Re: -var-update using formatted value

[Vladimir Prus <ghost@cs.msu.su>]

On Friday 18 January 2008 02:10:12 Nick Roberts wrote:
>  >     Update stored value when format changes.
>  >     
>  >     	* varobj.c (varobj_set_display_format): Recomputed
>  >     	print_value.
>  >     	(c_value_of_variable): Return print_value.
>  > 
>  > diff --git a/gdb/varobj.c b/gdb/varobj.c
>  > index d078bef..b0eb11a 100644
>  > --- a/gdb/varobj.c
>  > +++ b/gdb/varobj.c
>  > @@ -677,6 +677,13 @@ varobj_set_display_format (struct varobj *var,
>  >        var->format = variable_default_display (var);
>  >      }
>  >  
>  > +  if (varobj_value_is_changeable_p (var) 
>  > +      && var->value && !value_lazy (var->value))
>  > +    {
>  > +      free (var->print_value);
>  > +      var->print_value = value_get_print_value (var->value, var->format);
>  > +    }
>  > +
>  >    return var->format;
>  >  }
>  >
>  > @@ -2260,7 +2267,7 @@ c_value_of_variable (struct varobj *var)
>  >  
>  >  	    gdb_assert (varobj_value_is_changeable_p (var));
>  >  	    gdb_assert (!value_lazy (var->value));
>  > -	    return value_get_print_value (var->value, var->format);
>  > +	    return strdup (var->print_value);
>  >  	  }
>  >        }
>  >      }
> 
> I don't like this change.  If I change the format to hexadecimal, 11 -> 0xb
> say, the display should change, so I would like GDB to report it through
> -var-update.

Why? It seems to me that if user does "change format" in UI, then UI should:

  1. Change format
  2. Display the value shown according to the new format

I cannot imagine any usecase where the frontend would:

 1. Change format
 2. Step program
 3. Issue -var-update

- Volodya


>