Source code legality question

[C# Programming]

So I mentioned in passing to my boss a few weeks ago that I wrote a library "at home". He immediately said "cool, I own it". Now, he is often sarcastic and says weird stuff alot, so its hard to judge him. It is my understanding that if I do something "at home", he doesn't own anything. Questions may arise of course if I used company or proprietary knowledge, but its not really related except that at work I use C# and the library I wrote is in C#. It uses no company related knowledge. I never mentioned it again and he quickly forgot about it.

Whats the situation here? its more of a reusable "my bag of tricks" type DLL that every programmer has.

I kind of want to use parts of it at work (I do that with a C++ library already). In regards to the C++ library I just used it and he didn't really say anything and he knew about it. I just said "I'm using it for this component". So it would kind of be the same thing. I didn't ask for money in either situation and don't intend to. Its "free with all the source". I'm just not going to reinvent it at every place I go to.

Its kind of like no programmer is going to re-invent the wheel 5 times. lol.

I know the safe thing to do is to just never mention it again lol, but my interest outside of work is in the reusable toolkit type thing rather then finished applications, so that would be kind of useless if I can't use it at work.

I have no interest in selling it or posting it online, etc. As I said, its just "my bag of tricks.dll".