November 2012 - Boost-users - lists.preview.boost.org

[interprocess] Determine size of managed_shared_memory
by Kai Benndorf 12 Oct '19

12 Oct '19

Hi all, I want to create a managed_shared_memory in exactly the size I needed. Therefore I do something like this: size = sizeof( common_managed_shared_memory ); size += sizeof( MyClassInSharedMem ); managed_shared_memory segment(create_only, "name", size ); MyClassInSharedMem allocates itself some memory by segment->allocate(). I added this also to the size, but get a boost::interprocess::bad_alloc exception on allocating this additional memory. Are there some magic bytes I forgot to add? Many thanks in advance Kai

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[statechart] Passing parameters from event to State Local Storage
by Christophe Bourez 16 Nov '16

16 Nov '16

I need to maintain a parameter into the state local storage. This parameter is initially contained in the event that causes the transition to the target state. I give hereafter a small illustrative example. typename sc = boost::statechart; class EvTest : public sc::event<EvTest> { public: EvTest(std::size_t val) : value(val) {} std::size_t getValue() const { return this->value; } private: std::size_t value; }; class MyStateMachine; class StSource; class StTarget; class StSource : public sc::simple_state<StSource, MyStateMachine> { public: typedef sc::custom_reaction<EvTest> reactions; sc::result react(const EvTest &event) { // How to pass event.getValue() to the target state ? transit<StTarget>(); } }; class StTarget : public sc::simple_state<StTarget, MyStateMachine> { public: StTarget(std::size_t val) : val(value) {} private: std::size_t value; }; Thanks, Christophe

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Statechart serialization
by mbrodeur65 04 Mar '15

04 Mar '15

Hi, I'm looking for a solution to serialize boost::statechart objects. I'm aware that this feature is on the statechart library todo list but was wondering if there are any workaround to achieve this with the latest boost release (1.34) ? thanks for your help ! mbrodeur65 -- View this message in context: http://www.nabble.com/Statechart-serialization-tf4131326.html#a11749139 Sent from the Boost - Users mailing list archive at Nabble.com.

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[Thread] Read-write locks
by lfrfly＠icqmail.com 18 Sep '14

18 Sep '14

I'm trying to create a standard read/write lock using Boost Threads, and I'm having a bit of difficulty mapping the Boost concepts onto the usual ones. A read/write lock should have several states: Locked for reading (multiple threads may lock at once), locked for writing (only one thread may lock, and no threads may be locked for reading at the same time), and unlocked. Ideally it would be nice if an RWL which is locked for reading may temporarily upgrade to locked for writing, then return to the locked for reading state. Boost supports several relevant notions of locking: shared locking, upgrade locking, and exclusive locking. This to me is a confusing distinction. In particular, a shared_mutex seems appropriate as the basis for a RWL, but is lock_upgrade() the equivalent of a write lock and lock_shared the equivalent of a read lock? This is unclear. If "upgrade locking" is not the same as "exclusive locking", then is an upgrade lock actually exclusive? Could someone please clarify this.

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[Statechart] How to decide between post_event and process_event atrun time ?
by Philippe DAVID 22 Jul '14

22 Jul '14

Hi, I have a method in which I want to post/process an event. The thing is, this method can be called from outside the state machine (so I need to call process_event), or indirectly by a reaction of the state machine (in this case I must call post_event since process_event is not reentrant). I don't want to write 2 distinct methods to do this (one that calls post, and the other process), I would much rather prefer adding a 'if' in my method that tells me if I have to call process_event or post_event (if I'm being called indirectly by the state machine or not). Is there a way to do this with statechart ? regards, Philippe

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[asio] resolver::cancel() problem
by Matthew Edwards 14 Mar '14

14 Mar '14

In my application (and a separate test program) it seems as though the cancel() function on the resolver does not work as intended. For async resolves, the cancel functionality should abort them immediately and pass an 'operation aborted' error code to the callback handler. In my tests, I will resolve an invalid domain (this causes the resolve to take a few seconds, to demonstrate the problem), sleep for 100ms, then call cancel on the resolver object. No cancelling actually occurs, and the callback is simply triggered after a few seconds with a "No host found" error code, not the expected operation aborted. Has anyone experienced this before, or know how I might be using the resolver incorrectly?

