March 2013 - Boost-users - lists.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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[Range, Phoenix] What am I missing...
by Robert Jones 25 Apr '17

25 Apr '17

Hi Folks Can anyone explain the output of this program... #include <iostream> #include <boost/range/algorithm/copy.hpp> #include <boost/range/counting_range.hpp> #include <boost/range/adaptor/reversed.hpp> #include <boost/range/adaptor/transformed.hpp> #include <boost/phoenix/bind/bind_function.hpp> #include <boost/phoenix/core/argument.hpp> int f( int i ) { return i * 2; } int main( ) { using boost::adaptors::reversed; using boost::adaptors::transformed; using boost::counting_range; using boost::copy; using boost::phoenix::arg_names::_1; copy( counting_range( 1, 5 ) | reversed | transformed( f ), std::ostream_iterator<int>( std::cout, " " ) ); std::cout << std::endl; copy( counting_range( 1, 5 ) | reversed | transformed( bind( f, _1 ) ), std::ostream_iterator<int>( std::cout, " " ) ); std::cout << std::endl; } Which is... 8 6 4 2 1768406272 1768406272 1768406272 1768406272 I'm using Gcc 4.6.2 & Boost 1.53 Thx All.

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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 17 Sep '14

17 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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Server failing when BOOST_ASIO_ENABLE_HANDLER_TRACKING is active
by Gonzalo Garramuno 22 Jan '14

22 Jan '14

Trying to track down when the socket closes on my program, I turned on asio debugging. Server fails when BOOST_ASIO_ENABLE_HANDLER_TRACKING is active. Its stack trace is: g Scanning dependencies of target mrViewer [ 9%] Building CXX object mrViewer/src/CMakeFiles/mrViewer.dir/core/mrvServer.o Linking CXX executable ../../../bin/mrViewer [100%] Built target mrViewer # gga@gga-laptop1 /media/Linux/code/applications/mrViewer # mar ene 01 10:04 [8] $ mrViewer /media/Linux/movies/Tangled.mov [opengl] Using hardware shader profile: NVidia NV30 [opengl] mrViewer supports YUV images through shaders. [psql] Connected to database 'assets2d_development'. The code: boost::asio::io_service io_service; tcp::endpoint listen_endpoint(tcp::v4(), s->port); server rp(io_service, listen_endpoint, s->ui); io_service.run(); fails with: @asio|1357088683.200673|0|socket@0x7f303d8d2d00.close Got signal 11, faulty address is 0x1, from 0x4d222a [bt] Execution path: [bt] mrViewer(_ZN5boost4asio6detail15task_io_service16shutdown_serviceEv+0x3a) [0x4d222a] [bt] mrViewer(_ZN5boost4asio6detail15task_io_service16shutdown_serviceEv+0x3a) [0x4d222a] [bt] mrViewer() [0x4dd2c9] [bt] mrViewer(_ZN3mrv13server_threadEPKNS_10ServerDataE+0x408) [0x4e0e58] [bt] /usr/lib/libboost_thread.so.1.48.0(+0xdda9) [0x7f304e191da9] [bt] /lib/x86_64-linux-gnu/libpthread.so.0(+0x7e9a) [0x7f304f7f0e9a] [bt] /lib/x86_64-linux-gnu/libc.so.6(clone+0x6d) [0x7f304da1ccbd] without the #define the code works reliably except sometimes the socket closes unexpectedly.

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[boost.test] How to register custom exception for auto test?
by Jörg Becker 12 Jan '14

12 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/

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[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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[thread] synchronized_value: value and move semantics
by Vicente J. Botet Escriba 08 Jun '13

08 Jun '13

Hi, boost::synchronized_value (not released yet [1][2][3]) is based on [4]. See below part of this paper adapted to the Boost.Thread interface. Currently boost::synchronized_value is in addition Copyable and Swappable. I was wondering if it is worth adding value and move semantics to synchronized_value. Making it EqualityComparable, LessThanComparable and Movable if the underlying type satisfy these requirements will allow to store them on a Boost.Container/C++11 container. Do you see something completely wrong with this addition? Has some of you had a need for this? Could you share the context? Best, Vicente [1] https://svn.boost.org/svn/boost/trunk/boost/thread/synchronized_value.hpp [2] https://svn.boost.org/svn/boost/trunk/libs/thread/example/synchronized_valu… [3] https://svn.boost.org/svn/boost/trunk/libs/thread/example/synchronized_pers… [4] "Enforcing Correct Mutex Usage with Synchronized Values" by Anthony Williams http://www.drdobbs.com/cpp/enforcing-correct-mutex-usage-with-synch/2252002… ------------- [section The Problem with Mutexes] The key problem with protecting shared data with a mutex is that there is no easy way to associate the mutex with the data. It is thus relatively easy to accidentally write code that fails to lock the right mutex - or even locks the wrong mutex - and the compiler will not help you. std::mutex m1; int value1; std::mutex m2; int value2; int readValue1() { boost::lock_guard<boost::mutex> lk(m1); return value1; } int readValue2() { boost::lock_guard<boost::mutex> lk(m1); // oops: wrong mutex return value2; } Moreover, managing the mutex lock also clutters the source code, making it harder to see what is really going on. The use of synchronized_value solves both these problems - the mutex is intimately tied to the value, so you cannot access it without a lock, and yet access semantics are still straightforward. For simple accesses, synchronized_value behaves like a pointer-to-T; for example: boost::synchronized_value<std::string> value3; std::string readValue3() { return *value3; } void setValue3(std::string const& newVal) { *value3=newVal; } void appendToValue3(std::string const& extra) { value3->append(extra); } Both forms of pointer dereference return a proxy object rather than a real reference, to ensure that the lock on the mutex is held across the assignment or method call, but this is transparent to the user. [endsect] [/The Problem with Mutexes] [section Beyond Simple Accesses] The pointer-like semantics work very well for simple accesses such as assignment and calls to member functions. However, sometimes you need to perform an operation that requires multiple accesses under protection of the same lock, and that's what the synchronize() method provides. By calling synchronize() you obtain an strict_lock_ptr object that holds a lock on the mutex protecting the data, and which can be used to access the protected data. The lock is held until the strict_lock_ptr object is destroyed, so you can safely perform multi-part operations. The strict_lock_ptr object also acts as a pointer-to-T, just like synchronized_value does, but this time the lock is already held. For example, the following function adds a trailing slash to a path held in a synchronized_value. The use of the strict_lock_ptr object ensures that the string hasn't changed in between the query and the update. void addTrailingSlashIfMissing(boost::synchronized_value<std::string> & path) { boost::strict_lock_ptr<std::string> u=path.synchronize(); if(u->empty() || (*u->rbegin()!='/')) { *u+='/'; } } [endsect] [/Beyond Simple Accesses] [section Operations Across Multiple Objects] Though synchronized_value works very well for protecting a single object of type T, nothing that we've seen so far solves the problem of operations that require atomic access to multiple objects unless those objects can be combined within a single structure protected by a single mutex. One way to protect access to two synchronized_value objects is to construct a strict_lock_ptr for each object and use those to access the respective protected values; for instance: synchronized_value<std::queue<MessageType> > q1,q2; void transferMessage() { strict_lock_ptr<std::queue<MessageType> > u1 = q1.synchronize(); strict_lock_ptr<std::queue<MessageType> > u2 = q2.synchronize(); if(!u1->empty()) { u2->push_back(u1->front()); u1->pop_front(); } } This works well in some scenarios, but not all - if the same two objects are updated together in different sections of code then you need to take care to ensure that the strict_lock_ptr objects are constructed in the same sequence in all cases, otherwise you have the potential for deadlock. This is just the same as when acquiring any two mutexes. In order to be able to use the dead-lock free lock algorithms we need to use instead unique_lock_ptr, which is Lockable. synchronized_value<std::queue<MessageType> > q1,q2; void transferMessage() { unique_lock_ptr<std::queue<MessageType> > u1 = q1.unique_synchronize(boost::defer_lock); unique_lock_ptr<std::queue<MessageType> > u2 = q2.unique_synchronize(boost::defer_lock); boost::lock(u1,u2); // dead-lock free algorithm if(!u1->empty()) { u2->push_back(u1->front()); u1->pop_front(); } } [endsect] [/Operations Across Multiple Objects]

