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[Boost.Serialization] Unnecessary use of <iostream> in boost/serialization/export.hpp
by dariomt＠gmail.com 18 Oct '18

18 Oct '18

Hi, I see #include <iostream> in header boost/serialization/export.hpp, but that header uses nothing from namespace std. To me it looks like that #include is unnecessary, as all my code compiles fine if I remove that #include, but maybe I'm wrong. Was it included by mistake? PS: I'm using Boost 1.64, but I see the same #include in Boost 1.68

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Questions about Boost multiprecision library.
by A Z 11 Oct '18

11 Oct '18

I have some basic startup for use questions pertaining to the Boost multiprecision library. I have downloaded the set of 64 bit .dll files successfully online, and would like some help points to help me get going. *I have heard that there are some strange results that can happen if you are quizzing multiprecision for trigonometry and try to keep using the double type. Is this true, so that I can just kee relying on the std library instead? -What is the name of the 64 bit windows .dll, or .dll files, that are the ones for the multiprecision library? -If I wish to go into arbitrary precision and scale numbers, what is the type I should use for an integer? What is the #include statement I should use, and how do I specify the number of whole number points and decimal points, before starting my operations? -If I wish to go into arbitrary precision and scale numbers, what is the type I should use for a rational number? What is the #include statement I should use, and how do I specify the number of whole number points and decimal points, before starting my operations? -For these two types, I wish to do sine, cosine, tangent, arcsine, arccosine, arctangent, base 10 logarithm, base e logarithm, power, nth root. I also want to obtain pi, but also Euler's constant, to any number of significang figure or decimal places that I would like. -If the files are separate for the function support or not, what are the 64 bit .dll files for this? What #include statements should I use?

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signals2
by tim＠raisedbar.net 04 Oct '18

04 Oct '18

Hi, A friend pointed me at this library, as it may solve a problem for me. Am I correct in thinking that a signal can be activated once all of its slots are filled and not before? Best wishes. Tim Burgess Raised Bar Ltd. E: <mailto:tim@raisedbar.net> tim(a)raisedbar.net M: +44 (0)7989 486976

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Twenty years and time to retire
by Beman Dawes 04 Oct '18

04 Oct '18

The idea behind Boost was hatched in March, 1998, and the proposal document <https://www.boost.org/users/proposal.pdf> was released May 6, 1998. That makes Boost twenty years old, and makes me twenty years older. It is high time I retire from Boost; I haven't been able to contribute for some time now. Thanks to all of you who made Boost such an overwhelming success in the past and will drive Boost forward into a bright future! --Beman

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Making interprocess::message_queue use Windows_shared_memory instead of shared_memory_object
by Gaurav Sehgal 04 Oct '18

04 Oct '18

Hi, I am trying to make boost::interprocess::message_queue to use windows_shared_memory, instead of shared_memory_object. I have made the below changes to boost version 1.65.1 1) In ipc\message_queue.hpp, included windows_shared_memory.hpp instead of shared_memory_object.hpp 2) Changed typedef ipcdetail::managed_open_or_create_impl<shared_memory_object, 0, true, false> open_create_impl_t; to typedef ipcdetail::managed_open_or_create_impl<windows_shared_memory, 0, false, false> open_create_impl_t; 3) Changed the below in mq_hdr_t:: typedef ipcdetail::managed_open_or_create_impl<shared_memory_object, 0, true, false> open_create_impl_t; to typedef ipcdetail::managed_open_or_create_impl<windows_shared_memory, 0, false, false> open_create_impl_t; 4) Changed inline bool message_queue_t<VoidPointer>::remove(const char *name) { return shared_memory_object::remove(name); } to inline bool message_queue_t<VoidPointer>::remove(const char *name) { return true; } 5)Changed the below in detail\managed_open_or_create_impl.hpp template<bool dummy> static void truncate_device(DeviceAbstraction &dev, offset_t size, true_) { dev.truncate(size); } to template<bool dummy> static void truncate_device(DeviceAbstraction &dev, offset_t size, true_) { } After the above changes, no file is getting created and everything seems to work. Is there something else i should care about? Regards, Gaurav.

