How to specify parameters pvInfo (void*) and lpnLenghtNeeded (uint*) when calling GetUserObjectInformation?

[vitkuz573]

I'm trying to get the name of the desktop using GetUserObjectInformation.

    public static bool GetCurrentDesktop(out string desktopName)
    {
        desktopName = default;
    
        var inputDesktop = OpenInputDesktop_SafeHandle(0, true, 0x10000000);
    
        var desktopBytes = new byte[256];
        
        unsafe
        {
            if (!GetUserObjectInformation(inputDesktop, USER_OBJECT_INFORMATION_INDEX.UOI_NAME, /** how to use parameters? **/))
            {
                desktopName = string.Empty;
                return false;
            }
        }
        
        // Other code ...
        
        return true;
    }

[AArnott]

Like this:

static bool GetCurrentDesktop([NotNullWhen(true)] out string? desktopName)
{
    using var inputDesktop = OpenInputDesktop_SafeHandle(0, true, 0x10000000);

    unsafe
    {
        const int maxLength = 256;
        fixed (char* pDesktopBytes = new char[maxLength])
        {
            uint cbLengthNeeded;
            if (!GetUserObjectInformation(inputDesktop, USER_OBJECT_INFORMATION_INDEX.UOI_NAME, pDesktopBytes, maxLength, &cbLengthNeeded))
            {
                desktopName = null;
                return false;
            }

            int charLength = (int)cbLengthNeeded / sizeof(char) - 1; // discount the null terminator
            desktopName = new string(pDesktopBytes, 0, charLength);
            return true;
        }
    }
}

Of course error handling is still missing. But that's how you use pointers.

[vitkuz573]

Thank you so much!