April 2025 - Boost - lists.boost.org

Review Manager Volunteers
by Matt Borland 23 Apr '25

23 Apr '25

Hi All, Recently, we've seen a shortage of review managers: Joaquin has been looking for one for his bloom-filters library for a few weeks (now solved), and Dmitry recently withdrew his GDB debugging tools due to lack of review manager. Looking at the review schedule for the last few years[1] you'll find a number of repeated names and long-time contributors. In an effort to find new volunteers for review managers I would like to ask what are the showstoppers that keep you from wanting to be a review manager? Time, Training, Recognition, none of the above? I am genuinely curious in an effort to find new volunteers so we can continue to add great libraries to the project. Thank you, and Happy Easter to those that celebrate. Matt [1] https://www.boost.org/community/review_schedule.html

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Printf library suggestion
by Aaron Graham 22 Apr '25

22 Apr '25

I'd like to gauge the interest in adding the following library to boost: https://github.com/rokudev/rostd/blob/main/include/rostd/printx.hpp It's a simple library that checks and rewrites the format string at compile time in order to fortify it for use with printf, leaving the object code with only a call to the underlying C-standard printf-family function. It's a single header and requires C++20 or above (for cNTTP support). It contains these four functions: printf, sprintf, snprintf, fprintf These functions are used like so: printf<"Hello %s\n">("World!"); char buf[20]; sprintf<"Hello %s\n">(buf, "World!"); // yes, it's safe char buf[20]; snprintf<"Hello %s\n">(buf, sizeof buf, "World!"); fprintf<"Hello %s\n">(file, "World!"); Features/rationale: * It provides old-style printf (supports all standard printf specifiers). * Fully type-safe. No format string attacks. Issues are found at compile time. * Length modifiers are deduced; these format strings are portable. (No PRIu64 inttypes stuff needed anymore, just use %u) * Adds %? format specifier (print whatever type is there). * Compiles to std::printf (much smaller object code than std::format). * Provides a way for developers to easily adapt this printf formatting capability to their own functions (logging, etc.) More detailed rationale is here: https://github.com/rokudev/rostd/blob/main/doc/printx.adoc

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Unable to migrate from Oracle Linux 8 to Oracle Linux 9 due to Boost dependency
by Pavithra Raghavendran 22 Apr '25

22 Apr '25

Hi Team We are writing this mail requesting your assistance for boost related issue which we are facing while migrating from Oracle Linux 8 (OL8) to Oracle Linux 9 (OL9) OS. Issue Description: When we try to upgrade the OS from OL8 to OL9, we are seeing errors related to boost version 1.66.0 and the RPM which was already successfully installed on OL8 is getting removed. Note: On OL8 OS, the available version of boost from yum is boost-1.66.0 & on OL9 OS, the available version of boost from yum is boost-1.75.0. Brief: Our application RPM is compiled on an OL8 machine(development machine) and is dependent on boost library (linked dynamically). When we install this RPM on another OL8 machine(test machine), the RPM installation is successful. This is because the boost version in our RPM and the test OL8 machine matches i.e. both require boost-1.66.0. However, when we upgrade the OS from OL8 to OL9, the application RPM is getting removed with the errors as shown below. This is because OL9 has boost-1.75.0 libraries but our RPM has boost libraries which is dynamically linked with boost-1.66.0. [root@vm227-66-vm5 ~]# dnf install ocsm-6.0.0.0.0-608.x86_64.rpm Last metadata expiration check: 0:13:25 ago on Tue 25 Mar 2025 12:25:18 PM CET. Error: Problem: conflicting requests - nothing provides libboost_filesystem.so.1.66.0()(64bit) needed by ocsm-6.0.0.0.0-608.x86_64 from @commandline - nothing provides libboost_program_options.so.1.66.0()(64bit) needed by ocsm-6.0.0.0.0-608.x86_64 from @commandline - nothing provides libboost_regex.so.1.66.0()(64bit) needed by ocsm-6.0.0.0.0-608.x86_64 from @commandline - nothing provides libboost_system.so.1.66.0()(64bit) needed by ocsm-6.0.0.0.0-608.x86_64 from @commandline Analysis: To simulate this above scenario, we have written a very simple sample program using the boost library and compiled the code on OL8 OS and linked dynamically with boost version 1.66.0. Once RPM is ready, we installed it on an OL8 virtual machine. Installation is successful because our compiled RPM has boost-1.66.0 libraries(libboost_program_options.so.1.66.0) and OL8 supported version of boost is also 1.66.0. Now, when we upgrade the OS from OL8 to OL9, the default boost available on OL9 is boost-1.75.0, and since our RPM is linked with boost-1.66.0 libraries, installation is failing with the below errors (similar to the application errors mentioned in Brief section). [root@localhost ~]# sudo dnf install boost_demo-1.0.0-1.el8.x86_64.rpm Last metadata expiration check: 0:23:05 ago on Mon 21 Apr 2025 01:00:57 PM CEST. Error: Problem: conflicting requests - nothing provides libboost_program_options.so.1.66.0()(64bit) needed by boost_demo-1.0.0-1.el8.x86_64 from @commandline - nothing provides libboost_system.so.1.66.0()(64bit) needed by boost_demo-1.0.0-1.el8.x86_64 from @commandlin In our application, we have not linked to any specific version of boost dependency i.e. we have nowhere mentioned the version of boost to be used as 1.66.0. Since OL8 yum repo has boost-1.66.0, our application is considering version 1.66.0 while building RPM. However, while migrating from OL8 to OL9 we are seeing the above-mentioned issue and hence we are unable to complete the upgradation process which is crucial to our customers. Query: Can you please let us know how we can ensure that the OS gets upgraded from OL8 to OL9, without application RPM(linked dynamically to boost-.1.66.0) being removed. Thanks Pavithra