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undefined reference to `boost::log::v2_mt_posix::...
by Antonis Polykratis 01 Oct '18

01 Oct '18

Hello I face this error and I cannot figure out a fix. I use bjam to build the application code, and inside site-config file, I have also the following a section where I define BOOST_ALL_DYN_LINK: ''' using gcc : : : where I have defined <define> BOOST_ALL_DYN_LINK ''' I have build boost libraries with the following command: sudo bjam toolset=gcc --with-system --with-thread --with-timer --with-chrono --with-filesystem --with-program_options --with-timer *--with-log* --with-program_options --with-date_time --with-math --with-serialization --with-regex --with-chrono --with-atomic runtime-link=shared define=*BOOST_ALL_DYN_LINK* --prefix=/opt/boost_shared install | tee output.txt I also changed some files (macro definitions and jam files) because I had an error that system and filesystem are configured to be compiled both as static and shared. I compiled them as shared. When I build the application code, I have plenty of `boost::log::v2_mt_posix::...` error messages. Could you give me some guide why this problem exist? Thanks, Antonis

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error: ‘class boost::mutex’ has no member named ‘try_lock_for’
by Antonis Polykratis 28 Sep '18

28 Sep '18

Hi, I face this error, in linux, does this indicates that I have not build the library correctly? the error is in that line: boost/thread/lock_types.hpp:162:45 #ifdef BOOST_THREAD_USES_CHRONO template <class Clock, class Duration> unique_lock(Mutex& mtx, const chrono::time_point<Clock, Duration>& t) : m(&mtx), is_locked(mtx.try_lock_until(t)) { } template <class Rep, class Period> unique_lock(Mutex& mtx, const chrono::duration<Rep, Period>& d) : m(&mtx), is_locked(mtx.try_lock_for(d)) <--- here is the error { } #endif Thanks, Antonis

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Boost.Units Example: Convert between nautical mile and imperial foot
by Carel Combrink 27 Sep '18

27 Sep '18

Hi, I am trying to use Boost.Units to convert between different units. I have implemented the example code for the "Radar Beam Height" [1] section but trying to convert between nautical mile and imperial foot result in a compiler error: I have: typedef boost::units::quantity<boost::units::si::length> Meters; typedef boost::units::quantity<imperial::length> Feet; typedef boost::units::quantity<nautical::length> NMiles; double func() { // Working const Meters si1(300.0*nautical::miles); const Meters si2(300.0*imperial::feet); const Feet feet1(300.0*imperial::feet); const Feet feet2(300.0*boost::units::si::meters); const NMiles mile1(300.0*nautical::miles); const NMiles mile2(300.0*boost::units::si::meters); // BROKEN const Feet feet3(300.0*nautical::miles); const NMiles mile3(300.0*imperial::feet); } The first few works, converting between meters and the new units, but converting between the two does not work. To see the issue see the code on Compiler Explorer here: https://gcc.godbolt.org/z/MpvuMy How can I get this working? [1] https://www.boost.org/doc/libs/1_68_0/doc/html/boost_units/Examples.html#bo… Regards,

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Serialization with BOOST _CLASS_EXPORT_KEY() is not the same as registert_type<>()
by Kosby, Ray B. (GSFC-428.0)[COLUMBUS TECHNOLOGIES AND SERVICES INC] 25 Sep '18

