Re: [RFC][gdb/cli] Add convenience vars _wp_old_val and _wp_val

[Pedro Alves <pedro@palves.net>]

Hi,

On 2022-10-07 8:41 p.m., Tom Tromey wrote:
> Pedro> It can't be safely used in regular CLI after the watchpoint hit is process, though,
> Pedro> given another watchpoint may trigger meanwhile.  I mean, say, in non-stop, you do:
> 
> FWIW gdb probably already has this problem with some other convenience
> variables, like $_exitcode, $_exception, $_probe_*, ...

Hmm, indeed.  Good point.

> 
> So, maybe adding one more isn't so bad.  Or maybe now is when we want to
> think of a general solution.
> 
> I'm not sure this works though:
> 
> Pedro> A way to make this safer would be to make it a convenience function instead, that
> Pedro> takes as argument the number of the watchpoint, like:
> 
> ... because it seems to me that the same watchpoint can be hit any
> number of times.

Also true.

I withdraw my suggestion then.

I guess one way to address this would be to make it so that the
values were put in the value history, with their own unique history
numbers.  Like, e.g.:

  Hardware watchpoint 2: v

  Old value ($123) = 3
  New value ($124) = 2

Not sure about that.  Maybe we can think up something better.
For some other time.

Pedro Alves