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Extending boost graph edge class
by Rafael Gasperetti 03 May '16

03 May '16

Hi,My name is Rafael and I need to extend the edge class of de graph part of the boost lib, but I always find problems trying to do this. Can you help me with examples and explanations about how to do this?I read a lotação of places trying to do this but no help was found, please help me. Thanks a lot,Rafael

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[boost.multiprecision] print cpp_int with a thousands separator
by Tassilo Glander 03 May '16

03 May '16

Dear List, how can I control the thousands separator behavior when streaming a cpp_int to std::cout? I think it is not possible without changing the global locale, as cpp_int.str uses lexical_cast, which uses the global locale object to read the thousands separator character. This prevents me from having a custom formatting like below. Is there another way? Best, Tassilo #include <iostream> #include <locale> #include <iomanip> int main() { struct my_numpunct : std::numpunct<char> { protected : virtual char do_thousands_sep() const override { return '.' ; } virtual std::string do_grouping() const override { return "\03" ; } }; cpp_int testNum(1000); std::cout.imbue( std::locale( std::cout.getloc(), new my_numpunct ) ) ; std::cout << testNum << '\n' ; // still get 1000, desired is 1.000 }

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Multiprecision vector pass to function by reference
by Cooper, Bridgette R D 02 May '16

02 May '16

Hi, I am having some difficulties passing a vector of type std::vector<float128> to a function. I'm getting multiple errors out. The first few of which are: tql2.cpp:13:50: error: 'float128' was not declared in this scope void tql2(const int nm, int n, const std::vector<float128> & d, const std::vector<float128> & e, const std::vector< std::vector<float128> > & z, int ierr) ^ tql2.cpp:13:50: note: suggested alternative: In file included from tql2.cpp:1:0: /home/bcooper/Tarballs/boost_1_57_0/boost/multiprecision/float128.hpp:124:42: note: 'boost::multiprecision::float128' typedef number<float128_backend, et_off> float128; ^ tql2.cpp:13:58: error: template argument 1 is invalid void tql2(const int nm, int n, const std::vector<float128> & d, const std::vector<float128> & e, const std::vector< std::vector<float128> > & z, int ierr) ^ tql2.cpp:13:58: error: template argument 2 is invalid tql2.cpp:13:83: error: 'float128' was not declared in this scope void tql2(const int nm, int n, const std::vector<float128> & d, const std::vector<float128> & e, const std::vector< std::vector<float128> > & z, int ierr) ^ tql2.cpp:13:83: note: suggested alternative: In file included from tql2.cpp:1:0: /home/bcooper/Tarballs/boost_1_57_0/boost/multiprecision/float128.hpp:124:42: note: 'boost::multiprecision::float128' typedef number<float128_backend, et_off> float128; ^ The first few lines of my code are: #include <boost/multiprecision/float128.hpp> #include <boost/math/cstdfloat/cstdfloat_types.hpp> #include <boost/math/cstdfloat/cstdfloat_limits.hpp> #include <boost/math/cstdfloat/cstdfloat_cmath.hpp> #include <boost/math/cstdfloat/cstdfloat_iostream.hpp> extern "C"{ #include <quadmath.h> } #include <iostream> #include <vector> #include <iterator> void tql2(const int nm, int n, const std::vector<float128> & d, const std::vector<float128> & e, const std::vector< std::vector<float128> > & z, int ierr) { using namespace boost::multiprecision; ... } Not sure where I am going wrong? Any advice? Thanks,

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Re: [Boost-users] [boost.multiprecision] export_bits throws on a negative
by Tassilo Glander 02 May '16

02 May '16

Hi John, I opened tickets to track both issues: - Ticket #12170 (new Bugs) boost::multiprecision::export_bits throws on a negative cpp_int number - Ticket #12171 (new Feature Requests) boost::multiprecision should provide a hash function Best, Tassilo

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boost log facility multithreading issue
by David Frank 01 May '16