25 Sep '18

Hi, I’m trying to serialize a derived object with polymorphism into a file and deserialize to a base class pointer. This works when I use the register_type function but not the BOOST_CLASS_EXPORT_KEY() and BOOST_CLASS_IMPLEMENT() macros. I need to use the macros since I am using shared libraries. Here is a sample of code to demonstrate the problem. When run it gets a unregistered class exception. I’m using RHEL 7.4 with Boost 1.53. cat testera.h #ifndef testera_h #define testera_h #include <boost/serialization/serialization.hpp> #include <boost/archive/polymorphic_oarchive.hpp> #include <boost/archive/polymorphic_iarchive.hpp> #include <boost/serialization/export.hpp> #include <boost/serialization/string.hpp> class A { private: friend class boost::serialization::access; template< class Arch > void serialize( Arch &ar, const unsigned int ver ); public: A(); virtual ~A() {} void setStr( const std::string &s ); std::string getStr(); protected: std::string myStr; }; BOOST_CLASS_EXPORT_KEY(A) #endif boost_ptr> cat testera.C #include "testera.h" BOOST_CLASS_EXPORT_IMPLEMENT(A) template void A::serialize<boost::archive::polymorphic_oarchive>( boost::archive::polymorphic_oarchive &ar, const unsigned int ver ); template void A::serialize<boost::archive::polymorphic_iarchive>( boost::archive::polymorphic_iarchive &ar, const unsigned int ver ); A::A() : myStr( "a" ) { } void A::setStr( const std::string &s ) { myStr = s; } std::string A::getStr() { return myStr; } template<class Arch> void A::serialize( Arch &ar, const unsigned int ver ) { ar & myStr; } boost_ptr> cat testerb.h #ifndef testerb_h #define testerb_h #include "testera.h" class B : public A { private: friend class boost::serialization::access; template< class Arch > void serialize( Arch &ar, const unsigned int ver ); public: B(); virtual ~B() {} void set( const int i ); int get(); protected: int myI; }; BOOST_CLASS_EXPORT_KEY(B) #endif boost_ptr> cat testerb.C #include "testerb.h" BOOST_CLASS_EXPORT_IMPLEMENT(B) template void B::serialize<boost::archive::polymorphic_oarchive>( boost::archive::polymorphic_oarchive &ar, const unsigned int ver ); template void B::serialize<boost::archive::polymorphic_iarchive>( boost::archive::polymorphic_iarchive &ar, const unsigned int ver ); B::B(): myI( 1 ) { myStr = "b"; } void B::set( const int i ) { myI = i; } int B::get() { return myI; } template< class Arch > void B::serialize( Arch &ar, const unsigned int ver ) { // boost::serialization::void_cast_register< B, A >( static_cast< B *>( NULL ), static_cast< A * >( NULL ) ); ar & boost::serialization::base_object<A>( *this ); ar & myI; } int main( int argc, char *argv[] ) { int ret = 0; B obj; B obj2; obj.set( 2 ); A *ptr = NULL; B *bptr = NULL; bptr = &obj; ptr = &obj; if( argc > 1 ) { std::string fl = argv[ 1 ]; { std::ofstream ofl( fl.c_str() ); boost::archive::polymorphic_text_oarchive toar( ofl ); boost::archive::polymorphic_oarchive *oar = &toar; /* oar->register_type(static_cast<A *>(NULL)); oar->register_type(static_cast<B *>(NULL)); */ try { *oar & obj; // *oar & ptr; } catch( std::exception &e ) { std::cerr << "Error: archive from B to file " << fl << " - " << e.what() << std::endl; ret = 1; } } if( ! ret ) { ptr = NULL; bptr = NULL; { std::ifstream ifl( fl.c_str() ); boost::archive::polymorphic_text_iarchive tiar( ifl ); boost::archive::polymorphic_iarchive *iar = &tiar; /* iar->register_type(static_cast<A *>(NULL)); iar->register_type(static_cast<B *>(NULL)); */ try { *iar & ptr; // *iar & bptr; } catch( std::exception &e ) { std::cerr << "Error: archive from file " << fl << " to B * - " << e.what() << std::endl; ret = 1; } } if( ! ret ) { // std::cout << bptr->get() << std::endl; std::cout << static_cast<B*>( ptr )->get() << std::endl; } } } return ret; } testera and testerb are compiled into a shared library with this: boost_ptr> cat Makefile_lib CXXFLAGS = -c -ggdb3 -fPIC -funswitch-loops -fgcse-after-reload -std=c++11 LDFLAGS = -std=c++11 -lboost_serialization -lboost_thread -lboost_system -lboost_filesystem OBJLOC = obj OBJS = $(OBJLOC)/testera.o \ $(OBJLOC)/testerb.o LIBRARY_NAME = libtester.so libs:$(LIBRARY_NAME) $(LIBRARY_NAME): $(OBJS) ${CXX} -shared -o $@ $(OBJS) $(OBJLOC)/%.o: ./%.C $(CXX) $(CXXFLAGS) ./$*.C -o $(OBJLOC)/$*.o tester_mn is compiled into the executable with this: boost_ptr> cat Makefile_mn CXXFLAGS = -ggdb3 -funswitch-loops -fgcse-after-reload -std=c++11 LDFLAGS = -lboost_serialization -lboost_thread -lboost_system -lboost_filesystem -L. -ltester tester_mn: tester_mn.o ${CXX} $(CXXFLAGS) $(LDFLAGS) tester_mn.C -o $@ If I were to comment out the BOOST macros and uncomment the register_type() functions from tester_mn.C everything works. Is there a way to get the macros to work? -- Ray Kosby Software Engineer Columbus Technologies and Services, Inc www.columbususa.com<http://www.columbususa.com> Office - (301) 286-5095, fax - (301) 286-7475 NASA Goddard Space Flight Center, MS 452.1 Bldg 13 Rm 141 8800 Greenbelt Rd Greenbelt, MD 20771 USA

