October 2008 - Boost-users - lists.preview.boost.org

[ASIO] Thread safety of socket.write_some & socket.read_some
by James12 04 Nov '08

04 Nov '08

Hi, I'm a beginner in using boost asio library (and coding c++ too :). I am currently trying to code a simple application that handles some communication with a server through TCP/IP connection. My I/O Class has two threads that use synchronous socket operations on the same socket (which is a member of the class) Main thread: CApplication::Close() - socket.close() CApplication::Open() - socket.open(boost::asio::ip::tcp::v4()); - socket.write_some(boost::asio::buffer(initial_command)); - socket.read_some(boost::asio::buffer(initial_command_reply)); CApplication::Write(data from another class) - m_Socket.write_some Workerthread: CApplication::thread_Run() do { - socket.read_some(boost::asio::buffer((void *)&character, 1)); - package bytes to messages and pass them on to another class } while (!bClosed) My question is that is it safe to call write_some and read_some from different threads without synchronization. The application is now working w/o problems but I need to be sure that this is a safe way to do this before continuing development. Thanks for your reply, James -- View this message in context: http://www.nabble.com/-ASIO--Thread-safety-of-socket.write_some---socket.re… Sent from the Boost - Users mailing list archive at Nabble.com.

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[phoenix] accumulate with data member binding
by Christian Henning 03 Nov '08

03 Nov '08

Hi there, the following snippet doesn't compile which surprises me a little. Could somebody tell what's wrong? #include <algorithm> #include <vector> #include <numeric> #include <boost/spirit/include/phoenix_core.hpp> #include <boost/spirit/include/phoenix_operator.hpp> #include <boost/spirit/include/phoenix_bind.hpp> using namespace boost::phoenix; using namespace boost::phoenix::arg_names; using namespace std; struct point { double _prob; double _x; }; int _tmain(int argc, _TCHAR* argv[]) { std::vector< point > d; double sum_prob = std::accumulate( d.begin() , d.end() , 0.0 , bind( &point::_prob, arg1 ) ); return 0; } I'm using Visual Studio 2005. This is the error I'm getting: error C2296: '.*' : illegal, left operand has type 'double' [snip] Thanks ahead, Christian

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Boost + STLPort + msvc8.0
by Gould, Richard Kenneth 03 Nov '08

03 Nov '08

I've read the boost build manual section on building with STLPort and a number of other posts, but nothing seems to help. I have modified user_config.jam to contain using stlport : 5.1.6 : c:\\projects\\STLPort-5.1.6\\stlport c:\\projects\\STLPort-5.1.6\\lib ; and am building with bjam --build-dir="c:\temp\build-boost" --toolset=msvc-8.0 stdlib=stlport-5.1.6 threading=multi --with-serialization -a -d2 release stage However, it fails to build libboost_serialization-vc80-mt-p-1.36.0.lib, with errors propagating from ====== BEGIN OUTPUT ====== EXIT STATUS: -1073741515 ====== END OUTPUT ====== ...failed testing.capture-output c:\projects\build-boost\boost\bin.v2\libs\config\test\all\no_std_locale_ pass.test\msvc-8.0\release\stdlib-stlport-5.1.6\threading-multi\no_std_l ocale_pass.run... I've tried various versions of Boost and STLPort in various combinations, all with the same results. Any insights much appreciated. Kind regards Richard Gould This email and any attachments are confidential and may also be privileged. If you are not the addressee, do not disclose, copy, circulate or in any other way use or rely on the information contained in this email or any attachments. If received in error, notify the sender immediately and delete this email and any attachments from your system. Emails cannot be guaranteed to be secure or error free as the message and any attachments could be intercepted, corrupted, lost, delayed, incomplete or amended. Standard Chartered PLC and its subsidiaries do not accept liability for damage caused by this email or any attachments and may monitor email traffic. Standard Chartered PLC is incorporated in England with limited liability under company number 966425 and has its registered office at 1 Aldermanbury Square, London, EC2V 7SB. Standard Chartered Bank ("SCB") is incorporated in England with limited liability by Royal Charter 1853, under reference ZC18. The Principal Office of SCB is situated in England at 1 Aldermanbury Square, London EC2V 7SB. In the United Kingdom, SCB is authorised and regulated by the Financial Services Authority under FSA register number 114276. If you are receiving this email from SCB outside the UK, please click http://www.standardchartered.com/global/email_disclaimer.html to refer to the information on other jurisdictions.

