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[units] Question about user-defined value types
by W Z 23 Jan '12

23 Jan '12

Hi, I am using boost units library for a project in which I need to define quantities using rational numbers. I have a rational number class but am having trouble integrating it with units library. There seems to be a lot of places where the units library implementation assumes that the conversion values are expressed as double type. Is there a good way to get around this to make units library support rational numbers? Thanks, WZ

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Iterating over vertices in a specific region in a graph
by David Doria 22 Jan '12

22 Jan '12

If I manually create a grid graph in BGL (using adjacency_list, not grid_graph), is there a way to iterate over vertices in a specified rectangular region? Say I make a 100x100 grid graph, how would I iterate over the the center 5x5 vertices? Thanks, David

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Multicast sender
by Carlos Guimarães 22 Jan '12

22 Jan '12

Hi, Is there any portable way (by using boost) to send multicast messages through all network interfaces available on the host? I have managed to do it by setting outbound_interface option on the socket. However, how can I know which if_index are available? Also, it only works for IPv6. If I set a IPv4 address it always use the same interface. Any suggestion? Next is the code I'm using: // DATA HERE... ip::udp::socket sock(io); sock.open(ip::udp::v6()); // Set socket flags sock.set_option(boost::asio::socket_base::reuse_address(true)); if (strcmp(dst_ip, "ff02::1") == 0) { boost::asio::socket_base::broadcast option(true); sock.set_option(option); } sock.bind(ip::udp::endpoint(ip::address_v6::any(), src_port)); for(int i = 1; i <= 5; i++) { try { sock.set_option(ip::multicast::outbound_interface(i)); sock.set_option(ip::multicast::enable_loopback(false)); ip::udp::endpoint ep(ip::address::from_string(dst_ip), dst_port); sock.async_send_to(boost::asio::buffer(sbuff, slen), ep, boost::bind((&send_handler), placeholders::error)); } catch(...) { return; } }

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[Units] Issue with user defined quantities
by Pieter B. 22 Jan '12

22 Jan '12

LS, I have some problems working with user defined quantities/units in combination with unitless quantities (such as the results of a sin() or cos() operations).Taking the example of the 'nautical mile', which is presented in the documentation: ---START CODE --- namespace nautical { struct length_base_unit : boost::units::base_unit<length_base_unit, length_dimension, 1> { static std::string name() { return "nautical mile"; } static std::string symbol() { return "nmi"; } }; typedef boost::units::make_system<length_base_unit>::type system; typedef unit<length_dimension,system> length; static const length mile,miles; } BOOST_UNITS_DEFINE_CONVERSION_FACTOR(nautical::length_base_unit, boost::units::si::meter_base_unit, double, 1.852e3); ---END CODE --- The following does not compile: ---START CODE --- typedef quantity<boost::units::si::plane_angle> TAngleInRad; typedef boost::units::quantity<nautical::length> TNauticalDistanceInNMI; TNauticalDistanceInNMI NauticalDistanceInNMI; TNauticalDistanceInNMI SumNauticalDistanceInNMI = NauticalDistanceInNMI + NauticalDistanceInNMI; // OK TNauticalDistanceInNMI ScaledSumNauticalDistanceInNMI = NauticalDistanceInNMI + NauticalDistanceInNMI*sin(AngleInRad); // Last line does not compile due to lack of a suitable operator+ ---END CODE --- It does work correctly when using the 'nautical mile' as it has been defined in the library itself in "nautical_mile.hpp" (as a scaled base unit related to the si::meter): ---START CODE --- namespace metric { typedef scaled_base_unit<boost::units::si::meter_base_unit, scale<1852, static_rational<1> > > nautical_mile_base_unit; } // definition of the nautical mile from "nautical_mile.hpp" typedef boost::units::metric::nautical_mile_base_unit::unit_type nautical_mile_unit; typedef quantity<nautical_mile_unit> TNauticalDistanceInNMI; ---END CODE --- However, I don't think I can specify my user-defined units/quantities in this manner as they use a scale factor represented by an arbitrary floating point value. My perception is that the example of the documentation does not work due to the mixing of quantities from the si system (the sin() returns a dimensionless quantity in that system) with user-defined quantities in another ('nautical') system, while the 'nautical mile' from 'nautical_mile.hpp' is a scaled version of the si::meter and thus defined within the realms of the si::system - but please correct me if I am wrong here. My problem can thus be summarized as follows: - the solution from the documentation does not compile - the solution from 'nautical_mile.hpp' uses a scaled base unit which is limited to scaling factors of the form scale<Base,Exponent> and my question is therefore: how can I define my user-defined units/quantities in such a way that they allow the required operations while being related to base units by an arbitrary scale factor? Help would be highly appreciated, Pieter ------------------- Nautical mile version #1 (from the included nautical_mile.hpp): namespace metric { typedef scaled_base_unit<boost::units::si::meter_base_unit, scale<1852, static_rational<1> > > nautical_mile_base_unit; } template<> struct base_unit_info<metric::nautical_mile_base_unit> { static const char* name() { return("nautical mile"); } static const char* symbol() { return("nmi"); } }; typedef quantity<boost::units::si::plane_angle> TAngleInRad; typedef quantity<boost::units::si::length> TDistanceInM; typedef boost::units::metric::nautical_mile_base_unit::unit_type nautical_mile_unit; typedef quantity<nautical_mile_unit> TDistanceInNMI; typedef boost::units::quantity<nautical::length> TNauticalDistanceInNMI; # this is OK: TAngleInRad Angle(0.5*radians); TDistanceInNMI DistanceInNMI; TDistanceInNMI SumDistanceInNMI = DistanceInNMI + DistanceInNMI; TDistanceInNMI ScaledSumDistanceInNMI = DistanceInNMI + DistanceInNMI*sin(AngleInRad); TNauticalDistanceInNMI NauticalDistanceInNMI; TNauticalDistanceInNMI SumNauticalDistanceInNMI = NauticalDistanceInNMI + NauticalDistanceInNMI; TNauticalDistanceInNMI ScaledSum NauticalDistanceInNMI = NauticalDistanceInNMI + NauticalDistanceInNMI*sin(AngleInRad); // DOES NOT COMPILE for lack of a suitable operator+

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[phoenix] [cmath] lazy pow not working in boost 1.48
by alfC 22 Jan '12

22 Jan '12

Hi, Is this a bug in phoenix? the boost::phoenix::pow lazy function doesn't seem to work. My version is Boost 1.48 or maybe 1.49 (after svn update) -- Thanks, Alfredo #include<iostream> #include <boost/phoenix.hpp> #include <boost/phoenix/stl/cmath.hpp> using std::clog; using std::endl; int main(){ using namespace boost::phoenix::arg_names; clog << boost::phoenix::sin(arg1)(1.) << " " << std::sin(1.) << endl; // ok clog << boost::phoenix::pow(arg1, arg1)(2.) << " " << std::pow(2.,2.) << endl; // ^^^^------ error: no matching function for call to ‘pow(const boost::phoenix::expression::argument<1>::type&, double) return 0; }

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Why does boost thread copy a functor?
by Chris Cleeland 22 Jan '12

22 Jan '12

I had code similar to the following... Functor object: struct Task { operator()() { // thread main } smartfd p; }; Note that smartfd is a wrapper around a file descriptor. In its dtor it closes the fd. Then, elsewhere I set up an instance of Task and spawn it with boost::thread... Task t; t.p = // open file descriptor boost::thread thr(t); The spawned thread gets an instance of Task, but it's not the same instance as from the main. What is the rationale? -- Chris Cleeland

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Vote Boost Up for SourceForge Project of the Month
by Dave Abrahams 20 Jan '12

20 Jan '12

Folks, I was just informed that Boost is a top contender for SourceForge's February Project Of The Month. The vote is happening on TwtPoll, here: http://twtpoll.com/7vt4lq It's pretty close, so if you could vote Boost up, it could be good for our profile and our future. Thanks! -- Dave Abrahams BoostPro Computing http://www.boostpro.com

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Re: [Boost-users] Is there any functions that convert Chrono's time_point and duration to their Ptime equivalents?
by Iron Bug 20 Jan '12

20 Jan '12

I found such functions somewhere in boost's sandbox, in chrono development. There're some templates that can be used as examples and adopted for all such conversions. I think, they will be added to chrono, possibly. Look here: http://svn.boost.org/svn/boost/sandbox/chrono/boost/conversion/boost/

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[asio] Error "File exists" at connect
by Arash Abghari 20 Jan '12

20 Jan '12

Hi everybody, I am running a server and client using boost::asio. There are 10 clients sending requests simultaneously to the server. Sometimes one of the clients returns the error "File exist" when ip::tcp::socket::connect() is called. Do you have any idea what possibly could cause this error? Thanks, Arash

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Using filesystem::remove with wildcards
by toran 20 Jan '12

20 Jan '12

I am having trouble deleting files with boost::filesystem. Following code does not work for me (and I can't find the doc that explains how to do it). boost::filesystem::path pt("somepath"); pt /= ("*.data"); boost::filesystem::remove(pt); pt variable points to the valid set of files, but removal does not happened. I will appreciate an advise and may be pointing me to the right place in the docs. Thanks.

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Using shared_ptr with reference_wrapper
by Kelvin Chung 19 Jan '12

19 Jan '12

I am currently in the middle of a wrapper conundrum. I currently have the following: template <class Key, class Container> class ContainerWrapper { Container container; public: typedef Key key_type; protected: virtual const typename Container::key_type& mapKey(const key_type&) = 0; }; The idea of ContainerWrapper is that I want to disguise one Key type as another key type. But the following wrapper, intended to present a container of Key pointers as a container of Keys, presents a dangling reference problem: template <class Key, class Container> class HeapKeyWrapper : public ContainerWrapper<Key, Container> { // Container::key_type == boost::shared_ptr<Key> public: typedef Key key_type; protected: // Ignore the lack of boost::const_pointer_cast<Key>() below. The dangling reference is from the fact // that shared_from_this() doesn't return a reference. const boost::shared_ptr<Key>& mapKey(const key_type& key) { return key.shared_from_this(); } }; If I try to fix this by having mapKey() return by value, then this other wrapper breaks: template <class Key, class Container> class IdentityWrapper : public ContainerWrapper<Key, Container> { public: typedef Key key_type; protected: // Assume Key extends boost::enable_shared_from_this<Key>. // Returning by value would mean the returned value is a copy of key, and not the original // so calling shared_from_this() from the mapped key would break, say const Key& mapKey(const key_type& key) { return key; } }; I'm trying to fix the code so that both wrappers work (short of refactoring the mapKey() functionality to a functor of some sort), which leads me thinking about using boost::reference_wrapper in some way. (The problem that I have is that I could have IdentityWrapper::mapKey() return a reference_wrapper, but that violates the mapKey() interface.) This has also led me down to a related path - what if I changed my backing container to use reference_wrapper instead of shared_ptr? It seems to be that it is ill-advised: the container technically isn't holding the object, and so the objects in the container could be deallocated in the meantime, leaving me with containers full of dangling references. I have valid uses of both HeapKeyWrapper and IdentityWrapper elsewhere in my code, so what do you think should be the right choice given this dangling reference problem currently present in HeapKeyWrapper?

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[Chrono] Is there any functions that convert Chrono's time_point and duration to their Ptime equivalents?
by Matthew Jenks 19 Jan '12

19 Jan '12

Hello, I have been trying to find in the boost libraries if there are any interoperability functions for Boost::Chrono and Boost::Posix_Time? Does anyone know if they exist and what class they are in? Thanks, Matt

2 1

adjacency lists
by Neiderer, Andrew M CIV (US) 19 Jan '12

19 Jan '12

I am still learning graphs, BGL 1.48.0 so beginner questions: 1. not sure what adjacency list/matrix are used for other than building a graph for traversal. Or maybe this is it? 2. I need to build a sparse network. So I am using adjacency_list_io.cpp by Francois Faure (2001). In this example I can read(g2), but when outputting std::cout << write(g2) I get lots of translation errors :-( I know I do not give details here but maybe someone could guess a -D??? to make adjacency_list_io.hpp happy. (The read(g2) works fine) Or I can certainly provide some of the error message. Also has Dr. Nick Edmonds completed (or near completion) of "active-message" based release (MPI)? Thank you. Andrew M. Neiderer US Army Research Laboratory

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Boost-build targets order
by Jarosław Bober 19 Jan '12

19 Jan '12

Hello i have a quick question regarding targets in boost-build jamfiles. Let's say i have 3 targets defined in my jamroot and then I say: bjam target1 target2 target3 Is the order of building targets defined somehow? Regards

1 0

boost::thread and helgrind
by Frederick Roth 19 Jan '12

19 Jan '12

I am currently fooling around with boost::thread. After writing a short example program (featuring boost::thread and boost::interprocess::interprocess_semaphore), I ran helgrind against it and got some "Possible data race" errors. The program does nothing but start two threads and serialize them via the semaphore and I am unsure whether a) I did some error I am not aware of b) helgrind reports false positives I would be glad if someone could look at my code (attached) and give me a hint. Frederick Roth PS: Software versions are boost-1.47.0, valgrind-3.6.1, gcc 4.6.2, c++0x

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Newbie, just starting.
by Robillard, Greg L 18 Jan '12

18 Jan '12

I am trying to get my boost libraries up and running, so I can start using the test framework. When running: #define BOOST_TEST_MODULE const_string test #include <boost/test/unit_test.hpp> // EOF I get the following error: xlC_r -I /home/.../BoostTest/boost_1_48_0 newTest.cpp -o newTest ld: 0711-317 ERROR: Undefined symbol: boost::unit_test::__vftQ3_5boost9unit_test15unit_test_log_tQ3_5boost9unit_test13test_observer ld: 0711-317 ERROR: Undefined symbol: .boost::unit_test::framework::master_test_suite() ld: 0711-317 ERROR: Undefined symbol: .main ld: 0711-345 Use the -bloadmap or -bnoquiet option to obtain more information. Alternately, when I try to run: #include <boost/lambda/lambda.hpp> #include <iostream> #include <iterator> #include <algorithm> int main() { using namespace boost::lambda; typedef std::istream_iterator<int> in; std::for_each( in(std::cin), in(), std::cout << (_1 * 3) << " " ); } I receive the following error: "/home/.../BoostTest/boost_1_48_0/boost/lambda/detail/function_adaptors.hpp", line 29.1: 1540-0063 (S) The text ">" is unexpected. Any assistance would be great. Greg

2 1

boost::split_regex
by Brad Tilley 18 Jan '12

18 Jan '12

I'm experimenting with boost::split_regex and ran into an issue. The first three examples (results1, results2, results3) compile and work as expected. The last one (results4) does not compile. Here's the code I'm using: std::string str1("hello abc-ABC-aBc goodbye"); static const boost::regex re("-ABC-"); std::vector<boost::iterator_range<std::string::iterator> > results1; boost::ifind_all( results1, str1, "abc" ); std::vector<boost::iterator_range<std::string::iterator> > results2; boost::split(results2, str1, boost::is_any_of("-")); std::vector<std::string> results3; boost::split_regex(results3, str1, re); std::vector<boost::iterator_range<std::string::iterator> > results4; // compile error on this line: boost::split_regex(results4, str1, re); I've read the documents here: http://www.boost.org/doc/libs/1_48_0/doc/html/boost/algorithm/split_regex.h… and I believe my usage of split_regex is correct? It compiles and works with std::string (results3) but not with boost::iterator_range. The compiler error is long and verbose, so I'm hesitant to post it here. I was hoping that someone could look at the usage example I provided and see how I'm doing it wrong. I prefer iterator_range as it does not make a copy. Thanks for any advice! Brad

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Re: [Boost-users] how to calculate the Sample standard deviation using accumulators
by Victor Yankee 18 Jan '12

18 Jan '12

Hello Marshall, >On Jan 17, 2012, at 3:38 PM, Victor Yankee wrote: > >> How can I calculate the Sample Standard Deviation over a std::vector of doubles using accumulators? >> >>Or is there a faster way in boost math or some such? > > >Google is your friend (second hit for "boost accumulator standard deviation"): > http://stackoverflow.com/questions/7616511/calculate-mean-and-standard-devi… >and http://stackoverflow.com/questions/4316716/is-it-possible-to-use-boost-accu… > > > accumulator_set<double, stats<tag::variance> > acc; > for_each(a_vec.begin(), a_vec.end(), bind<void>(ref(acc), _1)); > > cout << mean(acc) << endl; > cout << sqrt(variance(acc)) << endl; But this is the POPULATION standard deviation (variance divided by N) I think. What I was asking for was how to calculated the SAMPLE standard deviation (variance devided by N-1). Thanks, Vic

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Re: [Boost-users] boost::asio::io_service::postand boost::asio::deadline_timer
by Marat Abrarov 18 Jan '12

18 Jan '12

Hi, Christopher. > I mean > now = current time > "Make biscuits 30 seconds from now." > "Clean the car 10 seconds from now." > "Ride your bike 45 seconds from now." > > Or does posting to the timer before it is "expired" interfere with the first > request? http://www.boost.org/doc/libs/1_48_0/doc/html/boost_asio/reference/basic_de… ~~~~~~~~~ Any pending asynchronous wait operations will be cancelled. The handler for each cancelled operation will be invoked with the boost::asio::error::operation_aborted error code. ~~~~~~~~~ Regards, Marat Abrarov.

