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From: David Abrahams (dave_at_[hidden])
Date: 2003-02-20 11:12:39

Gabriel Dos Reis <gdr_at_[hidden]> writes:

> David Abrahams <dave_at_[hidden]> writes:
> | Gabriel Dos Reis <gdr_at_[hidden]> writes:
> |
> | > However, my point is that
> | >
> | > * a class is closed: that is, by the time you put the closing brace,
> | > the "offset" of the data member is a compile-time constant.
> | >
> | > * the number of thread local variables is potentially unbounded,
> | > meaning that, using your analogy, the offset of the corresponding
> | > data-member is not known by the time the compiler finishes
> | > processing a given translation unit.
> |
> | OK... is that a problem?
> As I'm understanding the issue, yes. I would love to be proved wrong.
> | The address of a static global is not known
> | when the compiler finishes processing a given translation unit either.
> Sure the logical address is known.
> As opposed to the address of a variable with a TLS.

It has just one "logical address", which will turn out to correspond
to different physical addresses depending on the thread executing at
the time. When the implementation handles it at compile-time, it uses
only the logical address. At the compile-time/runtime boundary the
logical address is converted to a physical address by dereferencing
off the base TLS pointer. This is just like a data member pointer. I
still don't see a problem.

Dave Abrahams
Boost Consulting

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