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Re: [Boost-users] [Boost.Beast] Libraries augmenting Boost.Beast
by Damian Jarek 24 Sep '18

24 Sep '18

Hi Sean, I've been recently working on a library that is supposed to abstract some of the platform-specific aspects of TLS peer verification (e.g. accessing the OS cert store) and obtaining the system proxy information. The project is in its early stages but is actively being worked on (https://github.com/djarek/ netutils). Another library you might be interested in, though still fairly experimental is Foxy (https://github.com/LeonineKing1199/f3) which abstracts away HTTP session management. Best Regards, Damian Jarek

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Formal Review of Proposed Boost.Histogram Library is HALFWAY through
by Mateusz Loskot 22 Sep '18

22 Sep '18

Dear Boost Community, We've reach half-way through the formal review of Hans Dembinski's Histogram library. The review lasts until the end of September 26th. If you are interested in applications for mathematics, statistics graphics, image analysis, and such, or in the Histogram library itself, please consider reviewing the Histogram library by the end of September 26th. Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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[filesystem] Library maintainers needed
by Beman Dawes 22 Sep '18

22 Sep '18

I'm retiring, so Boost.Filesystem needs one or more maintainers. This is a high complexity library, further complicated by (1) requiring both Windows and non-Windows implementation code and (2) needing a major upgrade for compatibility with the new standard library version shipped in C++17. Furthermore, there are constant Pull Requests and Issues that arise, and these almost invariably take a lot of time for the maintainer to process. My personal opinion is that Boost should deprecate the Boost library in favor of the standard library implementations, and do only minimal maintenance for several years until most users have migrated to C++17 or later. But that's up to the new maintainers to decide. Thanks, --Beman

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[endian] Library maintainer needed
by Beman Dawes 22 Sep '18

22 Sep '18

I'm retiring, so Boost.Endian needs a maintainer. This is a low/medium complexity library that requires only minor effort to maintain. --Beman

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[timer] Library maintainer needed
by Beman Dawes 22 Sep '18

22 Sep '18

I'm retiring, so Boost.Timer needs a maintainer. This is a simple low complexity library, and requires little effort to effort to maintain. --Beman

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undefined reference to `boost::system::detail::generic_category_ncx()'
by Antonis Polykratis 20 Sep '18

20 Sep '18

Hello all, I am new to boost. I try to use some boost files in my program, but I have trouble with some of them. For example compiling the following program #include <boost/log/expressions/formatters/date_time.hpp> int main() { return 0; } with the command g++ -std=c++11 test.cpp -o main -I/home/user101/boost/ -L/home/user101/boost I have a message like the following /tmp/ccm6UOud.o: In function `boost::system::generic_category()': test.cpp:(.text._ZN5boost6system16generic_categoryEv[_ZN5boost6system16generic_c ategoryEv]+0x5): undefined reference to `boost::system::detail::generic_category _ncx()' I also tried to append -lboost_system in the command, but I take back the following message: /usr/bin/ld: cannot find -lboost_system collect2: error: ld returned 1 exit status Could you please guide me with that? I use boost_1_67 if that makes any difference (which I do not think so). Thanks, Antonis

