Re: volatile is ignored by my compiler?
"Hei" <hchan1980@gmail.com>
My confusion came after I read this article:
http://www.ddj.com/cpp/184403766
Did you actually read it beyond the title?
It is about supplementing the code using sync with type system checks.
It neve claims volatile would be a replacement to using mutex and locking.
I thought volatile made the compiler not to cache the variable in a
register, and so each thread would get a most updated copy.
Then why class Counter in the article has that Mutex? And the other shown
classes?
If I understand all the post correctly, even with volatile, a variable
can be cached in a CPU's cache, and CPU somehow can figure when to
flush if the variable is changed...such change has nothing to do with
threads at all?
In short, volatile has little to o with threading itself.
http://software.intel.com/en-us/blogs/2007/11/30/volatile-almost-useless-for-multi-threaded-programming/
AA just uses it as MAGIC to detect imprer access to a shared variable right
at compare time.
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