Dave Abrahams wrote:
on Thu Aug 25 2011, Alexander Terekhov <terekhov-AT-web.de> wrote:
Ilya Sokolov wrote:
AFAIK, in the example above another thread can't observe reordering without introducing UB.
I meant "observed" as in "check the sequence of writes in the generated code".
Do we care about what the generated code looks like? IIUC what counts is the sequence of memory states that another another thread can see.
But int can be simply changed to relaxed atomic<int> so that another thread can observe reordering without UB.
Sure.
I meant that for the example upthread, with an int instead of relaxed atomic<int>, another thread's code triggering UB does not prevent us from observing reordered writes in the writing thread's code (in generated code), by looking at it. Changing int to relaxed atomic<int> simply removes UB but does not change the relevant code in the writing thread. regards, alexander.