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Is boost::this_thread::sleep_for interruption point?
by Serg Gulko 22 May '13

22 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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[FunctionTypes] Testing for a general callable type.
by Robert Jones 24 Apr '13

24 Apr '13

Hi All Is there anything in Boost to help me test for a general type being callable with a specific signature? I've found Boost.FuncionTypes, which seems to be confined to *builtin* callable types, but has made me aware that all the const/volatile/reference variations might make a general test more complicated than I first thought. Any pointers much appreciated. Thx, Rob.

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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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[Boost.Coroutine] Problem compiling simple code with c++98 compiler
by Lukas Czaja 03 Apr '13

03 Apr '13

Hi, i was checking if my code is compatible with c++98 standard and i've encounterd compile error. With -std c++11 option everything works fine. Below i've written code causing same problem. #include <boost/coroutine/coroutine.hpp> #include <boost/coroutine/attributes.hpp> typedef boost::coroutines::coroutine<void( boost::system::error_code , std::size_t)> coro_t; struct coro_test{ coro_test() {} void coro_fun(typename coro_t::caller_type& ca)const{ boost::system::error_code ec; boost::tie(ec, boost::tuples::ignore) = ca.get(); ca(); } coro_t coro; }; int main(int argc, char *argv[]) { { boost::system::error_code ec; coro_t coro2; //default construction is ok coro_test ctest; //compile error , why ??? coro_t coro( boost::bind(&coro_test::coro_fun, &ctest, _1),coro_t::arguments( ec, 7)); coro = coro_t(boost::bind(&coro_test::coro_fun, &ctest, _1),coro_t::arguments( ec, 7)); } ... /usr/local/include/boost/type_traits/is_function.hpp:50: błąd:forming pointer to reference type 'boost::rv<boost::coroutines::coroutine<void(boost::system::error_code, long unsigned int)> >&' /usr/local/include/boost/type_traits/is_function.hpp:102: błąd:'value' is not a member of 'boost::detail::is_function_impl<boost::rv<boost::coroutines::coroutine<void(boost::system::error_code, long unsigned int)> >&>' /usr/local/include/boost/type_traits/is_convertible.hpp:354: błąd:'value' is not a member of 'boost::is_function<boost::rv<boost::coroutines::coroutine<void(boost::system::error_code, long unsigned int)> >&>' /usr/local/include/boost/utility/enable_if.hpp:59: błąd:'value' is not a member of 'boost::is_convertible<boost::coroutines::coroutine<void(boost::system::error_code, long unsigned int)>&, boost::rv<boost::coroutines::coroutine<void(boost::system::error_code, long unsigned int)> >&>' I work with Qt, g++ compiler on ubuntu 12.10 Is this library bug ?

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[serialization] serializing a pointer without causing object tracking
by Stefan Strasser 02 Apr '13

02 Apr '13

Hi everyone, Hi Robert, in case you'd like to answer this one, because I have a rather specific question about your library. Thank you in advance! I'd like to serialize an object and later reconstruct it from the serialized data: void save(T const &t){ ar << t; } T* load(){ T *t=new T(); //error ar >> *t; } T might not have a default constructor. so load_construct_data should be used. apparently the way to do this is to serialize through a pointer: void save(T const *t){ ar << t; } T *load(){ T *t; ar >> t; } this works, but it causes the type T to be tracked, if its object tracking is set to track_selectively. I don't want that. but I can't set it to track_never either, because if the type is serialized at another point in the program through a pointer, the type should be tracked. is there a solution to this? is there a serialization wrapper that says "don't track this type just because of this pointer"? what comes to mind as a solution is serializing as an object, and calling load/save_construct_data manually. but then there is another problem: void save(T const &t){ save_construct_data(t,version<T>::value); ar << t; } void load(T *unconstructed_t){ load_construct_data(unconstructed_t, ??? ); ar >> *t; } if the implementation level of T is object_class_info, the object version is loaded from the preamble when the object itself is loaded. there is no in between loading the version and loading the object, it's entirely handled in the non-header part of the library. so basically I have a solution when the implementation level is object_serializable (no version info, call load_construct_data manually), and when tracking is set to track_never (serialize as a pointer). but not for the default case, object_class_info with track_selectively. am I missing something? Stefan

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Newbie Interprocess message_thread user
by John Davies 01 Apr '13

01 Apr '13

I'm new to Boost and new to Linux. But old to Windows. So I'm doing some initial development in Windows XP. I have two executables made in different projects. I planned on using a message_queue to communicate between the two applications. But sending a message from one app does not make it to the other. I can add and handle messages from one thread to another within the same application. SO I know I have things partially setup correctly. But now I'm at a complete loss. Should two exe files be able to communicate through Boost message_queues? Or am I misunderstanding the whole thing?