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[graph] Query for interest: implicit de Bruijn graph
by Jeremiah Willcock 18 Jan '12

18 Jan '12

Would any Boost.Graph users be interested if I implemented an implicit de Bruijn graph? The graph would have the following benefits and drawbacks: - Would not use any storage, but would act as a d^k-vertex, d^(k+1)-edge (for alphabet size d and word length k) graph. - Would be exactly the de Bruijn graph (with no vertex merging or filtering); those features could be added on top, using filtered_graph and/or another wrapper layer. - A filtered_graph based on a sparse property map could "enable" vertices and edges to process in a given algorithm. - A separate layer could enable processing of chains of vertices together. - I could provide a reverse complement map for the base-4 case, as well as conversions between vertices and edges and strings of the correct length. If anyone is interested, I have a few questions as well: - What should the performance tradeoff be between accessing a vertex's incident edges vs. computing reverse complements? - Does the k-mer size (word length) need to be chosen at run-time, or would a compile-time setting be acceptable? -- Jeremiah Willcock

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Re: [Boost-users] [boost] Proposal for a Differential Evolution C++ library
by P Gregor 18 Jan '12

18 Jan '12

I could also help testing. regards, Piotr

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how to calculate the Sample standard deviation using accumulators Hello,
by Victor Yankee 18 Jan '12

18 Jan '12

Hello, How can I calculate the Sample Standard Deviation over a std::vector of doubles using accumulators? Or is there a faster way in boost math or somesuch? Thanks

2 1

boost::asio::io_service::post and boost::asio::deadline_timer
by Christopher 18 Jan '12

18 Jan '12

I am getting boost:asio::error::operation_aborted error codes for an unknown reason in my handlers. No where did a cancel or reset occur, nor was the deadline_time or the io_service destroyed. Does anyone know if I may post to the same io_service a deadline_timer was constructed with or if they will interfere with eachother? May I post multiple times to the deadline timer calling back different methods? I can't imagine why the abort would show up other than I am taking something for granted.

2 2

compiler warnings in
by Chris Cleeland 17 Jan '12

17 Jan '12

Using Boost 1_47_0, in checking some automated builds on a CentOS 4 machine, I get the following errors from the compiler there (gcc v3.4.6). ../../../boost/exception/detail/error_info_impl.hpp:43: warning: `class boost::error_info<tag_answer, int>' has virtual functions but non-virtual destructor Indeed, if I go back and compile the boost tests for exceptions, I get the same compiler warning. GCC 3.4.6 is listed as a tested compiler for 1.47.0; is this warning then expected? Or not? The change that silences the compiler is declaring the destructor of boost::error_info_base to be virtual, but I'm not entirely sure if that's correct. I'm also hesitant to make this change only for CentOS 4 as that will change the object layout in memory and could result in linker confusion, though one could argue that linking against the wrong library is an error unto itself. If there's a more appropriate place to report/discuss these sorts of issues, please point me towards them. Thanks! -- Chris Cleeland

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Jamfile.v2 for iostreams in Boost 1_48
by David Smith 17 Jan '12

17 Jan '12

Greetings, The Jamfile.v2 in the iostreams library of Boost 1_48 has the line (around 29): $(v) = [ modules.peek : $(v) ] ; Used to propogate path-constant settings to the local jam environment. I think it should be: $($(v)) = [ modules.peek : $(v) ] ; At least when I run with this the build of iostreams works correctly to compile bzip2 and zlib objects and fails otherwise. Has anyone else observed this? Regards David

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boost::mpl, c++11 and clang 3.0: compiler bug?
by Allan Nielsen 17 Jan '12

17 Jan '12

Hi The following code compiles fine under clang 3.0 but I get unexpected output: #include <iostream> #include <boost/mpl/for_each.hpp> #include <boost/mpl/vector.hpp> template< typename _state > struct AccSize{ size_t s = 0; _state xxxx; template<typename T> void operator()(T) { std::cout << s << " " << sizeof(T) << std::endl; s += sizeof(T); }; }; struct Foo { Foo () {} Foo (const Foo & rhs) {} }; struct A{}; int main(int argc, const char *argv[]) { using namespace std; AccSize < Foo > p; typedef boost::mpl::vector<int, int, int> list; boost::mpl::for_each< list >( p ); return 0; } The output I get is: 0 4 0 4 0 4 The output I expected is: 0 4 4 4 8 4 If I remove the copy constructor in Foo, it works as I expect, and if I do a "normal" initialization of AccSize::s it also works as I expect. Is this a bug? If so, how can it be reproduced without mpl::foreach Best regards Allan W. Nielsen

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[interprocess] hanging when open_or_create a mapped file
by yiling1 gong 17 Jan '12

17 Jan '12

hello, everyone: I’m a newbie to boost::interprocess, It’s really a cool library, so I try to write a simple program to test mapped file, it’s really simple: #include <boost/interprocess/managed_mapped_file.hpp> using namespace boost::interprocess; int main() { managed_mapped_file mfile(open_or_create, "/home/fractal/log.bin", 1024); //hanging here. return 0; } but it’s hanging on the creation of mapped file, I test it both on ubuntu 11.05(in virtualbox) and openSuse, the same problem remain. I’m sure the file exists, and I traced down the source code, it seems the program stuck in a while loop in function priv_open_or_create(...). except that, if I set the third argument of constructor from 1024 to 1, it’s even throw a exception( not good). any seggestion is appreciated!!!

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boost::interprocess::detail::managed_open_or_create_impl::priv_open_or_create function
by Raghu Gyambavantha 16 Jan '12

16 Jan '12

Boost-ers, When I try to allocate more elements from a managed shared memory segment than allowed, I don't seem to be getting an error from the boost library. It looks like the reason for it is because the call to "construct_func" from "priv_open_or_create" in "boost::interprocess::detail::managed_open_or_create_impl" returns true/false, but that return value is never checked. I saw this error with boost versrion 1.43.0, but that specific portion of the code doesn't seem to have changed even in 1.48.0. >From the looks of it, it seems like the construct_func should throw instead of returning, but in 1.43.0, it is returning a value. Should the return value be check and appropriate action be taken here or am I missing something. Any help is much appreciated. Thanks, -Raghu

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[BGL] Serialize boost::labeled_graph
by Alper Aydemir 15 Jan '12

15 Jan '12

Hi, Is there anyway to easily serialize labeled_graphs ? I can see that <boost/graph/adj_list_serialize.hpp> does it for adjacency lists, however no such header seem to exist for labeled graph type. -- Alper Aydemir

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Multi Threaded Server with boost asio
by mark pashley 15 Jan '12

15 Jan '12

I am looking at writing a multithreaded tcp server using boost ASIO. I have read through the tutorials and had a look at some of the examples and just want to check that my understanding is correct. The server will accept connections then service requests from multiple clients. My understanding is as follows: 1 The server uses "a single io_service and a thread pool calling io_service::run()" 2 All threads call io_service::run(). 3 The calls to io_service::run() are not within a strand, ergo completion handlers can run simultaneously. 4 When a request arrives one of the threads is chosen, it's read handler will be called 5 Another request may arrive,starting the read handler on a second thread 6 When one of the threads has finished handling the request it calls async_write, from within a strand 7 Another thread also finishes processing its request, it also calls async_write, from within a strand 8 The writes to the io_service are serialised via the strand, ergo they are thread safe. 9 When the write operation completes the thread calls async_read() 10 This call is not protected by a strand and the thread will be used for handling requests Is my understanding correct? -- View this message in context: http://boost.2283326.n4.nabble.com/Multi-Threaded-Server-with-boost-asio-tp… Sent from the Boost - Users mailing list archive at Nabble.com.

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What's the execution sequence of phoenix::lambda function?
by 饭桶 15 Jan '12

15 Jan '12

I'm a newbie for boost phoenix, I wrote a small piece of code but it totally confuses me about the execution sequence, you can check the code ------------------clip----------------- std::vector<int> v; v.push_back(1); ph::for_each(v, ph::lambda[ph::ref(cout)<<"a", ph::ref(cout)<<"b" ])(v); ph::for_each(arg1, ph::lambda[ph::ref(cout)<<"a", ph::for_each(v, ph::lambda[ph::ref(cout)<<"b", ph::ref(cout)<<"c" ]), ph::ref(cout)<<"d" ])(v); ------------------------clap-------------------------- The first output is "ab" but the second output is "dbca". It seams ph::for_each is lazy evaluate , but what is the correct one to make it execute from left to right? thanks -- 半亩薄田一头牛老婆孩子热炕头

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[asio] usb howto
by László Veréb 15 Jan '12

15 Jan '12

Hi All! I would like to use the asio library to communicate through usb with some devices. I looked the documentation, and searched the internet. It was said that it can be done, but I could not find any specific information. I found a code for (old) serial ports, it mentioned the usb, but nothing more. I think the important parts were: boost::asio::serial_port port; port.open(devname); port.set_option(***); where one can set these options boost::asio::serial_port_base::baud_rate, parity, character_size, flow_control, stop_bits Are these option also available for usb ports? For example the data flows (found by be) are not the same. Thanks beforehand for your reply and help. Laci

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Boost interprocess vector, creating multiple vector pointers
by Prasanth Madhavan 15 Jan '12

15 Jan '12

I want to insert a shared vector into a shared map using the following code: managed_shared_memory segment(create_only ,"MySharedMemory" ,65536); typedef allocator<int, managed_shared_memory::segment_manager> vecAllocator;typedef vector<int, vecAllocator> vec;typedef std::pair<int, vec* > ValueType;typedef allocator<ValueType, managed_shared_memory::segment_manager> ShmemAllocator;typedef multimap<int, vec*, std::less<int>, ShmemAllocator> MyMap; ShmemAllocator alloc_inst (segment.get_segment_manager());vecAllocator vectorallocator (segment.get_segment_manager()); MyMap *mymap = segment.construct<MyMap>("MyMap")(std::less<int>(),alloc_inst);vec *myvec = segment.construct<vec>("myvec")(vectorallocator);vec *myvec1 = segment.construct<vec>("myvec1")(vectorallocator); myvec->push_back(10);myvec->push_back(9);myvec->push_back(8);myvec1->push_back(987);myvec1->push_back(123);myvec1->push_back(456); for(int i = 0; i < 6; ++i){ for(int j = 0; j<6; j++) mymap->insert(std::pair<int, vec*>(i, myvec));}for(int i = 0; i < 6; ++i){ for(int j = 0; j<6; j++) mymap->insert(std::pair<int, vec*>(i, myvec1));}the code works.. but what i want to do is construct a vector without a name. that is do something like this vec *myvec = segment.construct<vec>(vectorallocator);vec *myvec1 = segment.construct<vec>(vectorallocator);so that if i put it inside a loop and there is no problem with naming them differently every loop. Is there a way to do so? Or atleast is there an automatic way to name them differently every loop? -- Prasanth Madhavan

3 2

[xpressive] sporadic crashes in multi-threaded code
by Ovanes Markarian 14 Jan '12

14 Jan '12

Hello *, I face some issue with sporadic crashes in xpressive which I think a result of a race condition. The use case is: a function which needs to parse smth create local regex objects: const sregex any_char = _; sregex const& rdelim = parser_->delimiter(); //some dynamic delimiter token const sregex re_prefix = bos >> (s1=-*by_ref(any_char)) >> *(s2=by_ref(rdelim)) >> eos ; calling this function from multiple threads results in a crash with (boost 1.42, gcc 4.3.5 on debian linux). I previously had more crashes, but moved all regex objects to global space as const objects and they seem to be fine now. This is the only place I left with a local regex. In the stack trace it seems like internals of the local object regex are freed via boost weak_ptr with possible double delete attempt. The stack-trace of the created core-dump during the crash can be accessed via: https://docs.google.com/open?id=0BzJl1eEH-CCGODU5N2JhOTAtNWMxMy00OGNhLThhNz… (Did not want to send addional 200k to the mailing list.) Many thanks for help, Ovanes

2 2

boost::interprocess and synchronization
by Juan Ramírez 13 Jan '12

13 Jan '12

Hi, I've been working a lot with interprocess communication, but using plain windows API. Now I'm thinking about changing the implementation to boost::interprocess, but a simple question arises: Does boost::interprocess provide any kind of synchronization? On past projects I used to create a global mutex and an avent (or semaphore) object, the global mutex makes sure that only one process is writing at the same time, and the event indicates that there is new data to read.. Does boost:.interprocess provide those objects under the hood or I have to use my own named mutex and conditions? Thanks a lot :) Saludos! Juan

1 1

Problems using boost::mpl::for_each
by Allan Nielsen 13 Jan '12

13 Jan '12

Hi, I have a function where I think mpl::for_each might be use full, but I can not get it to work: template<typename SYM> BaseGamePlateHash holdClear(const BaseGamePlateHash& h) { struct ClearSymbol { ClearSymbol(BaseGamePlateHash& h) : hash(h) { } template <typename _SYM> void operator()(_SYM) { hash.clear<_SYM>(); } BaseGamePlateHash& hash; }; BaseGamePlateHash new_hash = h; typedef typename boost::mpl::remove< SymbolCounts, SYM>::type ClearSymbols; ClearSymbol clearsymbol(new_hash); clearsymbol(SYM()); // this is working //boost::mpl::for_each< boost::mpl::vector<SYM> >( clearsymbol ); // not compiling, this is just a simple test //boost::mpl::for_each< ClearSymbols >( clearsymbol ); // not compiling, this is what I want to do... return new_hash; } I had the impression that the following two statements would do the same: clearsymbol(SYM()); // this is working should be equal to: boost::mpl::for_each< boost::mpl::vector<SYM> >( clearsymbol ); // not compiling But this does not seems to be the case... This is the compile error I get when enabling: boost::mpl::for_each< boost::mpl::vector<SYM> >( clearsymbol ); test7.cxx:303:13: error: 'holdClear(const BaseGamePlateHash &)::ClearSymbol::operator()(SymbolCntDice)::ClearSymbol::hash' is not a member of class 'ClearSymbol' hash.clear<_SYM>(); ^ /usr/local/include/boost/mpl/for_each.hpp:75:9: note: in instantiation of function template specialization 'holdClear(const BaseGamePlateHash &)::ClearSymbol::operator()<SymbolCntDice>' requested here aux::unwrap(f, 0)(boost::get(x)); ^ /usr/local/include/boost/mpl/for_each.hpp:100:5: note: in instantiation of function template specialization 'boost::mpl::aux::for_each_impl<false>::execute<boost::mpl::v_iter<boost::mpl::vector<SymbolCntDice, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, 0>, boost::mpl::v_iter<boost::mpl::vector<SymbolCntDice, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, 1>, boost::mpl::identity<mpl_::na>, ClearSymbol>' requested here aux::for_each_impl< boost::is_same<first,last>::value > ^ /usr/local/include/boost/mpl/for_each.hpp:111:5: note: in instantiation of function template specialization 'boost::mpl::for_each<boost::mpl::vector<SymbolCntDice, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::mpl::identity<mpl_::na>, ClearSymbol>' requested here for_each<Sequence, identity<> >(f); ^ test7.cxx:313:5: note: in instantiation of function template specialization 'boost::mpl::for_each<boost::mpl::vector<SymbolCntDice, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, ClearSymbol>' requested here boost::mpl::for_each< boost::mpl::vector<SYM> >( clearsymbol ); ^ test7.cxx:437:36: note: in instantiation of function template specialization 'holdClear<SymbolCntDice>' requested here BaseGamePlateHash hh = holdClear<SYM>( h ); ^ test7.cxx:386:13: note: in instantiation of function template specialization 'BaseGamePreCalc::create_hold_actions<SymbolCntDice>' requested here create_hold_actions<SymbolCntDice>(hash_enum.first); ^ 1 error generated. So, what have I done wrong? Best regards Allan W. Nielsen

2 1

Get fields from struct
by Matthijs Möhlmann 13 Jan '12

13 Jan '12

Hello all, I'm currently busy to get things like this working: struct person { std::string name; int age; }; int main(int argc, char **argv) { person p; p.name = "Matthijs" p.age = 1234; std::string key = "name"; // Now try to fetch the value based on the key string. std::cout << p.{key} << std::endl; // does not compile return 0; } Of course above doesn't work for obvious reasons. The closest I get is: struct person { std::string name; int age; }; namespace keys { struct name; struct age; } BOOST_FUSION_ADAPT_ASSOC_STRUCT( person, (std::string, name, keys::name) (int, age, keys::age) ); int main(int argc, char **argv) { person x; x.name = "Matthijs"; x.age = 1234; std::cout << "Name: " << boost::fusion::at_key<keys::name>(x) << std::endl; std::cout << "Age: " << boost::fusion::at_key<keys::age>(x) << std::endl; return 0; } Now my question, is there maybe another way to achieve this? Regards, Matthijs Möhlmann Cacholong