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[boost.test] How to register custom exception for auto test?
by Jörg Becker 13 Jan '14

13 Jan '14

Hi, I'm using the test library of boost 1.49.0 for my unit tests. It works fine so fare, but if my program throws an error, I get the default error message unknown location(0): fatal error in "excption1_test": unknown type, witch hides the original error message. I tried to register an error translator, but without success. Here is what I tried (modified test/test/custom_exception_test.cpp to use auto test with global fixture): #define BOOST_TEST_MODULE "boost test custom_exception_test" #include <boost/test/unit_test.hpp> #include <boost/test/unit_test_monitor.hpp> using namespace boost::unit_test; BOOST_AUTO_TEST_SUITE( custom_exception_testsuite ) struct my_exception1 { explicit my_exception1( int res_code ) : m_res_code( res_code ) {} int m_res_code; }; void throw_my_exception1() { throw my_exception1( 12 ); } void my_exception1_translator( my_exception1 ) { BOOST_TEST_MESSAGE( "Caught my_exception1" ); } class my_config { public: my_config () { unit_test_monitor.register_exception_translator<my_exception1>( &my_exception1_translator ); } }; BOOST_GLOBAL_FIXTURE( my_config ) BOOST_AUTO_TEST_CASE( excption1_test ) { throw_my_exception1(); } BOOST_AUTO_TEST_SUITE_END() Can anybody tell me what I'm missing? Thanks, Jörg

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using boost with net-snmp
by moshe levi 12 Sep '13

12 Sep '13

I wrote an example on how to integrate net-snmp with boost. please checkout http://blog-moshe.blogspot.co.il/

2 1

[BGL] Having a cost function as weight map
by Maxime van Noppen 06 Sep '13

06 Sep '13

Hi, I can't find how to do this pretty basic thing : having a function instead of a field to compute the cost of edges for various path finding algorithms. I couldn't find the answer in the documentation and Google was of no help. Did I miss something obvious ? Example : ------------------- #include <boost/graph/dijkstra_shortest_paths.hpp> #include <boost/graph/graph_traits.hpp> #include <boost/graph/adjacency_list.hpp> struct my_edge { double cost() const { return cost_ * 2; } double cost_; }; struct my_node { }; int main() { typedef boost::adjacency_list< boost::vecS, boost::vecS, boost::directedS, my_node, my_edge > graph_t; typedef boost::graph_traits<graph_t>::vertex_descriptor vertex_t; graph_t graph; vertex_t v /*= ... */; using boost::weight_map; // Works : boost::dijkstra_shortest_paths(graph, v, weight_map(boost::get(&my_edge::cost_, graph))); // Doesn't compile : //boost::dijkstra_shortest_paths(graph, v, // weight_map(boost::get(&my_edge::cost, graph))); } ------------------- Thanks ! -- Maxime

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Identify cycles in a undirected graph
by NsPx 20 Aug '13

20 Aug '13

Hi all, I use undirected_dfs to detect all cycles in a undirected graph. I detect a cycle with DFSVisitor.back_edge(e,g) but how can I get the list of vertices defining this cycle ? Thanks by advance

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Is boost::this_thread::sleep_for interruption point?
by Serg Gulko 23 May '13

23 May '13

Hello! According to documentation(v 1.50.0) call boost::this_thread::sleep_for can be interrupted. For some reason this functionality not works for me. Here is code sample: //Simple thread function void Test::worker(int delay) { try { boost::this_thread::sleep_for(boost::chrono::milliseconds(delay)); cout << "Doing some work" << endl; } catch (boost::thread_interrupted const& e) { cout << "INTERRUPTED" << endl; } } //Far in the code boost::thread workerThread(boost::bind(&Test::worker, this, 1200)); boost::this_thread::sleep(boost::posix_time::milliseconds(30)); workerThread.interrupt(); boost::this_thread::sleep(boost::posix_time::milliseconds(1500)); I always getting 'Doing some work'... -- View this message in context: http://boost.2283326.n4.nabble.com/Is-boost-this-thread-sleep-for-interrupt… Sent from the Boost - Users mailing list archive at Nabble.com.

