On Fri, Sep 21, 2012 at 3:15 PM, N.M. Maclaren <[email protected]> wrote:

It's there in the standard. In C99, which is more readily accessible and very similar to C90, the relevant wording is mainly in 5.1.2.3, 6.5 and 6.5.2.2.

This says nothing about a memory model. Practically speaking, volatile accesses and sequence points only say that the instructions generated by the compiler should be ordered/cannot be elided. It does not prevent the CPU from reordering and does not require memory barriers so that the effects become visible in some specified order. See C11 7.17.3 (Order and consistency) and 7.17.4 (Fences) for the sort of thing that we (and everyone else I have ever heard utter the phrase) mean when we say "memory model". http://en.wikipedia.org/wiki/Memory_model_(programming) http://kernel.org/pub/linux/kernel/people/paulmck/perfbook/perfbook.html