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ASIO io_service behaviour
by Philip Gaskell 02 Nov '08

02 Nov '08

Hi all, I have got some code to test the behavior of io_service. The relevant code is as follows: void ioservice_lifotest() { boost::asio::io_service io; boost::asio::deadline_timer t(io, boost::posix_time::seconds(6)); boost::asio::io_service io2; boost::asio::deadline_timer t1(io2, boost::posix_time::seconds(1)); boost::asio::deadline_timer t2(io2, boost::posix_time::seconds(2)); boost::asio::deadline_timer t3(io2, boost::posix_time::seconds(3)); boost::asio::deadline_timer t4(io2, boost::posix_time::seconds(4)); t.async_wait(printHello); t1.async_wait(print1); t2.async_wait(print2); t3.async_wait(print3); t4.async_wait(print4); io.run(); std::cout << "bleh\n"; io2.run(); std::cout << "done\n"; } printHello(), print1(), print2(), print3() and print4() are simple functions that print different messages to the console. I was expecting printHello to be called first, then print1, then print2, then print3 and print4, because that is the order the events were added to the io_service service. However these functions were called in reverse order. It is as though the underlying queue mechanism is actually a stack. I expect I have missed some of, or misunderstood the documentation, but a few hints as to what is happening will be appreciated. -- Regards, Phil E: philip.gaskell(a)momote.com | M: +44(0)7891 199 959 | W: www.momote.com EMAIL DISCLAIMER The contents of this electronic mail message and any attachments (collectively " this message") are confidential, possibly privileged and intended only for its addressee ("the addressee"). If received in error, please delete immediately without disclosing its contents to anyone. Neither the sender nor its management or employees will in any way be responsible for any advice, opinion, conclusion or other information contained in this message or arising from its disclosure. Registered office: 8 The Parks, Haydock, Newton-Le-Willows, Merseyside. WA12 0JQ Registered in England No. 4410772.

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[BGL] how to call Dijkstra
by Sandeep Gupta 02 Nov '08

02 Nov '08

Hi, I am missing something regarding the correct calling convention for Dijkstra algorithm. Here is the relevant part of the code: typedef boost::associative_property_map< std::map<Vertex, int> > intmapt; typedef boost::associative_property_map< std::map<Vertex, Vertex> > nodemapt; dijkstra_visitor<null_visitor> mynullvis; dijkstra_shortest_paths<Graph, dijkstra_visitor<null_visitor>, nodemapt, intmapt, intmapt, nodemapt, std::less<int>, std::plus<int>, std::numeric_limits<int>, std::numeric_limits<int> > (G, v, predmap, distmap, weightmap, indexmap, std::less<int>(), std::plus<int>(), std::numeric_limits<int>::max(), 0, mynullvis); I get an error as no matching function call dijkstra_shortest_paths. Appreciate some pointers as what could possibly be wrong. Thanks sandeep

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shared_ptr leaking memory and crashing / gcc 3.4.6
by Michael 01 Nov '08

01 Nov '08

Hello, I figured that shared_ptr (boost 3.4, but I don't think this is really a boost problem) will lose memory in the following example #include <boost/shared_ptr.hpp> struct X { int y; }; typedef boost::shared_ptr<X> XRef; XRef getx() { throw 0; } int main(int argc, char** argv) { while (true) { XRef myX; try { myX = getx(); } catch(...) { } } } Compile: g++ -I/usr/local/include test.C -o test On every iteration of the while loop it loses memory and after approx. 1 million iterations it dies with signal 10 or 11. Changing that pattern to try { XRef y = getx(); myX = y; } catch(...) { } fixes the problem (I assume in that case it will call shared_ptrs copy constructor instead of its assignment operator). Platform is FreeBSD 6, gcc 3.4.6. It only happens when compiled like above (without optimization). On optimization levels 2 and above (-O2) it works ok. Maybe somebody using gcc 3.4 can check if this also happens on other platforms. gcc 4 works ok without any issues, so I assume this is a compiler problem. It might still be a good idea to put a warning in the documentation about this. cheers Michael