01 May '16

Greetings,I have 4 threads, in each thread, I created its own log file using boost log facility, different from the ones in other thread.The problem is that the log entries I put into one file in one thread, got into all other log files in other threads, though the boost log instances are not shared among threads. Anyone know how to avoid this? Thanks, David

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boost/multiprecision/float128
by Cooper, Bridgette R D 01 May '16

01 May '16

I'm new to boost. I am trying to use the float128 type for calculating sqrts as a larger part of code, however I am not sure the values obtained are accurate to float128 precision. I have tried running the example for printing log(2) found here, I find the same for sqrt: http://www.boost.org/doc/libs/1_57_0/libs/multiprecision/doc/html/boost_mul… However, the value printed log(2) only agrees to 16 decimal places, i.e. double precision. The value I obtain is 0.693147180559945286226763982995180413 rather than 0.693147180559945309417232121458176575 I'm using: g++ (GCC) 4.8.2 20140120 (Red Hat 4.8.2-15) with boost 1.57.0. Any advice as to what I am doing incorrectly? My compile line is: g++ -I ~/$BOOSTLIB new.cpp -lquadmath -o new Thanks,

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[utility] BOOST_IDENTITY_TYPE drops const-ness of value types
by Nick Stokes 29 Apr '16

29 Apr '16

Looks like const value types, once passed thru BOOST_IDENTITY_TYPE, "becomes" non-const. Like so: // Attempt to implement a multi-argument utility macro, where arguments are // types, parenthesized only when required (by the user, when type has commas) #define ASSERT_EQUAL( t1, t2 ) \ static_assert( std::is_same< \ BOOST_IDENTITY_TYPE((t1)), BOOST_IDENTITY_TYPE((t2)) \ >::value, #t1 " not same as " #t2) // sanity check: static_asserts as expected ASSERT_EQUAL( int, double ); // sanity check: static_assert as expected for types with commas ASSERT_EQUAL( (std::pair<int, double>), (std::pair<double, int>) ); // Here is the failure: this is expected to assert but it doesnt! ASSERT_EQUAL( const int, int ); >From the implementation of BOOST_IDENTITY_TYPE, it is clear why this is happening, as the function signature is independent of const-ness of value type. Is this a bug? Or is this not the way BOOST_IDENTITY_TYPE is supposed to be used? Nick

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linking and including in visual studio
by David Medine 29 Apr '16

29 Apr '16

This is kind of a stupid question, and maybe more of a Windows/Visual Studio question than a boost one, but this has been troubling the back of my mind lately. Having learned to write and compile C++ code on Linux, I am always in the habit of explicitly stating the include and library paths for the compiler to search for, as well as the libraries themselves that need to be linked. However, I am revising some Visual Studio projects that use boost and I realized that the path I gave for 'Additional Library Directories' is $(BOOST_ROOT)/lib, but my version of boost hasn't got this directory (it's actually $(BOOST_ROOT)\libs). I then removed all references to boost from 'Additional Library Directories', and 'Additional Include Directories' and the application builds and runs swimmingly. This leads me to believe, that assigning the BOOST_ROOT environment variable in Windows is the only step that is needed for VS's auto linking magic to link correctly to boost. Am I right here, or is there something I am missing? Cheers, David

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Date and Time with Boost
by Counter Wall 28 Apr '16

28 Apr '16

What I want to do is read a text file containing a text string in ISO 8601 combined date and time in utc format (e.g. 2016-04-26T12:45:05+00:00). I also want to have the freedom to convert this between time zones and have accurate daylight savings time data. Boost::datetime seems to read in the string, but it looks like boost::locale is recommended for time zone conversions and DLS. Is there a way for me to have both?

