Hello all (and especially N1962 authors), As far as I can see, N1962 does not say what to do in case of a failure while evaluating and copying an oldof expression. For example, what shall Contract Programming do if there is a memory error while taking a copy of size() to later check the following postcondition? size() == oldof size() + 1 Given that oldof copies are taken just after preconditions are checked and before the body is executed, I am tempted to treat the oldof failure as a precondition failure and call the precondition_broken handler. An alternative would be to to treat the oldof failure as if it happened within the body. However, in this case the body will raise more errors (e.g., throw more exceptions) that it will raise without the oldof contracts so I don't think this is a good approach. In summary: 1) oldof expressions belong to the contract therefore I think oldof failures should result in calling one of the contract failure handlers (precondition_broken or postcondition_broken). 2) Given that eventual oldof failures happen before the body is executed (and just after the preconditions are checked), I think precondition_broken should be called (instead of postcondition_broken) in case of an oldof failure. The counter argument is that precondition failures indicate a bug in the caller. However, oldof failures indicate a system-level exception in the code that programs the program-- oldof failures are not bugs in neither the caller (precondition_broken) nor in the body implementation (postcondition_broken)... but if you follow this argument, you need to give up 1)... What do you think? Thank you. --Lorenzo -- View this message in context: http://boost.2283326.n4.nabble.com/boost-contract-oldof-failure-not-in-N1962... Sent from the Boost - Dev mailing list archive at Nabble.com.