2 1

boost::date_time with BOOST_DATE_TIME_POSIX_TIME_STD_CONFIG on MinGW: segfault on multithreading
by Yana A Kireyonok (aka Iron Bug) 13 Jan '12

13 Jan '12

Hello, everybody. Looks like I found a bug in date_time library when building with MinGW. I've built static boost 1.48.0 libraries under windows (Win7 64) with MinGW 3.20 (32 bit, GCC 4.6.1) with BOOST_DATE_TIME_POSIX_TIME_STD_CONFIG option and threading=multi link=static runtime-link=static address-model=32 In this case, when using threads (-mthreads) simple operations with timings fail. I simply created a thread that slept for some milliseconds ten times next and it fails. I traced a little, it fails inside date_time functions, called from this_thread::sleep() with SIGSEGV, segmentation fault. That happens in ctor of structure simple_time_rep, out of reasons, at first glance. Looks like this structure or maybe standard time functions of MinGW are not reentrant (this is my guess, I did not dig too deep in the causes of segfault). Without flag BOOST_DATE_TIME_POSIX_TIME_STD_CONFIG it's going all right with timings and threads. But when using precise timings and threading it fails. I also tried flags BOOST_HAS_WINTHREADS and _REENTRANT - that does not affect the case. BOOST_THREAD_USE_LIB was defined (to let it work with static libs). Is this a bug or problem of MinGW of certain version? I haven't found anything similar in bugtracker. Sincerely, Yana A. Kireyonok

1 0

const char* in shared memory object
by Sabine B 13 Jan '12

13 Jan '12

Hi all! I'm a newbie with boost and I'm struggling with objects in shared memory. The following struct is given: struct MyType{ int id; const char* name; const char* rep; MyType(){}; MyType(MyType* const& type){ id = type->id; name = type->name; rep = type->rep; }; Objects of MyType should be shared between processes in shared memory. I have no problem to put and extract the objects from shared space. But I'm struggling with the const char* pointers. I know that pointers are not allowed in shared memory, thats why I tried to realize with boost string by doing the following: typedef boost::interprocess::allocator<char,boost::interprocess::managed_shared_memory::segment_manager> CharAllocator; typedef boost::interprocess::basic_string<char, std::char_traits<char>, CharAllocator> MyString; boost::interprocess::managed_shared_memory segment(boost::interprocess::open_only, "MySharedMemory"); CharAllocator charallocator(segment.get_segment_manager()); struct MyType{ int id; MyString name; MyString rep; MyType(){}; MyType(MyType* const& type){ id = type->id; name = type->name; rep = type->rep; }; But this is not working because the segment and charallocator are not recognized in the struct and if I put boost::interprocess::managed_shared_memory segment(boost::interprocess::open_only, "MySharedMemory"); CharAllocator charallocator(segment.get_segment_manager()); In the struct I get compiler errors. Could anybody help me how I can realize const char* in an object that should be shared? Please help me! Thank you very much! Best regards, Sabine

2 2

Boost.Move template-function parameter
by Luke J. West 12 Jan '12

12 Jan '12

Hi. I'm trying to implement a template function that 'moves' it's parameter. Here's a simple moveable class... struct my_class { my_class() {} my_class(BOOST_RV_REF(my_class)) {} my_class& operator=(BOOST_COPY_ASSIGN_REF(my_class) c) {return *this;} BOOST_COPYABLE_AND_MOVABLE(my_class); }; And here is the function... template<typename T > void steal(BOOST_COPY_ASSIGN_REF(T) c) {} so it works fine when I do this... int main() { my_class c; steal<my_class >(c); } but not when I do this... int main() { int c; steal<int >(c); } It's as if 'int' is not a movable type which of course it trivially is. I read that Boost.Container classes are 'move aware' and I assume boost::vector<int > works, so what am I doing wrong - how to write my 'steal' function capable of moving it's argument when it's moveable class, but not breaking for primitives? Thanks, Luke (hopeful newbie!)

2 1

Question regarding boost::program_options
by Ankur Sinha 12 Jan '12

12 Jan '12

Hello, I've just started using boost. I'm making use of the program_options to take arguments for my tool. I've written the following: > mDesc.add_options() > ("help,h", "Print this usage message.") > ... > .... > .. > ("v-level,v",boost::program_options::value<int>(&mVerboseLevel),"Debug level: 1,2,3\n(default: 0)") > ("version",boost::program_options::value<std::string>()->zero_tokens(),"Package information: version etc.") > and then, I have a method, which I call in main(int argc, char **argv): > /* > *-------------------------------------------------------------------------------------- > * Class: Session > * Method: Session :: ParseCommandLine > * Description: Parse the command line > *-------------------------------------------------------------------------------------- > */ > int > Session::ParseCommandLine (int argc, char **argv) > { > boost::program_options::store(boost::program_options::parse_command_line(argc, argv, mDesc), mVariableMap); > /* notify required to save the values into my variables. */ > /* TODO: confirm this behaviour */ > boost::program_options::notify(mVariableMap); > > if (mVariableMap.count("help")) > { > std::cout << mDesc << std::endl; > return -1; > } > return 0; > } /* ----- end of method Session::ParseCommandLine ----- */ > However, when I invoke my tool, I get an exception (which I admit I haven't handled yet): > [ankur@ankur dump]$ ./src/test --version > terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::program_options::validation_error> >' > what(): in option 'version': at least one value required > Aborted (core dumped) > [ankur@ankur dump]$ > I'm referring this document[1] which says that zero_tokens() implies an argument may or may not be provided. Why is the exception coming up saying I need "at least one value"? What am I missing? Another query: is notify() necessary to save the values provided on the command line to the variables I pass in the add_options() from the variable map (to mVerboseLevel for instance)? [1] http://www.boost.org/doc/libs/1_42_0/doc/html/program_options/overview.html -- Thanks, Regards, Ankur: "FranciscoD" http://fedoraproject.org/wiki/User:Ankursinha http://dodoincfedora.wordpress.com/

1 0

[BGL] creating a single vertex for the loop in a graph
by srinivas boppu 12 Jan '12

12 Jan '12

Hello All, I am looking for the following in boost graph. I have a graph in which I am able to find out the loops. Now, I wanted to replace the whole loop with a single vertex in the same Graph. Is that possible ? if it is, can you suggest me how do it. Alternate way could be, I copy the loop and make another graph and add this whole graph as a "vertex" in initial graph. Can I add a "graph" as a vertex to existing graph? Thanks and regards, Srinivas Boppu

3 2

Boost, git or svn?
by Robert Jones 12 Jan '12

12 Jan '12

I'm confused about the current status of the svn -> git transition,if indeed any such transition is occuring. Boost main page still seems refer to the old SVN repository, but vault references are to a git-hub server. Can someone supply a few sentences of explanation. Thx. - Rob.

3 3

[Range] Range adaptors and compatibility with non-adapted iterators
by John M. Dlugosz 12 Jan '12

12 Jan '12

Consider something like this: themap_type::iterator search_for (int val) { return boost::find_if (themap|map_values, my_predicate(val)); } The return from the function chokes because the adapted iterator type cannot be convered back to the original type of iterator in the parent collection. This is more general. If I wasn't just returning through but using the result within the function, how do I test against end to see if find_if was successful? auto it2= boost::find_if (themap|map_values, my_predicate(val)); if (it2 == themap::end()) // same problem! This seems to be a problem with any algorithm that returns an iterator or otherwise makes the iterators used within the algorithm visible outside of it, even if such usage is just as an "end" flag and not really used to locate the element within the original collection for subsequent iteration. Am I missing something? Is there a good reason why the filtered iterator can't give up the inner original iterator? How do you use range adaptors in these situations? —John

4 6

Help needed in creating Regex...
by Subhash Nagre 12 Jan '12

12 Jan '12

Hi everyone, I need a help in creating a regular expression, I need to select only "Sentences" in String using Regex so I wrote the Code .. *boost::regex re( "(\\S.+?[.!?])(?=\\s+|$)" );* This code considers that sentences break at any of these three characters . ! ? but this code considers string "Mr. Obama" as 2 difference sentences (being a dot character in between), where as I want it to be only one sentence. I have a got a string vector of all the words which have to excluded. std::vector<std:string>exceptionVector; exceptionVector.pushback("Mr.") exceptionVector.pushback("Dr.") exceptionVector.pushback("Mrs.") Now in my regex, I want that if any of the words occur from my vector, it should NOT be a seperate sentence. Any idea how can I create this Regular expression Thanks in Advance -Subhash

3 2

asio raw with PF_PACKET and promiscuous mode?
by Chris Cleeland 11 Jan '12

11 Jan '12

Before I reinvent the wheel, has anybody put together an asio encapsulation of Linux' AF_PACKET sockets with SOCK_RAW? Also, I'm trying to wrap my brain around how I might represent the concept of an "endpoint" for a socket like this. Rather than an IPv4/v6 address, one binds to an interface. So, while there is a concept of a resolver, it resolves an interface name to an interface index value. >From a C/system call perspective, I need to do the following to get the ball rolling: 1. s = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL)) 2. sockaddr_ll myinterface = { .sll_family = AF_PACKET, .sll_protocol = htons(ETH_P_ALL), .sll_ifindex = interfaceIndex("eth0") }, then bind(s, &myinterface) 3. packet_mreq promiscuous_cmd = { .mr_ifindex = interfaceIndex("eth0"), .mr_type = PACKET_MR_PROMISC }, then setsockopt(s, PACKET_ADD_MEMBERSHIP, &promiscuous_cmd) I'm pretty sure that for #1, I need a class packet that models the Protocol concept. But where to put the rest is a bit fuzzier. Do I need to create a whole new "resolver" for interface names? I guess I should also note that, at least for the moment, this is just a means to an end, rather than the end itself. So, I don't need to craft the entire thing--I need to get enough working to be able to easily write some code that can capture all network packets on a given interface, e.g., class snooper { public: snooper(std::string interfacename); void start(); void stop(); ... }; so I can just do something like snooper s("eth0"); s.start(); ...capture stuff... s.stop(); (I'm obviously omitting the part where snooper would hook into objects that would receive and process captured packets, but I'd like for that to work similar to how one plumbs up receipt of udp packets.) -- Chris Cleeland

1 0

casting shared pointers to derived classes
by Don Wilde 11 Jan '12

11 Jan '12

Greetings, all - I am updating a neural network package from the DOS days to modern C++ standards. I have a shared_ptr to a vector of shared_ptrs of type Layer. This class has derived classes OutputLayer, MiddleLayer and InputLayer. Each of these has their own method for calculating output updates, so I need to be able to cast. from boost::shared_ptr<Layer> to static_cast<OutputLayer*>(). Unfortunately, VC++ 2010 will not allow me to do so. It won't even allow a reinterpret_cast. I've looked on the Web and I also have Schalling's guide to Boost. Thank you in advance for your guidance. I'm using boost_1_47_0, if that makes a difference. :D

4 4

[Fwd: How to print the structure of vector of boost::variant]
by Baba Prasad 11 Jan '12

11 Jan '12

Dear friends, please see the bellow my code and tell me how to get out this problem please.when I try to print values of variant it's giving the error as: std::ostream& operator<<(std::ostream&, const status_rsp&): worked.cpp:33: error: const struct status_rsp has no member named os worked.cpp:33: error: const class boost::variant<int, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_> has no member named channelid worked.cpp:33: error: expected ) before ; token worked.cpp:34: error: const class boost::variant<int, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost #include<vector> #include<iostream> #include<boost/variant.hpp> typedef int cid; typedef int n_queue; typedef boost::variant<chid> link_st_rs; typedef std::vector<link_st_rs> link_st_rs_list; typedef boost::variant<n_queue> link_de_rs; typedef std::vector<link_de_rs> link_de_rs_list; using namespace std; struct lparam { int value; }; typedef vector<lparam> link1; struct link_s_rsp { link1 ll; link_st_rs_list lsrl; link_de_rs_list ldrl; }; struct status_rsp { link_s_rsp rsp; friend std::ostream& operator<<(std::ostream& os , const status_rsp& sr) { os << "the value is " << sr.rsp.ll.front().value; os << "id" << sr.rsp.lsrl.front().chid; os << "val" << sr.rsp.ldrl.front().n_queue; return os; } }; typedef vector<status_rsp> srl; int main() { linkparam lp; lp.value =90; link_de_rs_list ldrl; lsrl.push_back(4); ldrl.push_back(3); status_rsp sr; sr.rsp.ll.push_back(lp); srl srl1; srl1.push_back(sr); link1::iterator iter2 = srl1.begin()->rsp.ll.begin(); cout << "A vlue is: " << iter2->value; link_st_rs_list::iterator iter3 = srl1.begin()->rsp.lsrl.begin(); cout << " B value " << iter3->chid; link_de_rs_list::iterator iter4 = srl1.begin()->rsp.ldrl.begin(); cout << "C value" < iter4->n_queue; cin.ignore(); return 0; } Best Regards BaBu -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.

2 1

Needs advices on design ( mpl or processor )
by Allan Nielsen 11 Jan '12

11 Jan '12

Hi This is not a specific questions directly related to Boost::mpl, but a request for help if somebody has the time... For the last couple of month I have been trying to learn to use the boost::mpl library. To learn to use the library I decided to use it for creating a "compressed-enum" library. The library should make it possible to store several enums in a single variable (for instance an unsigned int) Here is a simple example to give en idea: // example enums to play with struct TagA { enum Size { size = 4 }; enum Max { max = 3 }; enum E { A0 = 0, A1 = 1, A2 = 2, A3 = 3, }; }; struct TagB { enum Size { size = 4 }; enum Max { max = 3 }; enum E { B0 = 0, B1 = 1, B2 = 2, B3 = 3, }; }; struct TagC { enum Size { size = 4 }; enum Max { max = 3 }; enum E { C0 = 0, C1 = 1, C2 = 2, C3 = 3, }; }; struct First{}; struct Second{}; int main() { // using the compressed enums library typedef unsigned short STORAGE; typedef CompressedEnums< STORAGE, CompressedEnum<STORAGE, 1, TagA>, CompressedEnum<STORAGE, 4, TagB, First>, CompressedEnum<STORAGE, 16, TagB, Second>, CompressedEnumArray<STORAGE, 64, TagC, 5> > ENUMS; assert(sizeof(ENUMS) == 2)); ENUMS enums; enums.set<TagA>(TagA::A2); enums.set<Second>(TagB::B2); enums.set<3, TagC>(TagC::C2); cout << enums.get<TagA>() << " " << enums.get<Second>(TagB::B2) << " " << enums.get<3, TagC>(TagC::C2) << endl; } CompressedEnums contains the storage variable, and inherit from all its template arguments, and make their methods available through tags. CompressedEnum and CompressedEnumArray only contains static methods which can find the enum in the storage variable. Here is a snippet of my implementation: template < typename STORAGE_TYPE, int OFFSET, typename ENUM_CONTAINER, typename TAG = typename ENUM_CONTAINER::E > struct CompressedEnum { typedef TAG ACCESS_TAG; typedef typename ENUM_CONTAINER::E INNER_TYPE; enum Offset { offset = OFFSET }; enum Size { size = ENUM_CONTAINER::size }; static INNER_TYPE get(const STORAGE_TYPE& data) { return (INNER_TYPE)((data / OFFSET) % size); } ----%<----%<----%<----%<----%<----%<----%<----%<-- } template < typename STORAGE_TYPE, typename B00 = Dummy< 0>, typename B01 = Dummy< 1>, typename B02 = Dummy< 2>, typename B03 = Dummy< 3> > struct CompressedEnums : public B00, B01, B02, B03 { typedef boost::mpl::map<boost::mpl::pair<typename B00::ACCESS_TAG, B00>, boost::mpl::pair<typename B01::ACCESS_TAG, B01>, boost::mpl::pair<typename B02::ACCESS_TAG, B02>, boost::mpl::pair<typename B03::ACCESS_TAG, B03> > TYPE_MAP; template<typename TAG> typename boost::mpl::at<TYPE_MAP, TAG>::type::INNER_TYPE get() const { return boost::mpl::at<TYPE_MAP, TAG>::type::get(data); } ----%<----%<----%<----%<----%<----%<----%<----%<-- STORAGE_TYPE data; }; The code works and does what it is suppose to (as far as I know) but I'm not very happy with the interface: typedef CompressedEnums< STORAGE, // 1 because it is the first CompressedEnum<STORAGE, 1, TagA>, // 4 because TagA::size == 4 CompressedEnum<STORAGE, 4, TagB, First>, // 16 because TagA::size * TagB::size == 16 CompressedEnum<STORAGE, 16, TagB, Second>, // 64 because TagA::size * TagB::size * TagB::size == 64 CompressedEnumArray<STORAGE, 64, TagC, 5> > ENUMS; These magic numbers makes it very easy to make bugs when the code is restructured or changed, and it should be possible to calculate them automatic. If the magic numbers are replaced with their expresions the code will still break of the arguemnts are reordered. To accomplice this I have considered two solutions: macro or more templating... Using macroes I imagin the interface could look something like this: typedef CompressedEnums< STORAGE, ENUM_PACK( STORAGE, 1, (CompressedEnum, TagA) (CompressedEnum, TagB, First) (CompressedEnum, TagB, Second) (CompressedEnumArray, TagC, 5) ) > ENUMS; Which then would expand to the code manual entered above. Alternative using template I imagin that CompressedEnums could change CompressedEnum<STORAGE, 0, TagB, Second> -> CompressedEnum<STORAGE, 16, TagB, Second> automatic and then derive from that one automatic. I tried both, but non of my idea worked out very well, which is why I hope that one of you c++ experts could give me some hints. Best regards Allan W. Nielsen

5 28

depth_first_visit
by James Lindsay 10 Jan '12

10 Jan '12

Hello, I've found several questions regarding the depth_first_visit algorithm but I can't find a complete example anywhere. I was wondering if someone could post a complete example of the depth_first_visit algorithm in action, including how you created the color map. Thanks

3 2

[BGL / General] member of struct is a reference - why?
by Max Limper 10 Jan '12

10 Jan '12

Hi everybody, I was just going through the "File Dependency" example for the graph library and found this piece of code which is a very simple cycle detector: struct cycle_detector : public dfs_visitor<> { cycle_detector( bool& has_cycle) : _has_cycle(has_cycle) { } template <class Edge, class Graph> void back_edge(Edge, Graph&) { _has_cycle = true; } protected: bool& _has_cycle; }; It takes a reference and manipulates the externally declared variable hasCyle via that reference. I tried to change hasCylce to a "regular" member variable, and I just want to read it afterwards, like cycle_detector detector(); boost::depth_first_search(graph, boost::visitor(detector)); if (detector.foundCycles) { //do something } I also thought about giving the cycle detector other member variables, like a list of back edges that gets filled. However, I found that none of those variables gets set the right way, starting with the very simple "bool hasCycle" member. I guess there must be a reason why the person that made the example chose to use a reference, and it only works that way... any ideas why? Thanks a lot in advance.

