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[outcome] v2.1 progress report
by Niall Douglas 04 Jun '18

04 Jun '18

Dear Boost, Two months after you accepted Outcome into Boost, I am pleased to say that I believe that all the known bugs and very substantial source refactoring recommended by the peer review have been implemented (detailed changelog is appended below). What remains is a few months of maturing in real world use as all this severe refactoring needs to be tested outside a test suite, and of course the documentation which I don't intend to start work on until the autumn. The Boost edition has, obviously, received a major upgrade and it is now 100% "Boost native" in that it uses Boost.System and Boost.Exception now. The test suite for the Boost edition exclusively tests the Boost native edition, and it all passes. Outcome (both standalone and Boost editions) now can handle both Boost and std types freely intermixed as you see fit. A new "lite" single header edition exists which drags in virtually no system headers, and is hideously low impact on compile times as a result. ABI and API stability have been dumped to git repo with scripting to check the current library against the frozen dumps. This edition should make the corporate crowd very pleased. Very little should appear to have changed from the outside. Code written for v2.0 ought to, more or less, compile and work as before with v2.1. I would appreciate whatever help the Boost community can give in helping to test this edition. I expect new bugs to have been introduced given the severe source code refactoring, and new dual support for Boost and std as equals. My gratitude in advance. Niall --- ## v2.1 in progress [[project]](https://github.com/ned14/outcome/projects/1) - Boost edition is now 100% Boost, so defaults for `result` and `outcome` are `boost::system::error_code::errc_t` and `boost::exception_ptr`. Moreover, the test suite in the Boost edition now exclusively tests the Boost edition. One can, of course, freely use the standalone edition with Boost, and the Boost edition with `std` types. - Renamed ADL discovered customisation point `throw_as_system_error_with_payload()` to `outcome_throw_as_system_error_with_payload()`. - [#135](https://github.com/ned14/outcome/issues/135) - Added much clearer compile failure when user tries `result<T, T>` or `outcome` where two or more types are identical. Thanks to Andrzej Krzemieński for suggesting a technique which combines SFINAE correctness with the remaining ability for `result<T, T>` etc to be a valid type, but not constructible. - [#67](https://github.com/ned14/outcome/issues/67) - Fixed one of the oldest long open bugs in Outcome, that the noexcept unit tests failed on OS X for an unknown reason. - [#115](https://github.com/ned14/outcome/issues/115) - Outcome did not construct correctly from `failure_type`. - Inexplicably outcome's error + exception constructor had been removed. Nobody noticed during the Boost peer review, which is worrying seeing as that constructor is needed for one of the main advertised features to Boost! - [#107](https://github.com/ned14/outcome/issues/107) and [#116](https://github.com/ned14/outcome/issues/116) - `operator==` and `operator!=` now become disabled if the value, error and exception types do not implement the same operator. - Relatedly, both comparison operators simply didn't work right. Fixed. - [#109](https://github.com/ned14/outcome/issues/109) - `swap()` now has correct `noexcept` calculation and now correctly orders the swaps to be whichever is the throwing swap first. - Added reference dump of v2.1 ABI so we can check if ABI breakage detection works in the next set of changes, plus Travis job to check ABI and API compatibility per commit. - [#124](https://github.com/ned14/outcome/issues/124) - `OUTCOME_TRY` is now overloaded and selects `void` or `auto` edition according to input parameter count. - [#120](https://github.com/ned14/outcome/issues/120) - Fix generation of double underscored temporary variables in `OUTCOME_UNIQUE_NAME`, which is UB. - [#110](https://github.com/ned14/outcome/issues/110) - Separated `result` from its hard coded dependency on the `<system_error>` header. - Renamed `result` and `outcome` to `basic_result` and `basic_outcome`. - Renamed `result.hpp` into `basic_result.hpp`. - Moved `<system_error>` and `<exception>` dependent code into new `std_result.hpp` and `std_outcome.hpp` header files. - Added `boost_result.hpp` and `boost_outcome.hpp` which use Boost.System and Boost.Exception (these are `result.hpp` and `outcome.hpp` in the Boost edition). -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