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[bloom] Review Announcement: Boost.Bloom (May 13-22, 2025)
by Arnaud Becheler 21 Apr '25

21 Apr '25

Dear Boost community, The review of the Boost.Bloom library begins on May 13th, 2025, and will run through May 22nd, 2025. Boost.Bloom is a header-only C++ library written by Joaquín M López Muñoz, providing fast and flexible Bloom filters. These are space-efficient probabilistic data structures used to test set membership with a controllable false positive rate and minimal memory footprint. The library supports a variety of configurations and hash policies and is designed to integrate well with modern C++. You can find the library here: - Repo: https://github.com/joaquintides/bloom - Documentation: https://master.bloom.cpp.al/ Bloom filters are especially useful when: - You need to test if something is not in a large dataset, and can tolerate a small false positive rate. (e.g., avoiding duplicate URL crawls in a web crawler) - You need a memory-efficient structure to represent large sets (e.g., checking for the presence of DNA subsequences across massive genomic datasets) - You want to avoid expensive lookups for items that are definitely not present (e.g., filtering nonexistent records before querying a remote database). As always, we welcome all reviews — from quick impressions to detailed analysis. Your feedback helps ensure that the library meets Boost's high standards in terms of correctness, performance, documentation, and design. If you’re interested in contributing a review, please post to the Boost mailing list during the review period. Note: All links to other parts of Boost in the Boost.Bloom documentation are currently broken, as they were written with the assumption that the library was already integrated into Boost - please do not account for those in your review. Thank you in advance for your time and insights! Best regards, Arnaud Becheler Review Manager, Boost.Bloom

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Boost v1.88 Release Report
by Robert Beeston 18 Apr '25

18 Apr '25

The release report for v1.88 is now available, now packed with even more information including mailing list, slack, git commits and other statistical information that happened on the path to the current release. https://downloads.cppalliance.org/reports/boost_1_88_0_release_report.pdf *Rob Beeston* Creative Director C++ Alliance cppalliance.org

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[bloom] Looking for a review manager for candidate Boost.Bloom
by Joaquin M López Muñoz 18 Apr '25

18 Apr '25

Candidate Boost.Bloom has been endorsed by members of the community, so I'd like to proceed with the official review and for that a volunteer is needed to act as the Review Manager: Repo: https://github.com/joaquintides/bloom Docs: https://master.bloom.cpp.al/ These are the general requisites and assigned tasks for the Review Manager: https://www.boost.org/community/reviews.html#Review_Manager If you're interested, please respond to this post and/or contact me privately. Thank you! Joaquin M Lopez Munoz

