Let's assume I have a resident permit from the Schengen country A and plans to visit Schengen country B via a transit in Schengen country C. If I leave country A today and spend the over-night in country C in transit and arrive in country B tomorrow, will today count as a day spent in Schengen area under short-visits? Similarly, if I return from B to A via a transit in C, what is the situation?

According to the answer given here (see under 'Alternatives to short visits '), both these days does not count since I'll be from/to to the country of my resident. But I cannot find any official document to support this. Does anyone know where I can get official information? (Unfortunately, the person who posted the answer is not active on SE anymore. Therefore I decided to post this as a new questions)