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Re: [Boost-users] [CMake] [boost][b2] Differenciate 32bit and 64 bit binaries when using CMake.
by Klaim - Joël Lamotte 16 Apr '13

16 Apr '13

Júlio Hoffimann said: > > I don't know if i understood correctly, but you can set the library > directory by hand, please refer to > /usr/share/cmake-<version>/Modules/FindBoost.cmake, in particular the > variable BOOST_LIBRARYDIR. On Thu, Oct 11, 2012 at 1:29 PM, Miller, Frank <FMiller(a)sjm.com> wrote: > A simple solution would be to install only the 64bit version of boost > into a new directory and change the environment variable to point there. > Then FindBoost will only be able to see the version you want. > Thanks, this will solve my immediate problem, but it don't solve it in general. (I will use it though, so thanks) I can't guarantee where the boost libraries are installed, that's why I use FindBoost. My current understanding is that boost don't have a specific default lib dir for different address models, which is the source of the problem as FindBoost script can't rely on a protocol to find these lib files. Am I correct? Joel Lamotte

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can't get first example in boost tutorial to work
by 7stud 11 Mar '13

11 Mar '13

I'm trying to install boost on mac osx 10.4.7. I followed the tutorial "Getting Started on Unix Variants" found here: http://www.boost.org/doc/libs/1_35_0/ more/getting_started/unix-variants.html Following the instructions in the tutorial, I installed boost in /usr/local as instructed, so my directory structure is: /usr/local/boost_1_34_1/boost But when I run the first example in the tutorial: #include <boost/lambda/lambda.hpp> #include <iostream> #include <iterator> #include <algorithm> int main() { using namespace boost::lambda; typedef std::istream_iterator<int> in; std::for_each(in(std::cin), in(), std::cout << (_1 * 3) << " " ); } I get the error(among others): error: boost/lambda/lambda.hpp: No such file or directory If I change the include path to: #include </user/local/boost_1_34_1/boost/lambda/lambda.hpp> I get the error(among others): error: boost/lambda/core.hpp: No such file or directory But core.hpp is in the lambda directory: /usr/local/boost_1_34_1/boost/lambda$ ls algorithm.hpp control_structures.hpp lambda.hpp bind.hpp core.hpp loops.hpp casts.hpp detail numeric.hpp closures.hpp exceptions.hpp switch.hpp construct.hpp if.hpp I'm using the Xcode 2.4 IDE to run my C++ programs. I also tried to execute the program from the command line with the original include path: #include <boost/lambda/lambda.hpp> but I get the same error: ~/2testing/dir1$ g++ prog1.cpp prog1.cpp:1:35: error: boost/lambda/lambda.hpp: No such file or directory prog1.cpp: In function 'int main()': prog1.cpp:8: error: 'boost' has not been declared prog1.cpp:8: error: expected namespace-name before ';' token prog1.cpp:8: error: '<type error>' is not a namespace prog1.cpp:11: error: '_1' was not declared in this scope I get the same errors again with the full include path: #include </user/local/boost_1_34_1/boost/lambda/lambda.hpp> $ g++ prog1.cpp In file included from prog1.cpp:1: /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:14:33: error: boost/lambda/core.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:21:52: error: boost/lambda/detail/operator_actions.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:22:61: error: boost/lambda/detail/operator_lambda_func_base.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:23:63: error: boost/lambda/detail/operator_return_type_traits.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:26:45: error: boost/lambda/detail/operators.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:30:46: error: boost/lambda/detail/member_ptr.hpp: No such file or directory prog1.cpp: In function 'int main()': prog1.cpp:8: error: 'boost' has not been declared prog1.cpp:8: error: expected namespace-name before ';' token prog1.cpp:8: error: '<type error>' is not a namespace prog1.cpp:11: error: '_1' was not declared in this scope What path should I be using? Or, should I set an environment variable somewhere?

