Hi

In the house I just brought the toilet sits directly on top of the main waste stack on the second floor(it the only bathroom in the house). The main stack does not directly vent thought the roof, instead there is another pipe connected to the waste stack just below the toilet. This pipe continues up thought the roof and is the only vent, Also off of this pipe is a sink with a p trap.

I was just wondering if this is an ok set up?

Thanks