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Problems using for_each
by Michael Powell 31 Mar '13

31 Mar '13

Hello, I am struggling making for_each work right. I am using Sourcery targeting ARM. AFAIK, GCC is actually 4.7.2, and I am flagging -std=c++11. I'm not really picky how we get for_each done (or constructs like it). I'd like to avoid "macro-expansion" for obvious reasons (i.e. debug), and the always-infamous verbosity of a for loop, if possible. I've got the following: vector<rgb_type*> all; rgb_type rgb; rgb_type rgb2 = rgb.clone(); for_each(all.begin(), all.end(), cout << _1->r() << endl); With errors: _1 was not declared in this scope. (C++ Problem) That or, void rgb_printer_func(rgb_type* prgb) { cout << prgb->r() << endl; } for_each(all.begin(), all.end(), rgb_printer_func); With errors: Invalid arguments Candidates are: #1 for_each(#0, #0, #1) (Semantic Error) Thank you. Regards, Michael Powell

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Building Boost 1.53
by Michael Powell 30 Mar '13

30 Mar '13

Hello, I believe we're on the home stretch building boost and getting productive with it. But I have a couple of questions. When we run ./b2 to build boost with the PREFIX option, what actually lands there? I'm thinking we just locate that in our /path/to/boost/, which ends up being ./tools/boost_1_53_0 from our project workspace perspective. But, there are other insights I don't know about I am certain. Thanks much. Regards, Michael Powell

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[lockfree] Queue with shared_ptr as elements
by sguazt 30 Mar '13

30 Mar '13

Hello, Is it possible to use lockfree::queue with shared_ptr as element types? For instance, ---[code]--- #include <boost/lockfree/queue.hpp> #include <boost/smart_ptr.hpp> class foobar { }; int main() { typedef boost::shared_ptr<foobar> element_type; typedef boost::lockfree::queue<element_type> queue_type; queue_type queue; } ---[/code]--- If I compile the above code I get the following error: ---[error]--- boost_lockfree_mwmr_queue.cpp:13:13: required from here ~/projects/svn/boost-trunk/boost/lockfree/queue.hpp:81:5: error: invalid application of ‘sizeof’ to incomplete type ‘boost::STATIC_ASSERTION_FAILURE<false>’ ~/projects/svn/boost-trunk/boost/lockfree/queue.hpp:85:5: error: invalid application of ‘sizeof’ to incomplete type ‘boost::STATIC_ASSERTION_FAILURE<false>’ ---[/error]--- If I use "foobar" or "foobar*" as element_type, it works. I'm using - GCC 4.7.2 with the following options enabled: -Wextra -Wall -ansi -pedantic - boost SVN trunk version Thank you very much for helping. Best, -- Marco

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[fusion] [mpl] binary mpl::transform on empty std::tuple
by Nathan Ridge 30 Mar '13

30 Mar '13

Hello, Fusion provides adaptation code for treating an std::tuple as a Fusion sequence, and adaptation code for treating Fusion sequences as MPL sequences, but it seems that in the case of a binary mpl::transform on an empty std::tuple, the two do not work well together. When trying to compile the following code: #include <boost/mpl/transform.hpp> #include <boost/mpl/back_inserter.hpp> #include <boost/mpl/vector.hpp> #include <boost/fusion/adapted/std_tuple.hpp> #include <boost/fusion/adapted/mpl.hpp> #include <boost/fusion/mpl.hpp> struct first { template <typename T, typename U> struct apply { typedef T type; }; }; int main() { typedef std::tuple<> fusion_sequence1_type; typedef std::tuple<> fusion_sequence2_type; typedef boost::mpl::transform<fusion_sequence1_type, fusion_sequence2_type, first, boost::mpl::back_inserter<boost::mpl::vector<>> >::type result_type; } I get the following errors: In file included from test.cpp:4: In file included from boost/fusion/adapted/std_tuple.hpp:13: In file included from boost/fusion/adapted/std_tuple/detail/begin_impl.hpp:10: boost/fusion/adapted/std_tuple/std_tuple_iterator.hpp:45:13: error: implicit instantiation of undefined template 'std::tuple_element<0, std::tuple<> >' : std::tuple_element<Iterator::index, ^ boost/fusion/iterator/value_of.hpp:34:28: note: in instantiation of template class 'boost::fusion::std_tuple_iterator<std::tuple<>, 0>::value_of<boost::fusion::std_tuple_iterator<std::tuple<>, 0> >' requested here struct apply : Iterator::template value_of<Iterator> {}; ^ boost/fusion/iterator/value_of.hpp:51:15: note: in instantiation of template class 'boost::fusion::extension::value_of_impl<boost::fusion::iterator_facade_tag>::apply<boost::fusion::std_tuple_iterator<std::tuple<>, 0> >' requested here : extension::value_of_impl<typename detail::tag_of<Iterator>::type>:: ^ boost/fusion/iterator/mpl/fusion_iterator.hpp:46:45: note: in instantiation of template class 'boost::fusion::result_of::value_of<boost::fusion::std_tuple_iterator<std::tuple<>, 0> >' requested here typedef typename fusion::result_of::value_of<Iterator>::type type; ^ boost/mpl/iterator_category.hpp:27:22: note: in instantiation of template class 'boost::mpl::fusion_iterator<boost::fusion::std_tuple_iterator<std::tuple<>, 0> >' requested here typedef typename Iterator::category type; ^ boost/mpl/pair_view.hpp:152:20: note: in instantiation of template class 'boost::mpl::iterator_category<boost::mpl::fusion_iterator<boost::fusion::std_tuple_iterator<std::tuple<>, 0> > >' requested here typename iterator_category<iter1_>::type ^ boost/mpl/aux_/has_tag.hpp:20:1: note: (skipping 5 contexts in backtrace; use -ftemplate-backtrace-limit=0 to see all) BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(has_tag, tag, false) ^ boost/mpl/has_xxx.hpp:244:65: note: expanded from macro 'BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF' , boost::mpl::aux::type_wrapper<BOOST_MSVC_TYPENAME U::name>* = 0 \ ^ boost/mpl/transform.hpp:75:7: note: in instantiation of template class 'boost::mpl::fold<boost::mpl::pair_view<std::tuple<>, std::tuple<> >, boost::mpl::vector<mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::mpl::bind2<boost::mpl::push_back<mpl_::na, mpl_::na>, mpl_::arg<1>, boost::mpl::bind2<first, boost::mpl::bind1<boost::mpl::first<mpl_::na>, mpl_::arg<2> >, boost::mpl::bind1<boost::mpl::second<mpl_::na>, mpl_::arg<2> > > > >' requested here : fold< ^ boost/mpl/transform.hpp:114:1: note: in instantiation of template class 'boost::mpl::aux::transform2_impl<std::tuple<>, std::tuple<>, first, boost::mpl::back_inserter<boost::mpl::vector<mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na> > >' requested here BOOST_MPL_AUX_INSERTER_ALGORITHM_DEF(4, transform2) ^ boost/mpl/aux_/inserter_algorithm.hpp:44:7: note: expanded from macro 'BOOST_MPL_AUX_INSERTER_ALGORITHM_DEF' : aux::name##_impl<BOOST_MPL_PP_PARAMS(arity, P)> \ ^ boost/mpl/eval_if.hpp:38:22: note: in instantiation of template class 'boost::mpl::transform2<std::tuple<>, std::tuple<>, first, boost::mpl::back_inserter<boost::mpl::vector<mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na> > >' requested here typedef typename f_::type type; ^ boost/mpl/transform.hpp:138:1: note: in instantiation of template class 'boost::mpl::eval_if<boost::mpl::or_<boost::mpl::is_na<first>, boost::mpl::is_lambda_expression<std::tuple<> >, boost::mpl::not_<boost::mpl::is_sequence<std::tuple<> > >, mpl_::bool_<false>, mpl_::bool_<false> >, boost::mpl::transform1<std::tuple<>, std::tuple<>, first>, boost::mpl::transform2<std::tuple<>, std::tuple<>, first, boost::mpl::back_inserter<boost::mpl::vector<mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na> > > >' requested here AUX778076_TRANSFORM_DEF(transform) ^ boost/mpl/transform.hpp:125:22: note: expanded from macro 'AUX778076_TRANSFORM_DEF' typedef typename eval_if< \ ^ test.cpp:21:25: note: in instantiation of template class 'boost::mpl::transform<std::tuple<>, std::tuple<>, first, boost::mpl::back_inserter<boost::mpl::vector<mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na> > >' requested here typedef boost::mpl::transform<fusion_sequence1_type, ^ c++/4.8.0/tuple:672:12: note: template is declared here struct tuple_element; ^ 1 error generated. Seems like something is trying to call value_of on the begin iterator of the tuple, which in the case of an empty tuple is a past-the-end iterator. If I use non-empty tuples instead: typedef std::tuple<int> fusion_sequence1_type; typedef std::tuple<int> fusion_sequence2_type; It works fine. Unary mpl::transform works fine in either case. Am I doing something wrong, or is this a bug? Thanks, Nate

