On Saturday, 9 January 2016 at 17:24:47 UTC, Jin wrote:
On Saturday, 9 January 2016 at 16:29:07 UTC, Ola Fosheim
Grøstad wrote:
They have to be atomic if you want your code to be portable.
Do not want yet :-)
Okay I've just refreshed my mental X86/64 memory model :-) What
you've done should be okay from a CPU-reordering perspective. In
x86/64 Loads are not reordered with other loads and stores are
not reordered with other stores. So from a CPU perspective you
should be okay on X86/64.
There's still a grey area for me around possible *compiler*
re-orderings... there's nothing to stop the compiler reordering
those two lines with respect to each other because from an
'as-if-sequential' perspective those two operations are
commutative. Unfortunately I'm not well versed enough on the
internals of the three main compiler versions to give an opinion
on whether this will be a problem or not :-(
If your version is working for you on your platform/compiler, I'd
recommend maybe being a bit conservative and wrap your code with
appropriate version blocks until you know the answer to these
questions for the other platforms/compilers (ARM, GDC, LDC etc.).
And put appropriate explanation why that's the case in your
README.md. I think that's just a basic courtesy to other users
that you don't let them walk over a minefield without fair
warning :-)
Cheers,
A.
