Trace on Variable assignment

[Sean Hinde]

> > I had more in mind though being able to set up traces (or 
> conditional
> > watchpoints if you like) in a running system without 
> needing to change the
> > code.
> 
> What about a guard: watch/1 which could be combined with 
> the trace bif ? 

> Just a thought... /Tobbe

I'm thinking about the situation when the customer/local support guys are
asked to run a trace to feed back info about their system to a
supplier/developer. You could generate a patch and get them to load it, but
even better would be able to send them something to type at the shell to do
somethng like:

"Every time the transaction ID is divisible by 100, print that value and the
values of these other variables". The equivalent AXE-10 ese would be
something like:

on var a do: print var a, pr var b, print ia, pri time;

(my memory is a bit rusty so this probably isn't quite the right syntax)

ia would be instruction address i.e. where in the code the variable is set
or changed - our equivalent of m:f :-))

AXE10 doesn't have selective tracing on vars, they just limit the size of a
trace buffer, so we could do even better.

- Sean



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