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chaining functions input output
by MM 19 Feb '13

19 Feb '13

Hello, i have these 2 functions provided to me and I wonder whether they can somehow be chained without using intermediary memory? http://codepad.org/tTwkUQhp Rds, MM

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[Program Options] terminate parsing after first positional argument
by Stuart Pook 22 Jan '13

22 Jan '13

Hello, How can I tell Boost Program Options to stop parsing the arguments as soon as it finds a positional argument? I'd like to be able to parse the argument list "-v chmod -R -v 600 foo" as having one argument for my program (-v) and the rest as a std::vector of std::string (including the -v). In the attached program I have tried 2 different approaches. The first uses multitoken with the arguments "--command date -u -v", it fails because "-u" isn't known. The second uses collect_unrecognized with "chmod -R -v 600", it doesn't work because -v is interpreted by boost and doesn't end up in the vector. As someone said back in 2005, perhaps I'm trying to write xargs: http://thread.gmane.org/gmane.comp.lib.boost.user/9529/focus=9641 I know that I can ask my users to write a.out -v -- chmod -R -v 600 foo but I don't want to do that. I want them to write "a.out -v chmod -R -v 600 foo". The first positional argument should should tell boost to stop processing. Another slightly different question. If I have a multitoken option that takes doubles how can I get it to accept negative values? If I give my program "--floats 1 8 -4 6" where --floats starts a multitoken option that accepts double, I get an exception saying that "-4" is an unknown option. thanks Stuart This is what my test program gives me with boost 1.50: argv: dd --command date -u -v unrecognised option '-u' Allowed options: -v [ --verbose ] verbose --command arg command to run 2nd try argv: dd chmod -R -v 600 I'm verbose v: chmod -R 600 3rd try argv: dd --floats 1 8 -4 6 unrecognised option '-4' Allowed options: -v [ --verbose ] verbose -f [ --floats ] arg numbers and my program (formatted to fit in 80 characters) #include <boost/program_options.hpp> #include <boost/range/algorithm.hpp> #include <boost/program_options/parsers.hpp> #include <boost/program_options/options_description.hpp> #include <iostream> namespace po = boost::program_options; #define nelements(a) (sizeof (a) / sizeof (a)[0]) void print(char const * * b, char const * * e) { std::cout << "argv: "; std::copy(b, e, std::ostream_iterator<char const *>(std::cout, " ")); std::cout << std::endl; } int main(int argc, char ** argv) { { bool verbose; std::vector<std::string> command; po::options_description desc("Allowed options"); desc.add_options() ("verbose,v", po::bool_switch(&verbose)->default_value(false), "verbose") ("command", po::value<std::vector<std::string> >(&command) ->multitoken(), "command to run") ; char const * args[] = { "dd", "--command", "date", "-u", "-v", 0 }; print(args, args + nelements(args) - 1); po::variables_map vm; try { po::store(po::command_line_parser(nelements(args) - 1, args) .options(desc).run(), vm); po::notify(vm); if (verbose) std::cout << "I'm verbose\n"; std::cout << "command: "; boost::copy(command, std::ostream_iterator<std::string>(std::cout, " ")); std::cout << std::endl; } catch (boost::program_options::unknown_option & x) { std::cerr << x.what() << "\n" << desc << "\n"; } } std::cout << "2nd try\n"; { bool verbose; po::options_description desc("Allowed options"); desc.add_options() ("verbose,v", po::bool_switch(&verbose)->default_value(false), "verbose") ; char const * args[] = { "dd", "chmod", "-R", "-v", "600", 0 }; print(args, args + nelements(args) - 1); po::variables_map vm; po::parsed_options parsed = po::command_line_parser(nelements(args) - 1, args). options(desc).allow_unregistered().run(); try { po::store(parsed, vm); } catch (boost::program_options::unknown_option & x) { std::cerr << x.what() << "\n" << desc << "\n"; exit(2); } po::notify(vm); if (verbose) std::cout << "I'm verbose\n"; std::cout << "v: "; std::vector<std::string> v = po::collect_unrecognized( parsed.options, po::include_positional); boost::copy(v, std::ostream_iterator<std::string>(std::cout, " ")); std::cout << std::endl; } std::cout << "3rd try\n"; { bool verbose; std::vector<double> f; po::options_description all("Allowed options"); all.add_options() ("verbose,v", po::bool_switch(&verbose)->default_value(false), "verbose") ("floats,f", po::value<std::vector<double> >(&f)->multitoken(), "numbers") ; char const * args[] = { "dd", "--floats", "1", "8", "-4", "6", 0 }; print(args, args + nelements(args) - 1); po::variables_map vm; try { po::store(po::command_line_parser(nelements(args) - 1, args) .options(all).run(), vm); po::notify(vm); if (verbose) std::cout << "I'm verbose\n"; std::cout << "floats: "; boost::copy(f, std::ostream_iterator<double>(std::cout, " ")); std::cout << std::endl; } catch (boost::program_options::unknown_option & x) { std::cerr << x.what() << "\n" << all << "\n"; } } }