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Elegant solution to interview question about boost::fusion::vector
by Stuart 29 Mar '13

29 Mar '13

Hello everyone, I have stumbled over m2pq36bk97.fsf(a)boostpro.com in comp.lang.c++.moderated. I had never used boost before but I always try to solve interview questions. I found a solution that works, but I have the feeling that there must be a more elegant solution. The problem that was presented in the interview was the following: typedef boost::fusion::vector<int, double, float> row; std::vector<row> M; template <typename T> typename T::value_type Accumulate (T const &t) { typedef typename T::value_type value_type; return std::accumulate (t.begin (), t.end (), value_type ()); } Provide a function fun so that Accumulate (fun<0>(M)); computes the sum of the first column of M, or more generally Accumulate (fun<x>(M)); computes the sum of the xth column of M. The solution that was provided in m2pq36bk97.fsf(a)boostpro.com did not work out of the box, but I was able to fix it into the following solution: // Functor that extracts nth element of row vector. template <unsigned N> struct tuple_at { template <class Vector> typename boost::fusion::result_of::at_c<const Vector,N>::type operator()(Vector const& t) const { return boost::fusion::at_c<N, Vector>(t); } }; template <unsigned N, class M> auto fun(M const& x) -> decltype(x | boost::adaptors::transformed(tuple_at<N>())) { return x | boost::adaptors::transformed(tuple_at<N>()); } so that int main () { M.push_back(row (1, 1.0, 2.8)); M.push_back(row (2, 0.1, 2.8)); M.push_back(row (3, 0.01, 2.8)); std::cout << Accumulate(fun<1> (M)); } prints 1.11 as expected. However, I think that I should be able to achieve the same without the template tuple_at. I tried using a lambda: template <unsigned N, class M> auto fun(M const& x) -> decltype(x | boost::adaptors::transformed( [] (typename M::value_type const& x ) { return boost::fusion::at_c<N> (x); })) { auto retval = x | boost::adaptors::transformed( [] (typename M::value_type const& x ) { return boost::fusion::at_c<N> (x); }); return retval; } Unfortunately, this does not compile ("Lambda expression in an unevaluated operand"). I'm also not sure whether boost::adaptor::transformed can work with lambdas. I also tried to generate a functor object from boost::fusion::at_c using the following code from the internet: template<typename T> std::function<T> make_function (T* t) { return { t }; } template <unsigned N, class M> auto fun (M const& x) -> decltype(make_function(&boost::fusion::at_c<N, const M>)) { auto retval = make_function(&boost::fusion::at_c<N, const M> ); return retval } but this yields an error that I can't decipher yet: at.hpp:62:15: Implicit instantiation of undefined template 'boost::fusion::extension::at_impl<boost::fusion::non_fusion_tag>::apply<const std::__1::vector<boost::fusion::vector<int, double, float, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_>, std::__1::allocator<boost::fusion::vector<int, double, float, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_>>>, mpl_::int_<2>>' The ideal solution would be one where I don't have to write the functor object manually. Even more elegantly, I should be able to leave out the return type and let the compiler figure it out automatically. Unfortunately, I use llvm gcc 4.2, so the automatic return type evaluation is out of reach (although boost without this feature seems to be quite cumbersome). Can anyone provide some insights? Thanks in advance, Stuart

2 2

[chrono][thread] Best way to wait?
by Klaim - Joël Lamotte 29 Mar '13

29 Mar '13

Hi, can someone clarify: 1. what is the difference between: const auto wait_time = boost::chrono::miliseconds( 8 ); boost::mutex mutex; boost::unique_lock<boost::mutex> lock( mutex ); boost::condition_variable wait_condition; wait_condition.wait_for( lock, wait_time ); and const auto wait_time = boost::chrono::miliseconds( 8 ); boost::this_thread::sleep_for( wait_time ); 2. are there other ways to wait? (I mean make the thread sleep, not looping until it's time) Joel Lamotte

2 4

Some questions about vertex removal in subgraph
by Nicholas Mario Wardhana 29 Mar '13

