September 2013 - Boost-users - lists.preview.boost.org

[units] Convert from Degree Minutes to Degrees
by Ryan 21 Sep '13

21 Sep '13

Angles have their own system that define both radians and degrees. I would like to create the necessary type for minutes (this is 1/60 of a degree). My first thought was to create a scale unit with degrees as the base type. I couldn't determine how to enter the scale of 1/60. The other option is to define a new base unit. I would think using the degrees base unit would be a good reference, but it uses an "INTERNAL ONLY" macro call "BOOST_UNITS_DEFINE_BASE_UNIT_WITH_CONVERSIONS". What should I use to create a unit type that will convert from degree minutes to just degrees? Ryan

2 2

tcp::socket::is_open() is true after socket is closed
by niXman 20 Sep '13

20 Sep '13

Hi, In the following simple code: tcp::socket socket(ios); ... const bool iso1 = socket.is_open(); socket.close(); const bool iso2 = socket.is_open(); I get: iso1 == iso2 == true Why? Thanks. -- Regards, niXman ___________________________________________________ Dual-target(32 & 64-bit) MinGW compilers for 32 and 64-bit Windows: http://sourceforge.net/projects/mingwbuilds/ ___________________________________________________ Another online IDE: http://liveworkspace.org/

2 1

Getting ASIO application to link (undefined reference to `boost::system::generic_category())
by Ulf Samuelsson 20 Sep '13