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Manually cleaning up TSS data in boost 1.49
by Andrew Harvey 08 Dec '12

08 Dec '12

Hi, I am using boost::thread for a plug-in that is loaded by a third-party Linux application. I have no control over the host's threading or when it chooses to unload my code. Unfortunately I experience a crash every time the host thread unloads the .so and terminates. I get the following backtrace: (gdb) bt #0 0x00007fffde12c460 in ?? () #1 0x00000032cf607889 in start_thread () from /lib64/libpthread.so.0 #2 0x00000032cf2e5ccd in clone () from /lib64/libc.so.6 Not much to go on... I am pretty confident the crash is happening in a pthread key destructor registered by Boost. The only parts of the boost::thread library I am currently using are the synchronization classes: shared_mutex, shared_lock, unique_lock, upgrade_lock, upgrade_to_unique_lock I'm not directly using any thread-specific storage myself. What I would like to do is force boost to call its TSS destructor in my plug-in's destroy_dso() function. Is this at all possible? Many thanks, - Andrew

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Boost::Asio read_until and streambuf usage
by Gonzalo Garramuno 06 Dec '12

06 Dec '12

I have a server that sends three lines, each of which have to be parsed independently. I am using read_until but have a problem with its usage. When read_until reads once, the streambuf seems to contain the three lines but not in the istream and only when I call read_until several times, I get the lines. I am wondering how can I safely read_until the buffer is empty (the 3 or more lines are read) and then exit the loop. boost::asio::streambuf buf; while( 1 ) { size_t reply_length = boost::asio::read_until( socket_, buf, '\n' ); std::istream is(&buf); std::string reply; std::getline(is, reply); // only 1 line obtained }

3 4

Asio and software interrupts
by Joseph Sulewski 03 Dec '12

03 Dec '12

Hello, I’m use the Boost::Asio libraries to read data from multicast sockets. This is a high rate application that needs to listen to data coming on a large number of multicast addresses (up to 500 different addresses). I would like to funnel all the multicast traffic to a single class where the data can get handled very quickly. I have the code working now using the socket->async_receive_from() method but the system is getting bogged down handling a large number of software interrupts. 51% of the CPU time is spent handling software interrupts. I create each multicast socket (up to 500 of them) like so: socket = new udp::socket(io_service); socket->open(listenEndPoint.protocol()); socket->set_option(boost::asio::ip::udp::socket::resuse_address(true)); socket->bind(listenEndPoint); socket->set_option(boost::asio::ip::multicast::join_group(multicastAddress.to_v4())); Slightly after that I register for data like so: socket->async_receive_from(buffer,senderEndPoint,boost::bind(&EthernetCapture::receiveData,this,boost::asio::placeholders::bytes_transferred)); Is there a more efficient way to receive multicast data without incurring so many software interrupts? By the way this is for an application to run on 32 bit Linux for an embedded application. Thanks

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[Who's using boost?] Algocoders : books on c++11, Boost and Beyond
by Algocoders . 03 Dec '12

