Lock-time. Is this possible?

Question

Let says Bob is making a DvP offer (createrawexchange) to Alice. Can we put a time-limit for this offer?

What is the syntax for this?

Answer 1

There's no way to have a transaction output automatically unlock itself after a certain amount of time. Instead you would need to call lockunspent true (counterintuitively) with the txid/vout as a parameter. Also if the node is restarted all locking information is lost.

The way to safely disable an offer of exchange that you have distributed to others is to spend one of its inputs in another transaction.