How to convert string[] to char**?

Question

I have a library I'm dependent on that receives a struct with char** as one of the function's arguments.

I want to have a wrapper that receives a List<string> (or any string[] for that matter) and creates a char** to put in that struct. The compiler is OK with my code, but I'm really not sure I got the fixed and unsafe concepts right, and I'm afraid of unexpected consequences:

InternalAttributeKeys attrKeys;  // has { (char**) .keys , (int) .count }
unsafe 
{
    char*[] chars = new char*[keys.Count];
    for (var i = 0; i < keys.Count; ++i)
    {
        fixed (char* c = keys[i].ToCharArray())
        {
            chars[i] = c;
        }
    }
    fixed (char** keysPtr = chars)
    {
        attrKeys.keys = keysPtr;
    }
}
attrKeys.count = (uint) keys.Count;
return attrKeys;

Did I get it right?

Is there generally a better way to send a char** (for instance, can I send a char*[] instead and expect C# to do the conversion behind the scenes)?

Answer 1

Found this, seems to address my question from a different perspective (and it looks more robust than whatever I came up with):

How can I copy a array of strings into an unmanaged char double pointer?

I will use the Marshal.AllocHGlobal and create an IDisposable object to manage this memory.