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[beast] How do I select un-DEPRECATED interfaces?
by Brian Kuhl 04 Jun '18

04 Jun '18

Hi Experts, I’m working with an EAR release of VxWorks 7 with llvm v5.0 and VxWorks’ first C++14 STL ( Dinkum v700) and Boost v 1.67 ( Yes, the RTOS world moves slowly) I’ve gotten a clean compile of Beast with #define BOOST_BEAST_ALLOW_DEPRECATED #define BOOST_COROUTINES_NO_DEPRECATION_WARNING But I’m having trouble locating the logic that’s choosing these deprecated interfaces for me? Could someone point out the relevant logic? Many Thanks, Brian Kuhl Senior Manager – Information Development Wind River

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[Algorithm] contains(v, 1)
by Olaf van der Spek 03 Jun '18

03 Jun '18

Hi, vector<int> v; contains(v, 1); This doesn't work as contains expects two ranges (AFAIK). Is there some other function that's usable for this purpose? Should contains support a value for argument 2? Gr, -- Olaf

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[compressed_pair] [hof] [hana] What's the story with compressed_pair?
by Tom Westerhout 30 May '18

30 May '18

Hello! It looks like there are at least three different implementations of a "std::pair with EBO" in Boost: boost/utility/compressed_pair.hpp boost/hof/detail/compressed_pair.hpp boost/hana/pair.hpp Finally, there is also std::tuple which seems to also make use of EBO. I need similar functionality for a GSoC project I'm working on this year. So I'm wondering, is compressed pair considered a simple technicality that should be implemented from scratch every time I need it or shall I stick to one of the four mentioned implementations? I would much prefer to use Boost.Utility's one, but unfortunately it's neither constexpr-friendly nor noexcept-friendly... Is there some reason why it cannot be annotated with macros which expand to constexpr and noexcept when compiled with C++11 support? Or has no one just gotten around to do it? Thanks in advance, Tom

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[Hana] "basic_tuple.hpp" bug when building with VS2017
by Louis Dionne 30 May '18

30 May '18

> Hello, > > Just installed Boost and Visual Studio 2017 a few days ago. Visual Studio 2017 is known to be unable to compile Hana (and other libraries such as Range-v3). I will be working with the Microsoft folks to make it work as they explicitly reached out to me with that intent. Cheers, Louis

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[testing][regressions] All my regressions testers failing due to connection errors to GitHub
by Ion Gaztañaga 28 May '18

28 May '18

Hi, All my 4 testers (I have 4 machines running several Mingw targets) are always failing pulling new versions from GitHub. This problem started some days ago. I've tried to reset all machines, network equipment, disabling antivirus, firewall, modified http attributes, modified the regression script to use git protocol instead of https, etc. with no luck. I'm using Windows machines with official Git. Any clue on what's going on? Maybe Github recently does not like so many submodules? Example of failure (several libraries can fail during "git pull "--recurse-submodules""): ------------------- ------------------- ------------------- Fetching submodule libs/io fatal: unable to access 'https://github.com/boostorg/io.git/': OpenSSL SSL_read: SSL_ERROR_SYSCALL, errno 10054 Then: # git_source_checkout failed with message "GIT command "git pull "--recurse-submodules"" failed with code 1" # Retrying (5 more attempts). # Executing GIT command: c:\boost\develop\boost_root> git submodule foreach "git submodule deinit ." ------------------- ------------------- All retries fail and the script fails with error: ------------------- ------------------- ------------------- # git_source_checkout failed with message "GIT command "git pull "--recurse-submodules"" failed with code 1" # Giving up. Traceback (most recent call last): File "run.py", line 71, in <module> runner(root) File "c:\boost\develop\boost_regression_src\regression.py", line 286, in __init__ self.main() File "c:\boost\develop\boost_regression_src\regression.py", line 623, in main getattr(self,action_m)() File "c:\boost\develop\boost_regression_src\regression.py", line 578, in command_regression self.command_get_source() File "c:\boost\develop\boost_regression_src\regression.py", line 330, in command_get_source self.retry(self.git_source_checkout) File "c:\boost\develop\boost_regression_src\regression.py", line 662, in retry return f() File "c:\boost\develop\boost_regression_src\regression.py", line 875, in git_source_checkout self.git_checkout(git_info['boost'], self.git_branch(), clean) File "c:\boost\develop\boost_regression_src\regression.py", line 849, in git_checkout self.git_command( 'pull', '--recurse-submodules' ) File "c:\boost\develop\boost_regression_src\regression.py", line 834, in git_command raise Exception( 'GIT command "%s" failed with code %d' % (git_cli, rc) ) Exception: GIT command "git pull "--recurse-submodules"" failed with code 1 END 24/05/2018 15:28:37,46 ------------------- ------------------- ------------------- Errors are never in the same libraries, very few times the checkout succeeds and a regression is run. Anyone else having these problems? I've attached the log of one failure in case someone can see any clue. I really don't see how to solve this, so I won't be able to run regressions. Best, Ion

