From: user5857@newsgrouper.org.invalid   
      
   anton@mips.complang.tuwien.ac.at (Anton Ertl) posted:   
      
   > David Brown  writes:   
   > >"volatile" /does/ provide guarantees - it just doesn't provide enough   
   > >guarantees for multi-threaded coding on multi-core systems.  Basically,   
   > >it only works at the C abstract machine level - it does nothing that   
   > >affects the hardware.  So volatile writes are ordered at the C level,   
   > >but that says nothing about how they might progress through storage   
   > >queues, caches, inter-processor communication buses, or whatever.   
   >   
   > You describe in many words and not really to the point what can be   
   > explained concisely as: "volatile says nothing about memory ordering   
   > on hardware with weaker memory ordering than sequential consistency".   
   > If hardware guaranteed sequential consistency, volatile would provide   
   > guarantees that are as good on multi-core machines as on single-core   
   > machines.   
   >   
   > However, for concurrent manipulations of data structures, one wants   
   > atomic operations beyond load and store (even on single-core systems),   
      
   Such as ????   
      
   > and I don't think that C with just volatile gives you such guarantees.   
   >   
   > - anton   
      
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