20 Sep '13

Hi, Trying to get an ASIO example (udp_echo_client) to build on an Ubuntu 12.04 machine. It looks like both 1.46 and 1.48 can be installed. (I have installed 1.48). The libboost*.so all are linked vs 1.48, and the /usr/include/boost/version.hpp contains #define BOOST_LIB_VERSION "1_48" so I think that there should not be a version mismatch, I can build some really simple examples but, as soon as I add "asio" with the statement below, the build fails. using boost::asio::ip::udp; Fiirst problem is that `boost::system::generic_category()' is missing. When I grep the libboost libraries, they are only found in "libboost_[file]system[-mt].so" but these files are included in the link. Searching on Internet, also tells me to link with those libraries, which is not a help. Tried with "-mt" version as well. Added #include <boost/system/error_code.hpp> #include <boost/system/linux_error.hpp> without any change. What is going on? Running out of ideas... Thanks for any advice. /Ulf Samuelsson ---------------------------------------------------------- g++ -I/usr/include -Iinclude -L/usr/lib -lboost_filesystem -lboost_system -lpthread -std=c++0x -o udp_echo_client udp_echo_client.cpp /tmp/ccu20iRA.o: In function `__static_initialization_and_destruction_0(int, int)': udp_echo_client.cpp:(.text+0x58d): undefined reference to `boost::system::generic_category()' udp_echo_client.cpp:(.text+0x597): undefined reference to `boost::system::generic_category()' udp_echo_client.cpp:(.text+0x5a1): undefined reference to `boost::system::system_category()' /tmp/ccu20iRA.o: In function `boost::system::error_code::error_code()': udp_echo_client.cpp:(.text._ZN5boost6system10error_codeC2Ev[_ZN5boost6system10error_codeC5Ev]+0x10): undefined reference to `boost::system::system_category()' /tmp/ccu20iRA.o: In function `boost::asio::error::get_system_category()': udp_echo_client.cpp:(.text._ZN5boost4asio5error19get_system_categoryEv[boost::asio::error::get_system_category()]+0x7): undefined reference to `boost::system::system_category()' /tmp/ccu20iRA.o: In function `boost::asio::detail::posix_tss_ptr_create(unsigned int&)': udp_echo_client.cpp:(.text._ZN5boost4asio6detail20posix_tss_ptr_createERj[boost::asio::detail::posix_tss_ptr_create(unsigned int&)]+0x15): undefined reference to `pthread_key_create' /tmp/ccu20iRA.o: In function `boost::asio::detail::posix_thread::~posix_thread()': udp_echo_client.cpp:(.text._ZN5boost4asio6detail12posix_threadD2Ev[_ZN5boost4asio6detail12posix_threadD5Ev]+0x1d): undefined reference to `pthread_detach' /tmp/ccu20iRA.o: In function `boost::asio::detail::posix_thread::join()': udp_echo_client.cpp:(.text._ZN5boost4asio6detail12posix_thread4joinEv[boost::asio::detail::posix_thread::join()]+0x25): undefined reference to `pthread_join' /tmp/ccu20iRA.o: In function `boost::asio::detail::posix_thread::start_thread(boost::asio::detail::posix_thread::func_base*)': udp_echo_client.cpp:(.text._ZN5boost4asio6detail12posix_thread12start_threadEPNS2_9func_baseE[boost::asio::detail::posix_thread::start_thread(boost::asio::detail::posix_thread::func_base*)]+0x24): undefined reference to `pthread_create' /tmp/ccu20iRA.o: In function `boost::asio::detail::posix_tss_ptr<boost::asio::detail::call_stack<boost::asio::detail::task_io_service, boost::asio::detail::task_io_service::thread_info>::context>::~posix_tss_ptr()': udp_echo_client.cpp:(.text._ZN5boost4asio6detail13posix_tss_ptrINS1_10call_stackINS1_15task_io_serviceENS4_11thread_infoEE7contextEED2Ev[_ZN5boost4asio6detail13posix_tss_ptrINS1_10call_stackINS1_15task_io_serviceENS4_11thread_infoEE7contextEED5Ev]+0xf): undefined reference to `pthread_key_delete' /tmp/ccu20iRA.o: In function `boost::asio::detail::posix_tss_ptr<boost::asio::detail::call_stack<boost::asio::detail::task_io_service, boost::asio::detail::task_io_service::thread_info>::context>::operator boost::asio::detail::call_stack<boost::asio::detail::task_io_service, boost::asio::detail::task_io_service::thread_info>::context*() const': udp_echo_client.cpp:(.text._ZNK5boost4asio6detail13posix_tss_ptrINS1_10call_stackINS1_15task_io_serviceENS4_11thread_infoEE7contextEEcvPS7_Ev[boost::asio::detail::posix_tss_ptr<boost::asio::detail::call_stack<boost::asio::detail::task_io_service, boost::asio::detail::task_io_service::thread_info>::context>::operator boost::asio::detail::call_stack<boost::asio::detail::task_io_service, boost::asio::detail::task_io_service::thread_info>::context*() const]+0xf): undefined reference to `pthread_getspecific' /tmp/ccu20iRA.o: In function `boost::asio::detail::posix_tss_ptr<boost::asio::detail::call_stack<boost::asio::detail::strand_service::strand_impl, unsigned char>::context>::~posix_tss_ptr()': udp_echo_client.cpp:(.text._ZN5boost4asio6detail13posix_tss_ptrINS1_10call_stackINS1_14strand_service11strand_implEhE7contextEED2Ev[_ZN5boost4asio6detail13posix_tss_ptrINS1_10call_stackINS1_14strand_service11strand_implEhE7contextEED5Ev]+0xf): undefined reference to `pthread_key_delete' /tmp/ccu20iRA.o: In function `boost::asio::detail::posix_tss_ptr<boost::asio::detail::call_stack<boost::asio::detail::task_io_service, boost::asio::detail::task_io_service::thread_info>::context>::operator=(boost::asio::detail::call_stack<boost::asio::detail::task_io_service, boost::asio::detail::task_io_service::thread_info>::context*)': udp_echo_client.cpp:(.text._ZN5boost4asio6detail13posix_tss_ptrINS1_10call_stackINS1_15task_io_serviceENS4_11thread_infoEE7contextEEaSEPS7_[boost::asio::detail::posix_tss_ptr<boost::asio::detail::call_stack<boost::asio::detail::task_io_service, boost::asio::detail::task_io_service::thread_info>::context>::operator=(boost::asio::detail::call_stack<boost::asio::detail::task_io_service, boost::asio::detail::task_io_service::thread_info>::context*)]+0x16): undefined reference to `pthread_setspecific' collect2: ld returnerade avslutningsstatus 1 make: *** [udp_echo_client] Fel 1 -------------------------------------------------------------- Makefile: ------------------------------------------------------ # Using 1.48.0 in Ubuntu 12.04 BOOST=/usr INCLUDES += -I$(BOOST)/include -Iinclude LIBS +=-L$(BOOST)/lib -lboost_filesystem -lboost_system -lpthread CFLAGS=$(INCLUDES) $(LIBS) -std=c++0x all: udp_echo_client udp_echo_client: udp_echo_client.cpp g++ $(CFLAGS) -o $@ udp_echo_client.cpp clean: rm -f udp_echo_client rm -f *~ -------------------------------------------------------- Code from example: -------------------------------------------------------- // // blocking_udp_echo_client.cpp // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2013 Christopher M. Kohlhoff (chris at kohlhoff dot com) // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // #include <cstdlib> #include <cstring> #include <iostream> #include <boost/asio.hpp> using boost::asio::ip::udp; enum { max_length = 1024 }; int main(int argc, char* argv[]) { try { if (argc != 3) { std::cerr << "Usage: blocking_udp_echo_client <host> <port>\n"; return 1; } boost::asio::io_service io_service; udp::socket s(io_service, udp::endpoint(udp::v4(), 0)); udp::resolver resolver(io_service); udp::endpoint endpoint = *resolver.resolve({udp::v4(), argv[1], argv[2]}); std::cout << "Enter message: "; char request[max_length]; std::cin.getline(request, max_length); size_t request_length = std::strlen(request); s.send_to(boost::asio::buffer(request, request_length), endpoint); char reply[max_length]; udp::endpoint sender_endpoint; size_t reply_length = s.receive_from( boost::asio::buffer(reply, max_length), sender_endpoint); std::cout << "Reply is: "; std::cout.write(reply, reply_length); std::cout << "\n"; } catch (std::exception& e) { std::cerr << "Exception: " << e.what() << "\n"; } return 0; }

