Theres no function that returns the building worker.
I think you need it for things the worker should do after finishing the building.
In this case you can use the 'unit finishes building' which referrs to the building itself and then pick every unit of type worker in range (300 or so) and check if the current order is <empty string>.
I'm on a page about incorrect corrections, and spent the better part of like two hours trying to get someone to understand that -5^2 = -25, not 25, and then that post had comments get reposted because that group is self sustaining, and that person was in turn trying to explain what I just explained to them. And I'm taking that as a victory
I will be AFK for a couple of days you guys hold down the fort while I am gone. I will be checking in on my phone but that will severly limit me. Be back saturday!