On 05/03/13 10:58, David Paterson wrote: > On 5 March 2013 09:40, Jonathan Wakely <jwakely.gcc@xxxxxxxxx> wrote: >> On 5 March 2013 09:27, David Paterson wrote: >>> >>> In addition to Jonathan's answer on the use of "volatile", it's worth adding >>> that it's not only used for memory mapped hardware. There are many other >>> uses, such as inter-thread communication, or indeed the example you >>> show below. >> >> Only in broken code. > > LOL - well, it depends on your definition of "broken"... > >> volatile is not for multithreading, you need proper synchronization >> for interthread communication. "volatile" is often part of the synchronisation, but it is seldom sufficient on its own. So it is "used in inter-thread communication" in a sense. > > Not always. For very simple, non-critical uses you can just use a > volatile flag-type variable. Cheap and nasty, I agree, but useable. > In some cases that is true - particularly on small processors and embedded systems that don't have complications like caches, write buffers, superscaler cpus, etc. > Regards, > > David P. >