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Re: [Boost-users] cross-compilation x86_64-w64-ming32: undefined reference to `InterlockedIncrement'
by Frédéric Bron 19 Sep '13

19 Sep '13

> Solved this by adding define=BOOST_USE_WINDOWS_H and that forces the include > of windows.h and as such the different types of InterlockedIncrement. I tried that and it worked until I realized that including windows.h causes me lots of troubles in another library (wxWidgets) so that I cannot use this solution. What is in windows.h that should be copied in interlocked.hpp? I start to be desperate to build a 64 bit version of my program with mingw-w64... also, it is difficult because I have absolutly no idea of what these interlocked... mean. Regards, Frédéric

1 0

Variadic versions of all the vector200 map50 stuff
by Michael Steinberg 19 Sep '13

19 Sep '13

Hello, I'm currently tracking down all the slowdowns I encounter when using boost in my Visual Studio solutions. Much of the slowdowns seem to happen, because there's a wide inclusion-usage of <boost/typeof/vector.hpp> throughout boost. This seems to be a replicate of <boost/mpl/vector.hpp>, which is not as much used, but equally evil. Inclusion of any of these headers leads to a 20MB increase in Visual Studio IntelliSense database size. I tested to comment out the inclusion of all the generated <vectorXXX.hpp>. This indeed works fine and is a real relief in Visual Studio responsiveness, because although these headers seem to be included from everywhere, they dont seem to be actually used. Tracking down the inclusion paths proves difficult to me, because the Visual-Studio tool doesn't seem to be able to handle the Preprocessor-generated include directives that boost uses extensively (and I'm just a newbie). With the advent of variadic-enabled compilers (Visual Studio 2013RC just arrived), is anybody working on making this mpl-stuff variadic? That would be a major help for almost anybody using tools like IntelliSense or VisualAssist (the vector200.hpp is a wopping 2mb of totally redundant template goodness...). I think I could make the appropriate changes to my local copy, however I have no idea how to write proper boost-worthy code or even how to file it for inclusion. Also I'm not too sure why the different sized vectors have different names and if the client code relies on that, etc., but I could probably find out. Are there any "template-instantiation-coverage"-tests included, so I could check that my variadics are compatible in the use-cases? Any help would be appreciated! With Kind Regards Michael

2 1

[boost-regex] 1.47.0 regexp_search with match_partial does not return 'what'
by Frank Bergemann 18 Sep '13