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[C++ Now! 2012] Deadline extension: Call for Submissions, new deadline is January 20th, 2012
by Hartmut Kaiser 10 Jan '12

10 Jan '12

INAUGURAL C++ NOW! CONFERENCE 2012 Aspen CO, USA, May 14-18, 2012, www.cppnow.org CALL FOR SUBMISSIONS We invite you to submit session proposals to the Inaugural C++ Now! Conference: C++Now! 2012 (Aspen CO, USA, May 14 - 18, 2012). Based on the successful traditions of 5 years of BoostCon, which was the main face-to-face event for all things C++ and Boost (www.boost.org) C++Now! 2012 will present leading speakers from the whole C++ community. The conference name is changing to C++ Now! to reflect the current value of the language, the focus on its new state (from the new Standard), and the need to continually look to the future so the language remains useful to the C++ community. The focus of this conference will be the new C++11 language Standard and as usual Boost: what's new in C++, its Standard library, and in the Boost libraries, how to write and maintain them, how to evangelize or to deploy Boost within your organization. The new C++ Standard, but also the infrastructure and process of Boost, its vision and mission - no matter what you are interested in, it all comes together in the C++Now! sessions. Meet the colleagues, and feel the inspiration to support your work with C++ and Boost for the next year. The C++ Now! Conference is dedicated to discussion and education about C++, an open and free language and standard. Our Conference will focus on discussion and education about open source software usage and developments in the C++ developer and user community. To reflect the breadth of the C++ and Boost communities, the conference includes sessions aimed at three constituencies: C++ and Boost end-users, hard-core Boost library and tool developers, and researchers pushing the boundaries of computation. The program fosters interaction and engagement within and across those groups, with an emphasis on hands-on, participatory sessions. As a multi-paradigm language, C++ is a melting pot where the most compelling ideas from other programming communities are blended in powerful ways. Historically, some of the most popular sessions at C++Now! have highlighted these concepts, from DSLs to functional programming to transactional memory and more. Bring your C#, Python, Ruby or Haskell influences to bear in an environment that will broaden their exposure. IMPORTANT DATES New proposal submissions due: January 20th, 2012. UPDATED! Proposals decisions sent (tentative program): February 17th, 2012. Fully scheduled program available: February 25th, 2012. Session materials due: April 15th, 2012. BEST PRESENTATION AWARDS We know how much effort it takes to prepare talks for our conference. For this reason we will award the best presentations in the following categories: Best Presentation, Best Short Presentation, Best Tutorial, and Best Workshop. The awards will be given based on the audience's voting. Each award will include the author's name listed on the cover of the C++Now! website for that year and a plaque containing all the C++Now! conference information. SESSION TOPICS Topics of interest include, but are not restricted to, the following: * C++11 and how it changes life for users and library writers * General tutorial sessions on C++11, the C++11 Standardslibrary, and one or more Boost libraries * In-depth sessions on using specific Boost libraries * Case studies on using Boost * Experts panels * Advanced sessions on implementation techniques used within Boost libraries * Development workshops to extend or enhance existing Boost libraries * Workshops on design process * Infrastructure workshops such as Build tools, Website, Testing * Concepts and Generic Programming * Hardware and infrastructure presentations focused on how libraries can make better use of the technology * Software development tools and their application to C++ and or Boost * Other topics likely to be of great interest to Boost users and developers Interactive and collaborative sessions are encouraged, as this is the style of learning and participation that has proven most successful at such events. Sessions can be tutorial based, with an emphasis on interaction and participant involvement, or workshop based, whether hands-on programming or paper-based, discussion-driven collaborative work. SESSION FORMATS Presentations Presentations focus on a practitioner's ideas and experience with anything relevant to C++11, Boost and users. Panels Panels feature three or four people presenting their ideas and experiences relating to C++11 and Boost's relevant, controversial, emerging, or unresolved issues. Panels may be conducted in several ways, such as comparative, analytic, or historic. Tutorials Tutorials are sessions at which instructors teach conference participants specific skills relevant to C++11 and Boost. Workshops Workshops provide an active arena for advancements In Boost-relevant topics. Workshops provide the opportunity for experienced practitioners to develop new ideas about a topic of common interest and experience. Author's Corner These were introduced at BoostCon 2008, and were a great Presentations success They are short (30 minute) sessions, focusing on tips on usage and design. In addition, we're looking to uncover the hidden design gems in Boost libraries. Tool Vendors We actively encourage tool vendors and ISP's to submit presentations proposals for a special Tool Vendors Session Track aimed at products related to Boost and C++ (compilers, libraries, tools, etc.). Other formats may also be of interest. Don't hold back a proposal just because it doesn't fit into a pigeonhole. SUBMITTING A PROPOSAL Standard Sessions are 60 minutes. You may submit a proposal for fractions or multiples of 90-minutes. Fractional proposals will be grouped into 60 minute sessions covering related topics. Longer sessions, such as tutorials and classes, will be assigned 90 minute, three hour (i.e. half day), or six hour (i.e. full day) time slots. Please include: * The working title. * Type of session: presentation, panel, tutorial, workshop, authors corner, vendor track, other. * A paragraph or two describing the topic covered, suitable for the conference web site. * Proposed length: 10-20 minute short talks, 45 minutes, 90 minutes, half day, full day. * Alternate lengths, if you are willing to make adjustments: 10- 20 minute short-talks, 45 minutes, 90 minutes, half-day, full day. * Audience: users, developers, both. * Level: basic, intermediate, advanced. * A biography, suitable for the conference web site. * Your contact information (will not be made public). SUBMISSION DETAILS All submissions should be made through the EasyChair conference management system: http://www.easychair.org/conferences/?conf=cppnow2012. If you have not already registered at EasyChair, you will need to do so in order to submit your proposal. All submissions will go through a peer review process. Authors are invited (but are not required) to submit PDF versions of full papers of up to 10 pages in ACM conference proceedings format (see http://www.acm.org/sigs/publications/proceedings-templates) The full papers are not required unless you want them published in the proceedings. All accepted proposals will be made available in the Association for Computing Machinery (ACM) Digital Library (approval pending). Best papers, after further reviews, will be considered to be book chapters or journal articles in a renowned journal. The session materials go on the C++Now! website and will be available to attendees. For general information on the C++Now! 2012 paper submission or the scope of technical papers solicited, please refer to the conference website at www.cppnow.org. For any other questions about the submission process or paper format, please contact the Program Committee at cppnow2012(a)easychair.com. If you have any technical problems with EasyChair, please contact EasyChair for help. Note: Presenters must agree to grant a non-exclusive perpetual license to publish submitted materials, either electronically or in print, in any media related to C++ Now!. Hartmut Kaiser, email: hartmut.kaiser(a)gmail.com (Program Committee Chair) Dave Abrahams, email: dave(a)boostpro.com (Conference Chair) On behalf of the conference organizers

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Quick Unit Test Question
by Brad Tilley 10 Jan '12

10 Jan '12

Hey everyone, I can make BOOST_CHECK produce a failure message like this: BOOST_AUTO_TEST_CASE( test_case2 ) { BOOST_CHECK( 1+1 == 3 ); } But when I try BOOST_WARN, all tests pass: BOOST_AUTO_TEST_CASE( test_case3 ) { BOOST_WARN( 1+1 == 3 ); } Running 3 test cases... *** No errors detected Perhaps I'm doing something wrong. Can someone point me in the right direction? Both BOOST_REQUIRE and BOOST_CHECK work OK. It's only BOOST_WARN that does not work for my testing. Thanks, Brad

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Boost Review Wizard Report for January 2012
by Ronald Garcia 10 Jan '12

10 Jan '12

============================================== Review Wizard Status Report for January 2012 ============================================== News ==== 1. Type Traits Library Extensions Accepted 2. AutoIndex Tool Accepted 3. Heaps Library Accepted 4. Assign v2 Library Rejected 5. Type Traits Introspection Library Accepted 6. Lockfree Library Accepted 7. Algorithm Library Accepted 8. Atomic Library Accepted 9. Local Library Accepted 10. Context Mini-review Ongoing Open Issues =========== The following libraries have been reviewed and await reports from their review managers: * Conversion - reviewed August 2011; review manager: Gordon Woodhull. The following libraries have been accepted to Boost, but have not yet been submitted to SVN: * Constrained Value - accepted September 2010; author: Robert Kawulak * GIL.IO - accepted January 2011; author: Christian Henning. * Atomic - accepted July 2011; author Helge Bahmann * Lockfree - accepted August 2011; author: Tim Blechmann. * Algorithm - accepted December 2011; author: Marshall Clow The following libraries have been accepted and submitted to SVN, but have not yet appeared in a release: * Heaps - accepted June 2011; author: Tim Blechmann. * Type Traits Introspection - accepted August 2011; author: Edward Diener. The following libraries have been accepted provisionally to Boost, but have not been submitted for mini-review and full acceptance: * Log - accepted provisionally March 2010; author: Andrey Semashev. * Endian - accepted provisionally November 2011; author: Beman Dawes. After repeated failed attempts to contact the author, the following library has been marked as Orphaned. * Switch library, accepted provisionally January 2008 author: Steven Watanabe. General Announcements ===================== As always, we need experienced review managers. Please take a look at the list of libraries in need of managers and check out their descriptions. In general review managers are active boost participants, including library contributors, infrastructure contributors, and other mailing list participants with a substantial track record of constructive participation. If you can serve as review manager for any of them, email Ron Garcia or John Phillips, "rxg at cs dot cmu dot edu" and "phillips at pacific dot mps dot ohio-state dot edu" respectively. We are also suffering from a lack of reviewers. While we all understand time pressures and the need to complete paying work, the strength of Boost is based on the detailed and informed reviews submitted by you. If you are interested in reviewing a library but won't have time during the review period, you can always prepare your review ahead of time. No rule says you can only work on a review during the review period. A link to this report will be posted to www.boost.org. If you would like us to make any modifications or additions to this report before we do that, please email Ron or John. The review schedule is an unordered list of the libraries awaiting review. As such, any library on the schedule can be reviewed once the developer is ready, a review manager has been secured, and the manager, developer, and wizards agree on a date to schedule the review. Review Schedule =============== * Join (M) * Pimpl (M) * Sorting (M) * Quaternions, Vectors, Matrices (M) * Variadic Macro Data (M) * Block Pointer (M) * Network (M) * Singularity (M) * Predef (M) ``(M)`` marks libraries that need review managers. -------------------- Join ---- :Author: Yigong Liu :Review Manager: Needed :Download: http://channel.sourceforge.net/ :Description: Join is an asynchronous, message based C++ concurrency library based on join calculus. It is applicable both to multi-threaded applications and to the orchestration of asynchronous, event-based applications. It follows Comega's design and implementation and builds with Boost facilities. It provides a high level concurrency API with asynchronous methods, synchronous methods, and chords which are "join-patterns" defining the synchronization, asynchrony, and concurrency. Pimpl ----- :Author: Vladimir Batov :Review Manager: Needed :Download: | `Boost Vault <http://www.boost-consulting.com/vault/index.php?action=downloadfile&fil…>`__ | http://www.ddj.com/cpp/205918714 (documentation) :Description: The Pimpl idiom is a simple yet robust technique to minimize coupling via the separation of interface and implementation and then implementation hiding. This library provides a convenient yet flexible and generic deployment technique for the Pimpl idiom. It's seemingly complete and broadly applicable, yet minimal, simple and pleasant to use. Sorting ------- :Author: Steven Ross :Review Manager: Needed :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=al…>`__ :Description: A grouping of 3 templated hybrid radix/comparison-based sorting algorithms that provide superior worst-case and average-case performance to std::sort: integer_sort, which sorts fixed-size data types that support a rightshift (default of >>) and a comparison (default of <) operator. float_sort, which sorts standard floating-point numbers by safely casting them to integers. string_sort, which sorts variable-length data types, and is optimized for 8-bit character strings. All 3 algorithms have O(n(k/s + s)) runtime where k is the number of bits in the data type and s is a constant, and limited memory overhead (in the kB for realistic inputs). In testing, integer_sort varies from 35% faster to 2X as fast as std::sort, depending on processor, compiler optimizations, and data distribution. float_sort is roughly 70% faster than std::sort. string_sort is roughly 2X as fast as std::sort. Quaternions, Vectors, Matrices ------------------------------ :Author: Emil Dotchevski :Review Manager: Needed :Download: http://www.revergestudios.com/boost-qvm/ :Description: QVM defines a set of generic functions and operator overloads for working with quaternions, vectors and matrices of static size. The library also defines vector and matrix data types, however it allows users to introduce their own types by specializing the q_traits, v_traits and m_traits templates. Variadic Macro Data ------------------- :Author: Edward Diener :Review Manager: Needed :Download: `Boost Sandbox <http://svn.boost.org/svn/boost/sandbox/variadic_macro_data/>`__ :Description: The variadic_macro_data library adds support and functionality for variadic macros to Boost as well as integrating variadic macros with the Boost PP library without changing the latter library in any way. Block Pointer ------------- :Author: Phil Bouchard :Review Manager: Needed :Download: `Boost Sandbox <https://svn.boost.org/svn/boost/sandbox/block_ptr/>`__ :Description: Deterministic memory manager of constant complexity capable of handling cyclic collections. Network ------- :Author: Dean Michael Berris :Review Manager: Needed :Download: http://cplusplus-soup.com/2011/04/18/cpp-netlib-0-9-0-released/ :Description: This is a library that provides application layer protocol support using modern C++ techniques. It is light-weight, fast, cross-platform and is intended to be as easy to configure as possible. Singularity ----------- :Author: Ben Robinson :Review Manager: Needed :Download: https://github.com/icaretaker/Singularity :Description: The Singularity Design Pattern allows you to restrict any class to a single instance. Unlike the infamous Singleton, Singularity gives you direct control over the lifetime of the object, does not require you to grant global access to the object, nor does it limit you to the default constructor for that object. Predef ------ :Author: Rene Rivera :Review Manager: Needed :Download: http://tinyurl.com/73n6a3k :Description: The Predef library implements two simple tasks: 1. Definition of a single version number macro to provide consistent version number at the preprocessor level. 2. A collection of detected definitions for compilers, standard libraries, architectures, operating systems, and languages. Unlike the Boost Config Library it doesn't define language features and capabilities. But only defines presence of detected compilation context. Documentation and downloads are available in the sandbox.. Libraries under development =========================== See http://svn.boost.org/trac/boost/wiki/LibrariesUnderConstruction for a current listing of libraries under development.

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Re: [Boost-users] [Multi Index] equal_range from templated function fails to compile with gcc 4.6.1
by Jacob Metcalfe 10 Jan '12

10 Jan '12

Thanks for the quick reply, 51566 does seem very similar. I do not experience the issue from bug 9810 in any of the compilers where I have managed to reproduce the bug - from a quick look it looks somewhat different - and unfortunately changes to access_specifier.hpp don't solve the issue (changing the inheritance modifier or access modifiers in the derived class also does not seem to help). I experimented with a few changes but the only case that got rid of the error was the obvious change of making node_type public in index_base.hpp. In terms of gcc versions - so far I have reproduced the issue with 4.6.1, 4.6.2 and 4.5.2. Jacob.