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[Boost.Beast] Libraries augmenting Boost.Beast
by Sean Farrow 20 Sep '18

20 Sep '18

Hi all, Is there a list of open source libraries that augment Boost.Beast. I'm thinking things like OAuth/OpenID connect for example. Any help appreciated. Kind regards Sean.

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Fwd: Formal Review of Proposed Boost.Histogram Library
by Mateusz Loskot 19 Sep '18

19 Sep '18

FYI, We are reviewing Histogram library proposed to proposed . If you are interested in applications for mathematics, statistics, graphics, image analysis, and such, or in the Histogram library itself, please consider reviewing the Histogram library by the end of September 26th. Further details included below. You can post your review to the Boost development list to boost (at)lists.boost.org or directly to me to. Thank you! Mateusz Review Manager for the proposed Boost.Histogram ---------- Forwarded message --------- From: Mateusz Loskot <mateusz(a)loskot.net> Date: Mon, 17 Sep 2018 at 11:06 Subject: Formal Review of Proposed Boost.Histogram Library Starts TODAY To: <boost(a)lists.boost.org> Dear Boost Community, The formal review of Hans Dembinski's Histogram library starts TODAY, the September 17th, and lasts until September 26th, unless an extension occurs. =========== What is it? =========== Histogram is a header-only C++11 library, provides multi-dimensional histogram template class for counting, statistics and data exploration. The histogram class interface has been carefully designed to make the library * offer simple and convenient default behaviour * easy to learn and safe to use * convenient to use for one- as well as multi-dimensional analysis * compatible with STL algorithms * dependant only on C++11 standard library and optionally on Boost The author followed the "Don't pay for what you don't use" principle. The histogram class is customisable through policy classes, but the default policies were carefully crafted so that most users do not need to customize anything. The default policies guarantee the histogram to be safe to use as a black box, memory efficient, and very fast, where safety is related to overflow prevention and large values capping. This guarantees is one of unique features of the library in comparison to other implementations. The histogram class comes in two variants, which share a common interface: * static variant is optimised at compile-time to provide maximum performance, at the cost of reduced runtime flexibility and potentially larger executables; * dynamic variant is a bit slower, but configurable at run-time. Both variants of the histogram class provide optional serialization support implemented with Boost.Serialization. The library itself is header-only and the tests as well as examples can be built using both, Boost.Build and CMake. There are no dependencies required other than C++11 compiler. Optional dependencies include the GNU Scientific Library (GSL) and the ROOT framework from CERN which are needed the corresponding speed test programs used for performance comparison. A note on history: The library was first announced to the Boost community in May, 2016 [1] and the author received extensive feedback. Then, after a year of work posted second request for comments in April, 2017 [2]. =================== Getting the library =================== Checkout the `master` branch from the library git repository: https://github.com/HDembinski/histogram/ NOTE: The author follows the library submission process [3]: the master branch remains frozen for the period of the formal review, modifications in response to feedback should go to `develop` branch and big items may be worked and discussed via opening an issue on GitHub. Documentation: http://hdembinski.github.io/histogram/doc/html/ Website: http://hdembinski.github.io/histogram/ ================ Writing a review ================ Please, follow the official Boost formal review procedure [4]. If you feel this is an interesting library, then please submit your review to the Boost developer list (preferably), or the review manager to mateusz (at) loskot (dot) net. Here are some questions you might want to answer in your review: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? And finally, every review should answer this question: - Do you think the library should be accepted as a Boost library? Be sure to say this explicitly so that your other comments don't obscure your overall opinion. If needed, refer to the Boost Library Requirements and Guidelines [5]. Please, give constructive criticism! [1] https://lists.boost.org/Archives/boost/2016/05/229389.php [2] https://lists.boost.org/Archives/boost/2017/04/234410.php [3] https://www.boost.org/development/submissions.html#Review [4] https://www.boost.org/community/reviews.html [5] https://www.boost.org/development/requirements.html Mateusz Review Manager for the proposed Boost.Histogram -- Mateusz Loskot, http://mateusz.loskot.net

