[gawi]

Never trust a programmer who says he knows C++... Never trust someone who says he knows... Never trust a programmer... Never trust C++ ... Never C++...

At university, they taught me C++. I suffered a lot. So the minute I graduated, I stopped doing it. This was a valuable lesson after all.

If someone pretends to understand C++, just look at his code and say "Ok, so what happens if you add 'volatile' just here."

[gridspy]

And a good programmer will raise his eyebrow at you and coolly reply "a little less optimisation"

[jmtulloss]

I'm a C programmer, not a C++ one, but at least in C, you sometimes need volatile to have a correct program.

[gridspy]

Indeed.

The underling effect of volatile is that the compiler turns off certain optimisations to do with instruction reordering and aggressive caching in registers without stores.

However in most places that a typical non-firmware, non-driver programmer would use volatile they really should be using a memory fence (acquire, release or atomic store).