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extract objects from vector in shared memory
by Sabine B 09 Jan '12

09 Jan '12

Hello! I have again a question to using the boost vector with shared memory objects. I managed inserting the objects of type "MyType" into the vector with the following code: typedef boost::interprocess::allocator<MyType*, managed_shared_memory::segment_manager> ShmemAllocator; typedef boost::interprocess::vector<MyType*, ShmemAllocator> MyVector; struct shm_remove{ shm_remove(){shared_memory_object::remove("MySharedMemory");} ~shm_remove(){shared_memory_object::remove("MySharedMemory");} }remover; managed_shared_memory segment(create_only, "MySharedMemory", 65536); const ShmemAllocator alloc_inst(segment.get_segment_manager()); MyVector *vector = segment.construct<MyVector>("Vector")(alloc_inst); MyType *mytype = segment.construct<MyType>(anonymous_instance)(); MyVector->push_back(mytype); The problem is that I can't manage to extract the object from the vector. I always get a null pointer or a pointer to somewhere. This is the code for the child process: managed_shared_memory segment(open_only, "MySharedMemory"); vector = segment.find<MyVector>("Vector").first; MyType *mytype = vector->at(1); // program crashes when I try to print members of the object MyType or MyType mytype = (MyType&)vector->at(1); // object is empty Does anybody have any hint or an idea what I'm doing wrong? Thank you very much for your help! Best regards, Sabine

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[Multi Index] equal_range from templated function fails to compile with gcc 4.6.1
by Jacob Metcalfe 09 Jan '12

09 Jan '12

I’m having issues compiling some multi_index_container code after upgrading from gcc 4.3.4 to gcc 4.6.1 and wondering if anyone can shed some light. Perhaps this should be directed to gcc, but I have not been able to reduce this to not include multi_index. The contrived code below is the furthest I have been able to reduce the problem so far:**** ** ** 1 #include <boost/multi_index_container.hpp>**** 2 #include <boost/multi_index/ordered_index.hpp>**** 3 #include <boost/multi_index/member.hpp>**** 4 #include <boost/multi_index/composite_key.hpp>**** 5**** 6 using namespace boost::multi_index;**** 7**** 8 struct Data{**** 9 double _d;**** 10 };**** 11**** 12 typedef multi_index_container< Data,**** 13 indexed_by< ordered_non_unique<**** 14 composite_key< Data, member<Data, double, &Data::_d> >**** 15 > >**** 16 > Map;**** 17**** 18 template <int T>**** 19 void foo(){**** 20 Map mi;**** 21 mi.get<0>().equal_range(boost::make_tuple(0.0));**** 22 }**** 23 int main(){**** 24 foo<5>();**** 25 }**** ** ** The failures from gcc 4.6.1 are:**** ** ** boost/multi_index/detail/index_base.hpp: In function 'void foo() [with int T = 5]':**** boost/multi_index/detail/index_base.hpp:49:47: error: 'typedef struct boost::multi_index::detail::index_node_base<Data, std::allocator<Data> > boost::multi_index::detail::index_base<Data, boost ::multi_index::indexed_by<boost::multi_index::ordered_non_unique<boost ::multi_index::composite_key<Data, boost::multi_index::member<Data, double, &Data::_d> > > >, std::allocator<Data> >::node_type' is protected**** tstmi.cpp:24:10: error: within this context**** ** ** ** ** This code appears to compile fine under 4.3.4 and would compile with 4.6.1 if the useless template at line 18 was removed.**** ** ** Many thanks

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[boost.build] packaging with dependencies symbolic links
by Christophe Bourez 09 Jan '12

09 Jan '12

Hi, I have an executable project depending on other 3rd libraries (log4cplus, libxml2 ...). For each of these 3rd libraries, we recreate the missing Jamroot file. The executable is built (g++ under linux) with <link>shared property. When packaging, no symlinks to 3rd libraries are generated. Investigating boost.build, I found the property <install-no-version-symlinks> (Its default and unique value is 'on'). Is it related? If yes, may I workaround it? How can I package my executable with symlinks to 3rd library ? Thank you, Christophe

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Re: [Boost-users] Needs advices on design ( mpl or processor )
by Alex Perry 07 Jan '12

07 Jan '12

On 07 January 2012 23:28 Alex Perry wrote:- > I've been following this thread despite being a total novice with mpl (and > template meta-programming in general). However I'm not quite sure why > you are trying to pass the offset through the templates in the 1st place - can't > you just use standard : syntax and let the compiler work out the offsets? Oops just read some more messages in the thread and now understand what you were trying to do (which wasn't what I was doing at all) Sorry for the noise Alex

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Re: [Boost-users] Needs advices on design ( mpl or processor )
by Alex Perry 07 Jan '12

07 Jan '12

On Sat 07/01/2012 08:42 Allan Nielsen <a(a)awn.dk> wrote:- >I will try to illustrate my design problem in a more simple example: > >struct TagA { > enum Size { size = 4 }; > enum E { A0 = 0, A1 = 1, A2 = 2, A3 = 3, }; }; > ... I've been following this thread despite being a total novice with mpl (and template meta-programming in general). However I'm not quite sure why you are trying to pass the offset through the templates in the 1st place - can't you just use standard : syntax and let the compiler work out the offsets? Eg enum A { A0,A1,A2,A3,A4 }; enum B { B0,B1,B2,B3,B4 }; template <typename type1, int t1_numbits, typename type2, int t2_numbits> struct packed { type1 first : t1_numbits; type2 second : t2_numbits; }; Obviously accessing members via a name like first is far from ideal and specifying the size in the template would make this really unusable. However at this point my lack of knowledge of mpl kicks in - I'm sure there is some clever way of coding this up so that packed<A,B,C> is defined like mpl::vector<> which could provide a clean way of accessing the members. My total naive first attempt using partial specialisations on member functions sort of works under MSVC but fails totally on gcc - not sure if this is because this is a MS extension or whether its C++11 and so would work on a newer gcc - it works with VS2010 and VS2008 (I don't think there are any C++0x extensions in 2008) on windows 7 and fails to compile with gcc 4.1.2 on Linux. Linux errors start with :- test.cpp:53: error: explicit specialization in non-namespace scope 'struct packed<type1, type2, type3, type4>' test.cpp:53: error: enclosing class templates are not explicitly specialized It's also relying on the (probably nearly always true) assumption that the enum types packed together would always be unique so that using the type of the enum can find the unique member - this assumption should at least have some sort of compile assertion on it (mpl again I guess). It seems like an awful lot of boiler plate code would have to live behind the scenes to make this anything like useable though so not sure its worth exploring as a possible method but just in case it helps :- #include <iostream> //An enum we want to be able to compress enum A{A0,A1,A2,A3,A4}; //The bit size information for enum as per previous example code (NB this is actually wrong 3 is big enough to hold 0-7 but heck ...) struct tagA { typedef enum A enum_type; enum { size=4 }; }; //Wrapper for above tag info just to save typeing having shown it done manually above template <typename enumType,int size_ = 4> struct tag { typedef enumType enum_type; enum { size=size_ }; }; //Another couple of enums and tag structures for bit sizes enum B{B0,B1,B2,B3,B4}; typedef tag<B,4> tagB; enum C{ C0,C1,C2,C3,C4 }; typedef tag<C,3> tagC; //Just to check that size is actually doing something enum D{ D0,D1,D2,D3,D4 }; typedef tag<D,4> tagD; //Our packed structure template <typename type1,typename type2, typename type3, typename type4 > struct packed { //Just for clarity typedef typename type1::enum_type first_type; typedef typename type2::enum_type second_type; typedef typename type3::enum_type third_type; typedef typename type4::enum_type fourth_type; typedef packed<type1,type2,type3,type4> thistype; //Our packed enums using the specified bit sizes first_type first : type1::size; second_type second : type2::size; third_type third : type3::size; fourth_type fourth : type4::size; //All following is just to provide a simple get/set syntax rather than accessing via member names struct fail {}; //Only used for general case - fail will not convert to T hence compile error when used template <typename T> T get() const { return fail; }; //Specialisations to provide access to the (unique) members based on their types template<> first_type get<first_type>() const { return first;} template<> second_type get<second_type>() const { return second;} template<> third_type get<third_type>() const { return third;} template<> fourth_type get<fourth_type>() const { return fourth;} //May as well define == using the get() - note extra specialisation for whole structure equality template <typename T> bool operator == (T const & other ) const { return get<T>() == other; } template <> bool operator ==<thistype>(thistype const & other ) const { return other==get<type1::enum_type>() && other==get<type2::enum_type>() && other==get<type3::enum_type>() && other==get<type4::enum_type>(); } template <typename T> void set(T val) { return fail; }; //Specialisations to provide access to the (unique) members based on their types template<> void set<first_type>(first_type val) { first = val;} template<> void set<second_type>(second_type val) { second = val;} template<> void set<third_type>(third_type val) { third = val;} template<> void set<fourth_type>(fourth_type val) { fourth = val;} //May as well define operator = for convenient syntax l template <typename T> T operator =(T val) { set<T>(val); return val; }; }; //Oh yuk but it would be nice to pass the actual enum names rather than the tag structure name into our template //I couldn't think of any easy way other than a macro but surely there is some neater solution. #define make_packed_type(A,B,C,D) packed<tag##A,tag##B,tag##C,tag##D> int main( int , char** ) { packed<tagA,tagB,tagC,tagD> test; make_packed_type(A,B,C,D) test2; //Try the macro version test.first = A3; //Using the specific member name test.set<B>( B4 ); //Using template specialisation of member function test.set( C1 ); //Same but using ADL test = D3; //ADL on operator = test2 = A3; test2 = B4; test2 = C1; test2 = D3; //Hmm having 2nd thoughts on this syntax - it's probably too confusing and unexpected to allow std::cout << "In test A is " << test.first << " B is " << test.get<B>() << " C is " << test.get<C>() << " D is " << test.get<D>() << std::endl; std::cout << "Sizeof of test is " << sizeof( test ) << std::endl; std::cout << "Piecewise equality check is" << " ==A3 " << ((test == A3)?"true":"false") << " ==B4 " << ((test == B4)?"true":"false") << " ==C1 " << ((test == C1)?"true":"false") << " ==D3 " << ((test == D3)?"true":"false") << std::endl; std::cout << "Overall equality check test == test2 is " << (( test == test2 )?"true":"false") << std::endl; return 0; } Which returns (on windows) In test A is 3 B is 4 C is 1 D is 3 Sizeof of test is 4 Piecewise equality check is ==A3 true ==B4 true ==C1 true ==D3 true Overall equality check test == test2 is true As I said before don't know if this is of any use whatsoever to you (but it allowed me to avoid doing some real work while playing!) - As shown in the output the size of the structure is 4 bytes so is packing the 4 enums down into 1 int (without the : syntax used the sizeof this structure is 16 bytes) Alex

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boost ASIO/serialisation with different boost version. Bug or feature ?
by Avi Bahra 07 Jan '12

07 Jan '12

Currently I have built a client/server that uses ASIO with boost serialization. I built one set with boost 1.45 and another with boost 1.47 However: o start boost 1.45 server o ping using 1.47 client I get a boost::archive::archive_exception unsupported version o start boost 1.47 server o ping with boost 1.45 client Again I get a boost::archive::archive_exception unsupported version Given that there was no change in format of the ping, is this bug or feature ? Is there any way of disabling this feature of the archive , so exception is only thrown when there is format change? Any help appreciated. Ta, Avi

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Register variadic template as tags in a boost::mpl::map
by Allan Nielsen 07 Jan '12

07 Jan '12

In the following code, why can't I look up BB and CC in the mpl::map type_map? I would expect the map to look like this: map < pair<AA, A< xx > >, pair<BB, B< xx > >, pair<CC, C< xx > > > But it does not seem like this is the case... #include <iostream> #include <boost/type_traits/is_same.hpp> #include <boost/mpl/map.hpp> #include <boost/mpl/at.hpp> #include <boost/mpl/insert.hpp> struct AA {}; struct BB {}; struct CC {}; template<int OFFSET> struct A { typedef AA T; enum O { offset = OFFSET }; enum S { size = 2 }; }; template<int OFFSET> struct B { typedef AA T; enum O { offset = OFFSET }; enum S { size = 4 }; }; template<int OFFSET> struct C { typedef AA T; enum O { offset = OFFSET }; enum S { size = 4 }; }; template < template <int> class Head, template <int> class... Tail> struct X : public Head< X<Tail...>::size * X<Tail...>::offset >, public X<Tail...> { typedef Head< X<Tail...>::size * X<Tail...>::offset > _Head; enum O { offset = X<Tail...>::size * X<Tail...>::offset }; enum S { size = _Head::size * X<Tail...>::size }; typedef typename boost::mpl::insert < typename X<Tail...>::type_map, boost::mpl::pair<typename _Head::T, _Head > >::type type_map; template <typename T> int get_offset() { return boost::mpl::at<type_map, T>::type:: offset; } }; // base case template < template <int> class Head> struct X<Head> : public Head<1> { enum O { offset = Head<1>::offset }; enum S { size = Head<1>::size }; typedef boost::mpl::map< boost::mpl::pair< typename Head<1>::T, Head<1> > > type_map; }; int main() { X< A, B, C > x1; std::cout << x1.get_offset<CC>() << std::endl; // generates compile errors //std::cout << x1.get_offset<BB>() << std::endl; //std::cout << x1.get_offset<CC>() << std::endl; return 0; }

1 1

[BGL] getting an edge_descriptor of a reverse_graph
by Alex Hagen-Zanker 06 Jan '12

06 Jan '12

I upgraded from boost 1.45 to 1.48 and there are some breaking changes related to reverse_graph The main problem that I encounter is that boost::edge(u ,v, graph) returns a edge_descriptor to the graph that underlies reverse_graph, rather than reverse_graph itself . The following therefore does not compile: template<typename Graph> void foo(Graph& graph) { boost::graph_traits<Graph>::edge_descriptor e = boost::edge(0, 1, graph).first; } int main() { boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS> graph(2); foo(graph); // this line compiles foo(boost::make_reverse_graph(graph)); // this line does not compile } Do you have suggestions how to rewrite foo(Graph& graph) in order to generically work for both plain and reversed graphs? For now I have rewritten the boost::edge function in reverse_graph.hpp to return a pair<reverse_graph_edge_descriptor, bool> but that does not seem right. Thanks, Alex

2 6

unexpected behaviour of filtering_ostream
by Ed Keith 06 Jan '12

06 Jan '12

I have the following code: int main(int argc, char *argv[]) { io::filtering_ostream out; out.push(std::cout); out << "this is a test" << endl; out << std::cin.rdbuf(); } when I run it the string "this is a test" gets sent to cout, but input type into cin does not get echoed to cout. Can anyone clue my in as to why not? -EdK Ed Keith e_d_k(a)yahoo.com Blog: edkeith.blogspot.com

2 1

building boost.log on OSX 10.7.2 with boost 1_48
by Chris Bartlett 06 Jan '12

06 Jan '12

Hi all, I'm trying to build boost.log. I had it built and working against boost 1_47. I now have a clean 1_47 install on OSX (10.7.2) and I pulled boost.log from the trunk in sourceforge: https://boost-log.svn.sourceforge.net/svnroot/boost-log/trunk/ but when I build it, it reports that it needs 1_48. no problem - i'l build a boost 1_48 install and try that… boost 1_48 installed fine. I downloaded the boost.log from trunk and updated my kit and ran: ./bootstrap.sh -with-libraries=log --prefix=/usr/local --includedir=/usr/local/include --libdir=/usr/local/lib followed by: sudo ./b2 and I get the following: ...found 2606 targets... ...updating 9 targets... darwin.compile.c++ bin.v2/libs/log/build/darwin-4.2.1/release/threading-multi/tick_count.o libs/log/src/tick_count.cpp:220:5: error: #error Boost.Log: POSIX timers not supported on your platform "g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -dynamic -no-cpp- precomp -gdwarf-2 -fexceptions -fPIC -DBOOST_ALL_NO_LIB=1 DBOOST_DATE_TIME_DYN_LINK=1 - DBOOST_FILESYSTEM_DYN_LINK=1 -DBOOST_LOG_BUILDING_THE_LIB=1 -DBOOST_LOG_DLL - DBOOST_LOG_USE_NATIVE_SYSLOG=1 -DBOOST_SYSTEM_DYN_LINK=1 -DBOOST_THREAD_POSIX - DBOOST_THREAD_USE_DLL=1 - DDATE_TIME_INLINE -DNDEBUG -I"." -c -o "bin.v2/libs/log/build/darwin-4.2.1/release/threading-multi/tick_count.o" "libs/log/src/tick_count.cpp" Anyone shed any light on this? has the latest version of boost.log not been built on OSX lion? any help gratefully received, Chris

1 0

boost test: link time errors/regressions with boost 1.47 test
by Avi Bahra 06 Jan '12