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[asio] is the io_context queue FIFO?
by Frédéric 19 Sep '18

19 Sep '18

Is there a guarantee that the events posted using boost::asio::post() are called in the order of submission or can they be called in any order? Note that I have multiple threads running io_context.run(). Thanks, F

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[asio] How to prevent high load CPU by io_context::run ?
by Dmitrij V 18 Sep '18

18 Sep '18

Hi. After run io and after connection an one client, I have 25% CPU loading by server. What I doing wrong ? How can I minimize it ? PS: Client connected to TCP server without limits by time, - persistent connections... -- the best regards

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[asio] are defer/dispatch/post identical?
by Frédéric 18 Sep '18

18 Sep '18

Hi, Is there a difference between defer, dispatch and post free functions? They look very similar, there files look the same apart from the fact that they call defer, dispatch and post of the executor. The doc in executor seems to be the same. Thanks, F

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Cannot cast from std::string to seastar::sstring.
by José Guilherme Vanz 17 Sep '18

17 Sep '18

Hi guys, I'm investigating a [bug](https://github.com/scylladb/scylla/issues/2905) in the Seastar/lexical_cast and I got stuck. Let me introduce what's going on and the further investigation that I did. The Seastar framework uses the boost program options to parse the command line arguments. But when the user try to pass a command line argument of seastar::sstring (Seastar string type) with a white space, the lib tells us that is invalid value. Turns out the boost program options call lexical_cast to cast from std::string to seastar::sstring. This cast is failing. The lexical_cast uses a stream to extract the value from the source, but the operator>> stops in the white space. Making the second validation in the same [line](https://github.com/boostorg/lexical_cast/blob/boost-1.66.0/include/bo… false. Note, there is a [call](https://github.com/boostorg/lexical_cast/blob/boost-1.66.0/include/bo… to unsetf to ensure that the white space will be skipped: stream.unsetf(std::ios::skipws);. What's am I trying to do is figure out where the problems live? Is there a bug in boost or is a sstring implemantion problem? Am I missing something? Thanks!

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Re: [Boost-users] Looking for a mechanism (boost::asio
by Bjorn Reese 15 Sep '18

15 Sep '18

On 09/14/18 23:21, Tim Burgess via Boost-users wrote: > I need my main code to pause until I receive a response from the > hardware. I don’t want to use a timer, as this would be potentially Sounds like you need a promise/future.

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Re: [Boost-users] Looking for a mechanism (boost::asio
by tim＠raisedbar.net 15 Sep '18