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Re: [Boost-users] [boost.multiprecision] export_bits throws on a negative number
by Tassilo Glander 28 Apr '16

28 Apr '16

Hi John, thanks for stepping in. I would expect that the export just exports the memory representation of the number - maybe with flipped order via msv_first parameter. Especially, something exported via export_bits and than imported via import_bits should be the same, at least on the same platform. That said, I actually was just looking for a way to implement a hash function and thought it was straightforward to use chunks of char. But I could also compute the hash on the str() output. Tassilo

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[boost.multiprecision] export_bits throws on a negative cpp_int number
by Tassilo Glander 28 Apr '16

28 Apr '16

Dear List, When calling export_bits on a negative boost::multiprecision number based on cpp_int, an exception is thrown from the internal method msb ("testing individual bits in negative values is not supported"). boost::multiprecision::checked_int128_t i (-1); // use negative number std::vector<unsigned char> v; export_bits(i, std::back_inserter(v), 8); // throws How can I extract the content of a boost::multiprecision number? Boost documentation says, export_bits is designed to be used for data exchange, so in my understanding it would be a major flaw, if it cannot export supported values. I learnt that a workaround might be to directly access the backend's limbs, but this way I am accessing internals that may change. http://www.boost.org/doc/libs/master/libs/multiprecision/doc/html/boost_mul… I also asked this on http://stackoverflow.com/questions/36890928/boostmultiprecisionexport-bits-…, but this list is probably the better place. Thanks, Tassilo

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[PBGL] compilation of example/dijkstra_shortest_paths.cpp failed
by Eisuke Kawashima 27 Apr '16

27 Apr '16

Dear all, I tried to compile http://www.boost.org/doc/libs/1_60_0/libs/graph_parallel/example/dijkstra_sh ortest_paths.cpp, an example code of Parallel Boost Graph, resulting in faulure; example/breadth_first_search.cpp has no problem. My environment is: * GCC 4.9.2 * OpenMPI 1.10.2 * boost 1.60.0 * OS: Debian jessie The error, related to template, is long; the summary is: $ mpicxx -std=c++11 -lboost_mpi -lboost_serialization -lboost_system - lboost_graph_parallel dijkstra_shortest_paths.cpp In file included from boost/graph/dijkstra_shortest_paths.hpp:25:0, from dijkstra_shortest_paths.cpp:19: boost/pending/relaxed_heap.hpp: In instantiation of ‘bool boost::relaxed_heap... boost/graph/distributed/crauser_et_al_shortest_paths.hpp:377:54: required from ... boost/graph/distributed/detail/remote_update_set.hpp:148:7: required from ... boost/graph/distributed/crauser_et_al_shortest_paths.hpp:264:37: required from ... boost/graph/breadth_first_search.hpp:76:7: required from ... boost/graph/breadth_first_search.hpp:124:69: required from ... boost/graph/breadth_first_search.hpp:135:64: [ skipping 4 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ] boost/graph/distributed/dijkstra_shortest_paths.hpp:146:50: required from ... boost/graph/distributed/dijkstra_shortest_paths.hpp:200:45: required from ... boost/graph/dijkstra_shortest_paths.hpp:573:16: required from ... boost/graph/dijkstra_shortest_paths.hpp:595:35: required from ... boost/graph/dijkstra_shortest_paths.hpp:614:14: required from ... dijkstra_shortest_paths.cpp:74:64: required from here boost/pending/relaxed_heap.hpp:194:70: error: cannot convert ‘const value_type {aka const boost::optional<boost::detail::parallel::global_descriptor<long unsigned int> >}’ to ‘bool’ in return bool contains(const value_type& x) const { return groups[get(id, x)]; } ^ "-ftemplate-backtrace-limit=0" flag did not work. How to fix this? -- Eisuke Kawashima

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[boost-users][boost graph] edge_descriptor problem when copy from original graph
by Emerson Xu 26 Apr '16

26 Apr '16

Hi all, I have a boost graph copy problem that has been nagging me for a long time. My question is, is there anyway that I can construct a graph once, and reuse it multiple times, each time I may mutate the graph a bit. I have a class, which creates a boost graph with bundled vertex and edge properties (my own properties, vertices are routers in a network, while edges are logical links between routers). When creating the graph, some helper unordered maps are also created, like mapping from an edge_descriptor to a logical link name, from a router name to a vertex_descriptor, etc. Now there are multiple clients calling some method in the class. Current strategy is to construct a new boost graph instance for every client, and run the service on each graph instance. Now I want to improve the performance by avoiding constructing the graph for every client ( >100 clients are calling it simultaneously). So I am thinking that we can initialize only one base graph, and make it a copy for every client. Then the problem comes, since in the method the client needs use those helper unordered maps, but the data inside the maps are from that original base graph. Even if I use a copy constructor(deep copy) for each graph copy, some graph data is still inconsistent, like the edge_descriptor, for example, I can't use the hashmap with edge_descriptor as key, because this edge_descriptor only points to the memory address of base graph. Best, Emerson

