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Re: [Boost-users] Asio problems with async_read
by Alex Perry 08 Aug '11

08 Aug '11

Allan Nielsen wrote on Mon, 8 Aug 2011 14:13:08 +0200 > Hi > > I have a funciton where we I am using boost::asio to read from the > serial port of my computer. > > I have started out with an implementation which uses read, and I am > now trying to convert it to async_read because I want a time out. > > When I am trying to use the async_read version, I get timeouts after I > have read one or two charterers, even though I know there are more > charterers to be read on the wire. > Not sure that this is much help since I've never really used boost.asio and reading further down the thread it may be a problem with how you are calling it. However having done a lot of serial comms in the past seeing a couple of characters only whilst more data is on the wire I'd guess that the timeout is as a result of the low level serial hardware interrupt. The UART is probably signalling that its internal FIFO buffer is full and you need to read this promptly - quite how that all pans out and what daemon / service has the responsibility of reading this these days I haven't got the faintest - I was writing TSR's when I knew the gory technical details of this so life was much simpler. I'm actually impressed that you've found a computer that still has a serial port on it! Most seem to have gone over to the ubiquitous USB these days - though that may be the easiest solution - use USB and a usb/serial converter which would avoid having to rediscover the lost art of programming UART latch timings etc and give you a decent amount of low level buffering so you could ignore low level stuff and just read the data. http://www.bb-europe.com/tech_articles/USB_converters.asp?gclid=CPvOgur5v6o… or some such. HTH Alex

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Asio problems with async_read
by Allan Nielsen 08 Aug '11

08 Aug '11

Hi I have a funciton where we I am using boost::asio to read from the serial port of my computer. I have started out with an implementation which uses read, and I am now trying to convert it to async_read because I want a time out. When I am trying to use the async_read version, I get timeouts after I have read one or two charterers, even though I know there are more charterers to be read on the wire. Here is the code: void set_result( boost::optional<boost::system::error_code> * a, boost::system::error_code b ) { a->reset( b ); } std::vector<uint8_t> receive(boost::asio::io_service & io, boost::asio::serial_port & cctalk_port){ #if 0 boost::optional<boost::system::error_code> timer_result; boost::optional<boost::system::error_code> read_result; boost::asio::deadline_timer timer( io ); timer.expires_from_now( boost::posix_time::milliseconds(5000) ); timer.async_wait( boost::bind(&set_result, &timer_result, _1) ); boost::asio::streambuf result; boost::asio::async_read( cctalk_port, result, boost::asio::transfer_at_least(1), boost::bind( &set_result, &read_result, _1 )); while(1) { io.poll_one(); if ( read_result ) { timer.cancel(); std::vector<uint8_t> res(boost::asio::buffer_cast<const uint8_t * >(result.data()), boost::asio::buffer_cast<const uint8_t * >(result.data()) + result.size() ); return res; } else if ( timer_result ) { throw runtime_error("timeout"); } } throw runtime_error("Should not happend"); #else uint8_t c; boost::asio::read(cctalk_port, boost::asio::buffer(&c, 1)); std::vector<uint8_t> res; res.push_back(c); return res; #endif }

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need help on compile error about gregorian and regex
by Eric Lin 08 Aug '11

08 Aug '11

Dear Boost experts: when I compile a program(some example code from c++ book) it contain #include <boost/date_time/gregorian/gregorian.hpp> #include <boost/regex.hpp> and I got a lot compile error related about it on my g++ with boost 1.46.1 installed ------- ------- ----------------------------------------------------------------------------------------------------- eric@eric-laptop:~/cppcookbook/download/TESTDIR$ g++ -ltinyxml 14-3.cpp /tmp/cct65iz6.o: In function `unsigned short boost::date_time::month_str_to_ushort<boost::gregorian::greg_month>(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)': 14-3.cpp:(.text._ZN5boost9date_time19month_str_to_ushortINS_9gregorian10greg_monthEEEtRKSs[unsigned short boost::date_time::month_str_to_ushort<boost::gregorian::greg_month>(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)]+0x97): undefined reference to `boost::gregorian::greg_month::get_month_map_ptr()' /tmp/cct65iz6.o: In function `bool boost::regex_match<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >(__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, __gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::match_results<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > > >&, boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > > const&, boost::regex_constants::_match_flags)': 14-3.cpp:(.text._ZN5boost11regex_matchIN9__gnu_cxx17__normal_iteratorIPKcSsEESaINS_9sub_matchIS5_EEEcNS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEEEbT_SD_RNS_13match_resultsISD_T0_EERKNS_11basic_regexIT1_T2_EENS_15regex_constants12_match_flagsE[bool boost::regex_match<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >(__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, __gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::match_results<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > > >&, boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > > const&, boost::regex_constants::_match_flags)]+0x4c): undefined reference to `boost::re_detail::perl_matcher<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::match()' /tmp/cct65iz6.o: In function `boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::assign(char const*, char const*, unsigned int)': ------------------------------------------------------------------------------------------This is only front part of the whole errors------------------- these code is claimed worked on msvc++7.1 on window xp and you can download it from http://examples.oreilly.com/9780596007614/ 14-1.xml 14-2.h 14-3.cpp to test by yourself plz help and thanks a lot in advance, Eric(on g++ 4.5.2, linuxkernel 2.6.38-10)

