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[sync] Optimizing Boost's sync using futex2
by André Almeida 15 May '21

15 May '21

Hi there, I'm the author of futex2[0], a WIP new set of Linux's syscalls that allows userspace to write efficient sync mechanisms. I would like to hear from Boost's developers if the project would benefit from this new interface. >From Boost/sync's codebase, I can see that you are already familiar with futexes, but just in case: * What's futex? futex stands for "fast userspace mutexes". It's a syscall that basically exposes a wait queue, where userspace can ask to put threads to sleep and to wake them. The index of such queue is an unsigned int address (that is usually called a futex). It's value doesn't mean anything for the kernel, userspace is responsible to defining the rules of it and implementing the logic. * Why futex2? futex has long standing issues that seems impossible to be solved in the current interface, so we are designing a new set of syscalls taking those problems in account (more on that at [0]). It's not merged yet, and I'm researching some uses cases to validate and get feedback about the API. The new API has the following new features: * Variable sized futexes (6, 16, 32 and 64 bits): we aren't restrict to only 32 bits anymore, and this can be used for decreasing memory usage or to wait on an address * Wait for multiple futexes: this function enables userspace to wait on a list of futexes and wake on the first that triggers a wake. Our current use case for this is for game engines and to emulate WaitForMultipleObjects from WinAPI in Wine * NUMA-awarenes: current futex has a single global hash table that is allocated in some node. Every futex() call that happens on the other nodes will have a access penalty. At futex2, there'll be a single table per node, so you can specify which one you want to operate on to increase locality. The detailed description of the API can be seen in the documentation patch[1]. Do you think that Boost would benefit from it? Thanks, André - futex2 talk at OpenSource Summit: https://www.youtube.com/watch?v=eG6GMBTcPQ8 [0] https://lore.kernel.org/lkml/20210427231248.220501-1-andrealmeid@collabora.… [1] https://lore.kernel.org/lkml/20210427231248.220501-7-andrealmeid@collabora.…

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Final Notice: BinTray is shutting down 1-May (that's SATURDAY)
by Marshall Clow 07 May '21

07 May '21

Bintray is “sunsetting” on the 1st of May. At that time, you will be unable to download boost releases from there. Before that time, their service will be occasionally interrupted. The web site has been updated, all the download links now refer to https://boostorg.jfrog.io/artifactory/main/release/ <https://boostorg.jfrog.io/artifactory/main/release/> Example: Instead of downloading from: https://dl.bintray.com/boostorg/release/1.76.0/source/boost_1_76_0.tar.gz <https://dl.bintray.com/boostorg/release/1.76.0/source/boost_1_76_0.tar.gz> You should download from: https://boostorg.jfrog.io/artifactory/main/release/1.76.0/source/boost_1_76… <https://boostorg.jfrog.io/artifactory/main/release/1.76.0/source/boost_1_76…> This applies to all releases from 1.63.0 onward (The pre-1.63 releases are still hosted at SourceForge) — Marshall

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[GSoC] - Boost.Multiprecision Quad Double
by Γιάννης Γονιδέλης 07 May '21

07 May '21

Hello! Christopher, Unfortunately, due to some urgent issues I won't be able to contribute during the summer. Thus, in case you have been considering picking me I would ask you to make a new choice. Apologies, Giannis

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Google Summer of Code 2021
by David Bellot 05 May '21

05 May '21

Hi Boost community, The mentors are now finalizing their selection of the students. Google has been very generous this year with the number of slots we were allocated and we are happy to say that we will again have a nice (and large) team of incredible students developing with us this summer (or winter if you're down under like me). Stay tuned because we will announce the list of projects very soon. Best regards, David

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[Math] Standalone beta release
by John Maddock 05 May '21

05 May '21

Just a heads up that Boost.Math now has a (beta) standalone release at https://github.com/boostorg/math/releases/tag/v1.76-standalone-beta We would very much appreciate any interested parties giving it a whirl and reporting back. With many thanks to Matt Borland and Nick Thompson for making this possible! Best, John Maddock. -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

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wrong result in complex pow
by Gero Peterhoff 03 May '21

03 May '21

Hello, the pow-function pow(scalar, complex) in boost/math/cstdfloat/cstdfloat_complex_std.hpp get wrong result. Current implementation: inline complex<BOOST_CSTDFLOAT_EXTENDED_COMPLEX_FLOAT_TYPE> pow(const BOOST_CSTDFLOAT_EXTENDED_COMPLEX_FLOAT_TYPE& x, const complex<BOOST_CSTDFLOAT_EXTENDED_COMPLEX_FLOAT_TYPE>& a) { return std::exp(a * std::log(x)); } I think that's correct: inline complex<BOOST_CSTDFLOAT_EXTENDED_COMPLEX_FLOAT_TYPE> pow(const BOOST_CSTDFLOAT_EXTENDED_COMPLEX_FLOAT_TYPE& x, const complex<BOOST_CSTDFLOAT_EXTENDED_COMPLEX_FLOAT_TYPE>& a) { return std::exp(a * std::log(complex<BOOST_CSTDFLOAT_EXTENDED_COMPLEX_FLOAT_TYPE>(x))); } regards Gero

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Cannot build 1.76.0 for Windows (wrong path to compiler)
by Andreas Tscharner 03 May '21