18 Sep '13

2 1

Static map like array or range?
by Duane Murphy 18 Sep '13

18 Sep '13

I find myself often building lookup tables for conversion or mapping of one piece of data to another. Common conversions include * converting from one string to a different string (e.g. text translation), * converting from an enum to a descriptive string * converting from a string to an enum * converting from a string to a function or functor The key aspect of these lookup tables is that they are static. If the table is reasonably large, say 7-10 items, I ensure that the table is presorted and use lower_bounds() to search the table. Some uses have started using map_list_of() to initialize the map. My inner optimizer finds this disturbing as inherently static information is being allocated dynamically in order to due to the lookup. I believe it would be more intuitive if there was a map like interface to the lookup table. The implementation would use the static nature of the data to its advantage. In particular the implementation would not require the data to be copied, re-allocated, etc. I've been searching the boost libraries, but have not been able to find something like this. Thank you for your suggestions. …Duane

3 2

Copy fusion::vector -> {std,boost}::array
by Rodrigo Madera 17 Sep '13

17 Sep '13

Checking the archives, I see that a *lot* was discussed on [1], and there was a mention (waaay after much debate and proposed solutions) on having a copy and copy_if to do such copies. Mr. Steven Watanabe mentioned a copy impl was lying around his computer [2]. Did it actually make it into Boost? Thanks for any input, Rodrigo [1] http://lists.boost.org/boost-users/2010/10/63168.php [2] http://lists.boost.org/boost-users/2010/10/63343.php

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Generic “Observable” mixin based on Boost
by Павел Фролов 17 Sep '13

17 Sep '13

I find Observer pattern a very useful tool to decrease coupling between modules of a system. Boost provides Signals2 which can be used for that purpose. But adding Signal2 objects to arbitrary classes is not very convenient, because your must manually implement RegisterEvent/FireEvent functions. What I was looking for is a reusable mixin which could add “Observable” behavior to arbitrary class with minimal hassle. Ideally, the user of mixing must only provide event table which contains event tags and handler signatures, e.g. (in pseudocode): EventTable { EventA: void(), EventB: int(bool), ... } I came up with working proof of concept which uses CRTP-based mixin and traits class for event table declaration. I'm new to template meta-programming, so I'm looking forward to comments about possible improvements. In particular, I'm not very satisfied with syntax boost::fusion::pair<Show, boost::optional<boost::signals2::signal<void()>>> (see attachement). I think, I can do better by allowing user to specify just boost::fusion::pair<Show, void()> and then generate proper type with mpl::transform and/or fusion::transform. This way is shorter and implementation details (optional, signals2) are hidden from the user. The mixin code (full code with example usage in attachment): #include <utility> #include <boost/fusion/container/map.hpp> #include <boost/fusion/sequence/intrinsic/at_key.hpp> #include <boost/fusion/sequence/intrinsic/value_at_key.hpp> #include <boost/optional.hpp> #include <boost/signals2.hpp> #include <boost/utility/in_place_factory.hpp> //***************************************************************************** // EventSource mixin //***************************************************************************** // event source traits base (concrete event source must create specialization) template<typename ConcreteEventSource> struct Events; // event source mixin (using CRTP) template<typename ConcreteEventSource> class EventSource { public: typedef ::Events<ConcreteEventSource> Events; private: typedef typename Events::EventTable EventTable; // helper type generator template<typename Event> struct GetType { // boost::optional type typedef typename boost::fusion::result_of:: value_at_key<EventTable, Event>::type SignalWrapper; // boost::signal type for particular boost::optional type typedef typename SignalWrapper::value_type Signal; // slot return type for particular boost::signal type typedef typename Signal::result_type SignalReturnType; }; public: // connect event handler template<typename Event, typename Handler> void Connect(Handler&& handler) { GetSignal<Event>()->connect(std::move(handler)); } protected: // generate nullary signal template<typename Event> typename GetType<Event>::SignalReturnType FireEvent() { return GetSignal<Event>()->operator()(); } // generate unary signal template<typename Event, typename Arg1> typename GetType<Event>::SignalReturnType FireEvent(Arg1 arg1) { return GetSignal<Event>()->operator()(arg1); } // ... more overloads (MSVC does not support variadic templates) private: // creates signal if not exists, returns reference to it template<typename Event> typename GetType<Event>::SignalWrapper& GetSignal() { auto& signal = boost::fusion::at_key<Event>(signals_); if (!signal) signal = boost::in_place(); return signal; } EventTable signals_; };

