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Shared memory between Visual Studio build and MinGW build
by Da Xu 03 Mar '20

03 Mar '20

Hi folks, got a strange one here. I am trying to get two programs to communicate with each other on Windows 10 via shared memory. Both of them are using Boost 1.72, compiled from the same set of headers. I am only using the shared memory portion of boost. However, one is compiled with Visual studio 2019 community, and the other one is compiled with MinGW 64, g++ version 9.2.0. I have to use MinGW, because I am writing a plugin for another program, which only takes dlls compiled with MinGW. The program compiled with MinGW creates the shared memory and allocates several objects. Then I started the second program that was compiled with Visual Studio 2019. It was able to find and connect to the managed segment. When I am viewing the segment info from Visual Studio's debugger, everything looks ok. However, when I call get_free_memory(). It spits back 18446744073709551104, which is just bizarre. Then, when I tried to find_or_construct on the managed segment. It just hangs, apparently stuck in winapi::sleep_tick() with the following tracedll!boost::interprocess::winapi::sleep_tick() Line 1288 C++dll!boost::interprocess::ipcdetail::thread_sleep_tick() Line 187 C++dll!boost::interprocess::spin_wait::yield() Line 128 C++dll!boost::interprocess::ipcdetail::try_based_lock<boost::interprocess::ipcdetail::spin_mutex>(boost::interprocess::ipcdetail::spin_mutex & m) Line 71 C++dll!boost::interprocess::ipcdetail::spin_mutex::lock() Line 81 C++dll!boost::interprocess::ipcdetail::spin_recursive_mutex::lock() Line 95 C++dll!boost::interprocess::interprocess_recursive_mutex::lock() Line 165 C++dll!boost::interprocess::scoped_lock<boost::interprocess::interprocess_recursive_mutex>::scoped_lock<boost::interprocess::interprocess_recursive_mutex>(boost::interprocess::interprocess_recursive_mutex & m) Line 81 C++dll!boost::interprocess::segment_manager<char,boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,boost::interprocess::offset_ptr<void,__int64,unsigned __int64,0>,0>,boost::interprocess::iset_index>::priv_generic_named_construct<char>(unsigned char type, const char * name, unsigned __int64 num, bool try2find, bool dothrow, boost::interprocess::ipcdetail::in_place_interface & table, boost::interprocess::iset_index<boost::interprocess::ipcdetail::index_config<char,boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,boost::interprocess::offset_ptr<void,__int64,unsigned __int64,0>,0>>> & index, boost::interprocess::ipcdetail::bool_<1> is_intrusive) Line 1076 C++dll!boost::interprocess::segment_manager<char,boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,boost::interprocess::offset_ptr<void,__int64,unsigned __int64,0>,0>,boost::interprocess::iset_index>::priv_generic_construct(const char * name, unsigned __int64 num, bool try2find, bool dothrow, boost::interprocess::ipcdetail::in_place_interface & table) Line 760 C++dll!boost::interprocess::segment_manager<char,boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,boost::interprocess::offset_ptr<void,__int64,unsigned __int64,0>,0>,boost::interprocess::iset_index>::generic_construct<SharedMem_Info>(const char * name, unsigned __int64 num, bool try2find, bool dothrow, boost::interprocess::ipcdetail::in_place_interface & table) Line 705 C++dll!boost::interprocess::ipcdetail::named_proxy<boost::interprocess::segment_manager<char,boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,boost::interprocess::offset_ptr<void,__int64,unsigned __int64,0>,0>,boost::interprocess::iset_index>,SharedMem_Info,0>::operator()<char const (&)[17],int,int,int,int,bool,boost::interprocess::allocator<void,boost::interprocess::segment_manager<char,boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,boost::interprocess::offset_ptr<void,__int64,unsigned __int64,0>,0>,boost::interprocess::iset_index>> &>(const char[17] & <args_0>, int && <args_1>, int && <args_2>, int && <args_3>, int && <args_4>, bool && <args_5>, boost::interprocess::allocator<void,boost::interprocess::segment_manager<char,boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,boost::interprocess::offset_ptr<void,__int64,unsigned __int64,0>,0>,boost::interprocess::iset_index>> & <args_6>) Line 131 C++ It looks like it the segment manager was unable to get a mutex lock on the memory? But I don't believe I put a mutex lock on the segment manager from the other end. Everything works just fine if I am doing shared memory between two programs compiled with visual studio. So, it feels like somewhere some how memory alignment is off? Anybody ran into a similar issue before? Any help would be greatly appreciated! Thank you!!