29 Mar '13

Hi all, In the last few days I have been implementing partial I/O for a subgraph by saving and loading a subgraph (although actually it is only partial if we see it from the parent graph's point of view). So far, by modifying some code in Boost, I managed to save a child graph to a file, and also load two subgraphs which share a vertex without having that vertex duplicated. However, in addition to save and load, I also need to clear (i.e. remove all nodes and edges from) a subgraph, and I found that remove_vertex is not implemented; only remove_edge is. I noticed that as of now (March 2013) there is no plan to implement it [1]. I cannot use Jeremiah's suggestion there (and also in [2]) to use filtered_graph, because I need to physically remove the nodes and edges from memory, so I am thinking to implement it myself. I have a few questions about this. 1) Jeremiah said that "In particular, local vertex descriptors in subgraphs are indices into an std::vector, and so removing a vertex would invalidate many other vertex descriptors." [1] Am I right to assume that this statement is about m_global_vertex, which is of std::vector<vertex_descriptor> type? 2) Removing a vertex from a regular graph involves calling g.m_vertices.erase(..) (adjacency_list.hpp, line 1951). I found that m_vertices is also of type std::vector. So why does vertex removal work for regular graph, but supposedly not for subgraph? I use Boost version 1.53.0, and my subgraph configuration is typedef adjacency_list<vecS, vecS, undirectedS, property<vertex_index_t, int, VertexProperty>, property<edge_index_t, int, EdgeProperty> > RegularGraph; typedef subgraph<RegularGraph> Subgraph; where VertexProperty and EdgeProperty are respectively bundled properties for vertex and edge. Thank you very much! Best regards, Nicholas Mario Wardhana References: [1] https://svn.boost.org/trac/boost/ticket/4752 [2] http://boost.2283326.n4.nabble.com/Can-t-link-subgraphs-because-remove-vert…

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Re: [Boost-users] header-only libraries
by dib 27 Mar '13

27 Mar '13

> > >> I'd like to use the program_options library, but am reluctant to > >> require my users to build parts of Boost. Is there a strong > >> reason that this library cannot be header-only? > > You can build the necessary Boost CPP files as part of your own > build. > Asio (which is header-only) offers the possibility for "optional separate compilation" by including some ".../impl/src.hpp" in a source file and defining either "BOOST_ASIO_SEPARATE_COMPILATION" or "BOOST_ASIO_DYN_LINK", which very nicely lets the user choose which one suits best for his needs. Is there a reason why this isn't done for other libs like program_options, regex, etc., or has it (at least sometimes) just not been done because nobody wanted to do this extra-work? It is a very frequently asked question if/why not there is a header-only version, and although it is sometimes really not possible to make it header-only, most libs should work that way. Furthermore, in my experience specially commercial projects are reluctant to use libraries that have to be shipped with the own product, whereas it is no problem as long as they are "hidden" inside the binary.. Of course there are some disadvantages as shown in the discussion on stackoverflow, but giving the user a choice where possible should hugely increase acceptance and usage of those libraries. Greetings, dib PS: I just tried it with program_options and at least with my programs on linux it works fine, don't know how it is on other platforms or if I was just lucky: copy the src-files from libs/program_options/src to the include/boost/program_options/impl and do it "the asio-way", including the source files in a separate .cpp in my projects.. works fine and no linking is required any more.

3 4

header-only libraries
by ilya shlyakhter 26 Mar '13

26 Mar '13

Dear Boost experts, I'd like to use the program_options library, but am reluctant to require my users to build parts of Boost. Is there a strong reason that this library cannot be header-only? Or perhaps, it's possible to create a header-only version of this library? I have the same question for regex. Thanks, ilya

3 2

[MSM] "favor_compile_time" policy disables "kleene" events. (Bug?)
by Deniz Bahadir 25 Mar '13

25 Mar '13

Hi everyone, Hi Christophe, While trying to speedup compilation of my MSM/eUML-based state machine, I seem to have found a bug. I added the "favor_compile_time" policy to the type-definition of my state-machine as the documentation suggests. I did not use the macro "BOOST_MSM_BACK_GENERATE_PROCESS_EVENT" because I do not have any sub-statemachines. This did speed up compilation, however obviously by changing my transition-table: All "kleene"-events in my transition-table are ignored, when defining the state-machine with the "favor_compile_time" policy. Can anyone confirm this or am I using it wrong? (Was this policy supposed to work with eUML in the first place?) Thanks, Deniz PS: I am using GCC 4.7.2 with Boost 1.53.

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Broken Links?
by Hei Chan 25 Mar '13

25 Mar '13

Hi, On http://www.boost.org/doc/libs/1_53_0/libs/pool/doc/html/boost_pool/pool/poo…, all the graphs there seem broken. Anyone fixing it? Thanks in advance. Cheers, Hei

2 1

[boost::Statechart] posting a "serial timeout" event
by Andre de Jong 25 Mar '13

25 Mar '13

I've been using boost's asynchronous statechart to write a program. In this program I communicate with another device using an asynchronous serial port. I have a state that waits for a confirmation from the device over the serial port and then posts a "confirmation received" event. This works well but, I would also like to implement a "timeout" event. In previous programs I had been using switch case statements for my state machines where I had code that could be run each time the loop was run. This meant I could run code and check if I should change state due to something timing out. Like this: while(1){ switch (state){ case 0:{ sendMessage(); state = 1; sendTime = boost::chrono::steady_clock::now(); } break; case 1:{ if (isConfirmationReceived()){ // do something state = 2; } else if (boost::chrono::steady_clock::now() > start + boost::chrono::duration<double>(WAIT_LENGTH)){ //do something state = 3; } } break; // etc etc } } How would I implement something like this using boost::StateChart? Or, should i be thinking about this a completely different way?

1 0

Re: [Boost-users] Broken Links?
by Boost_mailinglist＠gmx.de 25 Mar '13

25 Mar '13

Hello, you can see the directory listing of the pictures under http://www.boost.org/doc/libs/1_53_0/libs/pool/doc/images/ -----Ursprüngliche Nachricht----- Gesendet: Montag, 25 März 2013 um 06:32:27 Uhr Von: "Hei Chan" <structurechart(a)yahoo.com> An: "boost-users(a)lists.boost.org" <boost-users(a)lists.boost.org> Betreff: [Boost-users] Broken Links? Hi, On�http://www.boost.org/doc/libs/1_53_0/libs/pool/doc/html/boost_pool/pool/…, all the graphs there seem broken. Anyone fixing it? Thanks in advance. Cheers, Hei _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

1 0

bad reloc address when compiling with mingw
by Leonardo Sá 24 Mar '13

24 Mar '13

Hi all, I have been trying to create an .exe that links to several boost libraries (date-time, python, etc.) using MinGW, cross compiling for windows on linux. I compiled boost using mingw without problems. When linking the exe, I am receiving the following error: CMakeFiles/fp_core_test.dir/objects.a(MockEnvironment.cpp.obj):MockEnvironment.cpp:(.text+0x381): undefined reference to `fp_core::Window::init(int, int, boost::shared_ptr<fp_core::Renderer>)' /usr/bin/i686-w64-mingw32-ld: CMakeFiles/fp_core_test.dir/objects.a(MockEnvironment.cpp.obj): bad reloc address 0x8 in section `.text$_ZN5boost6detail15sp_counted_baseC2Ev[boost::detail::sp_counted_base::sp_counted_base()] I have no idea what "bad reloc address" means. Googling wasn't much help. Anyone can give me a pointer in the right direction? Thanks!