1 0

[units]
by Robert Ramey 16 Sep '13

16 Sep '13

I have an urgent and definite need for the functionality which boost.units is meant to provide. The concept is quite simple so I had expected it to be relatively easy to use. I had anticipated spending a few hours perusing the documentation and examples, adding code to my application and moving on. T'was not to be. I'm now on day 3 (or 4?) trying to figure this thing out. The main hurdle is that the documentation is indecipherable. There are a number of templated classes defined which depend upon each other. I expect to find a page for each of the templates along with a description of what the template arguments should be. (Ideally these should be backed up with concept checking classes). Ideally there would be a small example showing how one would use these templates. It seems that the library is layered from low level ideas to higher level ones. The documentation touches on this - but its not really formalized. Theres a reference section which includes scores of things like base_units types for wide variety of units - but no where is there any indication how these should be used - not even in the examples are they used. There is a concept of "system" (of dimensions?) and the idea of mixing units from different systems and the idea that the same dimension (eg length) have multiple renderings in the system (nautical vs metric). I realize I've likely got this wrong and I'm not asking for anyone to explain this to me here - my point is that what should be very simple is incredibly confusing. I still haven't figured out whether it's only the documentation which is incomplete or if it is the actual logical design of the library itself is what's flawed. I'm still working on this. I don't remember much traffic on this list regarding this library and if I google information on boost C++ units library I don't get a whole lot of hits. This could mean that that the library is so easy to use no one ever needs to ask about it or it could be that almost no one every uses it. In Boost we don't gather statistics on usage by library so I don't which of these it might be. So my question is: Has anyone had good success with this library? How much effort did it take? What did you have to do to make it work. I would be curious about any other user feed back in these questions. Robert Ramey

2 1

Re: [Boost-users] [Boost] Command Line to run a specific Boost Test Case using BOOST_AUTO_TEST_CASE_TEMPLATE
by Hemanth Choudary M V (RBEI/ETA1) 16 Sep '13

16 Sep '13

Hi Gennadiy, I have tried the same with the Boost 1.54.0 (Release Version) and it is not working. Looking forward to the next version which supports this. Mit freundlichen Grüßen / Best Regards, Hemanth Choudary MV RBEI/ETA1

1 0

Overhead in boost IPC
by nithesh salian 16 Sep '13

16 Sep '13

Hi, I am interested in knowing the overhead associated with using boost message queue and shared memory. i.e., What is the latency associated with using these mechanisms for IPC? Thanks in advance. -- Regards, Nithesh Gangadhar Salian .

1 0

Re: [Boost-users] [units]
by Kelly, Dan 16 Sep '13

16 Sep '13

I have had much the same experience as you. The library seems to hold a lot of promise and is from what I can see very sophisticated. But I had the same problems with the documentation and examples. I struggled for some time to figure out the difference between units and base units (and dimensions and base dimensions) and when you would use each. If someone could put together a decent tutorial I'm sure I would use this library quite frequently. -----Original Message----- From: Robert Ramey [ramey(a)rrsd.com<mailto:ramey@rrsd.com>] Sent: Sunday, September 15, 2013 01:14 PM Eastern Standard Time To: boost-users(a)lists.boost.org Subject: [Boost-users] [units] I have an urgent and definite need for the functionality which boost.units is meant to provide. The concept is quite simple so I had expected it to be relatively easy to use. I had anticipated spending a few hours perusing the documentation and examples, adding code to my application and moving on. T'was not to be. I'm now on day 3 (or 4?) trying to figure this thing out. The main hurdle is that the documentation is indecipherable. There are a number of templated classes defined which depend upon each other. I expect to find a page for each of the templates along with a description of what the template arguments should be. (Ideally these should be backed up with concept checking classes). Ideally there would be a small example showing how one would use these templates. It seems that the library is layered from low level ideas to higher level ones. The documentation touches on this - but its not really formalized. Theres a reference section which includes scores of things like base_units types for wide variety of units - but no where is there any indication how these should be used - not even in the examples are they used. There is a concept of "system" (of dimensions?) and the idea of mixing units from different systems and the idea that the same dimension (eg length) have multiple renderings in the system (nautical vs metric). I realize I've likely got this wrong and I'm not asking for anyone to explain this to me here - my point is that what should be very simple is incredibly confusing. I still haven't figured out whether it's only the documentation which is incomplete or if it is the actual logical design of the library itself is what's flawed. I'm still working on this. I don't remember much traffic on this list regarding this library and if I google information on boost C++ units library I don't get a whole lot of hits. This could mean that that the library is so easy to use no one ever needs to ask about it or it could be that almost no one every uses it. In Boost we don't gather statistics on usage by library so I don't which of these it might be. So my question is: Has anyone had good success with this library? How much effort did it take? What did you have to do to make it work. I would be curious about any other user feed back in these questions. Robert Ramey _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users ________________________________ IMPORTANT: The information contained in this email and/or its attachments is confidential. If you are not the intended recipient, please notify the sender immediately by reply and immediately delete this message and all its attachments. Any review, use, reproduction, disclosure or dissemination of this message or any attachment by an unintended recipient is strictly prohibited. Neither this message nor any attachment is intended as or should be construed as an offer, solicitation or recommendation to buy or sell any security or other financial instrument. Neither the sender, his or her employer nor any of their respective affiliates makes any warranties as to the completeness or accuracy of any of the information contained herein or that this message or any of its attachments is free of viruses.

