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Boost Process continuously read output
by Surya Kiran Gullapalli 16 May '18

16 May '18

Hi, I'm trying to read outputs/logs from different processes and display them in a GUI. The processes will be running for long time and produce huge output. I'm planning to stream the output from those processes and display them according to my needs. All the while allow my gui application to take user inputs and perform other actions. What I've done here is, from main thread launch two threads for each process. One for launching the process and another for reading output from the process. This is the solution I've come up thus far. // Process Class class MyProcess { namespace bp = boost::process; boost::asio::io_service mService; // member variable of the class bp::ipstream mStream // member variable of the class std::thread mProcessThread, mReaderThread // member variables of the class. public void launch(); }; void MyProcess::launch() { mReaderThread = std::thread([&](){ std::string line; while(getline(mStream, line)) { std::cout << line << std::endl; } }); mProcessThread = std::thread([&]() { auto c = boost::child ("/path/of/executable", bp::std_out > mStream, mService); mService.run(); mStream.pipe().close(); } } // Main Gui class class MyGui { MyProcess process; void launchProcess(); } MyGui::launchProcess() { process.launch(); doSomethingElse(); } The program is working as expected so far. But I'm not sure if this is the correct solution. Please let me know if there's any alternative/better/correct solution Thanks, Surya

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how to add comments to boost property tree while export in xml file
by neelam baliyan 16 May '18

16 May '18

Hi All, I have read and store my complete configuration file in to boost property tree, now I want to export it to a xml file which i can do via function write_xml(). I wanted to add some comments inside my exported xml file. Please help me to know, how to add comments inside xml file while exporting data from boost property tree. Thanks & Regards Neelam

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Boost and Intellisense
by Leo Cacciari 16 May '18

16 May '18

Hi, I'm developing a windows application using boost libraries. Unfurtunately, some parameters of it are totally out of my control, nor I have the leverage needed to change it. Namely, - the application *must* use Visual C++ 9.0 runtime - the IDE to be used is capped at Visual Studio 2013 - to avoid problems with other related projects, the boost release should be 1.54.0 (here I have a modicum of liberty, as far as the previous two conditions are satisfied) I may live whit all of the above, however Intellisense has some glitches that are annoying me. For one, it appears unable to recognize the boost::asio::ip namespace. If I define a variable as, for instance boost::asio::ip::udp::endpoint ep; Intellisense marks 'ip' in red and keeps saying that ep is undefined (and consequently doesn't offer completion for its methods). I have tried including directly boost/asio/ip/udp.hpp and also putting an "using boost::asio::ip::udp" before the above definition as in #include <boost/asio/ip/udp.hpp> using boost::asio::ip::udp; udp::endpoint ep; but nothing changes (I'll gladly post a screenshot if I knew which is the accepted way to post images to this list). It should be noted that, aside from this and some analogous problems, Intellisense works fine, making the above even more annoying. Does anyone have a solution to this problem that do not violate the aforementioned constraints? Thanks in avance lc -- Leo Cacciari Aliae nationes servitutem pati possunt. Populi Romani est propria libertas.

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phoenix: BOOST_PHOENIX_NO_VARIADIC_EXPRESSION purpose
by MM 10 May '18

10 May '18

Hello (Thomas Heller, Joel de Guzman :-) ) In /usr/include/boost/phoenix/object/construct.hpp, there appears this preprocessor test on this macro BOOST_PHOENIX_NO_VARIADIC_EXPRESSION whereby the code either: 1. includes boost/phoenix/object/detail/cpp03/construct_expr.hpp , or 2. defines a expression inline Is that macro used to workaround some compiler limitations (and/or c++ std version) back in the day? I work with g++7 and std=c++14, and boost 1.64, and yet somehow boost/phoenix/object/detail/cpp03/construct_expr.hpp is included, and somewhere down the line a compilation error happens. The cpp03 is unnerving. Rds, MM

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Boost Graph Library(biconnected_components) issue
by Meghana.M Reddy 07 May '18