06 Jan '12

I have been using/linking with boost test, 1.39 -->1.45 Boost unit-test has been very robust on the whole However migrating to 1.47 I am getting links errors of the form: ld: 0711-317 ERROR: Undefined symbol: .boost::unit_test::ut_detail::auto_test_unit_registrar::auto_test_unit_registrar(boost::unit_test::basic_cstring<const char>) ld: 0711-317 ERROR: Undefined symbol: .boost::unit_test::unit_test_log_t::set_checkpoint(boost::unit_test::basic_cstring<const char>,unsigned long,boost::unit_test::basic_cstring<const char>) ld: 0711-317 ERROR: Undefined symbol: .boost::test_tools::tt_detail::check_impl(const boost::test_tools::predicate_result&,const boost::unit_test::lazy_ostream&,boost::unit_test::basic_cstring<const char>,unsigned long,boost::test_tools::tt_detail::tool_level,boost::test_tools::tt_detail::check_type,unsigned long,...) ld: 0711-317 ERROR: Undefined symbol: .boost::unit_test::ut_detail::normalize_test_case_name(boost::unit_test::basic_cstring<const char>) ld: 0711-317 ERROR: Undefined symbol: .boost::unit_test::test_case::test_case(boost::unit_test::basic_cstring<const char>,const boost::unit_test::callback0<boost::unit_test::ut_detail::unused>&) The problem is on AIX 5.3. using v11.1 compiler linking with libboost_unit_test_framework-mt-d.a has always worked in the past. The library compiles and links without any errors on other platforms like HPUX/acc,linux32/gcc,linux64/gcc Any help appreciated Best regards, Ta, Avi

1 0

Get All Words Offset in String using Boost regex
by S Nagre 06 Jan '12

06 Jan '12

Hello, I wish to determine the "start" and "length" of all the completed words in a string using Boost Regex For example I have a String "*Hello World and Google*" I would like to create a map like this... 1, 5 //First Character position and Length of Word "Hello" 7, 5 // First Character position and Length of Word World 14, 3 //First Character position and Length of Word "And" 18, 6 // First Character position and Length of Word "Google" This is the code I have written.. void CreateOffSetMap(std::string completeInStr) { std::map<int32, int32>OffSetMap; std::string escapeChar = "\\" ; std::string bChar = "b"; std::string dotChar = "."; std::string findWordInStr = escapeChar + bChar + dotChar + escapeChar + bChar; boost::regex regExpression(findWordInStr); boost::smatch what; std::string::const_iterator start = completeInStr.begin(); std::string::const_iterator end = completeInStr.end(); while (boost::regex_search(start, end, what, regExpression)) { int32 foundPos = what.position(); int32 foundLen = what.length(); int32 endOffSet = startOffSet + foundLen; std::string foundString(start + foundPos, start + foundPos + foundLen); OffSetMap[foundPos] = foundLen; start += foundPos + foundLen; } } But is not working correct as expected, Could Anyone tell me where I am doing wrong here ? Thanks in Advance Subhash

2 2

[Graph] need suggestion
by srinivas boppu 06 Jan '12

06 Jan '12

Hello All, I need a graph structure as follows. (Here my input is a Graph which I call it as " Control Flow Graph".) On this "Control Flow Graph", I run a algorithm it creates another graph, and on that I will run again the algorithm, it will create another "Graph" and it continues until it become a "Single Node". I should be able to access all the Graphs in each stage and my original graph information should be untouched. What is the best way to do it ? Any suggestions ? (Actually, I am trying to solve one problem using "Interval Based Analysis" of Control Flow Graphs. I would like to divide the given main control flow graph into disjoint intervals. You can have a look at the following link for more information http://nptel.iitm.ac.in/courses/106108052/module9/control-flow-ana-2.pdf ) Regards, Srinivas

2 2

Boost.Date_Time - Visual C++ 6
by asif saeed 06 Jan '12

06 Jan '12

Hi, Can DateTime build on Visual C++ 6? Has somebody already done it? Can you please point me to some online step-by-step instructions, a blog post or something that can help me to accomplish this? Thanks in advance, Asif

2 3

Boost::shared::memory consistency
by Josmon Paul 06 Jan '12

06 Jan '12

4 8

[BGL] Finding the descriptor for a given vertex
by Kelvin Chung 05 Jan '12

05 Jan '12

Suppose I have the following: template <class T> class Graph { // Adapter class that I use for my purposes typedef typename boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, T> innerGraph; typedef typename boost::graph_traits<innerGraph>::vertex_descriptor VertexDescriptor; innerGraph G; public: void addVertex(const T& vertex); bool containsVertex(const T& vertex) const; void addEdge(const T& from, const T& to); // More stuff here }; The intent of this adapter class is to basically abstract out all the mentions of stuff like the descriptors and such. So a good helper function to this end would be a function that retrieves the VertexDescriptor for a given T, if it exists. Is there such a function already in the BGL, or do I have to manage that separately (ie. having an external map)?

5 7

Auto-Linking in Visual Studio 2008
by Robert Abel 05 Jan '12

05 Jan '12

Hi, I recently began using boost in a project on Windows using MS Visual Studio 9.0 2008 using CMake, i.e. the project setup is auto-generated using the correct boost libraries as link targets. In my project, I link to boost_thread*.lib, which should be the import library for boost_thread*.dll. However, when I compile the project, the I get the following linking error: > Error 43 fatal error LNK1104: cannot open file > 'libboost_thread-vc90-mt-1_48.lib' rsb-chat-1 rsb-chat-1 So it seems necessary to have the static library present as well when linking the executable. At first I thought this was the default auto-linking behavior described in the documentation, i.e. static linking. However, once all needed static libraries are supplied, the final executable still needs the dynamic boost_*.dll libraries. This did not seem right to me... Now, when I disable auto-linking using > #define BOOST_ALL_NO_LIB the linker will not try to link the static libboost_thread*.lib, but instead use the boost_thread*.lib that was defined in the project settings. I couldn't find any documentation on this specific auto-linking behavior. * Is this expected behavior? Maybe MSVS-specific behavior? * Does the presence of the static library actually preclude some dynamic linking from occurring, thus making my executable bigger? * Or does the static library basically just need to be present and auto-linking will actually not use it when it's not appropriate? * Or does auto-linking mix and match, i.e. in my original case, when I supplied the static libraries: Did it link some functions statically, while others dynamically? Thanks, Robert

3 5

[type_traits] type_with_alignment<64> on gcc
by Ioannis Papadopoulos 05 Jan '12

05 Jan '12

Hi, Is there any particular reason that type_with_alignment does not support alignment more than 32 on gcc? I am trying to create an unordered_map of objects that are aligned to cache line size (64bytes) and it fails in type_with_alignment. This small example shows it: #include <boost/tr1/unordered_map.hpp> struct __attribute__((aligned(64)) A { int i; }; int main() { std::tr1::unordered_map<int, A> umap; umap[0] = A(); return 0; } In file included from /usr/local/boost/boost_1.48/include/boost/aligned_storage.hpp:21:0, from /usr/local/boost/boost_1.48/include/boost/type_traits/aligned_storage.hpp:11, from /usr/local/boost/boost_1.48/include/boost/unordered/detail/buckets.hpp:17, from /usr/local/boost/boost_1.48/include/boost/unordered/detail/table.hpp:10, from /usr/local/boost/boost_1.48/include/boost/unordered/detail/equivalent.hpp:14, from /usr/local/boost/boost_1.48/include/boost/unordered/unordered_map.hpp:18, from /usr/local/boost/boost_1.48/include/boost/unordered_map.hpp:16, from /usr/local/boost/boost_1.48/include/boost/tr1/unordered_map.hpp:21, from test.cc:1: /usr/local/boost/boost_1.48/include/boost/type_traits/type_with_alignment.hpp: In instantiation of ‘boost::detail::type_with_alignment_imp<64ul>’: /usr/local/boost/boost_1.48/include/boost/type_traits/type_with_alignment.hpp:216:7: instantiated from ‘boost::type_with_alignment<64ul>’ /usr/local/boost/boost_1.48/include/boost/mpl/eval_if.hpp:60:31: instantiated from ‘boost::mpl::eval_if_c<false, boost::mpl::identity<boost::detail::max_align>, boost::type_with_alignment<64ul> >’ /usr/local/boost/boost_1.48/include/boost/aligned_storage.hpp:55:21: instantiated from ‘boost::detail::aligned_storage::aligned_storage_imp<128ul, 64ul>::data_t’ /usr/local/boost/boost_1.48/include/boost/aligned_storage.hpp:56:7: instantiated from ‘boost::detail::aligned_storage::aligned_storage_imp<128ul, 64ul>’ /usr/local/boost/boost_1.48/include/boost/aligned_storage.hpp:73:7: instantiated from ‘boost::aligned_storage<128ul, 64ul>’ /usr/local/boost/boost_1.48/include/boost/unordered/detail/table.hpp:281:59: instantiated from ‘boost::unordered::detail::value_base<std::pair<const int, A> >’ /usr/local/boost/boost_1.48/include/boost/unordered/detail/unique.hpp:47:12: instantiated from ‘boost::unordered::detail::ptr_node<std::pair<const int, A> >’ /usr/local/boost/boost_1.48/include/boost/unordered/detail/unique.hpp:332:40: instantiated from ‘boost::unordered::detail::table_impl<Types>::value_type& boost::unordered::detail::table_impl<Types>::operator[](const key_type&) [with Types = boost::unordered::detail::map<std::allocator<std::pair<const int, A> >, int, boost::hash<int>, std::equal_to<int> >, boost::unordered::detail::table_impl<Types>::value_type = std::pair<const int, A>, boost::unordered::detail::table_impl<Types>::key_type = int]’ /usr/local/boost/boost_1.48/include/boost/unordered/unordered_map.hpp:1007:26: instantiated from ‘boost::unordered::unordered_map<K, T, H, P, A>::mapped_type& boost::unordered::unordered_map<K, T, H, P, A>::operator[](const key_type&) [with K = int, T = A, H = boost::hash<int>, P = std::equal_to<int>, A = std::allocator<std::pair<const int, A> >, boost::unordered::unordered_map<K, T, H, P, A>::mapped_type = A, boost::unordered::unordered_map<K, T, H, P, A>::key_type = int]’ test.cc:11:9: instantiated from here /usr/local/boost/boost_1.48/include/boost/type_traits/type_with_alignment.hpp:206:1: error: invalid application of ‘sizeof’ to incomplete type ‘boost::STATIC_ASSERTION_FAILURE<false>’ /usr/local/boost/boost_1.48/include/boost/type_traits/type_with_alignment.hpp:207:1: error: invalid application of ‘sizeof’ to incomplete type ‘boost::STATIC_ASSERTION_FAILURE<false>’ Is there any easy way to avoid this problem? Thanks

2 2

boost::filesystem::path construct from iterator
by Frank Kingswood 05 Jan '12

05 Jan '12

Hi I am getting surprising build errors when attempting to create a path from iterators. For example: boost::filesystem::path path("a/b/c"); boost::filesystem::path tail(path.begin(),path.end()); fails to build on the tail constructor. The actual error is about three screenfuls so I will omit this here for now. My intention is to do something a bit more interesting, e.g. path.begin()+1 to skip the leading path component. Thanks, Frank

1 0

boost:shared_ptr destructor, SIGBUS, MIPS 64
by sumanth krishna 05 Jan '12

05 Jan '12

I am using a STL list of boost shared pointer in my code and and it randomly dumps core. Below is the code snippet and the core stack. class A () { virtual ~A(); string getsomestring(); } class B: public A { } typedef shared_ptr<A> A_ptr; class C // singelton class { public: getList(list <A_ptr>& temp_list) { list<A_ptr>::iterator itr = _inv.begin(); for( ; itr != _inv.end(); itr++ ) { temp_list.push_back( (*itr) ); } getListContent ( list<string>& str_list) { list<A_ptr>::iterator itr = _inv.begin(); for( ; itr != _inv.end(); itr++ ) { str_list.push_back( (*itr)->getsomestring() ); } } private: list <A_ptr> _inv; } main() { C *c= new C; // create an instance ( its a singleton class) // On creating an instance of C, the private member variable inventory is populated. // inventory.push_back(A_ptr(new FRU ( fvar ))) thread 1 { list<A_ptr> var1; c->getList(var1); list <string> var2; c->getListContent(var2); } // End of thread delete c; } // end of main Now this code works fine for some iterations and then dumps core with the following stack ###################### Thread 1 (Thread 0x55567f7af0 (LWP 23773)): #0 0x0000000120038ecc in boost::detail::atomic_decrement (pw=0xa) sysroot/usr/include/boost/smart_ptr/detail/sp_counted_base_gcc_mips.hpp:66 #1 0x0000000120038f44 in boost::detail::sp_counted_base::release (this=0x2) #2 0x00000001200390ac in boost::detail::shared_count::~shared_count (this=0x1200b08d8, __in_chrg=<value optimized out>) #3 0x000000012003eaf4 in boost::shared_ptr<A>::~shared_ptr (this=0x1200b08d0, __in_chrg=<value optimized out>) #4 0x000000012003eb4c in __gnu_cxx::new_allocator<boost::shared_ptr<A> >::destroy (this=0xffffeaf640, __p=0x1200b08d0) #5 0x000000012003c9e0 in std::_List_base<boost::shared_ptr<A>, std::allocator<boost::shared_ptr<A> > >::_M_clear (this=0x1200a8ee8) #6 0x000000012003b4ac in std::_List_base<boost::shared_ptr<A>, std::allocator<boost::shared_ptr<A> > >::~_List_base (this=0x1200a8ee8, __in_chrg=<value optimized out>) #7 0x000000012003a0e8 in std::list<boost::shared_ptr<A>, std::allocator<boost::shared_ptr<A> > >::~list (this=0x1200a8ee8, __in_chrg=<value optimized out>) #8 0x0000000120068b64 in C::~C (this=0x1200a8e70, __in_chrg=<value optimized out>) ###################################################### This code is cross compiled for MIPS64 arch on linux x86_64 machine and is running on a 64 bit MIPS machine. I am not sure why it is dumping core. It dumps core giving a *SIGBUS* error. Do i have to specifically handle the delete operation of the List ? I am using the default destructor for "C" class and there is no pointers in the class A and Class A also doesnt have anything in its destructor, no memory allocations are done in Class A. Any suggestions regarding this problem would be highly helpful.

2 4

boost compilation error
by Prasanth Madhavan 05 Jan '12

05 Jan '12

I have a class using boost interprocess. some of the code used in it are here http://stackoverflow.com/questions/8653207/boost-interprocess-vector-creati… and here http://stackoverflow.com/questions/8517115/inserting-a-boost-vector-inside-… when i use g++ -c and compile it, it compiles. I have another big project with whom i would like to use this class. so i added it to that project, and made changes to accomodate the new class and use it. But when i compile it, it crashes with a really big error and i have no clue what the hell is going on. Please help. I have attached a sample output from make. One more thing. Inside the project. the class compiles fine. the attached message comes in when compiling another file that has the header file of this class attached to it. stats.hpp -> this is the header to the class that uses boost manager.hpp -> this has stats.hpp included filter.cpp -> this has manager.hpp included. -- Prasanth Madhavan

1 0

Properties error reading undirected graph with "read_graphviz"
by nunofaria 05 Jan '12

05 Jan '12

Hi, I am trying to read an undirected_graph from a .dot file with read_graphviz, but I seem to some problems regarding the properties of the graph, which are *vertex_index* and *edge_weight*. /terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::dynamic_const_put_error> >' what(): Attempt to put a value into a const property map: / The code I am using is followed: *typedef property<edge_weight_t, int> EdgeWeightProperty; typedef adjacency_list<vecS, vecS, undirectedS, no_property, EdgeWeightProperty> undirected_graph; typedef property_map<undirected_graph, edge_weight_t>::type weight_map_type; typedef property_traits<weight_map_type>::value_type weight_type; typedef std::pair<int, int> edge_t; undirected_graph read_graph(std::string filename, dynamic_properties * dp) { std::ifstream in(filename.c_str()); // ... check errors in file ... undirected_graph g(0); read_graphviz(in, g, *dp, "node_id"); in.close(); return g; } int main() { boost::dynamic_properties dp; // populate graph properties by reference undirected_graph g = read_graph("test_boost_graph.dot", &dp); dp.property("node_id", get(vertex_index, g)); dp.property("w", get(edge_weight, g)); // write to cout write_graphviz_dp(cout, g, dp, "node_id"); return 0; }* I think the example is pretty simple and it should work. However I don't get much when googling the resulting error. Does someone know what's this about? Thanks in advance -- View this message in context: http://boost.2283326.n4.nabble.com/Properties-error-reading-undirected-grap… Sent from the Boost - Users mailing list archive at Nabble.com.