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error when copying blocks into a dynamic_bitset
by Diab Jerius 26 Apr '16

26 Apr '16

Hi, I'm trying to initialize a dynamic_bitset<unsigned char> from a vector of blocks. Here's the code: #include <cstdlib> #include <vector> #include <boost/dynamic_bitset.hpp> typedef boost::dynamic_bitset<unsigned char> BitSet; typedef std::vector<BitSet::block_type> Block; int main(int argc, char* argv[]) { int nbits = atoi( argv[1] ); BitSet bits( nbits ); Block buffer; buffer.resize( bits.num_blocks(), 0xff ); boost::from_block_range(buffer.begin(),buffer.end(), bits ); return 0; } If the bitset size isn't a multiple of sizeof(unsigned char) (here 8) , ~dynamic_bitset() throws an exception. For example: % ./a.out 1 a.out: boost-1.60.0/include/boost/dynamic_bitset/dynamic_bitset.hpp:633: boost::dynamic_bitset<Block, Allocator>::~dynamic_bitset() [with Block = unsigned char; Allocator = std::allocator<unsigned char>]: Assertion `m_check_invariants()' failed. Aborted % ./a.out 8 % ./a.out 15 a.out: boost-1.60.0/boost/dynamic_bitset/dynamic_bitset.hpp:633: boost::dynamic_bitset<Block, Allocator>::~dynamic_bitset() [with Block = unsigned char; Allocator = std::allocator<unsigned char>]: Assertion `m_check_invariants()' failed. Aborted % ./a.out 16 % I see this with 1.59 & 1.60 using either g++ 4.7.2 or Apple LLVM version 6.0 (clang-600.0.57) (based on LLVM 3.5svn) I believe that I'm following the rules for the buffer type and size. Is there something I'm missing? Thanks! Diab

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Compiler errors using boost/program_options with Boost v 1.53 and v 1.59
by Christine Peters 26 Apr '16

26 Apr '16

Dear all, I had to reinstall my boost version as the cluster environment I'm working on has switched from Scientific Linux 6 to CentOS 7. When I'm now compiling my code including the header "#include <boost/program_options>", I will receive the following error message: In file included from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/mpl/aux_/arithmetic_op.hpp:34:0, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/mpl/times.hpp:19, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/mpl/multiplies.hpp:17, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/numeric/conversion/detail/is_subranged.hpp:17, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/numeric/conversion/detail/conversion_traits.hpp:21, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/numeric/conversion/conversion_traits.hpp:13, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/numeric/conversion/converter.hpp:13, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/numeric/conversion/cast.hpp:33, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/lexical_cast/detail/converter_numeric.hpp:37, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/lexical_cast/try_lexical_convert.hpp:34, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/lexical_cast.hpp:32, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/program_options/value_semantic.hpp:14, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/program_options/options_description.hpp:13, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/program_options.hpp:15, from /home/cp652127/EclipseWorkspace/AMD-Geant4.10/amd/externals/g4sipm/sample/include/ParticleSourceMessenger.hh:24, from /home/cp652127/EclipseWorkspace/AMD-Geant4.10/amd/externals/g4sipm/sample/include/AsciiPersistencyHandler.hh:20, from /home/cp652127/EclipseWorkspace/AMD-Geant4.10/amd/externals/g4sipm/sample/include/RunAction.hh:16, from /home/cp652127/EclipseWorkspace/AMD-Geant4.10/amd/externals/g4sipm/sample/src/RunAction.cc:9: /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/mpl/aux_/include_preprocessed.hpp:37:90: fatal error: boost/mpl/aux_/preprocessed/gcc/ostimes.hpp: No such file or directory # include BOOST_PP_STRINGIZE(boost/mpl/aux_/preprocessed/AUX778076_PREPROCESSED_HEADER) ^ compilation terminated. This fatal error occurs with my own boost installation (version 1.59.0) but also with the system default boost (version 1.53.0). It worked properly on Scientific Linux 6. Now, I'm using gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-4), CPU codename Intel Nehalem EX, LINUX, CENTOS 7.2 environment. I would be very glad if someone could help me. It seems that somehow the AUX778076 parameter defined in "boost/1_59_0/include/boost/mpl/times.hpp" is converted to ostimes during the compilation: I've changed, just for testing reasons!, in file "/boost/1_59_0/include/boost/mpl/times.hpp" the line "#define AUX778076_OP_NAME times" to "#define AUX778076_OP_NAME timestest" and then boost is searching for the correct header "timestest.hpp" but in the case of "#define AUX778076_OP_NAME times" it is searching for "ostimes.hpp" instead of "times.hpp". Thanks in advance for your help! Cheers, Christine

