August 2014 - Boost-users - lists.preview.boost.org

Re: [Boost-users] [ASIO] directory monitor ASIO extension
by Brian Wood 06 Aug '14

06 Aug '14

Niall Douglas writes > * Works reliably on Microsoft Windows (hard), Linux (slightly > easier), BSD and OS X (easiest by far of the lot). > I believe you. Having considered some of your previous comments in a different thread, on kqueue, I ported my code generator from Linux to BSD. I only found relief from a problem I was having by doing so. > Paul Kirth presented on this at C++ Now 2014. It is a surprisingly > tough engineering problem, and requires a design approaching ideal > for it to work at all. Are videos from that conference available yet? -- Brian Ebenezer Enterprises - In G-d we trust. http://webEbenezer.net

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[ASIO] directory monitor ASIO extension
by Szymon Gatner 06 Aug '14

06 Aug '14

Hi, I am going through code of directory monitor ASIO extension by Boris Schäling (http://www.highscore.de/boost/dir_monitor.zip) and I am wondering: what is the benefit of making this piece of code / library an ASIO extension. It just feels like it could be easier to use and implement if it wasn't? I hope I am missing something tho and looking here for enlightenment ;) Regards, Szymon Gatner

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why lockfree/queue.hpp requires has_trivial_assign and has_trivial_destructor to template type T
by 何子杰Hzj_jie 06 Aug '14

06 Aug '14

hi, all,as new to boost, i am looking for a solution to combine boost::lockfree::queue with std::function, i.e. boot::lockfree::queue<std::function>, but unfortunately, the implementation of the lockfree queue required the T to be trivial assignable and trivial destructible.with some basic investigation to the implementation of boost::lockfree::queue, the assignment operator is using when pop or unsynchronized_pop, it calls detail::copy_payload, which is using operator= or constructor and operator=. though overloaded assignment operator may use more time and cause the pop function to wait for longer time, i do not see it would block the logic.for the destruction, queue implementation always calls pool.template destruct instead deallocate, which means even for a default destructor, it will also be called. so is this a defect or by-design behavior of the lockfree queue? thank you in advanced. .Hzj_jie

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[msm] State Machine and Dependency Injection
by Kris 05 Aug '14

05 Aug '14

Hi, Recently I have implemented Dependency Injection library, which I proposed to boost last week (http://boost.2283326.n4.nabble.com/is-there-any-interest-in-a-dependency-in…) Right now I wanted to shared how dependency injection might be integrated with Boost.MSM (eUML) and would really glad for any feedback. Boost.MSM is a great library, unfortunately actions/guards have to have empty constructor and whole logic has to be handled via Finite State Machine. Such approach is hard to maintain and test, so would be great to have possibility to implement action/guards without FSM dependency and with proper dependency injection instead. More information: http://krzysztof-jusiak.github.io/di/boost/libs/di/doc/html/di/examples/int… Hello World: class guard : public euml_action<guard> { public: guard(shared_ptr<data> data = nullptr, shared_ptr<other_data> = nullptr); // default constructor is required by eUML template<typename TEvent> bool operator()(const TEvent&) const; // no FSM dependency }; class action : public euml_action<action> { public: action(shared_ptr<data> data = nullptr, shared_ptr<other_data> = nullptr); // default constructor is required by eUML template<typename TEvent> void operator()(const TEvent&); // no FSM dependency }; class state_machine_ : public state_machine_def<state_machine_> { public: using initial_state = state1; BOOST_MSM_EUML_DECLARE_TRANSITION_TABLE(( state1() + event() [guard()] / action() == state2() ), transition_table) }; using state_machine = back::state_machine< state_machine_ , back::use_dependency_injection // Boost.DI dependency injection policy >; auto sm = di::make_injector().create<state_machine>(); // create state machine / actions, guards and their dependencies will be injected via DI framework sm.process_event(event()); Hot it works? * we do implement actions/guards with any dependencies we need * we add use_dependency_injection policy in state machine definition * we create state machine using dependency injection framework library What MSM with DI actually give us? * actions/guards are really easy to test / code doesn't require FSM dependency - loosely coupled * signature change of actions/guards may not require binding configuration changes (if it's not an interface or it's an interface already bound) * FSM is just a declarative abstraction - we don't need to test it * we can use all DI goods for controlling how dependencies will be injected - see https://github.com/krzysztof-jusiak/di Project (with workings tests): https://github.com/krzysztof-jusiak/msm Comparison between usage of Boost.MSM with DI and without it: http://krzysztof-jusiak.github.io/di/boost/libs/di/doc/html/di/examples/int… Looking forward to hear from you. Any feedback is more than welcome. Cheers, Kris -- View this message in context: http://boost.2283326.n4.nabble.com/msm-State-Machine-and-Dependency-Injecti… Sent from the Boost - Users mailing list archive at Nabble.com.