15 Sep '18

OK, I’ve just read the preamble for the ASIO library (Chapter 32) and it seems that this library, whilst extremely useful, does exactly the opposite of what I’m trying to achieve, as it allows main code execution to continue whilst waiting for a response from an external device. I need my main code to pause until I receive a response from the hardware. I don’t want to use a timer, as this would be potentially unreliable - I can never know how long a pause would be required and there would be the danger of having the code hanging around wasting time if the timer value is too generous. Best wishes. Tim Burgess From: Boost-users <boost-users-bounces(a)lists.boost.org> On Behalf Of Tim Burgess via Boost-users Sent: 14 September 2018 20:49 To: boost-users(a)lists.boost.org Cc: tim(a)raisedbar.net Subject: Re: [Boost-users] Looking for a mechanism Thanks – I’ll go and do some reading. Just to add more information: the hardware is a MIDI device, with the sent messages being groups of 6 individual short MIDI messages, so a total of 18 7-bit bytes per transmitted query. The response messages are groups of 4 MIDI short messages. There is something like 200 parameters to be queried – the MIDI connection is either via traditional DIN cables with a transfer rate of 31kbps, or over USB. Over the USB connection the manufacturer estimates that I should be able to get a full set of responses back in around 100ms. I’m using the rtMIDI library to do the heavy lifting in terms of handling the MIDI I/O devices and handling themessage formatting. Best wishes. Tim Burgess From: Boost-users <boost-users-bounces(a)lists.boost.org <mailto:boost-users-bounces@lists.boost.org> > On Behalf Of Keith Bennett via Boost-users Sent: 14 September 2018 18:54 To: boost-users(a)lists.boost.org <mailto:boost-users@lists.boost.org> Cc: Keith Bennett <kanezor(a)gmail.com <mailto:kanezor@gmail.com> > Subject: Re: [Boost-users] Looking for a mechanism Without more information it'd be hard to say. Are you familiar with Boost ASIO? It's a common method of handling asynchronous communication, though how much it can be used in your situation may depend on the particular hardware interface. The typical situation for a single-threaded process is to set up an executor context, maybe set up signal handlers, then make an asynchronous call using ASIO's objects. When making the asynchronous calls, you provide a callback function object. Your callback function object may then make another request during its processing. ASIO handles the under-the-hood abstraction (and generally simplifies it for most situations). But it's up to you to ensure that your call sequence is safe: for example ASIO will not prevent you from making multiple simultaneous writes to the same file descriptor despite it being unsafe in many situations. My understanding is that your callback is placed onto a function queue rather than called directly (contrast to POSIX signals where the OS interrupts whatever function is running right now). That can hurt your response performance if you're doing long-running tasks so it's worth considering. On Fri, Sep 14, 2018 at 12:03 PM Tim Burgess via Boost-users <boost-users(a)lists.boost.org <mailto:boost-users@lists.boost.org> > wrote: Hi, I’m trying to find a method of solving the problem detailed below using Boost (or an alternative: 1 – I have to send a series of messages to a hardware device to query its internal parameter values at application load-time. This I can do; 2 – I have a callback that receives responses from the hardware, though I get some replies go missing due to saturation; 3 * The hardware manufacturer tells me that I should send 1 query then wait for the response before sending the next query. I could use Sleep, but this depends on a specific wait time and I’m not sure if it suspends all processing, including my callback, so this doesn’t look satisfactory. What I’m looking for is a “wait until response” kind of thing, but I haven’t found such a thing so far, though I have found several wait routines for handling multiple threads. I’d appreciate any guidance as to what to look for, as my searches are obviously not asking the right questions. Best wishes. Tim Burgess Raised Bar Ltd. E: tim(a)raisedbar.net <mailto:tim@raisedbar.net> M: +44 (0)7989 486976 _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org <mailto:Boost-users@lists.boost.org> https://lists.boost.org/mailman/listinfo.cgi/boost-users -- Keith Bennett

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Looking for a mechanism
by tim＠raisedbar.net 14 Sep '18

14 Sep '18

Hi, I'm trying to find a method of solving the problem detailed below using Boost (or an alternative: 1 - I have to send a series of messages to a hardware device to query its internal parameter values at application load-time. This I can do; 2 - I have a callback that receives responses from the hardware, though I get some replies go missing due to saturation; 3 * The hardware manufacturer tells me that I should send 1 query then wait for the response before sending the next query. I could use Sleep, but this depends on a specific wait time and I'm not sure if it suspends all processing, including my callback, so this doesn't look satisfactory. What I'm looking for is a "wait until response" kind of thing, but I haven't found such a thing so far, though I have found several wait routines for handling multiple threads. I'd appreciate any guidance as to what to look for, as my searches are obviously not asking the right questions. Best wishes. Tim Burgess Raised Bar Ltd. E: <mailto:tim@raisedbar.net> tim(a)raisedbar.net M: +44 (0)7989 486976

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[Beast] Downloading multiple urls in parallel
by Sean Farrow 13 Sep '18

13 Sep '18

Hi, Are there functions within beast to allow me to start downloading multiple url's in parallel and then handle each returned result with a different continuation function? Any help appreciated. Kind regards Sean.

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