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boost.preprocessor BOOST_PP_SEQ_FOR_EACH shows strange error messages
by aliko 07 Aug '11

07 Aug '11

Hi! I'm trying to utilize preprocessor library for the first time and my questions probably are too stupid for this list but I have not found another place to ask.:) In series of projects I have a repetitive task with defining many variables and structures based on configuration of embedded platform. First I've tried to generate array of numbers from ADC, the main definition from which all the variables and structures should be created. But I've got a strange error messages which I can't interpret right way. My code is: ********************************************************************** #include <boost/preprocessor/seq.hpp> #include <boost/preprocessor/tuple.hpp> #define POS_NAME 0 #define POS_PIN 1 #define POS_SKIP 2 #define POS_K 3 #define POS_TYPES 4 #define POS_SCALES 5 #define NFIELDS 6 #define NSIGS 5 enum {DISCRETE, ANALOG, CONTROL, MEASURE, END_TYPES}; //NAME, PIN, SKIP, FILTERK, DATATYPES, SCALES #define ADC ( \ (POSITION, 0, 0, 100, (ANALOG, CONTROL, MEASURE), \ (((DISCRETE, ANALOG) (1000, 4000) (0, 20000)) \ ((ANALOG, CONTROL) (4000, 20000) (0, 10000)) \ ((ANALOG, MEASURE) (4000, 20000) (0, 3000)))), \ (CURRENT, 1, 0, 100, (ANALOG, CONTROL), \ (((DISCRETE, ANALOG) (1000, 4000) (0, 20000)) \ ((ANALOG, CONTROL) (4000, 20000) (0, 10000)))), \ (HALL, 2, 0, 100, (ANALOG, CONTROL), \ (((DISCRETE, ANALOG) (1000, 4000) (0, 20000)) \ ((ANALOG, CONTROL) (4000, 20000) (0, 10000)))), \ (PRESSURE, 4, 0, 100, (ANALOG, CONTROL, MEASURE), \ (((DISCRETE, ANALOG), (1000, 4000) (0, 20000)) \ ((ANALOG, CONTROL) (4000, 20000) (0, 10000)) \ ((ANALOG, MEASURE) (4000, 20000) (0, 3000)))), \ (TEMPERATURE, 10, 0, 100, (CONTROL, MEASURE), \ (((DISCRETE, CONTROL) (1000, 4000) (0, 20000)) \ ((CONTROL, MEASURE) (4000, 20000) (0, 3000)))) \ ) #define WITH_NUMBERS(Z0, Z1, SEQ) BOOST_PP_SEQ_ELEM(1, SEQ), BOOST_PP_SEQ_ELEM(2, SEQ), #define TO_NUMBERS(Z0, Z1, SEQ) BOOST_PP_SEQ_FOR_EACH(WITH_NUMBERS, _, SEQ) #define TO_SCALES(Z0, Z1, TUPLE) BOOST_PP_SEQ_FOR_EACH(TO_NUMBERS, _, BOOST_PP_TUPLE_ELEM(NFIELDS, POS_SCALES, TUPLE)) unsigned int bounds[] = {BOOST_PP_SEQ_FOR_EACH(TO_SCALES, _, BOOST_PP_TUPLE_TO_SEQ(NSIGS, ADC))}; ********************************************************************** The errors are: ./test_preprocess.cpp:56:1: error: ‘TO_NUMBERS’ was not declared in this scope ./test_preprocess.cpp:56:1: error: ‘_’ was not declared in this scope ./test_preprocess.cpp:56:1: error: ‘(0, (._74)1u)’ cannot be used as a function ./test_preprocess.cpp:56:1: error: ‘(0, (._74)2u)’ cannot be used as a function ./test_preprocess.cpp:56:1: error: ‘(0, (._74)3u)’ cannot be used as a function ./test_preprocess.cpp:56:1: error: ‘BOOST_PP_SEQ_FOR_EACH’ was not declared in this scope ... end so on Why it's not sees TO_NUMBERS definition?