1 0

Problems using boost::interprocess on Mac OS X
by Robert Bielik 05 Jan '12

05 Jan '12

Hi All, I'm trying to use boost::interprocess::named_mutex (1.47.0) on Mac OS X (10.6.7) with GCC 4.0, but I get loads of errors when compiling, the first ones shown here: /boost_1_47_0/boost/interprocess/sync/emulation/named_creation_functor.hpp:38:0 /boost_1_47_0/boost/interprocess/sync/emulation/named_creation_functor.hpp:38: error: expected type-specifier before 'Lm_arg' /boost_1_47_0/boost/interprocess/sync/emulation/named_creation_functor.hpp:38:0 /boost_1_47_0/boost/interprocess/sync/emulation/named_creation_functor.hpp:38: error: expected `)' before 'Lm_arg' /boost_1_47_0/boost/interprocess/sync/emulation/named_creation_functor.hpp:38:0 /boost_1_47_0/boost/interprocess/sync/emulation/named_creation_functor.hpp:38: error: expected `;' before 'Lm_arg' /boost_1_47_0/boost/exception/exception.hpp:320:0 /boost_1_47_0/boost/exception/exception.hpp:320: error: anachronistic old-style base class initializer /boost_1_47_0/boost/exception/exception.hpp:320:0 /boost_1_47_0/boost/exception/exception.hpp:320: error: unnamed initializer for 'boost::exception_detail::error_info_injector<T>', which uses multiple inheritance /boost_1_47_0/boost/exception/exception.hpp:321:0 /boost_1_47_0/boost/exception/exception.hpp:321: error: 'Lx' was not declared in this scope /boost_1_47_0/boost/exception/exception.hpp:418:0 /boost_1_47_0/boost/exception/exception.hpp:418: error: anachronistic old-style base class initializer /boost_1_47_0/boost/exception/exception.hpp:418:0 /boost_1_47_0/boost/exception/exception.hpp:418: error: unnamed initializer for 'boost::exception_detail::clone_impl<T>', which uses multiple inheritance /boost_1_47_0/boost/exception/exception.hpp:419:0 /boost_1_47_0/boost/exception/exception.hpp:419: error: 'Lx' was not declared in this scope ... Any ideas how to fix this ? TIA /Rob

2 2

[Phoenix][v3] Argument/State dependent return type of actors?
by Josef Weinbub 05 Jan '12

05 Jan '12

Hi Recently I made myself familiar with Phoenix v3, more specifically with actors. I did a few test implementations, and I wondered if there is a way to access the argument types (nested in the context's environment) and/or the type of the state(s) (nested in the proto expression) for the actor's result type declaration. Have a look at the following actor dummy implementation, especially at the line ''typedef int result_type;'': (for the sake of completeness, the complete actor implementation is provided) ------------------------------------------------------------ BOOST_PHOENIX_DEFINE_EXPRESSION( (boost)(phoenix)(myactor) , (boost::phoenix::meta_grammar) ) struct myactor_eval { // ------------------------ // the result type can not be made dependable from // one of the actors argument types .. it is // typedef int result_type; // ------------------------ template <typename StateExpr, typename Context> result_type operator()(StateExpr const& state_expr, Context & ctx) const { return -1; } }; namespace boost { namespace phoenix { template <> struct default_actions::when< rule::myactor> : boost::phoenix::call< ::myactor_eval> {}; template <typename T> typename expression::myactor<T>::type const inline myactor(T& t) { return expression::myactor<T>::make(t); } }} ------------------------------------------------------------ As I already stated, I wonder if there is a way to have access to the argument and state types for the result type, maybe as it was possible in Phoenix v2 via a nested template struct which got the same template parameters as the functor, like the simple example in the following: ------------------------------------------------------------ struct myactor_eval { template <typename StateExpr, typename Context> struct result { typedef typename result_of::env<Context>::type Environment; typedef typename remove_reference< Environment>::type::args_type Args; typedef typename result_of::value_at_c< Args, 0>::type Parameter; // make the result type argument dependent! typedef typename Parameter::value_type type; }; ... }; ------------------------------------------------------------ I do hope that I haven't overlooked something in the docs, sorry if I did. Thanks for your support! Cheers, Josef Weinbub

2 3

Re: [Boost-users] [Iostreams] Buffering nonblocking I/O
by Nat Linden 05 Jan '12

05 Jan '12

On Wed, Jan 4, 2012 at 5:21 PM, Chris Cleeland <chris.cleeland(a)gmail.com> wrote: > On Wed, Jan 4, 2012 at 1:44 PM, Nat Linden <nat(a)lindenlab.com> wrote: >> Let's postulate a new Boost.Iostreams Concept to describe an object >> capable of buffering data between producer and consumer. >> Until we can settle on a better name, as a placeholder, let's just >> call this a Queue. > You could call this thing a "conduit". Interesting! Although the term doesn't quite jump out at me, I can understand the metaphor, and to my knowledge it has the virtue of not already being hopelessly overloaded. If other people like it, I could go with that. >> ... I actually need an unbounded Queue for this. > > AND > >> It would also be possible to implement a Queue based on an actual OS pipe. > > Beware that OS pipes are bounded. Yup, I know that. Sorry I wasn't clearer: I intended to suggest three different plausible implementations of the Queue/Conduit concept, with variations on the one I'm actually planning to build. For an unbounded implementation I'm toying with a std::list< std::basic_string<Ch> >. I consider it interesting that you could fairly simply build an implementation around an OS pipe, but that doesn't address the use case that interests me most at the moment. I tossed it out there for purposes of illustration -- I guess a bit too tersely.

1 0

[geometry] GGL mailing list moved
by Mateusz Loskot 04 Jan '12

04 Jan '12

Hi, To Whom It May Concern... The Boost.Geometry library mailing list has moved from ggl at lists.osgeo.org server to geometry at lists.boost.org server. All existing subscribers and archives have been moved to the new server. The new list is available at: http://lists.boost.org/mailman/listinfo.cgi/geometry as well as listed on the main page: http://lists.boost.org/ It is also mirrored at Nabble: http://boost-geometry.203548.n3.nabble.com/ (Mirror at gmane.org may be added in future.) The old list at lists.osgeo.org will be wiped out soon. If anyone experiences any problems with the new geometry at lists.boost.org, please contact me directly. I'd like to thank OSGeo Foundation for hosting the first mailing list and the Boost mailman admins for help with the new one. Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

1 0

[Iostreams] Buffering nonblocking I/O
by Nat Linden 04 Jan '12

04 Jan '12

I find myself wanting to extend Boost.Iostreams to support (at least a particular use case for) nonblocking I/O. I'd like to sketch a couple concepts, hoping you will improve and generalize the notion. In particular, it's easily possible that I don't yet understand Iostreams well enough: what I'm describing may well fit into existing Concepts better than I realize. Boost.Iostreams intends to provide more complete support for nonblocking I/O in future [0]. We can hope that a discussion around these ideas could help evolve the library in that direction. First I want to acknowledge Alexander Nasonov's work from 2003 [1]. I haven't used or even looked at his "iostream-like pipes" library [2] because I'm dubious about registering with Yahoo! before being allowed to download it. (John Torjo seems to have had some trouble too. [3]) If it were posted somewhere more freely accessible, I'd be interested to examine it because I think there's at least conceptual overlap. Let's postulate a new Boost.Iostreams Concept to describe an object capable of buffering data between producer and consumer. It's not quite a Filter because, as I understand it, control is passed to a Filter at only one end. An InputFilter receives control at the consumer end; it forwards the call to its upstream Source. Conversely, an OutputFilter receives control at the producer end, forwarding the call to its downstream Sink. I'm talking about an object that receives control at both the producer and consumer end, providing a buffer between them. My first thought was to call this concept a Pipe because it bears a strong conceptual resemblance to OS pipes. But others in the aforementioned mail thread ([4], [5]) point out that using the word "pipe" in connection with Iostreams (or C++ streams in general) is too easily misinterpreted: one tends to assume a stream interface to a real OS pipe. Other plausible names are "buffer" or "synchronization channel" [4] or "message queue." Talking about a "buffer stream" versus a "streambuf" could fairly quickly get confusing. I shy away from any form of "channel" simply because, in our own code base, the word "channel" is already overloaded to mean four or five vastly different things. Of course "message queue" already has another specific meaning too. [6] Until we can settle on a better name, as a placeholder, let's just call this a Queue. Naturally the producer end should model Sink, and the consumer end should model Source. Why elevate this to a concept? Why not just provide a class? Because different use cases suggest different implementations -- all of which could be plug-compatible. To the extent I understand it, Alexander's library [1] appears to be targeted at cross-thread message passing. It implicitly handles thread synchronization. He also mentions unlimited vs. limited capacity, that is, a bounded max size: when the buffer is full, a producer will block until a consumer has eaten some of the pending data. Unless I went off the rails somewhere, this would be a valid model of the Queue concept. My use case targets an interactive program built around an event loop. I'm not passing data between different threads, so thread synchronization would be unnecessary overhead. Instead, every iteration of the main loop I intend to poll a nonblocking source and a nonblocking sink. I want to use a couple such Queue objects to buffer the data. The application logic must be able to write data to a std::ostream. (If the producer end of a Queue models Sink, it should be straightforward to construct such an ostream based on this Queue.) Because the Sink underlying an ostream operation must model Blocking, I actually need an unbounded Queue for this. Then each iteration of the main loop will attempt to write all pending data on the nonblocking sink; data actually written can be consumed from the Queue. Unwritten data will be handled by subsequent iterations. The input side is similar. Each iteration of the main loop will attempt to fill a temporary buffer from the nonblocking source; the data it obtains will be put into the other Queue. (This can be a bounded Queue: given a way to determine how much buffer remains available, we can limit the size of the nonblocking read.) Presently there will be "enough" data for the application logic to read an istream attached to the consumer side of the Queue. This is so we can guarantee that the application-level istream read operation can be completely satisfied without blocking. Determination of "enough" is of course protocol-specific, as is the means for notifying the application logic. I would want such details to belong to a specific instance of the concept, perhaps a subclass of a provided base class, rather than part of the Queue concept itself. I've been speaking of a nonblocking "source" and "sink" (in lowercase) because, for me, these are actually APR I/O functions. But it occurs to me that we could provide adapters to existing Iostreams Source and Sink objects, using the Iostreams conventions for nonblocking I/O. One need only arrange to poll the adapters periodically. It would also be possible to implement a Queue based on an actual OS pipe. Does this avenue seem worth pursuing? I'm going to build something like this anyway, but (a) I hope you can help me improve the abstractions and (b) it may be worth trying to Boostify the code for possible contribution. [0] http://www.boost.org/doc/libs/1_48_0/libs/iostreams/doc/guide/asynchronous.… [1] http://lists.boost.org/Archives/boost/2003/08/51289.php [2] http://groups.yahoo.com/group/boost/files/pipes.zip [3] http://lists.boost.org/Archives/boost/2003/08/51310.php [4] http://lists.boost.org/Archives/boost/2003/08/51405.php [5] http://lists.boost.org/Archives/boost/2003/08/51448.php [6] http://www.amqp.org/

1 0

[Container] deque emplace() requirements
by Szymon Gatner 04 Jan '12

04 Jan '12

Hi, question: why container::deque<T>::emplace_back() requires T to be copyable? Shouldn't it just be using placement new operator with passed c-tor params? Unless growing of deque causes elements to be copied which is not what I want at all (hence deque and not vector). Cheers, Simon -- Szymon Gatner The Lordz Games Studio www.thelordzgamesstudio.com

3 5

boost vector including non standard objects
by Sabine B 04 Jan '12

04 Jan '12

Hello! I would like to create a vector in shared memory which includes objects of a class Listener*. Listener* was created by my own and is therefore no standard. When I try the following, using the boost interprocess library: typedef boost::interprocess::allocator<Listener*, managed_shared_memory::segment_manager> ShmemAllocator; typedef boost::interprocess::vector<Listener*, ShmemAllocator> MyVector; MyVector *ListenerVector; managed_shared_memory segment(create_only, "MySharedMemory", 65536); const ShmemAllocator alloc_inst(segment.get_segment_manager()); ListenerVector = segment.construct<MyVector>("ListenerVector")(alloc_inst); ListenerVector->push_back((Listener*)listener); The code works perfectly when I use a vector with integers, but it crashes when I use a vector with objects of my own class. I wanted to ask if it is possible to create a boost vector holding a non standard object and if so what I do wrong. Thank you very much for your help! Best regards, Sabine

2 1

[phoenix] ambiguity between std::begin/end and phoenix::begin/end due to ADL
by Nathan Ridge 04 Jan '12

04 Jan '12

Hello, I am running into a problem where an unqualified call to begin() on a range type whose template parameters include a Boost.Phoenix type (for examle filtered_range<Pred, R> where Pred is a phoenix function) is ambiguous because, in addition to the intended std::begin, phoenix::begin is being found by ADL. What can be done about this? There exists precedent for placing boost::xxx::begin/end functions in ADL barrier namespaces because C++11 encourages unqualified calls to begin/end (specifically, this was done for boost::range::begin/end). Should the same thing be done for Phoenix? Here is a minimal example that reproduces the problem: #include <iterator> #include <boost/range/adaptor/filtered.hpp> #include <boost/phoenix/phoenix.hpp> using std::begin; int main() { using boost::phoenix::arg_names::arg1; using boost::adaptors::filtered; int v[5]; const auto& f = v | filtered(arg1 < 0); begin(f); } And here are the errors, with GCC 4.7: test.cpp: In function 'int main()': test.cpp:15:12: error: call of overloaded 'begin( const boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less , boost::proto::argsns_::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal , boost::proto::argsns_::term< boost::phoenix::argument<1> >, 0l > >, boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal , boost::proto::argsns_::term<int>, 0l > > >, 2l > >, int [5] > & )' is ambiguous test.cpp:15:12: candidates are: In file included from string:53:0, from c++/4.7.0/bits/locale_classes.h:42, from ios_base.h:43, [STL Decryptor: Suppressed 3 more STL standard header messages] from test.cpp:1: c++/4.7.0/bits/range_access.h:58:5: decltype ( __cont.begin() ) begin( const boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost::proto::argsns_ ::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term< boost::phoenix::argument<1> >, 0l> >, boost ::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term<int>, 0l> > >, 2l> >, int [5]>; decltype (__cont.begin()) = boost::filter_iterator< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost::proto::argsns_ ::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term< boost::phoenix::argument<1> >, 0l> >, boost ::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term<int>, 0l> > >, 2l> >, int *> &) c++/4.7.0/bits/range_access.h:48:5: decltype ( __cont.begin() ) begin( const boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost::proto::argsns_ ::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term< boost::phoenix::argument<1> >, 0l> >, boost ::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term<int>, 0l> > >, 2l> >, int [5]>; decltype (__cont.begin()) = boost::filter_iterator< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost::proto::argsns_ ::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term< boost::phoenix::argument<1> >, 0l> >, boost ::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term<int>, 0l> > >, 2l> >, int *> &) In file included from boost/boost/phoenix/stl/container.hpp:11:0, from boost/boost/phoenix/stl.hpp:16, from boost/boost/phoenix/phoenix.hpp:18, from test.cpp:4: boost/boost/phoenix/stl/container/container.hpp:794:1: const boost ::phoenix::detail::expression::function_eval< boost::phoenix::stl::begin, boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost::proto::argsns_ ::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term< boost::phoenix::argument<1> >, 0l> >, boost ::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term<int>, 0l> > >, 2l> >, int [5]>; boost::phoenix::detail::expression::function_eval< boost::phoenix::stl::begin, A0>::type = boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::phoenix::detail::tag::function_eval, boost::proto ::argsns_::list2< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost::proto ::argsns_::term<boost::phoenix::stl::begin>, 0l>, boost ::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost::proto ::argsns_::term< boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost ::proto::argsns_::list2< boost::phoenix::actor< boost::proto::exprns_ ::basic_expr< boost::proto::tagns_::tag ::terminal, boost::proto ::argsns_::term< boost::phoenix ::argument<1> >, 0l> >, boost::phoenix::actor< boost::proto::exprns_ ::basic_expr< boost::proto::tagns_::tag ::terminal, boost::proto ::argsns_::term<int>, 0l> > >, 2l> >, int [5]> >, 0l> >, 2l> > >::type boost::phoenix::begin( const boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost::proto::argsns_ ::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term< boost::phoenix::argument<1> >, 0l> >, boost ::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term<int>, 0l> > >, 2l> >, int [5]>; boost::phoenix::detail::expression::function_eval< boost::phoenix::stl::begin, A0>::type = boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::phoenix::detail::tag::function_eval, boost::proto ::argsns_::list2< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost::proto ::argsns_::term<boost::phoenix::stl::begin>, 0l>, boost ::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost::proto ::argsns_::term< boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost ::proto::argsns_::list2< boost::phoenix::actor< boost::proto::exprns_ ::basic_expr< boost::proto::tagns_::tag ::terminal, boost::proto ::argsns_::term< boost::phoenix ::argument<1> >, 0l> >, boost::phoenix::actor< boost::proto::exprns_ ::basic_expr< boost::proto::tagns_::tag ::terminal, boost::proto ::argsns_::term<int>, 0l> > >, 2l> >, int [5]> >, 0l> >, 2l> > &) Thanks, Nate

3 2

[Build] getting Started - library naming.
by Robert Jones 04 Jan '12

04 Jan '12

Morning All, So, I've followed the Getting Started guide pretty faithfully I think; specifically on Fedora 13, Gcc 4.4.5 I've used... $ cd path/to/boost_1_48_0 $ ./bootstrap.sh --prefix=path/to/installation/prefix --show-libraries $ ./b2 install --prefix=path/to/installation/prefix That all seems to have worked Ok, and I have source and libraries in the appropriate prefix. Then I come to section 6, and in particular section 6.1, which talks about library naming. My libraries don't appear to be named according to this structure. Taking, for example, Boost.Regex I have libboost_regex.a libboost_regex.so libboost_regex.so.1.48.0 with no mention of toolsets or ABI tags. Does all the naming stuff only apply if you haven't used the host's default/native toolset? Thx, - Rob.