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Typo in BGL Subgraph
by Eisuke Kawashima 23 Apr '16

23 Apr '16

Dear all, I submitted the following to boost-docs but have received no response, so also submitting to boost-users. The last part of Boost Graph Library: Subgraph <http://www.boost.org/doc/libs/release/libs/graph/doc/subgraph.html> (since Boost 1.40) > > struct my_vertex { ... }; > typedef property<vertex_index_t, std::size_t, vertex_prop> vertex_prop; > struct my_edge { ... }; > typedef property<edge_index_t, std::size_t, vertex_prop> edge_prop; should be > > struct my_vertex { ... }; > typedef property<vertex_index_t, std::size_t, my_vertex> vertex_prop; > struct my_edge { ... }; > typedef property<edge_index_t, std::size_t, my_edge> edge_prop; Additionally I want you to note how to modify GraphProperties of boost::subgraph (or whether it is not implemented). Regards, -- Eisuke Kawashima email: e.kawaschima(a)gmail.com

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[interprocess] posix_recursive_mutex constructor never called, fails to init mutex
by Adrian Cheater 23 Apr '16

23 Apr '16

This was submitted as a bug (https://svn.boost.org/trac/boost/ticket/12150) but I don't know that this is actually a boost bug, possibly a OSX or clang issue, or maybe I'm just doing something silly, so I'm hoping someone here can shed some light on the issue. I'm trying to use boost's shared memory system to get data from another application, but while it works fine on Ubuntu 15.10 with boost 1.58 and 1.60 on gcc, clang-3.6 and clang-3.7, it throws an exception when it attempts to acquire the mutex lock on OSX because the mutex has not been initialized. Placing a breakpoint in the constructor for the recursive_lock never gets hit, and I'm not sure why. Hopefully someone with more OSX experience can help me sort this out. Thanks very much for your time.

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Compiler does not give error for missing serialize function
by Elizabeta 22 Apr '16

22 Apr '16

Hi I have the following code : class MyClass { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive &ar, const unsigned int version) {} }; class MyClass2 : public MyClass {}; MyClass2* ss = new MyClass2; std::ofstream ofs("C:\\test.xml"); boost::archive::xml_oarchive oa(ofs); oa & boost::serialization::make_nvp("test",ss); I am serializing trough the derived class pointer. The derived class doesnot have serialize function. The Base have. And I was expecting compiler to give me error that MyClass2 doesnot have serialize function. But this code compiles without errors. I am using vs2010. -- View this message in context: http://boost.2283326.n4.nabble.com/Compiler-does-not-give-error-for-missing… Sent from the Boost - Users mailing list archive at Nabble.com.