1 0

newbie problem with Program Option string value
by Neil Sutton 24 Mar '13

24 Mar '13

I am having problems getting a program option to work. The option should enable a user to enter a location when they select the '--location' option. so, if you type --location canada, the code should store the supplied string - canada and pass it on to the program. This is a typical program option with nothing special. But I cannot seem to get it to work! Please look at this: ---------------------------------------------------- std::string place_option; // a global variable po::options_description general("General options"); general.add_options() ("location", po::value<std::string>(), "location of your home"); // there are other non string options po::variables_map vm; po::store(po::parse_command_line(ac,av, general),vm); po::notify(vm); if(vm.count("help")) { std::cout << general << "\n"; return 0; } if(vm.count("version, v")) { std::cout << "version aplha\n"; } if(vm.count("location")) { place_option = vm["location"].as<std::string>(); // should pass the string value entered at command line to std::string place. } If i run my program with eg 'myprogram --location disney' I get: terminate called after throwing an instance of 'std::logic_error' what(): basic_string::_S_construct NULL not valid Aborted ------------------------------ Now I have tried a few variations of the code. The examples show where an int value is supplied and retrieved. I cannot work out how to do - what should be very trivial. I simply want to recover the value associated with 'location' i.e a std::string entered at the command line. I then want to pass that value on to my program to do something with it. I do not understand the error. Can someone kindly show me the correct syntax to accomplish this please? Kind regards.

3 2

[iostreams] mapped_file path issue
by Alexandre 24 Mar '13

24 Mar '13

Hello, After reading through all the documentation and examples I could read, I still can't get the following piece of code to work . I assume that when you pass a new_file_size and a path to the mapped_file_params class , it will then open the file at the location desired when I call the constructor of mapped_file with the mapped_file_params object in parameter. But the only thing it does is to create a file with a weird name , like "%F8/134" in the project working directory, not where I told it to. Maybe I'm wrong and one should create file before specifying it to the mapped_file? After reading the doc, I was under the assumption that it created a new file when you fill in the new_file_size param. and specifies the filename. Anyone experienced this before? Any advice on how to resolve this? Here's the code: boost::iostreams::mapped_file_params param(filename); // filename is a std::string with the correct path param.flags = boost::iostreams::mapped_file::mapmode::readwrite; param.new_file_size = sizeNeeded; // sizeNeeded is the size of the data param.length = sizeNeeded; boost::iostreams::mapped_file fileMap(param); // at this point the file is created … Thanks for your time, Alexandre

1 0

[BGL] boost::disjoint_set getting new representative after link()
by Adi Shavit 23 Mar '13

23 Mar '13

Hi, I'm using boost::disjoint_sets_with_storage<>. After calling link(rep1, rep2), I want to know the new rep - the representative of the merged set. Obviously, I can call find_set(rep1) to find it. I assume that the extra call to find_set incurs an additional run-time cost per call to link. Is this true or is the call immediate (as in returning the immediate parent of rep1)? If it does incur a run-time cost, then we know that the new-rep is *either *rep1 or rep2. Is there some other way to know which one it is? On a related matter, I am also tracking the *size *of the sets for each link(). Does knowing the size of the rep set before the link help in determining which of rep1 or rep2 will be the new rep? Is there a simple way to extend boost::disjoint_sets_with_storage<> to do the size tracking internally (currenlty I keep an external size vector per rep to keep track of the link()s). Thanks, Adi

2 2

erase and put methods in property tree lib of boost
by Sashidhar Guntury 23 Mar '13

23 Mar '13

I have been trying to use the put and erase methods in boost's property tree library with very limited success. I have tried to go through the documentation but it seems really esoteric with no real example to demonstrate. This is what I would like to do - I have a json object. I look for a particular key (call it "title") and extract the corresponding value (call it "Eric Clapton"), do something with "Eric Clapton" (say change it to "ec") insert it in the place of the old value. Now, should I do an "erase" to remove the previous entry and then "put" the new pair? Will "put" replace the old value? void doSomething(const ptree& node) { ... BOOST_FOREACH(const ptree::value_type& child, node.get_child("artists")) { string text = child.second.get<string>("title"); // do something to the text to give text2 child.second.put("title", text2); } ... } The above code gives an error which is equally hard to understand. I was hoping someone would shed some light. thanks Sashidhar

2 2

[BGL] Error C2679 when inserting edge property to subgraph
by Nicholas Mario Wardhana 22 Mar '13

22 Mar '13

Hi all, Could somebody tell me how to add a bundled edge property for subgraph, please? The code, based on [1], is as follows. // code starts #include <boost/config.hpp> #include <boost/graph/subgraph.hpp> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/graph_utility.hpp> using namespace std; using namespace boost; struct VertexProperty { int intValue; }; struct EdgeProperty { std::size_t biconnected_component; int intValue; }; typedef adjacency_list<vecS, vecS, undirectedS, VertexProperty, property<edge_index_t, int, EdgeProperty> > PlainGraph; typedef subgraph<PlainGraph> Graph; int main(int argc, char* argv[]) { PlainGraph g1; Graph g(2); VertexProperty v0; v0.intValue = 1; VertexProperty v1; v0.intValue = 1; EdgeProperty e; e.biconnected_component = 0; e.intValue = 0; add_edge(0, 1, g); put(get(vertex_bundle,g), 0, v0); // OK put(get(vertex_bundle,g), 1, v1); // OK put(get(edge_bundle,g), 0, e); // error here return 0; } // code ends The error is as follows: // error starts 1>D:\API\boost_1_53_0\boost/property_map/property_map.hpp(361): error C2679: binary '[' : no operator found which takes a right-hand operand of type 'int' (or there is no acceptable conversion) 1> D:\API\boost_1_53_0\boost/graph/subgraph.hpp(797): could be 'EdgeProperty &boost::subgraph_global_property_map<GraphPtr,PropertyMap,Tag>::operator [](boost::detail::edge_desc_impl<Directed,Vertex>) const' 1> with 1> [ 1> GraphPtr=boost::subgraph<PlainGraph> , 1> PropertyMap=boost::adj_list_edge_property_map<boost::undirected_tag,EdgeProperty,EdgeProperty &,unsigned __int64,boost::property<boost::edge_index_t,int,EdgeProperty>,boost::edge_bundle_t>, 1> Tag=boost::edge_bundle_t, 1> Directed=boost::undirected_tag, 1> Vertex=unsigned __int64 1> ] 1> while trying to match the argument list '(const boost::subgraph_global_property_map<GraphPtr,PropertyMap,Tag>, int)' 1> with 1> [ 1> GraphPtr=boost::subgraph<PlainGraph> , 1> PropertyMap=boost::adj_list_edge_property_map<boost::undirected_tag,EdgeProperty,EdgeProperty &,unsigned __int64,boost::property<boost::edge_index_t,int,EdgeProperty>,boost::edge_bundle_t>, 1> Tag=boost::edge_bundle_t 1> ] 1> main.cpp(74) : see reference to function template instantiation 'void boost::put<boost::subgraph_global_property_map<GraphPtr,PropertyMap,Tag>,EdgeProperty&,int,EdgeProperty>(const boost::put_get_helper<Reference,LvaluePropertyMap> &,K,const V &)' being compiled 1> with 1> [ 1> GraphPtr=boost::subgraph<PlainGraph> , 1> PropertyMap=boost::adj_list_edge_property_map<boost::undirected_tag,EdgeProperty,EdgeProperty &,unsigned __int64,boost::property<boost::edge_index_t,int,EdgeProperty>,boost::edge_bundle_t>, 1> Tag=boost::edge_bundle_t, 1> Reference=EdgeProperty &, 1> LvaluePropertyMap=boost::subgraph_global_property_map<boost::subgraph<PlainGraph> ,boost::adj_list_edge_property_map<boost::undirected_tag,EdgeProperty,EdgeProperty &,unsigned __int64,boost::property<boost::edge_index_t,int,EdgeProperty>,boost::edge_bundle_t>,boost::edge_bundle_t>, 1> K=int, 1> V=EdgeProperty 1> ] 1> // error ends I found a few other threads [2, 3] about this, but their solutions don't solve the problem. BTW I use Visual Studio 2010 on Windows 7 64-bit. The Boost version is 1.53.0. Thank you! Best regards, Nicholas Mario Wardhana References: [1] http://boost.2283326.n4.nabble.com/BGL-Bundled-Properties-in-subgraphs-td25… [2] http://stackoverflow.com/questions/7608031/boost-subgraph-and-bundled-prope… [3] https://groups.google.com/forum/?fromgroups=#!topic/boost-list/5EIkKybaUTY