1 1

[stringalgo] Splitting based on sequence of elements
by Edward Diener 04 Jan '12

04 Jan '12

Is it possible to use the boost::algorithm::split function to split a sequence based on a subsequence match rather than on individual elements of the sequence ?

1 1

Using BGL with mutexes
by Kelvin Chung 03 Jan '12

03 Jan '12

I wish to use multiple threads to build a graph, and to topologically sort it. It would appear that the easiest way is to construct a graph adapter like so: template <class T> class Graph { boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, T> internalGraph; boost::shared_mutex mutex; // read-write lock enabler // Add other suitable adapter methods here }; I'm wondering whether this is the better idea over using the PBGL, since it seems that the PBGL is more complicated. My specific scenario is that T is a functor type whose operation is expensive, and may depend on calling a similar functor (determining the dependent functors needed is cheap); thus, I'm trying to obtain all of the functors and then ordering them so that all dependent functors are always evaluated before the functor itself is evaluated. Thus, each thread would do something like this: Graph<T>& dependencyGraph = ...; // shared graph std::deque<T> tasks; // initially populated list while (!tasks.empty()) { T task = tasks.front(); tasks.pop_front(); std::list<T> dependents = task.getDependents(); for (std::list<T>::const_iterator it = dependents.begin(); it != dependents.end(); ++it) { dependencyGraph.addEdge(task, *it); // Creates a new vertex if either vertex does not exist tasks.push_back(*it); } } No vertices or edges are ever removed from the graph, unless the whole graph is being destroyed. Would bundling a mutex and a graph be a good idea for this purpose?

2 3

help with boost/numeric/operators.hpp
by Robert Ramey 03 Jan '12

03 Jan '12

I'm haveing some problems figuring out how to use boost/numeric/operators library. OK - I understand how to use template<class T> struct my_type : boost::numeric::operators<T> { T & operator+=(T & rhs); // automatically generate operator+, etc // ... }; so that one can use my_type<int> x, y, z; z = x + y; // etc.. There is a simple example like this in the documentation. So far so good. Now given: int & operator+=(int & lhs, my_type<int>); I want to use operators<T, U> to generate int operator+(int & lhs, my_type<int>); // etc. After studying the documenation, examples and code, the best I can come up with is: template<class T, class U> class helper : public boost::operators<T, U>{ }; T operator+(T & lhs, U & rhs){ helper<T, U>::operator+(lhs, rhs); // automatically generated + operator } // other non member operators forwarding to helper Am I doing this corrrectly? How did the authors of operators.hpp intend the two argument versions to be used? Robert Ramey

2 1

[C++ Now! 2012] Reminder: Call for Submissions, deadline is January 10th, 2012
by Hartmut Kaiser 03 Jan '12

03 Jan '12

INAUGURAL C++ NOW! CONFERENCE 2012 Aspen CO, USA, May 14-18, 2012, www.cppnow.org CALL FOR SUBMISSIONS We invite you to submit session proposals to the Inaugural C++ Now! Conference: C++Now! 2012 (Aspen CO, USA, May 14 - 18, 2012). Based on the successful traditions of 5 years of BoostCon, which was the main face-to-face event for all things C++ and Boost (www.boost.org) C++Now! 2012 will present leading speakers from the whole C++ community. The conference name is changing to C++ Now! to reflect the current value of the language, the focus on its new state (from the new Standard), and the need to continually look to the future so the language remains useful to the C++ community. The focus of this conference will be the new C++11 language Standard and as usual Boost: what's new in C++, its Standard library, and in the Boost libraries, how to write and maintain them, how to evangelize or to deploy Boost within your organization. The new C++ Standard, but also the infrastructure and process of Boost, its vision and mission - no matter what you are interested in, it all comes together in the C++Now! sessions. Meet the colleagues, and feel the inspiration to support your work with C++ and Boost for the next year. The C++ Now! Conference is dedicated to discussion and education about C++, an open and free language and standard. Our Conference will focus on discussion and education about open source software usage and developments in the C++ developer and user community. To reflect the breadth of the C++ and Boost communities, the conference includes sessions aimed at three constituencies: C++ and Boost end-users, hard-core Boost library and tool developers, and researchers pushing the boundaries of computation. The program fosters interaction and engagement within and across those groups, with an emphasis on hands-on, participatory sessions. As a multi-paradigm language, C++ is a melting pot where the most compelling ideas from other programming communities are blended in powerful ways. Historically, some of the most popular sessions at C++Now! have highlighted these concepts, from DSLs to functional programming to transactional memory and more. Bring your C#, Python, Ruby or Haskell influences to bear in an environment that will broaden their exposure. IMPORTANT DATES New proposal submissions due: January 10th, 2012. Proposals decisions sent (tentative program): February 17th, 2012. Fully scheduled program available: February 25th, 2012. Session materials due: April 15th, 2012. BEST PRESENTATION AWARDS We know how much effort it takes to prepare talks for our conference. For this reason we will award the best presentations in the following categories: Best Presentation, Best Short Presentation, Best Tutorial, and Best Workshop. The awards will be given based on the audience's voting. Each award will include the author's name listed on the cover of the C++Now! website for that year and a plaque containing all the C++Now! conference information. SESSION TOPICS Topics of interest include, but are not restricted to, the following: * C++11 and how it changes life for users and library writers * General tutorial sessions on C++11, the C++11 Standardslibrary, and one or more Boost libraries * In-depth sessions on using specific Boost libraries * Case studies on using Boost * Experts panels * Advanced sessions on implementation techniques used within Boost libraries * Development workshops to extend or enhance existing Boost libraries * Workshops on design process * Infrastructure workshops such as Build tools, Website, Testing * Concepts and Generic Programming * Hardware and infrastructure presentations focused on how libraries can make better use of the technology * Software development tools and their application to C++ and or Boost * Other topics likely to be of great interest to Boost users and developers Interactive and collaborative sessions are encouraged, as this is the style of learning and participation that has proven most successful at such events. Sessions can be tutorial based, with an emphasis on interaction and participant involvement, or workshop based, whether hands-on programming or paper-based, discussion-driven collaborative work. SESSION FORMATS Presentations Presentations focus on a practitioner's ideas and experience with anything relevant to C++11, Boost and users. Panels Panels feature three or four people presenting their ideas and experiences relating to C++11 and Boost's relevant, controversial, emerging, or unresolved issues. Panels may be conducted in several ways, such as comparative, analytic, or historic. Tutorials Tutorials are sessions at which instructors teach conference participants specific skills relevant to C++11 and Boost. Workshops Workshops provide an active arena for advancements In Boost-relevant topics. Workshops provide the opportunity for experienced practitioners to develop new ideas about a topic of common interest and experience. Author's Corner These were introduced at BoostCon 2008, and were a great Presentations success They are short (30 minute) sessions, focusing on tips on usage and design. In addition, we're looking to uncover the hidden design gems in Boost libraries. Tool Vendors We actively encourage tool vendors and ISP's to submit presentations proposals for a special Tool Vendors Session Track aimed at products related to Boost and C++ (compilers, libraries, tools, etc.). Other formats may also be of interest. Don't hold back a proposal just because it doesn't fit into a pigeonhole. SUBMITTING A PROPOSAL Standard Sessions are 60 minutes. You may submit a proposal for fractions or multiples of 90-minutes. Fractional proposals will be grouped into 60 minute sessions covering related topics. Longer sessions, such as tutorials and classes, will be assigned 90 minute, three hour (i.e. half day), or six hour (i.e. full day) time slots. Please include: * The working title. * Type of session: presentation, panel, tutorial, workshop, authors corner, vendor track, other. * A paragraph or two describing the topic covered, suitable for the conference web site. * Proposed length: 10-20 minute short talks, 45 minutes, 90 minutes, half day, full day. * Alternate lengths, if you are willing to make adjustments: 10- 20 minute short-talks, 45 minutes, 90 minutes, half-day, full day. * Audience: users, developers, both. * Level: basic, intermediate, advanced. * A biography, suitable for the conference web site. * Your contact information (will not be made public). SUBMISSION DETAILS All submissions should be made through the EasyChair conference management system: http://www.easychair.org/conferences/?conf=cppnow2012. If you have not already registered at EasyChair, you will need to do so in order to submit your proposal. All submissions will go through a peer review process. Authors are invited (but are not required) to submit PDF versions of full papers of up to 10 pages in ACM conference proceedings format (see http://www.acm.org/sigs/publications/proceedings-templates) The full papers are not required unless you want them published in the proceedings. All accepted proposals will be made available in the Association for Computing Machinery (ACM) Digital Library (approval pending). Best papers, after further reviews, will be considered to be book chapters or journal articles in a renowned journal. The session materials go on the C++Now! website and will be available to attendees. For general information on the C++Now! 2012 paper submission or the scope of technical papers solicited, please refer to the conference website at www.cppnow.org. For any other questions about the submission process or paper format, please contact the Program Committee at cppnow2012(a)easychair.com. If you have any technical problems with EasyChair, please contact EasyChair for help. Note: Presenters must agree to grant a non-exclusive perpetual license to publish submitted materials, either electronically or in print, in any media related to C++ Now!. Hartmut Kaiser, email: hartmut.kaiser(a)gmail.com (Program Committee Chair) Dave Abrahams, email: dave(a)boostpro.com (Conference Chair) On behalf of the conference organizers

1 0

property type trait
by Amir Yazdanbakhsh 02 Jan '12

02 Jan '12

Hi, I new to boost graph library. The thing that I have in my mind is to find the type of property that passed to a function and execute something based on that. I implemented two bundled properties each for vertex and edge. I want to implement a general function, say print a property, if the passed property is a vertex property the function should iterate over vertices and print out them and if it's edge property it should iterate over edges. Is it any way to do that? Thanks Best Regards, A. Yazdanbakhsh >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> PhD. Student School of Electrical and Computer Engineering University of Wisconsin-Madison E-mail: yazdanbakhsh(a)wisc.edu <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

2 1

[multi_array]bug in strides calculation with some storage orderings
by Larry Evans 02 Jan '12

02 Jan '12

If I understand correctly, the multi_array storage order determines which strides are larger than others. In short: if( order[I]>order[I+1]) then stride[I]>stride[I+1] However, the output from the attached code shows that this is not always true. In the attached code, the mono_tonic_print function tests the conditions and prints out the results. The following partial output: :count=3 :permut_v={ 1, 2, 0} :permut_i={ 2, 0, 1} :ma.ordering(*)==permut_v=1 :multi_array_strides:strides()={ 12, 1, 3} :monotonically increasing={ 0, 0} :is_mono_tonic=0 :expected_strides:{ 4, 8, 1} :monotonically increasing={ 1, 1} :is_mono_tonic=1 :count=4 :permut_v={ 2, 0, 1} :permut_i={ 1, 2, 0} :ma.ordering(*)==permut_v=1 :multi_array_strides:strides()={ 4, 8, 1} :monotonically increasing={ 0, 0} :is_mono_tonic=0 :expected_strides:{ 12, 1, 3} :monotonically increasing={ 1, 1} :is_mono_tonic=1 shows that the multi_array code fails this monotonic constrait when the order is one of: :permut_v={ 1, 2, 0} :permut_v={ 2, 0, 1} The code also shows a possible solution. This possible solution uses the inverse permutation instead of the original permutation to calculate the strides, as shown in the expected_strides function. There's also a macro, NO_INVERT_PERMUT, which, if defined, has expected_strides reproduce the multi_array strides, which may help narrow down the source of the error in multi_array's stride calculation. The output is also attached. If macro INDENT_OUTPUT is defined, the code requires: http://svn.boost.org/svn/boost/sandbox/variadic_templates/boost/iostreams/f… http://svn.boost.org/svn/boost/sandbox/variadic_templates/boost/iostreams/u… http://svn.boost.org/svn/boost/sandbox/variadic_templates/boost/utility/tra… http://svn.boost.org/svn/boost/sandbox/variadic_templates/boost/utility/ind… If you don't want to download those, then the output will not be nicely indented as shown in the attached output. HTH. -regards, Larry

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iterate over vertices with special propoerty
by Amir Yazdanbakhsh 01 Jan '12

01 Jan '12

Hi, I want to write an iterator which returns the vertices with a special property. For example have an functions which takes a graph and a string and returns an iterator over all the vertices that have this string as their name. Thanks Best Regards, A. Yazdanbakhsh >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> PhD. Student School of Electrical and Computer Engineering University of Wisconsin-Madison E-mail: yazdanbakhsh(a)wisc.edu <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

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[inteprocess] timed_lock absolute time
by Edward Diener 01 Jan '12

01 Jan '12

Is the "absolute time" mentioned when using a mutex and timed_lock a local time or a UTC time ? I am guessing a local time but I just want to make sure.

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Re: [Boost-users] Problem with Interpocess offset_ptr
by mike＠tesla.rcub.bg.ac.rs 30 Dec '11

30 Dec '11

Thank you Ion, it solved my problem. Qtree now works good and fast!

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Build error on Solaris 10
by İhsan Doğan 30 Dec '11

30 Dec '11

Hi, I'm new to Boost and while trying to build it on Solaris 10 using the sun Toolset and the and Sun Studio 12.1 compiler I'm running into this issue: sun.archive bin.v2/libs/exception/build/sun/release/link-static/stdlib-sun-stlport/threading-multi/libboost_exception.a "CC" -xar -o "bin.v2/libs/exception/build/sun/release/link-static/stdlib-sun-stlport/threading-multi/libboost_exception.a" "bin.v2/libs/exception/build/sun/release/link-static/stdlib-sun-stlport/threading-multi/clone_current_exception_non_intrusive.o" common.copy stage/lib/libboost_exception.a cp "bin.v2/libs/exception/build/sun/release/link-static/stdlib-sun-stlport/threading-multi/libboost_exception.a" "stage/lib/libboost_exception.a" ...failed updating 4 targets... I'm kinda stuck here. What could be the reason for this error? Ihsan -- ihsan(a)dogan.ch http://blog.dogan.ch/

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tcp error “more data is available”
by herzl&revital sham 29 Dec '11

29 Dec '11

I build a sync udp server via boost::asio follow bellow I bind to interface Socket.open(EndPoint.protocol()); Socket.set_option(boost::asio::ip::udp::socket::reuse_address(true)); Socket.bind(EndPoint); and read char mybuffer[1450]; Socket.async_receive_from( boost::asio::buffer(mybuffer, 1450), senderEndpoint_, boost::bind(&MsgReceiver::HandleReceive, this, boost::asio::placeholders::error, buffer, boost::asio::placeholders::bytes_transferred) ); then i send data to this server like below: yes "AAAAAAAAAAAAAAAAAaaAAAAAAA" | nc -u 172.16.0.12 1234 I get "more data is available" error message in HandleReceive and my system Crashes. I debugger this is all io_services status 0 > 5768 Worker Thread _threadstartex boost::asio::detail::win_iocp_io_service::work_finished Normal 0

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boost::interprocess::string
by Josmon Paul 29 Dec '11

29 Dec '11

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Problem with Interpocess offset_ptr
by mike＠tesla.rcub.bg.ac.rs 29 Dec '11

29 Dec '11

Hi, I need to store in the shared memory structure for Quadtree. It is a class with 4 pointers for tree regions and vector of points: class CNode4 { ... CNode4* node0; CNode4* node1; CNode4* node2; CNode4* node3; vector<vec2> pointArray; }; I have tried with class CNode4 { ... offset_ptr<CSNode4> node0; ... }; and using as: typedef allocator<void, managed_shared_memory::segment_manager> void_allocator; const void_allocator alloc_void(segment.get_segment_manager()); CSNode4* rootNode = segment.construct<CSNode4> (_RootNode) (alloc_void); rootNode->node0 = new CSNode4(alloc_void,...); this works until I try to static_cast node0 offset_ptr<CSNode4> N1 = static_cast<CSNode4*>(rootNode->node0); I get: (MSVC 2010, boost 1.42) error C2440: 'static_cast' : cannot convert from 'boost::interprocess::offset_ptr<PointedType>' to 'CSNode4 *' what am I doing wrong? Thanks, Ivan

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Build boost with Apple's LLVM 3.0
by Daniel Dilts 29 Dec '11

29 Dec '11

I am building boost on OS X 10.7.2. Using ./bootstrap.sh ./b2 sudo ./b2 install it appears to build with the GCC 4.2.1 toolchain. How would I change this so that it builds using the LLVM 3.0 toolchain?

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