03 Dec '12

Algocoders <http://www.algocoders.com> Algocoders has been using boost since last 6+ years with a mission to help people build a better software eco-system by standing on the shoulder of giants. If it wasn't not for boost, then it could have been really difficult for us to build our framework based on sound mathematical foundation of computer science using modern C++. It is the pioneering efforts at boost towards "Using and Extending C++11, Boost and Beyond" which has motivated us to devote ourself in developing bullet-size capsules in the form of tiny booklets with industrial-set framework to lift the thin veil with initial focus on practical usage of C++11 vis-a-vis mathematical foundation behind it. Web Page : http://www.algocoders.com Enthused by boost, we are working tirelessly towards *publishing a series of books(or booklets) which will bridge the gap between esoteric and street-side ones. Initial focus will be on C++11, Boost, Loki, STL, Algorithms, Data Structures, Multi-threading, Design Patterns, gcc, clang, valgrind.* *First book in this series is :*(will be available by end of November 2012) *Foundation of Algorithms in C++11, Volume 1* Using and Extending C++11, Boost and BeyondList of books(in progress): - *C++11 Algorithms : *Using and Extending C++11, Boost and Beyond - *Smart Pointers** : Tips and Techniques in C++ :* Using and Extending C++11, Boost and Beyond - *C++11 FAQs :* Using and Extending C++11, Boost and Beyond - *Concepts & Traits C++ **:* Using and Extending C++11, Boost and Beyond and so on. We use almost all the libraries under boost including trunk and branches, especially Spirit, Phoenix, Proto, MPL, Fusion to mention a few. Thanks, Algocoders www.algocoders.com

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boost managed shared memory: RUN FAILED
by Olivier Austina 03 Dec '12

03 Dec '12

Hello, I try to run an example from this online book( http://en.highscore.de/cpp/boost/interprocesscommunication.html) and I got "RUN FAILED (exit value 1, total time: 938ms) ". I am using Netbeans. This is the example: #include <boost/interprocess/managed_shared_memory.hpp> #include <iostream> int main() { boost::interprocess::shared_memory_object::remove("Highscore"); boost::interprocess::managed_shared_memory managed_shm(boost::interprocess::open_or_create, "Highscore", 1024); int *i = managed_shm.construct<int>("Integer")(99); std::cout << *i << std::endl; std::pair<int*, std::size_t> p = managed_shm.find<int>("Integer"); if (p.first) std::cout << *p.first << std::endl; } Thanks very much. -- Regards Austina

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Serialization newbie, memory being overwritten?
by Lasse Laursen 03 Dec '12

03 Dec '12

Hello to you, I wonder if you might be able to solve this conundrum I've been pondering. The boost (1.51) serialization library is giving me some trouble. I've been battling back and forth with the library, and I'm beginning to think I'm missing some key element. At first, I had issues to just getting things written out to a file without crashes. As far as I could tell, this particular problem was compounded by the fact, that I tried to simplify my code by just writing a single primitive referenced by a pointer to an object containing said primitive. As I've since come to learn, serializing pointed-to primitives is apparently not trivial. I have since, gotten the serialization class to properly write out a few simple member primitives from my class, but when I read them back using the exact same function, it seems as though a lot - if not all - of the pre-existing data in the object, which I am not serializing, gets overwritten. As far as I have been able to tell from the tutorials, I am doing everything exactly by the book. I was also concerned that maybe boost doesn't allow partial serialization, but this shouldn't be an issue either as far as I can tell. I must be making some sort of colossal mistake that I just cannot see. My in and out code is fairly straight forward: std::string streamPath = PTMFilePath.string(); std::ifstream ifs(streamPath); boost::archive::xml_iarchive ia(ifs); ia >> BOOST_SERIALIZATION_NVP(aStream); ----- std::string streamPath = PTMFilePath.string(); std::ofstream ofs(streamPath); boost::archive::xml_oarchive oa(ofs); oa << BOOST_SERIALIZATION_NVP(aStream); ------ My serialization function: template<class Archive> void serialize(Archive &ar, const unsigned int file_version) { ar & BOOST_SERIALIZATION_NVP(nrOfSamples); } ------ aStream is a pointer to a custom class, where I have allowed boost access. I am really confused as to what is causing this. Both pointed to data and regular primitives in the aStream class are wiped/altered as soon as the program enteres the serialize function, and even before the actual data seems to be read. I must be overlooking something really basic here. I hope someone can whack me with the solution stick... Thanks, Lasse