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[boost][units]: Looking for more elegant ways to define RPM and velocity[km/h]
by Dennis Gertitschke 22 Mar '13

22 Mar '13

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Martin Lester : 3/22/2013 4:03:04 AM
by Martin Lester 21 Mar '13

21 Mar '13

http://www.sanjose-personalinjuryattorney.com/btjh/bdmm.aabn Martin Lester 3/22/2013 4:03:04 AM

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[Thread] Constructing a move-only object asyncronously
by Alexander Lamaison 20 Mar '13

20 Mar '13

I'm trying to create a move-only object asyncronously using Boost.Thread unique_future but I'm running into trouble: error C2248: 'A::A' : cannot access private member declared in class 'A' c:\users\awl03\documents\visual studio 2005\projects\boost_1_51_0\boost\thread\future.hpp 493 I've tried all sorts of ways to work around this but always end up with some variation or other of this error message. What am I doing wrong? The code is below. The setup is: Visual Studio 2005 Boost 1.51 Thanks, Alex #include <boost/noncopyable.hpp> #include <boost/move/move.hpp> #include <boost/thread/future.hpp> #include <boost/thread/thread.hpp> using namespace boost; class A : public noncopyable { BOOST_MOVABLE_BUT_NOT_COPYABLE(A) public: A(int i) {} A(BOOST_RV_REF(A) other) {} A& operator=(BOOST_RV_REF(A) other) {} }; A create_a() { return A(42); } unique_future<A> async_create_a() { packaged_task<A> task(create_a); unique_future<A> result = task.get_future(); thread(move(task)).detach(); return move(result); } int main() { A a = async_create_a().get(); return 0; } -- Swish - Easy SFTP for Windows Explorer (http://www.swish-sftp.org)

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Re: [Boost-users] [graph] problem with weight_map ? (brandes_betweenness_centrality)
by The Maschine 20 Mar '13

20 Mar '13

Hi, ## > EdgeWeightProperty weight = getWeight(a, b); // 0f ... 2.0f Can you just assign a double to a boost::property<...> object? That should probably not be allowed. ## I found the example here and made my code: http://programmingexamples.net/wiki/CPP/Boost/BGL/DijkstraUndirected ### What happens if you write an explicit loop over all of the edges and use put(edge_weight, g, e) directly? Does that change any of the results? -- Jeremiah Willcock ### In not sure what you mean? Im not a super expert, can you please explain your thought more? Best, Tasos

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Boost Geometry Compilation Errors
by Joel Markham 20 Mar '13

20 Mar '13

Trying to use the boost geometry library. Have a very simple example from the boost geometry home page int main(int argc, const char * argv[]) { double points[][2] = {{2.0, 1.3}, {4.1, 3.0}, {5.3, 2.6}, {2.9, 0.7}, {2.0, 1.3}}; bgm::polygon<bgm::d2::point_xy<double> > poly; bg::append(poly, points); boost::tuple<double, double> p = boost::make_tuple(3.7, 2.0); std::cout << "Point p is in polygon? " << std::boolalpha << bg::within(p, poly) << std::endl; … } When trying to build on my Mac I get compiler warnings: point_type.hpp No matching function for call to 'assertion_failed" coordinate_type.hpp No matching function for call to 'assertion_failed" convert_point_to_point.hpp Call to function 'get that is neither visible in the template definition or found… access.hpp Nom member named 'get in boost::geometry::core_dispatch… Is there something wrong with the boost libraries installed via macports?

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[BGL] Dijkstra/A* with large graph
by Nicholas Mario Wardhana 20 Mar '13

20 Mar '13

Hi all, I am wondering if with Boost Graph Library, I can do either of these two things: 1) Merge several small graphs into one large graph 2) Save and load only a portion of a large graph at a time? So the background is as follows. I have a large geometric graph (i.e. a graph with 3D coordinate custom vertex properties), which I want to use for path planning. The graph can be too large to be stored in the memory (if I understand correctly, BGL uses STL data structures, which have limits for the number of elements), so I implement the large graph as multiple small graphs (let's just call them mini-graphs). This way, I can save the mini-graphs to hard-disk, and load only the necessary mini-graphs to plan the path (I have cost function to determine the mini-graphs using Dijkstra). The problem is, this breaks the connectivity of the original graph, and I also have to add some points to two mini-graphs. Running Dijkstra/A* is consequently not straightforward, since the starting and the goal nodes can be in different mini-graphs. The two aforementioned solutions can be used as a workaround. Using approach #1, I can combine the chosen mini-graphs into one, on which I can directly run Dijkstra/A*. In approach #2, I just have one variable of graph, while the mini-graphs can just be implemented as extra properties of the nodes and edges. This way, I can select which nodes and edges to load from the files (e.g. if a node has a mini-graph ID of 1, load the node). Having said that, I don't know how to implement those approaches with BGL. It seems to me that subgraph provides a hierarchically structured graph, but is it possible to just load a subgraph without loading the whole graph? BTW, I am wondering if BGL has an external memory variant, like Parallel BGL for multi-core environment? If not, is anybody aware if there is such library (preferrably free to use for research purpose)? Thank you! Best regards, Nicholas Mario Wardhana