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non-deterministic state diagram
by Andrej van der Zee 01 Nov '08

01 Nov '08

Hi, I need to calculate the non-deterministic state diagram from raw data and was wondering how boost can hep me. More specific, I have many state transition sequences (lets say up to 100-thousand) that all start at state A, such as: A -> B -> D -> B -> E A -> D -> B -> C -> B A -> E -> D -> F -> D Now I want to calculate the non-deterministic state diagram with a chance for each transition, and desirable in real-time. For example, for the raw data above, the transition for A -> B is 0.33. My question is how boost can help me: * Which library is best to represent the state diagram? * Does the library help in calculation of the state diagram from raw data? Thank you, Andrej

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using boost::tokenizer within boost::bimap
by Sean Farrow 01 Nov '08

01 Nov '08

Hi: I'd like to use boost::tokenizer in boost::bimap. I currently have: boost::bimaps::bimap<boost::bimaps::unordered_set_of<boost::tokenizer<bo ost::char_separator<char>>>, std::string> CodeList; I'm getting the following errors: 1>------ Build started: Project: VDux, Configuration: Release Win32 ------ 1>Compiling... 1>VDux.cpp 1>c:\program files\boost\boost/functional/hash/extensions.hpp(72) : error C2665: 'boost::hash_value' : none of the 16 overloads could convert all the argument types 1> c:\program files\boost\boost/functional/hash/hash.hpp(33): could be 'size_t boost::hash_value(bool)' 1> c:\program files\boost\boost/functional/hash/hash.hpp(34): or 'size_t boost::hash_value(char)' 1> c:\program files\boost\boost/functional/hash/hash.hpp(35): or 'size_t boost::hash_value(unsigned char)' 1> c:\program files\boost\boost/functional/hash/hash.hpp(36): or 'size_t boost::hash_value(signed char)' 1> c:\program files\boost\boost/functional/hash/hash.hpp(37): or 'size_t boost::hash_value(short)' 1> c:\program files\boost\boost/functional/hash/hash.hpp(38): or 'size_t boost::hash_value(unsigned short)' 1> c:\program files\boost\boost/functional/hash/hash.hpp(39): or 'size_t boost::hash_value(int)' 1> c:\program files\boost\boost/functional/hash/hash.hpp(40): or 'size_t boost::hash_value(unsigned int)' 1> c:\program files\boost\boost/functional/hash/hash.hpp(41): or 'size_t boost::hash_value(long)' 1> c:\program files\boost\boost/functional/hash/hash.hpp(42): or 'size_t boost::hash_value(unsigned long)' 1> c:\program files\boost\boost/functional/hash/hash.hpp(45): or 'size_t boost::hash_value(wchar_t)' 1> c:\program files\boost\boost/functional/hash/hash.hpp(49): or 'size_t boost::hash_value(boost::long_long_type)' 1> c:\program files\boost\boost/functional/hash/hash.hpp(50): or 'size_t boost::hash_value(boost::ulong_long_type)' 1> c:\program files\boost\boost/functional/hash/hash.hpp(67): or 'size_t boost::hash_value(float)' 1> c:\program files\boost\boost/functional/hash/hash.hpp(68): or 'size_t boost::hash_value(double)' 1> c:\program files\boost\boost/functional/hash/hash.hpp(69): or 'size_t boost::hash_value(long double)' 1> while trying to match the argument list '(const boost::tokenizer<TokenizerFunc>)' 1> with 1> [ 1> TokenizerFunc=boost::char_separator<char> 1> ] 1> c:\program files\boost\boost/functional/hash/extensions.hpp(71) : while