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The state of modular Boost
by René Ferdinand Rivera Morell 16 Apr '25

16 Apr '25

Hello fellow developers, As you might remember many months ago I started asking library maintainers to merge the build (and sometimes source) changes needed to make it possible to consume Boost libraries in a modular way. At this point a good number of libraries have merged those PRs. And there have been a pair of Boost releases containing those changes. But there is still work to do. So far, we have: * 119 PRs merged so far! * 4 PRs needing work before they can be merged. * 1 PR that was merged to master but never merged to develop. * 45 PRs that can be merged immediately. What I'm asking now is for "forgiveness" as it were. The 45 PRs above are either PRs where the authors gave permission to the Boost github owners to review and merge. Or are for libraries that are effectively unmaintained (the authors did not respond to the PR or to the various requests for how to manage the changes, and haven't seen changes in them for some years). And the recent changes I made to the PRs was not with the build changes. But instead to fix the unmaintained CI of the libraries as they otherwise just did not work. What I want it for the github org owners to go ahead and merge these 45 PRs: https://github.com/users/grafikrobot/projects/1/views/7 Thank you. -- -- René Ferdinand Rivera Morell -- Don't Assume Anything -- No Supongas Nada -- Robot Dreams - http://robot-dreams.net

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[OpenMethod] Boost.OpenMethod review scheduled
by Дмитрий Архипов 14 Apr '25

14 Apr '25

The review for the proposed Boost.OpenMethod library by Jean-Louis Leroy is scheduled to take place from April 28 to May 07. OpenMethods solve the Expression Problem by making it possible to define free virtual functions, i.e. virtual functions that exist outside of a class The library repository is here: https://github.com/jll63/Boost.OpenMethod. The documentation is here: https://jll63.github.io/Boost.OpenMethod.

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Pretty printer module
by Дмитрий Архипов 14 Apr '25

14 Apr '25

Recently Niall Douglas posted about his idea to embed GDB pretty printers into binaries using a header. At the time I was thinking about a good way to deploy pretty printers for JSON that facilitates their autoloading. After Niall's post I experimented a little bit more, and I came to the conclusion that indeed nothing beats embedding via a C++ header in terms of convenience. At the same time I was also thinking about testing that pretty printers do in fact work. Given that pretty printers (usually) are implemented as a Python module, it initially looked like one could just run a Python program and import GDB Python modules. But actually you cannot. It turns out, though, you can run a Python script with GDB as the interpreter. After several iterations I arrived at this setup: https://github.com/boostorg/json/blob/develop/test/printers.cpp. A script converts this file into a Python script that uses GDB to break on certain lines and check if a particular expression produces a particular output when printed. While doing all this I thought that most of this work can be useful to other libraries. So, I moved the reusable parts into a separate directory (https://github.com/boostorg/json/tree/develop/pretty_printers) and added both a b2 module, and a CMake module. For B2. Importing: https://github.com/boostorg/json/blob/develop/build.jam#L8-L9 https://github.com/boostorg/json/blob/develop/build/Jamfile#L13 (Re)generating the header: https://github.com/boostorg/json/blob/develop/build/Jamfile#L88-L95 Testing: https://github.com/boostorg/json/blob/develop/test/Jamfile#L96-L101 For CMake: Importing: https://github.com/boostorg/json/blob/develop/CMakeLists.txt#L54-L55 (Re)generating the header: https://github.com/boostorg/json/blob/develop/CMakeLists.txt#L56-L63 Testing: https://github.com/boostorg/json/blob/develop/test/CMakeLists.txt#L80-L88 My questions to the community: do you find this useful? Would you use it in your Boost or non-Boost library? If you do, the module should be moved to tools rather than stay in libs/json.

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[Release] The master branch is now open
by Marshall Clow 13 Apr '25

13 Apr '25

Thanks to everyone for their patience. The next release cycle will begin in late June. — The release managers.

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