03 May '21

Hello World, I try, according to the "Get started guide" >bootstrap.bat in the main boost directory. I get an error, because "C:\Program Files(x86)" ... contains a space and is not double quoted. So I replace all set "B2_CXX=%CXX% ..." with set "B2_CXX="%CXX%" ..." in tools\build\src\engine\config_toolset.bat After that I have the following problem: D:\Projects\development\QUARTIS-related\boost>.\bootstrap.bat Building Boost.Build engine LOCALAPPDATA=C:\Users\ATs\AppData\Local Found with vswhere C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise Found with vswhere C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise Call_If_Exists "C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\Common7\Tools\..\..\VC\Auxiliary\Build\vcvarsall.bat" AMD64 ********************************************************************** ** Visual Studio 2019 Developer Command Prompt v16.9.4 ** Copyright (c) 2021 Microsoft Corporation ********************************************************************** [vcvarsall.bat] Environment initialized for: 'x64' ### ### Using 'vc142' toolset. ### D:\Projects\development\QUARTIS-related\boost\tools\build\src\engine>"C:/Program Files (x86)/Microsoft Visual Studio/2019/Enterprise/VC/Tools/MSVC/14.27.29110/bin/Hostx64/x64/cl.exe" /nologo /MP /MT /TP /Feb2 /wd4996 /O2 /GL /EHsc -DNDEBUG builtins.cpp class.cpp command.cpp compile.cpp constants.cpp cwd.cpp debug.cpp debugger.cpp execcmd.cpp execnt.cpp filent.cpp filesys.cpp frames.cpp function.cpp glob.cpp hash.cpp hcache.cpp hdrmacro.cpp headers.cpp jam.cpp jamgram.cpp lists.cpp make.cpp make1.cpp md5.cpp mem.cpp modules.cpp native.cpp object.cpp option.cpp output.cpp parse.cpp pathnt.cpp pathsys.cpp regexp.cpp rules.cpp scan.cpp search.cpp jam_strings.cpp startup.cpp subst.cpp sysinfo.cpp timestamp.cpp variable.cpp w32_getreg.cpp modules/order.cpp modules/path.cpp modules/property-set.cpp modules/regex.cpp modules/sequence.cpp modules/set.cpp /link kernel32.lib advapi32.lib user32.lib Das System kann den angegebenen Pfad nicht finden. It tries to start "C:/Program Files (x86)/Microsoft Visual Studio/2019/Enterprise/VC/Tools/MSVC/14.27.29110/bin/Hostx64/x64/cl.exe". Unfortunately at my system, I don't have this path. I have C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Tools\MSVC\14.28.29910... Please note the different number after "MSVC" What is the problem? How can I fix this? TIA and best regards Andreas -- ("`-''-/").___..--''"`-._ `o_ o ) `-. ( ).`-.__.`) (_Y_.)' ._ ) `._ `. ``-..-' _..`--'_..-_/ /--'_.' .' (il).-'' (li).' ((!.-' Andreas Tscharner andy(a)stupidmail.ch ICQ-No. 14356454

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Persistent CI failures for old compilers
by Jeff Garland 02 May '21

02 May '21

On at least the clang 3.8 and gcc4.8 I'm seeing python errors block the CI from running correctly. Downloading/unpacking pip==20.3.4 Cannot fetch index base URL https://pypi.python.org/simple/ Could not find any downloads that satisfy the requirement pip==20.3.4 Which of course has nothing to do with the compiler. Here's an active change where the CI is running. https://github.com/boostorg/date_time/pull/192 So the question is -- are these two old and now unsupported? Is there some CI setup change I need? I'd like to stop having to override the CI obviously. Thanks, Jeff

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Re: [boost] C++Now 2021 -- Library in a Week: Boosting Boost
by Bjorn Reese 02 May '21

02 May '21

On 2021-05-01 00:55, Jeff Garland via Boost wrote: > Every year at the end of the session, I solicit ideas from the community > about what 'library' we should work on in the following year. One Boost.Tokenizer could do with a modernization. It generates a lot of code for even simple tokenizations, which makes it unsuitable for embedded devices. Some issues to consider: * Separate the browsing API from the conversion API. ** The browsing API should use string_view. ** The conversion API should use output buffers instead of returing a string. * Provide an API with narrow contracts * Provide a constexpr API.

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C++Now 2021 -- Library in a Week: Boosting Boost
by Jeff Garland 01 May '21

01 May '21

C++Now 2021 is next week. For those that have never been, every year we have a workshop session called Library in a Week. While the goal of the session might be obvious from the title, needless to say, final Boost libraries don't happen in a week. So, actually, the real underlying goal is to build boost community and discuss c++ library design with projects that don't conflict with attendees day jobs. Every year at the end of the session, I solicit ideas from the community about what 'library' we should work on in the following year. One consistent suggestion has been to work on boost community maintenance. With the conference all virtual this year, I think this is the year to do it. The goal will be to generate pull requests from new or even old boost participants to improve our code base. While I'm sure we could wander around the various libraries and find issues that need some work to generate pull requests, I'm posting this looking for suggestions from the bigger community. Note that this doesn't need to be exclusive to new code -- it can be documentation or tests. Are there particular libraries we should look at? Are there particular issues that someone would like a hand tackling? Are there some upgrades to newer c++ features that someone could jump in on? Thanks, Jeff

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