On Tue, Sep 30, 2025 at 8:53 PM Herb Sutter via SG21 <sg21_at_[hidden]>
wrote:

> This reminds me, I wanted to +Michael to ask for a fact-check:
>
>
>
> Michael, I’ve been told by several people that when SG15 (tooling) did
> discuss contracts and build systems at a recent meeting, no one in the room
> raised any objections, including experts in the room who were and are
> opposed to contracts in C++26.
>

For reference, that discussion likely refers to the Wroclaw 2024 meeting,
where P3321r0 (Contracts interaction with Tooling, by Joshua Berne) was
discussed, minutes at
https://wiki.edg.com/bin/view/Wg21wroclaw2024/SG15Minutes .


> Is that summary correct? Please correct if I’m misinformed or
> misunderstood!
>
>
>
>
>
>
>
>
>
> *From:* SG15 <sg15-bounces_at_[hidden]> *On Behalf Of *René
> Ferdinand Rivera Morell via SG15
> *Sent:* Tuesday, September 30, 2025 11:26 AM
> *To:* sg21_at_[hidden]; ISO C++ Tooling Study Group <
> sg15_at_[hidden]>
> *Cc:* René Ferdinand Rivera Morell <grafikrobot_at_[hidden]>
> *Subject:* Re: [isocpp-sg15] [isocpp-admin] Swedish mirror committee
> consideration on the current working draft
>
>
>
> On Wed, Sep 24, 2025 at 8:36 AM René Ferdinand Rivera Morell <
> grafikrobot_at_[hidden]> wrote:
>
> On Wed, Sep 24, 2025 at 6:10 AM Harald Achitz via Admin <
> admin_at_[hidden]> wrote:
>
> The Swedish SC22 mirror committee TK611/AG09 has discussed the current
> working draft of C++26 and identified concerns regarding contract
> assertions. We have summarized these in the attached document.
>
> As convener, I see it as my duty to mediate these concerns. I would
> therefore appreciate guidance on how to proceed and to ensure that our
> experts’ concerns, as well as similar concerns from others, are taken
> into account.
>
>
>
> From the comments:
>
>
>
> Contracts introduce several new build configurations. The impact on the
> build system and binary
> dependency management has not received sufficient focus.
>
>
>
> I wanted to address the fears regarding build systems. But I didn't have
> time to write up implemented examples until yesterday. Last night I
> implemented Contracts build support for B2 (aka Boost.Build). It took me
> less than an hour to implement that support. The parts of that are these
> segments (the rest are documentation comments and examples):
>
>
>
> <
> https://github.com/bfgroup/b2/commit/3b20a4e16594b19a38f006a7af051c775bf0e1c9#diff-0fc008a10b15f249e1b7f2dffc067eadae061007e7b8a83122cb6a562ce0de11R20-R24
> >
>
> <
> https://github.com/bfgroup/b2/commit/3b20a4e16594b19a38f006a7af051c775bf0e1c9#diff-0fc008a10b15f249e1b7f2dffc067eadae061007e7b8a83122cb6a562ce0de11R45-R48
> >
>
> <
> https://github.com/bfgroup/b2/commit/3b20a4e16594b19a38f006a7af051c775bf0e1c9#diff-33537906d8dfd13afc76c7734b09d22c4d7716e45250cefc65ae2086b26e560cR719-R724
> >
>
>
>
> I also created a simple example showing the matrix of using static vs
> dynamic linking a library with contracts, vs enforce/ignore semantics on
> main(), vs enforce/ignore semantics on the library. That's in this repo <
> https://github.com/grafikrobot/cpp_contracts_example>.
>
>
>
> The comparison I like to raise with that is that I have yet to implement
> Modules support in B2 because that has-taken / is-taking serious amount of
> reengineering.
>
>
>
>
>
> --
>
> -- René Ferdinand Rivera Morell
> -- Don't Assume Anything -- No Supongas Nada
> -- Robot Dreams - http://robot-dreams.net
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>