07 May '18

Hi, I am working on the Boost Graph Library, currently trying to create an interface of the biconnected_components method to a Python code. I used the example code available here <https://www.boost.org/doc/libs/1_67_0/libs/graph/example/biconnected_compon…> for the method and modified it for my purpose. The template of the method is here <https://www.boost.org/doc/libs/1_67_0/libs/graph/doc/biconnected_components…>. The final code seems fine but I get an error while compiling it. And the errors are related to adjacency.hpp which I have not changed so I'm confused as to what the exact problem is. Hoping someone can help me out. My code: class BoostGraph { private: typedef typename boost::adjacency_list< OutEdgeListS, VertexListS, DirectedS, boost::property<boost::vertex_index_t, v_index>, EdgeProperty, boost::no_property, EdgeListS> adjacency_list; typedef typename boost::property_map<adjacency_list, boost::edge_index_t>::type components; public: adjacency_list graph; std::vector<v_index> bc_tree() { components components_bc = get(boost::edge_index, graph); std::size_t num_comps = biconnected_components(graph, components_bc); std::cerr << "Found " << num_comps << " biconnected components.\n"; std::vector<vertex_descriptor> art_points; articulation_points(graph, std::back_inserter(art_points)); std::cerr << "Found " << art_points.size() << " articulation points.\n"; std::vector<v_index> to_return; return to_return; } The error I'm getting: build/cythonized/sage/graphs/base/boost_graph.cpp:3730:26: required from here /home/meghana/Documents/sage_gsoc/sage_may/sage/local/ include/boost/graph/detail/adjacency_list.hpp:2696:29: error: forming reference to void typedef value_type& reference; ^ /home/meghana/Documents/sage_gsoc/sage_may/sage/local/ include/boost/graph/detail/adjacency_list.hpp:2697:35: error: forming reference to void typedef const value_type& const_reference; ^ /home/meghana/Documents/sage_gsoc/sage_may/sage/local/ include/boost/graph/detail/adjacency_list.hpp:2701:61: error: forming reference to void typename Graph::vertex_descriptor,Property,Tag> type; ^ /home/meghana/Documents/sage_gsoc/sage_may/sage/local/ include/boost/graph/detail/adjacency_list.hpp:2704:68: error: forming reference to void typename Graph::vertex_descriptor,const Property, Tag> const_type; ^ error: command 'gcc' failed with exit status 1 Makefile:33: recipe for target 'sage' failed make: *** [sage] Error 1 Thank you, Meghana

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Installing pre-built binaries on Windows with Docker
by Matthew Berry 04 May '18

04 May '18

Hi, I tried installing pre-built 1.67 binaries from https://dl.bintray.com/boostorg/release/1.67.0/binaries/ in a Windows Server Docker container but am running into an issue where the installation does not complete. I ran the installer exe in silent mode. A lot of the files including headers are installed, but not the lib directory with the binaries. The Inno Setup log does not indicate an error, it just stops writing in the middle of the installation. Does anyone know why installation does not complete? Has anyone been able to install pre-built libraries in a Windows Docker container? Any help would be appreciated. Thanks, Matt

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Why is BOOST_OS_WINDOWS defined on Linux
by David Demelier 04 May '18

04 May '18

Hello, Everything is in the title, the following code compiles and shows "Windows" even though I'm running Fedora 28. I can't understand. #include <iostream> #include <boost/predef.h> int main() { #if defined(BOOST_OS_WINDOWS) puts("Windows"); #endif } I'm using Boost 1.66 with GCC 8.0.1. Regards, -- David

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Bi-Directional Links in call to Push-Relabel Max Flow (UNCLASSIFIED)
by Glover, Anthony E CTR USARMY RDECOM (US) 03 May '18

03 May '18

CLASSIFICATION: UNCLASSIFIED Hello, I am new to the Boost Graph library and had a question concerning the Push-Relabel Max Flow method. From the documentation, it states: The CapacityEdgeMap argument cap must map each edge in E to a positive number, and each edge in ET to 0. >From looking at the examples provided, it appears that an edge is added with some non-zero capacity and then the reverse edge is created with a capacity of 0 as the documentation states is needed. However, if I truly want a reverse edge with non-zero capacity, it appears that I have to create a second pair of edges going the other direction. I end up creating 4 total edges to handle the bi-directional flow capacity. Is that truly how the graph should be configured in order to use the method? Maybe I'm just not using it as designed. Thank You, Tony CLASSIFICATION: UNCLASSIFIED

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Veracode Scan
by Abhijit Dutta 03 May '18

03 May '18

Hi There, As part of release practice in our org., we have run Veracode (static) scan on our application which uses BOOST. We got good amount of error pointing to the BOOST libraries. Detecting the false positives and fixing the code will be a tedious task. So, want to know if anyone in the community has faced such situations and want to share their experience on resolving those. ~Thanx Abhijit

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help
by Radekkostra＠seznam.cz 30 Apr '18

30 Apr '18

hello, i am trying to build boost, but i have problems. First is in log(bootstrap.log - could not find "vswhere") and second is when compiling boost(this command :.\b2 --toolset=msvc link=shared,static address -model=64 --with-system --with-filesystem -j 4(5 failed,12skipped,79 updated).

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