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Incorrect assertion in Boost.Exception?
by Thorsten Dahlheimer 02 Dec '12

02 Dec '12

Hello, we want to use Boost.Exception (1.47.0) with MS Visual Studio 2010 in a project that consists of several DLLs and a main executable. We have situations where we store an error_info into an exception from inside a DLL and access it again from another DLL/the EXE, e.g.: dll.cpp: void func() { BOOST_THROW_EXCEPTION(my_exception() << my_info(42)); } exe.cpp: try { func(); } catch (boost::exception& e) { std::cout << *boost::get_error_info<my_info>(e) << std::endl; } Now at runtime, when the error info is accessed, the following assertion in boost::exception_detail::error_info_container_impl::get() fails: BOOST_ASSERT( BOOST_EXCEPTION_DYNAMIC_TYPEID(*p).type_==ti.type_ ); As far as we can see, this happens because MSVC++ uses seperate type_info objects in each dll/exe, and the above assertion compares pointers to type_infos instead of the objects themselves. We believe this is a bug on the Boost side, since type_info objects for the same type are generally not guaranteed to be unique. Are we correct with that? Thanks, Thorsten

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Re: [Boost-users] [Range & c++0x Lambdas] Can this be done?
by John M. Dlugosz 01 Dec '12

01 Dec '12

I had the same issue and posted it a few months ago. I wrote to the MS VS forum that their std::result_of should work correctly with both old and new formats; in particular use the declared result_type if it exists (which in general lets the user override the deduced type, great for compatibility issues). Actually doing that robustly is a bit of a maze of metaprogramming. I ended up making a local my_namespace::result_of that I just handles what I needed, and only when I asked for it. That doesn't help the existing range templates, but such a change could be put back into boost::result_of. Meanwhile, for different reasons, I made a macro that abstracts the different syntax between C++11 lambdas and Apple Block Closures. The latter generates a suitable lambda class complete with result_of member. That makes me think that you could have a macro that wraps a compiler-generated lambda expression in another class that inherits the operator() etc. and adds in the result_of typedef to simply use decltype. —John Date: Wed, 21 Nov 2012 10:15:18 -0700 From: Nathan Crookston <nathan.crookston(a)gmail.com> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] [Range & c++0x Lambdas] Can this be done? Message-ID: <CAMb0s=1qtLcOiXTd5h7b2qkOSiYqjEVeN-m=rafJRHKDU6y6Cg(a)mail.gmail.com> Content-Type: text/plain; charset="iso-8859-1" Rob, On Wed, Nov 21, 2012 at 6:39 AM, Robert Jones <robertgbjones(a)gmail.com>wrote: >> Can the last line, labelled NOT Ok, be made to work? I think the lambda >> does >> not publish its result as a bind does, so I suspect it's hopeless. Any >> thoughts? >> // NOT Ok >> boost::range::push_back( out, in | transformed( []( S & s ) { return >> s.i; } ) ); >> } >> >> It seems trivial to have a nested result_type in all cases with a lambda. > However, in C++11 there's no need for it due to decltype. > > Sadly, some compilers fall into a gap where result_of (boost or std) > doesn't use decltype and lambdas don't publish tr1-style result_type -- > leaving code like the above in the lurch. > > Michel Morin wrote some code for adapting such a case which may be of > interest to you: http://lists.boost.org/boost-users/2012/01/72879.php > > HTH, > Nate >

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Boost.Wave getting raw input tokens for code transformation
by Frank Birbacher 30 Nov '12

