[PATCH] PR gdb/15871: Unavailable entry value is not shown correctly

[Mark Kettenis]

> Date: Wed, 21 Aug 2013 15:35:40 +0100
> From: Pedro Alves <palves@redhat.com>
> 
> On 08/13/2013 08:39 AM, Yao Qi wrote:
> > However, when I run this test, I find j@entry is something like,
> > j@entry=<error reading variable: Cannot access memory at address 0x8049788>
> > instead of unavailable.
> > 
> > I don't emit a fail for it because I am not very sure it is expected
> > to be "unavailable".  I am fine to kfail it.
> > 
> > I looked into a little, and looks reading entry value doesn't use
> > value availability-aware API.  It is not an easy fix to me.
> 
> I looked into this.  Here's a patch.  Let me know what you think.

I think you should simply define the return codes as negative numbers.