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Re: atomic accesses


Segher Boessenkool wrote:
As I said before, I think any words of this form SHOULD NOT be added.
All it does is add words to the documentation that provide NO
guarantee of anything -- but in a way that will confuse those who
don't read it carefully enough into thinking that they DID get some
sort of guarantee.

The idea is to _do_ provide that guarantee. If the GCC code does not agree with the GCC documentation, the code has a bug ;-)

In other words, a statement like that has clear negative value.

I disagree. People are relying on this undocumented GCC behaviour already, and when things break, chaos ensues. If we change this to be documented behaviour, at least it is clear where the problem lies (namely, with the compiler), and things can be fixed easily.

The two big questions are:

1) Do we *want* to guarantee any behaviour in this area?

2) Exactly *what* behaviour?

This would ba a gcc extension. History does not favour such extensions: we've been unable to define them well enough, for one thing.

Andrew.


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