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Download permissions off
by Forwarding 29 Feb '20

29 Feb '20

Cannot seem to download sources. A sampling of directories, e.g. https://dl.bintray.com/boostorg/release/1.72.0/source/, all yield the following when choosing one of the archives:Forbidden!This is a new development, download was OK yesterday morning.Thx.-Matthew

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(SOLVED) Re: [Boost.Test] duplicate symbol '_main' (manual test registration)
by Andrew McFarlane 29 Feb '20

29 Feb '20

Hello all, I just wanted to let you know that I figured out my problem. It had nothing to do with Boost.Test and had everything to do with my Makefile. My Makefile was literally telling g++ to try and compile main.cpp twice and place the output in bin. - I had defined an implicit rule to compile all .cpp files to .o files, like so: $(ODIR_TEST)/%.o : $(SDIR_TEST)/%.cpp $(CC) $(CXXFLAGS) -c $< -o $@ - And silly me, I wrote the default rule as follows: $(OUTDIR)/$(PROG) : $(SDIR_TEST)/main.cpp $(TEST_OBJS) $(CC) $(CXXFLAGS) -o $@ $^ $(TEST_OBJS) is just a list of all .o files prefixed with ./bin/. As you can imagine, taking $(SDIR_TEST)/main.cpp out of the list of prerequisites completely fixed the issue. I was able to compile and run all 34 tests successfully from one executable. Hurray!! It feels good to have figured this out, especially because I was able to do so on my own, but also makes me feel quite silly. Oh well, now I know. My apologies for burdening your inboxes with my stupidity. - AJ

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Re: [Boost-users] Boost-users Digest, Vol 5327, Issue 1
by Andrew McFarlane 29 Feb '20

29 Feb '20

Okay, I have almost completely fixed my problems. I just spent the past hour: - creating test case headers for each test translation unit (don't worry, I sped this up using a macro hehe) - inserting static test case method declarations privately in said headers - eliminating method redefinitions by toying with test translation unit #includes I am ALMOST there. Going to start a new issue, as my current problem is now vastly different from what is stated in the subject line. Consider the original problem for this issue SOLVED. Cheers! On Fri, Feb 28, 2020 at 9:04 PM <boost-users-request(a)lists.boost.org> wrote: > Send Boost-users mailing list submissions to > boost-users(a)lists.boost.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.boost.org/mailman/listinfo.cgi/boost-users > or, via email, send a message with subject or body 'help' to > boost-users-request(a)lists.boost.org > > You can reach the person managing the list at > boost-users-owner(a)lists.boost.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Boost-users digest..." > > > Today's Topics: > > 1. [Boost.Test] linking with shared lib (cannot find main) > (Andrew McFarlane) > 2. Re: [Boost.Test] linking with shared lib (cannot find main) > (Andrew McFarlane) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 28 Feb 2020 18:50:38 -0800 > From: Andrew McFarlane <andrew.mcfarlane52(a)gmail.com> > To: Boost users list <boost-users(a)lists.boost.org> > Subject: [Boost-users] [Boost.Test] linking with shared lib (cannot > find main) > Message-ID: > < > CAG90r9S4rCVPXACn5o6zG9xZQe9oucr7zR6PYHKHqgdUGGJ1Bw(a)mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > Hi all, > > I have been using Boost.Test for about a month now. Big fan so far, except > for the atrocious compilation times, hence why I am moving toward using the > shared library. > > using b2 to build and install Boost.Test's libs was simple enough, though > after making the noted changes here: > > https://www.boost.org/doc/libs/1_72_0/libs/test/doc/html/boost_test/adv_sce… > > to customize the module's entry point, g++ cannot find the main executable: > > Undefined symbols for architecture x86_64: > > "_main", referenced from: > > implicit entry/start for main executable > > ld: symbol(s) not found for architecture x86_64 > > clang: error: linker command failed with exit code 1 (use -v to see > invocation) > > make: *** [Guest_T] Error 1 > > I tried digging through the docs for more information, but I came up short. > > For more context, I have written unit tests for each of my classes. For > example, if my classes were A, B, and C, I would have A_T.cpp, B_T.cpp, and > C_T.cpp for unit tests. > > - Should each of the unit tests have their own main() function? (I would > think not..) > > - If not, how do I instruct g++ to first compile main.cpp before attempting > to compile anything else? > > If you are curious, here are the contents of my Makefile: > > PROG := main > > CC := g++ > > SDIR := ../src > > PKG_DIRS := $(shell ls $(SDIR)) > > CXXFLAGS = -v -Wall -std=c++11 -I$(SDIR_TEST) \ > > $(addprefix -I$(SDIR)/,$(PKG_DIRS)) -I$(BOOST_ROOT) \ > > -L$(BOOST_LIBS) -Wl,-rpath,$(BOOST_LIBS) -lboost_unit_test_framework > > ODIR_TEST = ./bin > > SDIR_TEST = ./src > > OUTDIR = ./execs > > ODIR = ../sim/bin > > > TEST_EXEC_NAMES = $(notdir $(basename $(wildcard $(SDIR_TEST)/*.cpp))) > > > $(OUTDIR)/$(PROG) : $(SDIR_TEST)/main.cpp > > $(CC) $(CXXFLAGS) -o $@ $< > > > $(OUTDIR)/$(PROG) : $(TEST_EXEC_NAMES) > > $(CC) $(CXXFLAGS) -o $@ $^ > > > % : $(SDIR_TEST)/%.cpp > > $(CC) $(CXXFLAGS) -o $(OUTDIR)/$@ $^ > > >From what I can tell, g++ is failing to find the main the executable > because it is attempting to compile one of my unit test files first. This > may or may not be the case; either way, I would appreciate some help or > direction as to what I should read to learn more about this. > > Let me know if you need more info. > > Thanks in advance. > > - AJ >