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[gsoc16] Summer of Code 2016 shall proceed after all
by Niall Douglas 22 Apr '16

22 Apr '16

Dear Boost, We are very glad to announce that non-Google funding has been found to continue the Summer of Code for the following veteran student projects in Summer 2016: A. Boost Document, mentored by Antony Polukhin. Veteran student: Anurag Ghosh https://anuragxel.github.io/boost-document/ B. Boost.Compute, mentored by Kyle Lutz. Veteran student: Jakub Szuppe https://boostorg.github.io/compute/ C. Boost.Http, mentored by Bjorn Reese. Veteran student: Vinícius dos Santos Oliveira https://boostgsoc14.github.io/boost.http/ All three of these projects shall see a Summer of Code as if it were Google Summer of Code following the same timeline, mentor and student stipends, and progress acceptance criteria. Our thanks to the students and mentors for being so patient during the organisation of this funding. This all happened very quickly and much faster than Boost org processes normally happen - it would not have been possible without the efforts of Jon Kalb and Bryce Adelstein Lelbach, the latter of whom wrote up a great funding request worth reading at https://goo.gl/7v3VMK. Thanks are also due to the Boost Steering Committee for moving so quickly to vote on this, and to Boris Schäling for finding sponsorship for this effort. And finally congratulations to the veteran students! Niall and Bryce --- Boost C++ Libraries Google Summer of Code 2016 admin https://svn.boost.org/trac/boost/wiki/SoC2016

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measuring distance between a point and a segment
by Juliette Pera 22 Apr '16

22 Apr '16

Dear all, I am currently trying to use the boost library in order to measure the shortest distance between a point and a list of segments. I am declaring a segment to which I append the two points of my segment and the I calculate the distance from my point P to the segment. xsegment_t segment; geom::append(segment,geom::make_point(A[0],A[1])); geom::append(segment,geom::make_point(B[0],B[1])); double distance2 = geom::distance(segment,geom::make_point(P[0],P[1])); The issue is that I measure every time the same distance even if the segment is different. Does anyone knows from where that issue can come from? Thank you in advance, Juliette Pera

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[units] division with absolute temperature
by João Leal 19 Apr '16

19 Apr '16

Hello, I'm trying to use absolute temperature in some expressions. Unfortunately I'm having some issues with the compilation. For instance, if I divide an absolute temperature by itself I would expect to get 1 dimensionless, however that will cause a compilation error. #include <iostream> #include <boost/units/absolute.hpp> #include <boost/units/io.hpp> #include <boost/units/quantity.hpp> #include <boost/units/systems/si.hpp> #include <boost/units/systems/si/io.hpp> int main(int argc, char** argv) { using namespace boost::units; quantity<si::temperature> rT(273.15 * si::kelvin); // relative temperature quantity<si::dimensionless> v; v = rT / rT; std::cout << v << std::endl; // 1 dimensionless quantity<absolute<si::temperature> > aT(273.15 * absolute<si::temperature>()); // absolute temperature //v = aT / aT; // uncommenting this line will cause compilation errors //std::cout << v << std::endl; // 1 dimensionless return 0; } If I uncomment the line with v = aT / aT, in ubuntu 15.10 with boost 1.58 and gcc 5.2.1, I get the error: (...) /usr/include/boost/units/operators.hpp:81:5: error: no match for ‘operator/’ (operand types are ‘boost::units::absolute<boost::units::unit<boost::units::list<boost::units::dim<boost::units::temperature_base_dimension, boost::units::static_rational<1l> >, boost::units::dimensionless_type>, boost::units::homogeneous_system<boost::units::list<boost::units::si::meter_base_unit, boost::units::list<boost::units::scaled_base_unit<boost::units::cgs::gram_base_unit, boost::units::scale<10l, boost::units::static_rational<3l> > >, boost::units::list<boost::units::si::second_base_unit, boost::units::list<boost::units::si::ampere_base_unit, boost::units::list<boost::units::si::kelvin_base_unit, boost::units::list<boost::units::si::mole_base_unit, boost::units::list<boost::units::si::candela_base_unit, boost::units::list<boost::units::angle::radian_base_unit, boost::units::list<boost::units::angle::steradian_base_unit, boost::units::dimensionless_type> > > > > > > > > > > >’ and ‘boost::units::absolute<boost::units::unit<boost::units::list<boost::units::dim<boost::units::temperature_base_dimension, boost::units::static_rational<1l> >, boost::units::dimensionless_type>, boost::units::homogeneous_system<boost::units::list<boost::units::si::meter_base_unit, boost::units::list<boost::units::scaled_base_unit<boost::units::cgs::gram_base_unit, boost::units::scale<10l, boost::units::static_rational<3l> > >, boost::units::list<boost::units::si::second_base_unit, boost::units::list<boost::units::si::ampere_base_unit, boost::units::list<boost::units::si::kelvin_base_unit, boost::units::list<boost::units::si::mole_base_unit, boost::units::list<boost::units::si::candela_base_unit, boost::units::list<boost::units::angle::radian_base_unit, boost::units::list<boost::units::angle::steradian_base_unit, boost::units::dimensionless_type> > > > > > > > > > > >’) BOOST_TYPEOF_NESTED_TYPEDEF_TPL(nested, (typeof_::make<X>()/typeof_::make<Y>())) (...) I could add something like namespace boost { namespace units { template<class Unit, class X, class Y> struct divide_typeof_helper<quantity<absolute<Unit>, X>, quantity<absolute<Unit>, Y> > { typedef typename divide_typeof_helper<X, Y>::type value_type; typedef typename divide_typeof_helper<Unit, Unit>::type unit_type; typedef quantity <unit_type, value_type> type; }; } } but that would not work in more complex examples, e.g.: #include <boost/units/systems/si/codata/physico-chemical_constants.hpp> (...) using namespace boost::units::si::constants::codata; typedef boost::mpl::divides<boost::units::energy_dimension, boost::units::amount_dimension>::type Ea_dimension; typedef boost::units::unit<Ea_dimension, boost::units::si::system> Ea; quantity<Ea> ea(0); auto x = ea / (R * aT); Any help would be most appreciated, João Leal