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[1.56.0] Release candidates available
by Marshall Clow 04 Aug '14

04 Aug '14

Release candidate files for 1.65.0 are available at http://boost.cowic.de/rc/ As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. This helps ensure the candidates build OK before we push them out to SourceForge. The files (and associated md5s) are: MD5 (boost_1_56_0_rc1.7z) = 0ac22b92b24209286d48e4c41925cd9f MD5 (boost_1_56_0_rc1.tar.bz2) = 5b5bfa99244b1ac5737323decceb19c2 MD5 (boost_1_56_0_rc1.tar.gz) = 2047cdd4e09cda34e7f10fec0f821175 MD5 (boost_1_56_0_rc1.zip) = 0c544f6acc85550b15cdc9221f2ac0c9 Thanks! -- The release managers

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[serialization] Please help me solve this compile error.
by Paul Blampspied 04 Aug '14

04 Aug '14

I am tearing my hair out over this, partly because I believe the code used to compile. I just can't see what the problem is. I enclose all the pertinent code as I cannot say which bits are irrelevant. There are two classes: ManagedArray which is an array of data without size or capacity data (this is stored elsewhere). PersistentManagedArray which I wrote to enable ManagedArrays to be serialized. The error message is produced in 'main': error: no match for 'operator<<' in 'oa << PersistentManagedArray<int>((* & size), (* & capacity), (* & ints))' It seems to me that I have defined the necessary serialize member function with the right signature. Commented out is code I wrote some time ago which used separate load and save functions. This, I believe, used to work. #include <fstream> #include <boost/archive/binary_oarchive.hpp> #include <boost/archive/binary_iarchive.hpp> #include <string> using namespace std; //**************************************************************************************************************************** template<class T> class ManagedArray { public: T *values; ManagedArray() { values = NULL; } ~ManagedArray() { if (values) { delete [] values; } } //Changes array size. If array grows, the new values are unintialized. void resize(unsigned oldSize, unsigned newSize) { if (oldSize==newSize) return; T *newValues = (newSize==0) ? NULL : new T[newSize]; if (oldSize!=0) { T *oldValue, *newValue; T *end = values + (oldSize<newSize ? oldSize : newSize); for(oldValue=values, newValue=newValues; oldValue<end; oldValue++, newValue++) { *newValue = *oldValue; } } if (values) { delete [] values; } values = newValues; } //Changes array size. If array grows, the new values are initialised to copies of a prototype, initValue. void resize(unsigned oldSize, unsigned newSize, T &initValue) { if (oldSize==newSize) return; T *newValues = (newSize==0) ? NULL : new T[newSize]; T *oldValue = values; T *newValue = newValues; if (oldSize!=0) { T *oldEnd = values + (oldSize<newSize ? oldSize : newSize); for(; oldValue<oldEnd; oldValue++, newValue++) { *newValue = *oldValue; } } T *newEnd = newValues + newSize; for(; newValue<newEnd; newValue++) { *newValue = initValue; } delete [] values; values = newValues; } inline T &operator[](unsigned index) { return values[index]; } inline const T &operator[](unsigned index) const { return values[index]; } }; //**************************************************************************************************************************** //This class helps to save a ManagedArray in a Boost archive // Usage: // ar & PersistentManagedArray(size, capacity, array); template<class T> class PersistentManagedArray { public: PersistentManagedArray(unsigned &size, unsigned &capacity, ManagedArray<T> &managedArray) : _size(size), _capacity(capacity), _managedArray(managedArray) {valueArrayExists = (_managedArray.values!=NULL);} private: unsigned &_size; unsigned &_capacity; ManagedArray<T> &_managedArray; bool valueArrayExists; friend class boost::serialization::access; // template<class Archive> // void save(Archive & ar, const unsigned int version) const { // ar & valueArrayExists; // if (valueArrayExists) { // for(unsigned i=0; i<_size; i++) { // ar & _managedArray.values[i]; // } // } // } // template<class Archive> // void load(Archive & ar, const unsigned int version) { // _managedArray.values = NULL; // ar & valueArrayExists; // if (valueArrayExists) { // _managedArray.resize(0, _capacity); // for(unsigned i=0; i<_size; i++) { // ar & _managedArray.values[i]; // } // } // } // BOOST_SERIALIZATION_SPLIT_MEMBER() template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & valueArrayExists; ar & _size; ar & _capacity; if (Archive::is_loading::value) { delete _managedArray.values; _managedArray.values = new T[_capacity]; } for(unsigned i=0; i<_size; i++) { ar & _managedArray.values[i]; } } }; int main(int argc, char *argv[]) { ManagedArray<int> ints; unsigned size; unsigned capacity; string fileName = "data.xxx"; ofstream file(fileName.c_str(), ios::out|ios::binary); if (file.good()) { boost::archive::binary_oarchive oa(file); oa << PersistentManagedArray<int>(size, capacity, ints); //This line does not compile ! } }

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[1.56.0] Release Candidate 2 available
by Eric Niebler 04 Aug '14

04 Aug '14

We've created a second release candidate to fix a few issues. The three fixes since RC1 are listed at the end of this mail. The files for 1.56.0 RC2 are available at: http://boost.cowic.de/rc/ As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. The files (and associated md5s) are: MD5 (boost_1_56_0_rc2.7z) = 2e1688886aede1c3348e131a0e73a031 MD5 (boost_1_56_0_rc2.tar.bz2) = 2079fabbfb9fb046e6e12e381eff20fa MD5 (boost_1_56_0_rc2.tar.gz) = 96fe9c5f70759399217dc7ee113ecdd3 MD5 (boost_1_56_0_rc2.zip) = df42b60e120841fc3893de7c2529fc4a Thanks! -- The release managers === Changes Since RC1 === Boost.Thread bug is causing coroutine build to fail on gcc 4.6 in C++11 mode. https://github.com/boostorg/thread/pull/21 Boost.Graph broken on MSVC-12 and gcc-4.4. https://github.com/boostorg/graph/pull/14 Boost.System broken on cygwin, local_free_on_destruction not defined. https://github.com/boostorg/system/pull/4

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