1 0

[coroutine] Resuming of coroutine from another thread
by Jason Roehm 16 Sep '13

16 Sep '13

I'm thinking up a design for a task-processing system that uses Boost.Asio and Boost.Coroutine. As part of that design, I would have a pool of worker threads executing work items. During processing of a particular work item, it's possible that the worker might need to wait on some other operation (e.g. I/O) to complete. However, while it waits, I'd like to put that thread to work doing something else useful from the queue. I was thinking of using coroutines to provide the ability to suspend the processing of one task, restarting it later when it is ready to move forward again. In my hypothetical framework, the thread that finishes the work might not be the same one that started it in the first place. I recently came across this Stack Overflow question: http://stackoverflow.com/questions/8557067/thread-safe-coroutines-with-asio which inquired as to the safety of creating a coroutine in one thread and then resuming it in another. The answers there indicate that this is not supported, and they link to Boost.Coroutine documentation that explains the underlying problems and why it isn't supported. However, that documentation was from the original Boost.Coroutine by Giovanni Deretta (which I'm not sure was ever actually accepted into Boost). The latest version by Oliver Kowalke indicates that it is a follow-up on that library, but doesn't have any specific caveats in the documentation regarding the interaction between threads and coroutines. Does the contemporary Boost.Coroutine have the same limitation, or is it safe to create a coroutine in one thread and then resume it in another? Jason

2 1

Max Boost Fusion tuple parameters
by Rodrigo Madera 15 Sep '13

15 Sep '13

Hello, What is the maximum Boost Fusion tuple param count? I was thinking of using it for about 200-300 elements. Anyone done this? I've heard of defines for this, but never actually *knew* of anyone actually doing it. Thanks, Rodrigo Madera

4 11

Too many EOF's using boost::asio
by ustulation 13 Sep '13

13 Sep '13

I have a TCP server and client with following read and write functions: ----------------- Writes ---------------------- void SomeClass::startWrite() { //m_writeBuffer is boost::asio::streambuf..m_writeQueue is std::deque<std::string> m_writeBuffer.sputn(&m_writeQueue.at(0)[0], m_writeQueue.at(0).size()); //m_objStrandWrite is boost::asio::strand boost::asio::async_write( getSocket(), m_writeBuffer, m_objStrandWrite.wrap([this](const boost::system::error_code &e, std::size_t bytesTxd){writeHandler(e, bytesTxd);}) ); } void SomeClass::writeHandler(const boost::system::error_code &refErrorCode, std::size_t bytesTxd) { if(!m_bIsStopped) { m_writeQueue.pop_front(); if(refErrorCode) { if(refErrorCode != boost::asio::error::operation_aborted) { std::cerr << "Write Error: " << refErrorCode.message() << std::endl; stop(); } } else { if(!m_writeQueue.empty()) { startWrite(); } } } } ------------------- Reads ----------------- void SomeClass::startRead() { //m_readBuffer is boost::asio::streambuf..m_objStrandRead is boost::asio::strand boost::asio::async_read_until( getSocket(), m_readBuffer, m_szTermString, m_objStrandRead.wrap([this](const boost::system::error_code &e, std::size_t bytesRxd){readHandler(e, bytesRxd);}) ); } void SomeClass::readHandler(const boost::system::error_code &refErrorCode, std::size_t bytesRxd) { if(!m_bIsStopped) { if(refErrorCode) { if(refErrorCode != boost::asio::error::operation_aborted) { std::cerr << "Read error: " << refErrorCode.message() << std::endl; stop(); } } else { if(bytesRxd) { std::string szRxdData; szRxdData.resize(bytesRxd); m_readBuffer.sgetn(&szRxdData[0], bytesRxd); } startRead(); } } } I get very frequent End Of File (EOF) error on client's read. It is not always but frequent. I am running a threadpool by asking multiple std::threads to execute io_service::run() which never quits until io_service::stop() is called. The data given by the server is almost never more than 5MB. As you see in the code, for any error I call stop() which shuts down the connection gracefully. <Q> *Is there something wrong I'm doing because I see no reason for EOF error. Why should the server close/shutdown the connection?* The code does not do that explicitly. Anyway it is random - out of 10 times maybe 5 are successful reads and 5 become EOF's and I have to restart my client executable to connect again in each of those cases. Other sockets don't do that - eg., I've tested with QTcpSocket of Qt framework and it works all the time (no randomness). -- View this message in context: http://boost.2283326.n4.nabble.com/Too-many-EOF-s-using-boost-asio-tp465117… Sent from the Boost - Users mailing list archive at Nabble.com.

