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Re: [std-proposals] Fwd: set_new_handler extension

From: Phil Bouchard <boost_at_[hidden]>
Date: Mon, 20 Feb 2023 16:07:29 -0500
Ah-ha you're right that since C++11 it does that. Ok so my apologizes
for not being aware of that.

I just tested the attached shared library test and it does indeed return:

int main()
void foo()
1) new(size_t), size = 4
3) delete(void*)
2) new[](size_t), size = 40
5) delete[](void* ptr)

I'll test it under Windows later as well.


Regards,

On 2/20/23 14:51, Julien Villemure-Fréchette via Std-Proposals wrote:
> > But there's still the issue where a user would like to use a more
> efficient
> thread-local or allocation rate based allocator.
>
> global operator new and delete can be replaced by a non inline, non
> static global operator new with equivalent signature; any uses of a
> new/delete expression (with equivalent signature) or direct call to
> operator new/delete from anywhere, including the standard library, will
> pick the user definition, no declaration of this replacement need to be
> in scope (ie, it is always implicitly visible, as would be the default
> implementation provided by the standard library).
>
> See overloads 1-8 of operator new
> https://en.cppreference.com/w/cpp/memory/new/operator_new
> <https://en.cppreference.com/w/cpp/memory/new/operator_new>
>
> overloads 1-12 of
> https://en.cppreference.com/w/cpp/memory/new/operator_delete
> <https://en.cppreference.com/w/cpp/memory/new/operator_delete>
>
> Note: As explained in the specification, providing a single replacement
> for `operator new(size_t)` and `operator `delete(void*)` is sufficient
> to cover all non alignment-aware overloads.
>
> Julien V.
>
>
> On February 20, 2023 12:20:57 p.m. EST, Thiago Macieira via
> Std-Proposals <std-proposals_at_[hidden]> wrote:
>
> On Saturday, 18 February 2023 21:42:30 PST Phil Bouchard via
> Std-Proposals
> wrote:
>
> But there's still the issue where a user would like to use a
> more efficient
> thread-local or allocation rate based allocator.
>
>
> And what's stopping you and them from using a different allocator?
> You *can*
> replace malloc for your application. I do that for mine.
>
> Replacing it for already-compiled DLLs is a different story. But
> since DLLs are
> not part of the standard, its discussion is out of scope. The fact
> is that
> DLLs allow two functions called "malloc" to exist in two different
> DLLs and be
> called from another set of two different DLLs, without a problem[*],
> so long as
> one set doesn't try to free() pointers from the other. The C++
> standard calls
> this "violation of the One Definition Rule".
>
> BTW, replacing malloc() is not a required part of the C or C++
> standards. It's
> an extension to them that most toolchains support.
>
> [*] you usually don't want this, but it's *possible* by design.
>
>

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Received on 2023-02-20 21:07:31