RFR: 8367149: Add ergonomic construction for creating ad-hoc VMErrorCallback [v2]

[Stefan Karlsson]

On Thu, 11 Sep 2025 05:27:53 GMT, Axel Boldt-Christmas <aboldtch at openjdk.org> wrote:

>> src/hotspot/share/utilities/vmError.hpp line 254:
>> 
>>> 252: };
>>> 253: 
>>> 254: // Ergonomic construction for creating ad-hoc VMErrorCallback which automatically
>> 
>> Does `Ergonomic construction` have specific meanings in cpp/this context? If not, I wonder if `lightweight` is clearer, as it is less technical.
>
> Not that I know of. 
> 
> I ment it to mean that this is type with makes it ergonomic (as in, efficient and comfortable) to create an ad-hoc VMErrorCallback. So rather than having to do something like:
> ```C++
>    struct AdHocVMErrorCallback : public VMErrorCallback {
>       ThisType& _instance;
>       ValueType _value;
> 
>       AdHocVMErrorCallback(ThisType& instance) 
>         : _instance(instance), 
>           _value(_instance.get_important_value) {}
> 
>       void call(outputStream* st) final {
>         // Dump the important bits.
>         st->print("Prior value: ");
>         _value.print_on(st);
>         st->print("During crash: ")
>         _instance.get_the_value().print_on(st);
>         // Dump whole the whole state.
>         _instance.print_on(st);
>       }
>   } on_error(*this);
> 
> you can use this construction with a lambda.
> 
> Not sure if lightweight capture I intended to convey, but it also seems like `Ergonomic construction` missed the mark. Maybe just call it `A construction for creating ad-hoc VMErrorCallback`

Maybe `convenient` would be an apt word here?

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PR Review Comment: https://git.openjdk.org/jdk/pull/27159#discussion_r2338932845