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[GSoC] Boost C++ and Slack channel
by Mateusz Loskot 27 Feb '20

27 Feb '20

Hi, I'm forwarding David's announcement copied below and available at https://lists.boost.org/Archives/boost/2020/02/248254.php You can join that Slack workspace at https://cppalliance.org/slack/ ML ------ Hi Boost community, we have a dedicated channel on Slack for all the discussions regarding the Google Summer of Code. Please join us on cpplang.slack.com on the channell #boost-gsoc. Cheers, David

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[boost::regex] Build static library with ICU support on windows
by Eko palypse 27 Feb '20

27 Feb '20

I'm confused about the different post I've found on the web therefore would appreciate if someone could answer if it is possible to build a static regex library with ICU support on windows? Thank you Eren

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Stieltjes polynomial
by N A 26 Feb '20

26 Feb '20

Hi, With regard to the article on Boost: Legendre-Stieltjes Polynomials - 1.66.0 | | | | Legendre-Stieltjes Polynomials - 1.66.0 | | | Can anyone help me to compute the stieltjes polynomials please? I'm coding in VBA and I'm looking for some recursive rules to calculate same. ThanksVick

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[GSoC] My piece of advice to students
by Mateusz Loskot 24 Feb '20

24 Feb '20

Dear Student, You are planning to participate in GSoC and develop some new features for the Boost libraries. Awesome! So, you want to introduce yourself to the community as soon as possible. Awesome! However, before posting your first question to the Boost mailing list, please, do read the official GSoC student guides [0]. All of it. [0] https://google.github.io/gsocguides/student/ I also recommend to read through other resources dedicated for students, especially this one from Google [1], one from a former student [2] as well as advice from Boost GSoC former student Louis Dionne [3]. [1] https://opensource.googleblog.com/2011/03/dos-and-donts-of-google-summer-of… [2] https://medium.com/@akshikawijesundara/google-summer-of-code-dos-and-do-not… [3] https://github.com/boostorg/wiki/wiki/Google-Summer-of-Code%3A-Advice-From-… Once you get through the general GSoC materials, it's a good idea to start browsing Boost resources, from intro [3] through netiquette [4] to wiki [5]. On [3] and [5] you will find links to past and current project ideas for Boost libraries. Browse it, read it, and learn what kind of projects Boost community develops during GSoC. Start thinking about what interests you, which Boost library, which project, what you'd like to develop as GSoC student. [4] https://www.boost.org/community/gsoc.html [5] https://www.boost.org/community/policy.html [6] https://github.com/boostorg/wiki/wiki Meanwhile, it's a good idea to "Make First Contact" [0]. Subscribe to the boost (developers) and boost-user or library-specific mailing list at https://lists.boost.org join Boost channels on Slack at https://cppalliance.org/slack/ and start discussing your participation, project ideas, etc. Although the student guides [0] use the phrase about "communicating directly with potential mentors", it does NOT mean exchanging private e-mails with mentors asking "Are you interested to mentor me?". GSoC does not work this way. In my opinion, the word "directly" means to interact directly with the community where, obviously, potential mentors are members too. The Boost organization and mentors will have chance to select students and projects they wish to mentor during the selection process - a secret, you can learn about it from GSoC guides for mentors [8]. Yes, the selection is a competitive process. [8] https://google.github.io/gsocguides/mentor/selecting-a-student Next, start discussing project of your interest, start asking questions, investigate ways to contribute to Boost, start working on competency tests Mind you, competency test is Boost way to verify minimum necessary skills. I personally think Boost should also ask for a bug fix [2] explains: "Some organizations make it a must for you to fix a bug in their code base before submitting a proposal but some do not. Your chances are always high if you can fix a bug in the code." Submitting a pull request with a small feature is also a good idea, something to discuss with mentors/maintainers of library of your interest Pull requests will allow you to gain hands-on experience with workflow of peer reviews, continuous communication, addressing problems, testing your solution, using the infrastructure, being exposed to stress of 'annoying' requests from maintainers to fix this, tweak that... :-) For example, it worked well for Boost.GIL (you can PRs at https://github.com/boostorg/gil) "you have to go early even if you go to hell" [2] GSoC IS hard work! Make sure to start early, to take a proactive stance, to do your homework before you start asking questions, to expect no babysitting. Imagine the GSoC runs back in times when there is no StackOverflow, no web archives, no web search,... There really is no excuse for not searching the web first nowadays. Even compilers can do that! https://arxiv.org/abs/1906.11456 "To grow in life, be willing to suffer" ~David Goggins Have a great time during GSoC and good luck! Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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[Boost.Python] C++/Python Hybrid App in 2020
by Andrew McFarlane 22 Feb '20