4 5

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

12 Sep '13

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

2 1

ICMP Ping example running problem
by shunguang 12 Sep '13

12 Sep '13

Hi all, When i run *ping.cpp * at .\boost_1_53_0\doc\html\boost_asio\example\icmp, it comes with the error message: "Exception: open: An attempt was made to access a socket in a way forbidden by its access permissions". Debug shows that it comes from calling ",* socket_ (io_service , icmp::v4() )*" in the constructor. Google says the running computer must have administrator right, i do have it. i also checked my firewall settings, it looks fine to me also. Does anyone can give a help? Thanks, -shunguang -- View this message in context: http://boost.2283326.n4.nabble.com/ICMP-Ping-example-running-problem-tp4651… Sent from the Boost - Users mailing list archive at Nabble.com.

2 4

[coroutine] help with code from docs
by Jeff Flinn 12 Sep '13

12 Sep '13

I'm trying to understand coroutine usage with boost 1.53.0. I'm getting an assertion when running the code snippet from the docs "Creating a coroutine" from http://www.boost.org/doc/libs/1_53_0/libs/coroutine/doc/html/coroutine/coro… #include <boost/coroutine/all.hpp> #include <string> typedef boost::coroutines::coroutine< int (std::string const&) > coro_t; // void f( boost::coroutine< std::string const&( int) > & ca) void f( coro_t::caller_type & ca) { std::string str( ca.get() ); // asserts here! ca(7); } int main(int argc, char* argv[]) { std::string str("abc"); coro_t c(f); c(str); // pass argument int res = c.get(); // returned value return 0; } Asserts in coroutine_get.hpp line 43: BOOST_ASSERT( static_cast< D const* >( this)->impl_->result_); Is the snippet from the doc incorrect or am I doing something else wrong. Thanks, Jeff

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boost::tr1::tuple or boost::tuple? how to compile the same code with both -std=c++98 and -std=c++11?
by Frédéric Bron 12 Sep '13

12 Sep '13

This small program compiles nicely with g++ 4.6.4 and -std=c++98 and boost 1.52.0: #include <iostream> #include <boost/math/tools/roots.hpp> #include <boost/tr1/tuple.hpp> std::tr1::tuple<double, double> f(double x) { return std::tr1::tuple<double, double>(x, 1.); } int main() { std::cout<<boost::math::tools::newton_raphson_iterate(f, 10., -9., +20., 10); return 0; } Now, I would like to be able to compile that program also with g++ 4.8.1 and -std=c++11 (I changed also boost to 1.53.0). If I do not change anything, std::tr1::tuple is replaced by std::tuple and I get the following error (see attached log): path/to/boost/include/boost/math/tools/roots.hpp:202:32: error: no match for 'operator=' (operand types are 'std::tuple<double&, double&>' and 'boost::fusion::tuple<double, double>') I tried to replace <boost/tr1/tuple.hpp> and std::tr1::tuple by <boost/tuple/tuple.hpp> and boost::tuple without any success. What should I do to have the same code compile with both -std=c++98 and -std=c++11? Regards, Frédéric

