Dirk Eddelbuettel wrote the R package 'RcppSpdlog' providing R integration for 'spdlog'. It includes the (header-only) C++ sources for 'spdlog' which in turn includes parts of 'fmt'. See below for details. -- spdlog -------------------------------------------------------- Gabi Melman is the principal author of 'spdlog'. As the upstream source state, there are also many contributors. The list of (100+) contributors (going back to 2014) can obtained from GitHub via https://github.com/gabime/spdlog/graphs/contributors Files: inst/include/spdlog/* Copyright: (c) 2014-2020 Gabi Melman Copyright: (c) 2015-present, Gabi Melman & spdlog contributors License: MIT Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: . The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. . THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. -- fmt ----------------------------------------------------------- Victor Zverovic is the principal author of 'fmt'. As the upstream source state, there are also many contributors. The list of (100+) contributors (going back to 2012) can obtained from GitHub via https://github.com/fmtlib/fmt/graphs/contributors Files: inst/include/spdlog/fmt/bundled/* Copyright: (c) 2012 - present, Victor Zverovic Upstream-Name: fmt Source: https://github.com/gabime/spdlog/tree/v1.x/include/spdlog/fmt/bundled -- other files --------------------------------------------------- File: inst/include/spdlog/fmt/bundled/chrono.h Copyright: (c) 2019 Paul Dreik Source: https://github.com/pauldreik/safe_duration_cast File: inst/include/spdlog/fmt/bundled/ranges.h Copyright (c) 2012 - present, Victor Zverovich Copyright (c) 2018 - present, Remotion (Igor Schulz) Source: https://github.com/gabime/spdlog/tree/v1.x/include/spdlog/fmt/bundled/ranges.h File: inst/include/spdlog/sinks/msvc_sink.h Copyright(c) 2016 Alexander Dalshov. Source: https://github.com/gabime/spdlog/tree/v1.x/include/spdlog/sinks/msvc_sink.h File: inst/include/spdlog/sinks/systemd_sink.h Copyright(c) 2019 ZVYAGIN.Alexander@gmail.com Source: https://github.com/gabime/spdlog/tree/v1.x/include/spdlog/sinks/systemd_sink.h