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Boost statechart, how can i transit to previous state using deep_history or shallow history
by juls 16 Apr '16

16 Apr '16

I have a difficulty in understanding the boost statechart history functionality. I have the following state machine. struct InButtonPressed : sc::event<InButtonPressed> {}; struct OutButtonPressed : sc::event<OutButtonPressed> {}; struct InButtonPressed : sc::event<InButtonPressed> {}; struct InputProceed: sc::event<InputProceed> {}; struct OutputProceed: sc::event<OutputProceed> {}; struct CancelEvent: sc::event<CancelEvent> {}; struct Proceed: sc::event<Proceed> {}; struct Revert: sc::event<InputProceed> {}; struct RH_StateMachine : bsc::state_machine< RH_StateMachine, Idle > {}; struct Idle : bsc::state< Idle, RH_StateMachine> { Idle(my_context ctx) : my_base(ctx){ std::cout << "[+] Idle" << std::endl; } ~Idle(){std::cout << "[-] leaving Idle state... \n";} typedef boost::mpl::list< bsc::transition< InButtonPressed, Input>, bsc::transition< OutButtonPressed, Output> >reactions; }; struct Input : bsc::state< Input, RH_StateMachine> { Input(my_context ctx) : my_base(ctx){ std::cout << "[+] Input" << std::endl; } ~Input(){std::cout << "[-] leaving Input state... \n";} typedef boost::bsc::transition< CancelEvent, Cancel> >reactions; }; struct Output : bsc::state< Output, RH_StateMachine> { Output(my_context ctx) : my_base(ctx){ std::cout << "[+] Output" << std::endl; } ~Output(){std::cout << "[-] leaving Output state... \n";} typedef boost::bsc::transition< CancelEvent, Cancel> >reactions; }; struct Cancel::bsc::state<Cancel, RH_StateMAchine>{ Cancel(my_context ctx) : my_base(ctx){ std::cout << "[+] Cancel" << std::endl; } ~Cancel(){std::cout << "[-] leaving Cancel state... \n";} typedef boost::mpl::list< bsc::transition< Proceed, CanceledConfirmed>, bsc::transition< Revert, *"PREVIOUS_STATE"*> >reactions; }; How do i implement transitioning to previous state using deep_history or shallow history, when i can transit to a state from many different states? In the above state machine i want to transit from Cancel state to the previous state when the revert event is triggered, but i have already transited in Cancel state from either Input or Output state... Thank you in advance. -- View this message in context: http://boost.2283326.n4.nabble.com/Boost-statechart-how-can-i-transit-to-pr… Sent from the Boost - Users mailing list archive at Nabble.com.

