Re: [PATCH] Add configure flag for operator new (std::nothrow)

[Daniel Gutson <daniel.gutson@tallertechnologies.com>]

On Wed, Nov 4, 2015 at 3:20 AM, Jonathan Wakely <jwakely.gcc@gmail.com> wrote:
> On 4 November 2015 at 02:11, Daniel Gutson wrote:
>> Since this is a nothrow new, we thought that probably the system
>> might not be exceptions-friendly (such as certain embedded systems),
>> so we wanted to provide the new_handler the ability to do something else
>> other than trying to allocate memory and keep the function iterating.
>
> That could be done using an alternative overload of operator new
> instead of altering the semantics of the standard one (that could be
> provided as a GNU extension, for example).
>
>> In fact, our idea is that since the nothrow new can indeed return nullptr,
>> let the new_handler do something else and leave the no-memory-consequence
>> to the caller.
>> This new flag enables just that.
>
>
> The default configuration already allows the caller to deal with
> allocation failure from the nothrow version of new, by not installing
> a new-handler installed, and dealing with a null return value. How
> would I use this alternative configuration? Since the behaviour only
> changes when a new-handler is installed, presumably I'm meant to
> install some kind of new-handler that does something else ... but
> what? The patch should include documentation explaining when and how
> to use this option.

Real use cases: statistics and logging. It's a (one time) callback
reporting that something went wrong,
but not intended to fix things e.g. by attempting to free more memory.




-- 

Daniel F. Gutson
Chief Engineering Officer, SPD

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