compiling class template member function 'size_t boost::hash<T>::operator ()(const T &) const' 1> with 1> [ 1> T=boost::tokenizer<boost::char_separator<char>> 1> ] 1> c:\program files\boost\boost/concept_check.hpp(334) : see reference to class template instantiation 'boost::hash<T>' being compiled 1> with 1> [ 1> T=boost::tokenizer<boost::char_separator<char>> 1> ] 1> c:\program files\boost\boost/concept_check.hpp(317) : see reference to class template instantiation 'boost::UnaryFunction<Func,Return,Arg>' being compiled 1> with 1> [ 1> Func=boost::hash<boost::tokenizer<boost::char_separator<char>>>, 1> Return=size_t, 1> Arg=boost::tokenizer<boost::char_separator<char>> 1> ] 1> c:\program files\boost\boost/concept/detail/has_constraints.hpp(40) : see reference to class template instantiation 'boost::UnaryFunctionConcept<Func,Return,Arg>' being compiled 1> with 1> [ 1> Func=boost::hash<boost::tokenizer<boost::char_separator<char>>>, 1> Return=size_t, 1> Arg=boost::tokenizer<boost::char_separator<char>> 1> ] 1> c:\program files\boost\boost/concept/detail/msvc.hpp(52) : see reference to class template instantiation 'boost::concept::not_satisfied<Model>' being compiled 1> with 1> [ 1> Model=boost::UnaryFunctionConcept<boost::hash<boost::tokenizer<boost::ch ar_separator<char>>>,size_t,boost::tokenizer<boost::char_separator<char> >> 1> ] 1> c:\program files\boost\boost/bimap/unordered_set_of.hpp(142) : see reference to class template instantiation 'boost::concept::require<Model>' being compiled 1> with 1> [ 1> Model=boost::UnaryFunctionConcept<boost::hash<boost::tokenizer<boost::ch ar_separator<char>>>,size_t,boost::tokenizer<boost::char_separator<char> >> 1> ] 1> c:\program files\boost\boost/bimap/detail/manage_bimap_key.hpp(69) : see reference to class template instantiation 'boost::bimaps::unordered_set_of<KeyType>::lazy_concept_checked' being compiled 1> with 1> [ 1> KeyType=boost::tokenizer<boost::char_separator<char>> 1> ] 1> c:\program files\boost\boost/bimap/detail/bimap_core.hpp(90) : see reference to class template instantiation 'boost::bimaps::detail::manage_bimap_key<Type>' being compiled 1> with 1> [ 1> Type=boost::bimaps::unordered_set_of<boost::tokenizer<boost::char_separa tor<char>>> 1> ] 1> c:\program files\boost\boost/bimap/bimap.hpp(137) : see reference to class template instantiation 'boost::bimaps::detail::bimap_core<LeftSetType,RightSetType,AP1,AP2,AP3> ' being compiled 1> with 1> [ 1> LeftSetType=boost::bimaps::unordered_set_of<boost::tokenizer<boost::char _separator<char>>>, 1> RightSetType=std::string, 1> AP1=boost::mpl::na, 1> AP2=boost::mpl::na, 1> AP3=boost::mpl::na 1> ] 1> .\VDux.cpp(51) : see reference to class template instantiation 'boost::bimaps::bimap<KeyTypeA,KeyTypeB>' being compiled 1> with 1> [ 1> KeyTypeA=boost::bimaps::unordered_set_of<boost::tokenizer<boost::char_se parator<char>>>, 1> KeyTypeB=std::string 1> ] 1>Build log was saved at "file://f:\hd\work\Freedom Of Speech\V-Ware\V-Dux\Dll\Release\BuildLog.htm" 1>VDux - 1 error(s), 0 warning(s) ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== using visual studio 2008. Anyone give me any pointers. Cheers Sean.

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Re: [Boost-users] Problem linking boost filesystem 1_36_0 on ubuntu gcc 4.2
by Kevin Stevens 31 Oct '08