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option to let program_options remove the flags it recognises
by Brice Rebsamen 14 Apr '16

14 Apr '16

I believe it would be good to add an option to program_options to tell it to remove the flags it recognizes. That would allow to make it work with some other parsers such as gflags etc.

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[property_tree] Json parser with invalid JSON string
by Sébastien Gallou 13 Apr '16

13 Apr '16

Hi all, I experience a strange behavior of parsing non-JSON data with JSON parser. I can create a property_tree from a simple non-JSON string, without exception. And serializing back the result throws : boost::property_tree::ptree m_tree; // Non-JSON to ptree using JSON parser std::istringstream is("1"); // Simple value, non-JSON boost::property_tree::json_parser::read_json(is, m_tree); // ==> No exception, I now have a valid ptree object. // ptree back to JSON std::ostringstream buf; boost::property_tree::json_parser::write_json(buf, m_tree, false); // ==> Exception How can I filter input values that will not be serializable later (= verify that input value is well JSON formatted) ? Thanks for your help, S. Gallou

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boost with c++11
by Christian Meesters 13 Apr '16

13 Apr '16

Dear All, Perhaps my question has been covered already, in this case a pointer to the relevant docs / thread would be highly appreciated. However, I have not been able to find the answer on my question: My code makes use of the C++11 standard and the standard libraries. I feel tempted to employ more current features, also beyond C++11, eventually. When downloading the boost 1.60.0 release and compiling with cxxflags='-std=c++11 -march=native' toolset=gcc linkflags=-stdlib=libc++ supplied to b2 compilation of my software (with gcc 5.3.0) leads to a number of warning messages and deprecation messages related to unused variables or redifined symbols, e.g.: - boost_1_60_0/include/boost/system/error_code.hpp:223:36: warning: ‘boost::system::native_ecat’ defined but not used [-Wunused-variable] static const error_category & native_ecat = system_category(); - /boost_1_60_0/include/boost/iostreams/chain.hpp:256:14: warning: ‘template<class> class std::auto_ptr’ is deprecated [-Wdeprecated-declarations] std::auto_ptr<streambuf_t> In file included from /cluster/gcc/5.3.0/include/c++/5.3.0/memory:81:0, from trunk/src/ngs_io.cpp:8: /cluster/gcc/5.3.0/include/c++/5.3.0/bits/unique_ptr.h:49:28: note: declared here template<typename> class auto_ptr; - /usr/include/boost/iostreams/detail/adapter/concept_adapter.hpp:35:7: note: ‘boost::iostreams::detail::concept_adapter<boost::iostreams::basic_gzip_decompressor<> >::concept_adapter(const boost::iostreams::detail::concept_adapter<boost::iostreams::basic_gzip_decompressor<> >&)’ is implicitly deleted because the default definition would be ill-formed: class concept_adapter { ^ etc. And most importantly this error: /usr/include/boost/iostreams/detail/adapter/concept_adapter.hpp:35:7: error: use of deleted function ‘boost::iostreams::basic_gzip_decompressor<>::basic_gzip_decompressor(const boost::iostreams::basic_gzip_decompressor<>&)’ My g++ compiler flags (other than output and source file) are: -c -fopenmp -O3 -march=native -Wall -ansi -pedantic -Wuninitialized -std=c++11 The code compiles fine with a git pull from May last year, yet I do not recall what I have done differently. So, can anybody tell me how to set up boost, such that compilation and linking against C++11 std-libraries works? I understand that Best regards, Christian Meesters

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