30 Nov '12

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi! I'm trying to utilize Wave for simple code transformations. My starting point is to do an identity mapping through Wave: read in a source file, tokenize it, and output it again. The output shall be the same as the input on a byte by byte basis. I modified the cpp_lexer example to just output the token.value() texts. From that I discovered whitespace in "# define" will be dropped. Ok, fixed this by modifying Wave source code. Now my main problem are line continuations using backslash like in multiline macro definitions. Those get processed at a very low level, I guess. The backslash will never be reported as a token, but the adjacent characters will be fused into one token. Is there a way to define a "raw" token mode that would report the backslash and keep the adjacent characters as distinct tokens? I don't understand the tokenizer level at all. Frank -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.17 (Darwin) Comment: GPGTools - http://gpgtools.org Comment: keyserver x-hkp://pool.sks-keyservers.net iEYEARECAAYFAlC1w/8ACgkQhAOUmAZhnmrUsQCeIVBxkYTUg1qIU2DTsSZuh5u1 2v8AniMF44HV4agBashrP81N6XN3bTW1 =A8Sp -----END PGP SIGNATURE-----

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serialization of recursive objects
by kean 29 Nov '12

29 Nov '12

Hello everybody, I defined the following objects to be serialized: class MyElementObject { friend class boost::serialization::access; public: template<class Archive> void serialize(Archive & ar, const unsigned int version) { } }; template<class T> class MyRecursiveObject { friend class boost::serialization::access; public: T element; std::vector<MyRecursiveObject<T> > children; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & element; ar & children; } }; I then run the following code: int main() { //MyRecursiveObject initialization MyRecursiveObject<MyElementObject> rec_object; rec_object.children.push_back(MyRecursiveObject<MyElementObject>()); rec_object.children[0].children.push_back(MyRecursiveObject<MyElementObject>()); //create vector of pointers to MyRecursiveObject's elements vector<MyElementObject *> elt_ptrs; elt_ptrs.push_back(&rec_object.element); elt_ptrs.push_back(&rec_object.children[0].element); elt_ptrs.push_back(&rec_object.children[0].children[0].element); //serialize MyRecursiveObject and the vector of pointers { ofstream ofs("filename"); boost::archive::text_oarchive oa(ofs); oa << rec_object; oa << elt_ptrs; } //create new MyRecursiveObject and vector of pointers for deserialization MyRecursiveObject<MyElementObject> rec_object_deserialized; rec_object_deserialized.children.push_back(MyRecursiveObject<MyElementObject>()); rec_object_deserialized.children[0].children.push_back(MyRecursiveObject<MyElementObject>()); vector<MyElementObject *> elt_ptrs_deserialized; //deserialize { ifstream ifs("filename"); boost::archive::text_iarchive ia(ifs); ia >> rec_object_deserialized; ia >> elt_ptrs_deserialized; } //compare deserialized pointers cout<<"elt_ptrs first level="<<elt_ptrs_deserialized[0] <<" expected="<<&rec_object_deserialized.element<<endl; cout<<"elt_ptrs second level="<<elt_ptrs_deserialized[1] <<" expected="<<&rec_object_deserialized.children[0].element<<endl; cout<<"elt_ptrs third level="<<elt_ptrs_deserialized[2] <<" expected="<<&rec_object_deserialized.children[0].children[0].element<<endl; return 0; } And I always get an output similar to the following one: elt_ptrs first level=<b>0x7fff57c787c0* expected=*0x7fff57c787c0* elt_ptrs second level=*0x18e7020* expected=*0x18e7020* elt_ptrs third level=*0xffff8000ab5564f0* expected=*0x18e7450* As can be seen from the output I manage to deserialize pointers that point to elements down to the second recursion level of MyRecursiveObject. As soon as I try to do it with pointers to the third level or even deeper the deserialization fails. Am I using boost::serialization wrongly? Note that the MyRecursiveObject is always successfully deserialized, no matter how many levels it has. I encounter the problem only deserializing pointers to its elements. Thank you in advance Kean -- View this message in context: http://boost.2283326.n4.nabble.com/serialization-of-recursive-objects-tp463… Sent from the Boost - Users mailing list archive at Nabble.com.

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