, REG_SZ, (const BYTE*)L"test", strlen("test"));

    system("PAUSE");
    return 0;
}

Output in registry is "te" instead of "test".

Answer 1

The final parameter to RegSetValueEx has to be the size in bytes of the value, including the terminating null. You're giving the length in characters (and each character needs two bytes) and not including the null.

sizeof(L"test") would work, I think, or you could use (strlen("test")+1) * sizeof(wchar_t)

See https://msdn.microsoft.com/en-us/library/windows/desktop/ms724923(v=vs.85).aspx