Hub is here

During Q2 2026, I’ve been working in the following areas:

The Boost official review took place April 16-26. The library was accepted as part of Boost.Container. Many thanks to the review manager, Ion Gaztañaga, and all the people who participated: Arnaud Becheler, Matt Bentley, Matt Borland, Dominique Devienne, Peter Dimov, Emil Dotchevski, Amlal El Mahrouss, Alexander Grund, Seth Heeren, Andrzej Krzemieński, Christian Mazakas, Andrey Semashev, Peter Turcan. During April-June I implemented the feedback received (PR#20), and after that Ion took over and migrated the code and documentation to Boost.Container (adding some interesting performance improvements that I helped a bit with). boost::container::hub will be released in Boost 1.92 (August 2026), after which the original repo will be deprecated or removed.

• Added interoperability with C++20 ranges to all the containers in the library (PR#355).
• Reviewed and merged PR#348 from Daniel Král (performance issue with closed-addressing containers when rehashing at very large container sizes).
• Written maintenance fixes PR#346, PR#351, PR#352, PR#353, PR#354.
• Addressed documentation issues #349, #350.

• Fancy pointer support has been extended so that multi_index_container iterators now store references to the elements through the allocator’s pointer type (PR#100). In particular, this means that iterators can now be placed in shared memory using Boost.Interprocess allocators.
• Reviewed and merged PR#94 from Daniel Král (performance issue when rehashing at very large container sizes).
• Reviewed and merged PR#98 from Jonathan Wakely.
• Written maintenance fixes PR#97, PR#99.

As discussed in a previous entry, recent changes in libc++ v22 broke this library. These changes are related to the fact that non-heterogeneous lookup for associative containers is poorly specified in the C++ standard. I filed a LWG issue and defended a resolution with the LEWG that was consistent with the original semantic assumptions of Boost.ICL, but this resolution was not accepted (Brno, May 10). There was a fix on hold (PR#54) pending acceptance from ICL’s maintainer, but he’s been unavailable and in the end I requested write permission to the repo and merged the PR so that it makes it in time for Boost 1.92. The PR includes some additional fixes not related to the core issue.

• Reviewed and merged PR#46 from Jonathan Wakely.
• Written maintenance fix PR#47.

I had the honor to participate remotely in the Boost.Graph Workshop held in Paris, May 6, where I presented some simple ideas towards modernization of BGL API.

• I’ve been helping a bit with Mark Cooper’s very successful Boost Blueprint series on X.
• Supporting the community as a member of the Fiscal Sponsorship Committee (FSC).