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GCC versions
by Ian Emmons 28 May '18

28 May '18

Apologies if this is off topic, but the audience here is perfect for this question: I need to support CentOS version 7 with my C++ software. The version of GCC that is supported out-of-the-box on that version of Linux is rather old -- it supports C++11, but not C++14, and of course I would like to use a newer standard. Is it common practice on Linux to install a later version of GCC than the out-of-the-box on version? If so, how do you handle the run-time shared library dependencies? Any pointers would be helpful. Thanks, Ian

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Boost multiprecision differential fuzzer running on Google's oss-fuzz
by Guido Vranken 28 May '18

28 May '18

Dear list, I built a bignum differential fuzzer [1] that has been running on Google's oss-fuzz service [2] for a while. It performs the same mathematical operations (addition, subtraction, multiplication, modular exponentation, etc) across multiple bignum libraries (eg. OpenSSL + Boost multiprecision), compares their results and crashes if they don't match. This effort has so far found a couple of (minor) bugs in OpenSSL and Go. As soon as a mismatch is found, oss-fuzz will send a notification e-mail to the developers of the various bignum libraries so the bug can be examined and resolved. At which e-mail address(es) do the developers of Boost wish to receive these notifications? Please bear in mind that the notifications will contain potentially security-sensitive information so the recipient may not be a public mailing list. Currently, a potential bug is found only every couple of weeks, so recipients do not have to worry about a lot of incoming traffic. If you wish to write comments to the fuzzer's private bug tracker, the e-mail you specify must be linked to a Google account. To all others who are reading this, please feel welcome to submit pull requests to the Boost multiprecision module of my fuzzer [3] if these modifications increase the scope (code coverage) and probability of finding bugs. Thanks, Guido [1] https://github.com/guidovranken/bignum-fuzzer [2] https://github.com/google/oss-fuzz [3] https://github.com/guidovranken/bignum-fuzzer/tree/master/modules/cpp_boost

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[windows] Wni32/Vigorf.A trojan in boost_1_67_0-msvc-14.1-64.exe?
by Mateusz Loskot 28 May '18

28 May '18

Hi, One user reported via #boost at cpplang.slack.com that Windows Defender reported trojan in the latest Windows binaries. I checked myself and I can confirm the latest up-to-date Windows Defender is detecting Vigorf.A in the installer archive. Is this false report? Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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Boost.DisjointSets and Boost.Container
by James E. King, III 27 May '18

27 May '18

Currently the disjoint_sets repository ( https://github.com/boostorg/disjoint_sets) holds a single class in "boost/pending" that is only used by the graph and graph_parallel projects (that I can tell...). I'd like us to consider taking disjoint_sets out of pending state and make it official as part of Boost Containers. Both Graph and GraphParallel require linking already, and they may already use Boost.Containers (I haven't checked). disjoint_sets is header-only however and this might cause problems for anyone relying on it, however since it's in boost/pending, I wonder if anyone is actually using it. Given the pending designation on it however, a breaking change seems reasonable to me. It will reduce the burden on the CMT, and container has at least some CI on it already. Thoughts? - Jim

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