[cpp-threads] Failed compare-and-swap

[Chris Thomasson]

----- Original Message ----- 
From: "Lawrence Crowl" <Lawrence at Crowl.org>
To: "C++ threads standardisation" <cpp-threads at decadentplace.org.uk>
Sent: Sunday, July 29, 2007 2:58 PM
Subject: [cpp-threads] Failed compare-and-swap


> Are the synchronization semantics of a failed compare-and-swap
> any different from those of a successful one?


They sure can be:

http://groups.google.com/group/comp.programming.threads/msg/b6a4eec6cbba625b

http://groups.google.com/group/comp.programming.threads/msg/8db5e8cdf03459d1


Its mostly an implementation detail. For instance, you could not know for 
sure if you can depend on the return value of the InterlockedCompareExchange 
in the failure case... However, Neill Clift from Microsoft says he would 
consider this to be a bug. This can boil down to a QoI issue...