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Regex on Windows2012
by Michael Xanadu 11 Sep '13

11 Sep '13

Hi guys, I developed a little application called MyProgram.exe (Win7, VS2008 SP1, Qt 4.8.4) and a little DLL called MyLibrary.dll. The DLL uses BOOST's regex engine 1.5. The executable calls the DLL via couple of functions, one function inside the DLL uses the regex engine. I've tested the environment on Windows7 and all is OK. BUT: If I copy the application and the DLL to Windows2012 I see that the executable crashes if I use it. I took a closer look to the issue and found out that the cause for the crash seems to be the regex engine inside the DLL. If regex functions will be called inside the DLL, it crashes and also the application does. AND: The strange thing is, that this problem seems to occur only on Windows2012 and only if the regex engine is inside a DLL. If I use Windows7 instead or uses the regex engine inside an executable on Windows2012 - everything works fine. I've already tried a lot to solve the problem, including using different linking approaches (BOOST as shared DLL etc.). I wonder if anybody had similar issues or can give me a hint of what went wrong? Regards, Michael

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syntax error reporting from imported python modules
by Richi Lists 11 Sep '13

11 Sep '13

Hi, when I execute a python script that contains errors, I get nice and complete information from boost::python::error_already_set about the error and it's location. If the script that contains a syntax error is not executed directly, but imported from the main script, I don't get that exception. Instead it returns from the function as if everything was successful. When I check the result, the tasks from the other files were performed, just the stuff from the erroneous file is missing. Do I need to somehow attach the error reporting to the imported files? Rgds Richard

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[BOOST]BOOST_AUTO_TEST_CASE_TEMPLATE usage
by Hemanth Choudary M V (RBEI/ETA1) 11 Sep '13

11 Sep '13

Hi, In the code snippet below, The 3rd parameter in the BOOST_AUTO_TEST_CASE_TEMPLATE is a boost::mpl::list. Is the 3rd parameter restricted only to boost::mpl::list or anything else can also be used? #define BOOST_TEST_MODULE example #include <boost/test/included/unit_test.hpp> #include <boost/test/test_case_template.hpp> #include <boost/mpl/list.hpp> //____________________________________________________________________________// typedef boost::mpl::list<long long,unsigned char> test_types; BOOST_AUTO_TEST_CASE_TEMPLATE( my_test, T, test_types ) { BOOST_CHECK_EQUAL( sizeof(T), (unsigned)4 ); } //_ Mit freundlichen Grüßen / Best Regards, Hemanth Choudary MV RBEI/ETA1

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shared_ptr to this
by Gonzalo Garramuno 10 Sep '13

10 Sep '13

I have an application where I need to pass "this" in a callback belonging to a class to a function using a shared_ptr in another thread In code: struct Data { Data( void* p ) : ptr( p ) { } boost::shared_ptr<void> ptr; }; void threadA( Data* d ) { boost::shared_ptr<void> ptr( d->ptr ); delete d; // use ptr } class A { void init_thread() { Data* data = new Data( this ); boost.thread t( boost::bind( threadA, data ) ); } }; The problem is obvious. Once threadA closes, the shared ptr is destroyed as its count is 0 and as it points to the this of class A this gets deleted too. However my class A is still active and should not get deleted. How can I work around this?

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[wave] Wave macro expansion problem
by Edward Diener 10 Sep '13

10 Sep '13

The code: // test_macros_o.cpp #define f(a) f(x + (a)) #define x 2 #define g f #define h g(~ int main() { #pragma wave trace(enable) h 5); #pragma wave trace(disable) return 0; } In the latest C++ standard at 16.3.5 paragraph 5 the expansion of 'h 5)' is given as: f(2 * (~5)) but the wave.exe driver gives: C:\Programming\VersionControl\boost\libs\vmd\test\test_macros_o.cpp:11:3: h C:\Programming\VersionControl\boost\libs\vmd\test\test_macros_o.cpp:4:9: see macro definition: h [ g(~ rescanning [ C:\Programming\VersionControl\boost\libs\vmd\test\test_macros_o.cpp:3:9: see macro definition: g [ f rescanning [ f ] ]

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