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Re: [PATCH] MI: lvalues and variable_editable
On Fri, Nov 02, 2007 at 05:21:52PM +1300, Nick Roberts wrote:
> In that case for such a varobj, var->value == NULL must indicate that the
> memory was inaccessible at the _last_ update, or creation, and it may no longer
> be inaccessible. Describing it as "noneditable" may then be a bit misleading.
The next time it's -var-update'd it may get a new value; presumably
the IDE does that periodically.
> I'm surprised that there is "no way to be sure without trying to write". I
> know that 0x0 is inaccessible memory, and presumably the OS has a better idea
> about what is and isn't accessible.
It won't tell us, though. Most systems have no interface to ask this
question. Unix ptrace doesn't, hardware JTAG doesn't... whether you
can always write to RAM from a hardware JTAG device depends on whether
you're going through the MMU (memory management unit) or not for
writes.
--
Daniel Jacobowitz
CodeSourcery