22 Feb '20

Hi all, I read on the Boost.Python FAQ that for Mac OSX users, the library is currently known only to work with the GCC compiler. Thus far, I have been using clang++. I will make the switch, so long that it does increase my odds of encountering difficulties down the road. What do we think here? In the context of front-end dev in Python for a C++ application, is Boost.Python worth making the switch from clang++ to gcc? Would I be better off using something else (i.e. wxPython)? I really love using Boost (I've found use for Test, Signals2, and Asio), but I don't want to let my Boost bias lead me to make a poor choice. I know this question is a tad subjective; I apologize for that. I would like the Python extension to be as seamless as possible, and I am only going to be using Python for front-end code. The interface between the two would likely be with sockets. I am sure I could answer this myself via experimentation, but I wanted to get a feel from the Boost community before doing so. Thanks in advance! *- AJ*

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Newbie Question Shared Memory Containers/Allocators
by Da Xu 14 Feb '20

14 Feb '20

Hi everybody, how are you? I am a completely noob when it comes to Boost. :D But not a noob when it comes to C++. Though, am a bit noobish when it comes to C++14 and beyond :D I am trying to construct a complex data container, which has a vector of floats, on managed shared memory. I followed the documentation, added the appropriate headers and made the following declarations: typedef managed_windows_shared_memory::segment_manager segment_manager_t; typedef allocator<void, segment_manager_t> void_allocator; typedef basic_string<char, std::char_traits<char>, char_allocator> shared_string; typedef allocator<float, segment_manager_t> float_allocator; typedef vector<float, float_allocator> float_vector; typedef allocator<float_vector, segment_manager_t> float_vector_allocator; class ComplexContainer {shared_string name;float_vector channelData; public:ComplexContainer(const char * name_, const float* data_start, const float* data_end, const void_allocator& void_alloc) : name(name_), channelData(data_start, data_end, void_alloc) {} ComplexContainer(const void_allocator& void_alloc) : name(void_alloc), channelData(void_alloc){} ComplexContainer() {} } but I am getting these errors at compile: 1>D:\Libraries\boost_1_72_0\boost\container\vector.hpp(310,23): error C2512: 'boost::interprocess::allocator<float,segment_manager_t>::allocator': no appropriate default constructor available1>D:\Libraries\boost_1_72_0\boost\container\vector.hpp(308): message : while compiling class template member function 'boost::container::vector_alloc_holder<boost::interprocess::allocator<float,segment_manager_t>,unsigned __int64,boost::move_detail::integral_constant<unsigned int,2>>::vector_alloc_holder(void) noexcept(false)'1>D:\Libraries\boost_1_72_0\boost\container\vector.hpp(832): message : see reference to function template instantiation 'boost::container::vector_alloc_holder<boost::interprocess::allocator<float,segment_manager_t>,unsigned __int64,boost::move_detail::integral_constant<unsigned int,2>>::vector_alloc_holder(void) noexcept(false)' being compiled1>D:\Libraries\boost_1_72_0\boost\container\vector.hpp(779): message : see reference to class template instantiation 'boost::container::vector_alloc_holder<boost::interprocess::allocator<float,segment_manager_t>,unsigned __int64,boost::move_detail::integral_constant<unsigned int,2>>' being compiled message : see reference to class template instantiation 'boost::container::vector<float,float_allocator,void>' being compiled That doesn't make a whole lot of sense, since it seems to be referring to the "float_allocator" typedef. But float is not an object, it has no constructor. Any help would be greatly appreciated! Thank you! Da.

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