On 5/10/07, Jesper Juhl <[EMAIL PROTECTED]> wrote:
On 10/05/07, Satyam Sharma <[EMAIL PROTECTED]> wrote: > On 5/10/07, Jesper Juhl <[EMAIL PROTECTED]> wrote: > > [snip] > > you write: "... that the variable could be changed outside of the > > current thread of execution ..." > > > > I suggest: "... that the variable could be changed outside of the > > current thread of execution - a sort of simple atomic variable ..." > > I'm not so sure here. Why would any C programmer (worth his weight in > salt) think that volatile objects are automatically _atomic_? AtI honestly don't really know, but I've encountered that confusion a few times. Both from friends who (for some reason) believed that and from documents on the web that implied it, aparently it's a common confusion - a few examples: http://lists.freebsd.org/pipermail/freebsd-perl/2004-June/000124.html "... volatile (atomic) fixes the problem. ..." http://blogs.msdn.com/ricom/archive/2006/04/28/586406.aspx "That's the point of the volatile keyword. It makes sure that the line "dict = d;" is atomic." http://forum.java.sun.com/thread.jspa?threadID=5126877&start=0 "A volatile variable is also guaranteed to be read or written as an atomic operation ..." (yes, this link talks about Java, which I don't know, but if java volatile means atomic, that might explain why some people assume the same for C).
Perl / Microsoft / Java programmers are probably not worth their weight in salt anyway :-) I'm not an expert in any of the above platforms either, so don't know if the semantics of "volatile" in those other languages are different from that in C -- and this document clearly applies to only the kernel (and thus C). But if this volatile == atomic disease is indeed common among _C_ programmers too, then your suggested addition would make sense. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