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99 Bottles of Beer using Boost MPL, feedback invited
by Alastair Rankine 07 Aug '11

07 Aug '11

So inspired by http://programmingpraxis.com/2011/08/05/ninety-nine-bottles-of-beer/ , I decided to attempt to generate the lyrics to the 99 bottles of beer song. To make it interesting I decided to use Boost MPL to generate the lyrics using template metaprogramming. Here is my attempt. https://gist.github.com/1130306 It compiles with gcc 4.2 against boost 1.47. Given that I am pretty inexperienced with MPL I would very much appreciate some constructive criticism. I'd specifically like to know if the code can be cleaned up to be simpler or to perform better. Also I'm not entirely happy with the duplication in the PrintX functors, would definitely like to get a better approach here. Thanks,

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[Fusion] Is there an assignment function for any two conformant sequences?
by someguy 07 Aug '11

07 Aug '11

Is there a function like "assign(dest_fusion_seq,src_fusion_seq)" which does recursive element-wise assignment between any two conformant fusion sequences(including adapted ones)? I didn't find one but I think there should be such functionality. -- View this message in context: http://boost.2283326.n4.nabble.com/Fusion-Is-there-an-assignment-function-f… Sent from the Boost - Users mailing list archive at Nabble.com.

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[Boost.Serialization] Serializing "abstract" classes
by Júlio Hoffimann 06 Aug '11

06 Aug '11

Dear all, I'm using Boost 1.45... I've read Boost.Serialization docs so many times and can't understand why my testcase is not working as expected. According to the following three links, we need to address serialization of derived classes with "abstract" base class by using boost macros: http://www.boost.org/doc/libs/1_47_0/libs/serialization/doc/traits.html#exp… http://www.boost.org/doc/libs/1_47_0/libs/serialization/doc/special.html#ex… http://www.boost.org/doc/libs/1_47_0/libs/serialization/doc/traits.html#abs… I did my testcase ( http://codepad.org/6ETp1Ac0 ) completely based on the demo: http://www.boost.org/doc/libs/1_47_0/libs/serialization/example/demo.cpp Compiling and running shows that the derived class archive contains just the base class data members. What is happening? How can i solve this problem? I really appreciate any help, Júlio.

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Another baffling error message
by Eric Fowler 06 Aug '11

06 Aug '11

Sorry to have to ask the list for help, but I am once again stumped. Perhaps you will find this easy. I have some classes defined: using namespace std; using namespace boost; class POS{..stuff..} class LEN{...stuff...} typedef adjacency_list<vecS, vecS, undirectedS, POS, LEN> DG; typedef graph_traits<DG>::vertex_descriptor Vertex; typedef graph_traits<DG>::edge_descriptor Edge; class DelaunayGraph: public DG { public: void foo() { Edge e = whatever(); remove_edge(e, *this); // <<<<----THIS BLOWS UP ..stuff... } The error I am getting is: c:\documents and settings\eric\my documents\visual studio 2008\projects\shuttle\delaunay\trunk\delaunaygraph.h(371) : error C2661: 'boost::undirected_graph_helper<Config>::remove_edge' : no overloaded function takes 2 arguments with [ Config=boost::detail::adj_list_gen<boost::adjacency_list<boost::vecS,boost::vecS,boost::undirectedS,POS,LEN>,boost::vecS,boost::vecS,boost::undirectedS,boost::property<boost::vertex_bundle_t,POS>,boost::property<boost::edge_bundle_t,LEN>,boost::no_property,boost::listS>::config ] What am I doing wrong in this instance, and what design principle am I violating? Eric

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datetime will not be parsed
by Kraus Philipp 06 Aug '11

06 Aug '11

Hello, I use this code for parsing a string into a datetime: boost::local_time::local_date_time l_datetime(boost::date_time::not_a_date_time); std::istringstream l_datestream("Sat Aug 06 10:52:26 +0000 2011"); l_datestream.imbue( std::locale( std::locale::classic(), new boost::local_time::local_time_input_facet("%a %b %d %H:%M:%S %q %Y")) ); l_datestream >> l_datetime; But the l_datetime is always set to "not a date time". I think the parameter within the input facet are correct, so I don't understand why the string is not be parsed. Can anyone help me please to create a working solution? Thanks Phil

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question about boost::intrusive_ptr
by Mahmood Naderan 06 Aug '11

06 Aug '11

Hi I used boost::intrusive_ptr in a function, say foo(), like this: boost::intrusive_ptr<BranchFeedback> theFeedback ( new BranchFeedback() ); std::vector< std::vector< BPredState > > theFetchState; .... theFeedback->theBPState = &theFetchState[anIndex][!anOne]; The difinition of BranchFeedback and BPredState are: struct BranchFeedback : boost::counted_base { ... boost::intrusive_ptr<BPredState> theBPState; }; struct BPredState : boost::counted_base { ... uint32_t theGShare; uint32_t theSerial; }; The problem is when foo() reaches the end (I mean '}'), I get segmentation fault which points to ~intrusive_ptr() { if(p_ != 0) intrusive_ptr_release(p_); } I thought I used the intrusive_ptr in a correct way. Is there any consideration that I missed? Thanks, // Naderan *Mahmood;

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