Re: [boost] [thread] Use of _ReadWriteBarrier

From: Anthony Williams (anthony_w.geo_at_[hidden])
Date: 2007-10-08 09:28:16

"Hartmut Kaiser" <hartmut.kaiser_at_[hidden]> writes:

>> > _ReadWriteBarrier stops the compiler from reordering. Going to a 
>> > non-intrinsic InterlockedCompareExchange will also have 
>> this effect, 
>> > but it might be possible to achieve it in another (cheaper) 
>> > compiler-specific way; __asm__ ( :::"memory" ) is the GCC 
>> equivalent. 
>> > Borland may already not reorder across a volatile read; 
>> this needs to be tested.
>> 
>> Totally agreed. The easiest change to make mingw and Borland 
>> non-broken was to use ICE, but it is definitely overkill if 
>> there's a cheaper way.
>> 
>> All that's need here is a compiler barrier; I couldn't find 
>> an equivalent in the Borland docs this morning, but that 
>> doesn't mean there isn't one. Does __asm__ ( :::"memory" ) 
>> work on mingw? If so, I'll use that rather than ICE for mingw.
>
> FWIW, Intel V10 on Windows seems not to implement _ReadWriteBarrier neither
> (at least we get linker errors there as well).

Yes, I spotted that. Hopefully this morning's fix will help there too. Does
Intel v10 have an equivalent to _ReadWriteBarrier?

Anthony
-- 
Anthony Williams
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