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accessing last element in boost multi-index
by Mahmood Naderan 19 Mar '13

19 Mar '13

Hi Using boost::multiindex, I am looking for a method to retrieve the the last element. Something like rbegin(). As I looked in to the manual page, http://www.boost.org/doc/libs/1_53_0/libs/multi_index/doc/tutorial/basics.h…, I could not find such function. Problem with end() is that it points to the last_element+1 which is null. Regards, Mahmood

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[graph] problem with weight_map ? (brandes_betweenness_centrality)
by The Maschine 19 Mar '13

19 Mar '13

Hi all, I think I've got a problem with the way I use the weight property map in my betweenness_centrality (and maybe other locations too). I've got a graph like that: typedef boost::property<boost::edge_weight_t, double> EdgeWeightProperty; typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, VertexProperties, EdgeWeightProperty> unGraph; And I add edges with weights like that (simplified): EdgeWeightProperty weight = getWeight(a, b); // 0f ... 2.0f std::pair<unGraph::edge_descriptor, bool> e = boost::add_edge(a, b, weight, m_ugraph); Than I try to do the brandes_centrality_betweenness: std::vector< double > v_centrality_vec(boost::num_vertices(m_ugraph), 0.0); boost::brandes_betweenness_centrality(m_ugraph , boost::centrality_map(boost::make_iterator_property_map(v_centrality_vec.begin(),boost::get(boost::vertex_index, m_ugraph),double())).vertex_index_map(get(boost::vertex_index, m_ugraph)).weight_map(get(boost::edge_weight, m_ugraph)) ); But I get crazy results... 1) I have checked by hand that my "getWeight" (my weights) are OK. 2) I have set _ALL_ weights to 1.0 (almost as if brandes was using BFS internally), Again I get the _SAME_ crazy results! So there is something wrong with the way Im using the weight_map. What am I missing?? Best, Tasos

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[regex] using partial_match?
by Armel Asselin 19 Mar '13

19 Mar '13

[boost 1.53.0] Hello, I'd like to find in a stream of text either "abcd" or "ab". The text is not bounded in size, so I think I should use partial_match. However I present it the following text: "hello abc<cut_here>d, how are you?" it reports to find "ab" and does not wait for the second block to be appended. #include "boost/regex.hpp" int main(int argc, char* argv[]) { boost::regex re ("abcd|ab"); std::string str ("hello abc"); boost::match_results<std::string::const_iterator> results; bool found = boost::regex_search (str.cbegin(), str.cend(), results, re, boost::regex_constants::match_partial); if (!found || results[0].matched) printf("problem...\n"); return 0; } Am I doing something wrong? I see in the specification that "Specifies that if no match can be found, then ....", isn't this specification flowed? should not it be "if the regular expression engine needs to check past the end of the block of text, and the start matches partially, ...." ? I hope I am wrong and there are good flags to pass.... Regards Armel

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[range] contiguous iterators
by Stefan Strasser 18 Mar '13

18 Mar '13

Hi everyone, is there any way to generically determine at compiletime whether an iterator or a boost range refers to contiguous memory? i.e. &*(it+1) == (&*it)+1 some type trait like is_contiguous<T *>::value == true is_contiguous<vector<T>::iterator>::value == true is_contiguous<std::list<T>::iterator>::value == false ?

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Android: segfault while writing to archive during Serialization
by wespaugh 18 Mar '13

18 Mar '13

Greetings! New to discussion, apologies in advance for any inadvertent misuse of terminology / standards. (also, I tried e-mailing this post directly last night, but it doesn't appear to have shown up, yet. double-apologies if double-post). I'm trying to port my project, which involves some serialization code, to Android. I followed instructions to build boost 1.49 found here: https://github.com/MysticTreeGames/Boost-for-Android and can successfully compile my application using crystax NDK r7 (gcc 4.5.3) , and link it to the Serialization library. Unfortunately! When my application calls the serialization code to send my object to the archive, it crashes. I've reduced my actual code to try and isolate the crash in a way I can post here. std::ofstream outStream(MAP_SAVE_FILE, std::ios_base::binary); boost::archive::text_oarchive outputArchive(outStream, 1); Classroom *c = new Classroom(); CCLog("Outputting archive"); // outputArchive << mapInstance; outputArchive << c; The crash occurs at outputArchive << c; "Fatal signal 11 (SIGEGV) at 0xdeadbaad (code=1), thread 1870 (Thread-97)" which is a segfault, in Androidvania. Ideally I want to be outputting that mapInstance variable that's commented out to archive, but for sanity's sake I made a silly little Classroom class, which I'll include for sanity's sake: class Classroom { friend class boost::serialization::access; template <class Archive> void serialize( Archive &ar, const unsigned int version ) { ar & studentCount; } int studentCount; public: Classroom() { studentCount = 1; } ~Classroom(){} }; I've run across several red flags about wchar support in Android or on gcc versions, so I'm inclined to think that's related. Then again, it appears as though my boost configuration files were aware of the compiler version when it built (that Mystic Tree link at the top really does seem to be on top of things, if anyone's interested), which is how the program was able to compile and run, at all. I'm almost 100% certain this is related to the Android NDK, either the gcc version or the gnu-stl, because I can compile and run this code on Windows through Visual studio with no problem, but it crashes on Android. I've made sure that my app has write permissions to the internal storage being used. I can even write out text files using basic std::ostreams without a crash. I am not at all familiar with dealing with these sorts of compiler- or platform-specific issues; I have a bachelor's in SE which taught me design patterns, architecture, and project management, but nothing like this. I'd greatly appreciate some direction in learning how to work through these kinds of problems, (although I'd even more greatly appreciate an actual solution to the problem I'm seeing). Thanks in advance for any assistance. -- View this message in context: http://boost.2283326.n4.nabble.com/Android-segfault-while-writing-to-archiv… Sent from the Boost - Users mailing list archive at Nabble.com.

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boost serialization of std::pair
by Andrew Smith 18 Mar '13

18 Mar '13

Hi, Is there any way of customizing the element names given to serialization of std::pair via xml_oarchive. Im think of something like the|||BOOST_SERIALIZATION_NVP mechanism. In particular Im looking to serialize std::map with custom elemnet names to replace '<first>' and '<second>' Thanks Andy |

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