RcppSpdlog 0.0.27 on CRAN: C++20 Accommodations

Thu, 12 Feb 2026 08:59:00 CDT

Version 0.0.27 of RcppSpdlog arrived on CRAN moments ago, and will be uploaded to Debian and built for r2u shortly. The (nice) documentation site will be refreshed too. RcppSpdlog bundles spdlog, a wonderful header-only C++ logging library with all the bells and whistles you would want that was written by Gabi Melman, and also includes fmt by Victor Zverovich. You can learn more at the nice package documention site.

Brian Ripley has now turned C++20 on as a default for R-devel (aka R 4.6.0 ‘to be’), and this turned up misbehvior in packages using RcppSpdlog such as our spdl wrapper (offering a nicer interface from both R and C++) when relying on std::format. So for now, we turned this off and remain with fmt::format from the fmt library while we investigate further.

The NEWS entry for this release follows.

Changes in RcppSpdlog version 0.0.27 (2026-02-11)

Under C++20 or later, keep relying on fmt::format until issues experienced using std::format can be identified and resolved

Courtesy of my CRANberries, there is also a diffstat report detailing changes. More detailed information is on the RcppSpdlog page, or the package documention site.