31 Oct '08

Answering my own question. Hopefully someone can google this error in the future and fix it a lot quicker than the several hours it took me.... The problem was that I was not correctly specifying the include headers. I had entered -I/path/to/boost_1_36_0/boost not -I/path/to/boost_1_36_0. I thought I had that path right because everything was compiling. What I did not take into account was that boost 1_34_1 was installed via the package manager by the administrator of the system so the include files were automatically being picked up despite me not explicitly specifying them. The interfaces I was using did not change, but the underlying code did, hence my code still compiled, but refused to link and unfortunately spit out misleading errors. -K From: Kevin Stevens Sent: Thursday, October 30, 2008 5:15 PM To: 'boost-users(a)lists.boost.org' Subject: Problem linking boost filesystem 1_36_0 on ubuntu gcc 4.2 Hello, when I am trying to link boost::filesystem into my program I am receiving link errors. I am trying to convert from boost 1_34_1 to 1_36_0- previously this built against 1_34_1 without any issue. When I link I get the following error: /home/kstevens/code/CrossingEngine/../lib/libtypes.a(Config_Constants.o): In function `boost::enable_if<boost::filesystem::is_basic_path<boost::filesystem::basic_path<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::filesystem::path_traits> >, bool>::type boost::filesystem::exists<boost::filesystem::basic_path<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::filesystem::path_traits> >(boost::filesystem::basic_path<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::filesystem::path_traits> const&)': /usr/include/boost/filesystem/operations.hpp:279: undefined reference to `boost::filesystem::detail::status_api(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, int&)' I did an objdump -CT on libboost_filesystem-gcc42-mt-1_36.so and got the following two functions as output but not the one the linker appears to be looking for: 000000000000c4e0 g DF .text 00000000000000e3 Base boost::filesystem::detail::status_api(std::string const&, boost::system::error_code&) 000000000000c720 g DF .text 00000000000000e3 Base boost::filesystem::detail::symlink_status_api(std::string const&, boost::system::error_code&) Could this be a bad build? Am I missing something- perhaps I need to link another file in? I built 1_36_0 myself using a default configuration other than telling it where to put the output libs. I have ensured that I am linking against and including headers from 1_36_0, and have also made a clean build. Is there anything else I should try? Thank you, -Kevin This is my code snippet that uses boost::filesystem: //Create Directory if it does not already exist. if(!boost::filesystem::exists(reportFilePath)) { cout << "output path: " << reportFilePath << " did not exist, which may indicate a different configuration than was intended, creating directory now." << endl; try { boost::filesystem::path path(reportFilePath); boost::filesystem::create_directory(path); } catch(boost::filesystem::filesystem_error e) { cout << "Error: " << e.what() << endl; } }

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Re: [Boost-users] [boost::pool] using many pools in the application
by Lang Stefan 31 Oct '08

31 Oct '08

Hi, Since little help is forthcoming, here are some pointers: I did look into the pool library some time back (boost version 1.34.1) in search of a solution to some severe performance and memory management issues. In short, I was rather disappointed, for various reasons: 1. memory blocks allocated by boost::fast_pool tended to never get freed again until the end of the program, because the release mechanism was (is?) disabled. This meant my memory management problems got even worse! 2. modifying the code to enable the release mechanism didn't help - for some reason it never got called! 3. the basic method of adjusting the pool size in case it ran out of memory, was doubling it's size. This aggravated the above problems through allocating a lot more memory than was needed most of the time. In fact, when I tested it, fast_pool eventually ran out of memory at about the same time the the local member variable storing the memory increment size sufferd an overflow! I managed to fix this locally by deriving my own pool class from the existing one and overriding a method. In effect I restricted the maximum memory block size to a couple of MB. It worked for me, but wasn't sufficiently general as a fix for the library, especially as I still didn't understand all of the inner workings at that time. 4. support for the pool library seems to have been dropped several years ago, although someone did a few minor fixes a couple of months ago (I believe they were incorporated in version 1.35). Regarding your question, the general idea of the boost::pool classes are singleton pool objects that each serve any object of either a particular type (object_pool) or a particular size (all others if I understood them correctly), so depending on the kind of pool you use you get exactly one pool object per type or object size, not multiple. To fix the issues you mentioned, you (or someone else) would have to do several things: 1. fix the memory allocation so it is limited to some reasonable size (I'd suggest to add this maximumum blocksize to the parameter list either of the pool constructors or the templates) 2. fix the release mechanism. What I would do is add a usage counter to each memory block that allows for easy control of emptied blocks. They should work similar to shared pointer usage semantics. 3. Add a mechanism to monitor fill status and do some kind of garbage collection. This is where it's starting to get tricky: If you find a memory block that is almost 'empty' then you might want to shove the remaining data somewhere else - but you can't do so if someone outside your control is pointing to it! It would be possible though if you never hand out raw pointers to pooled objects, but shared pointers. But then you would need to retain a copy of each shared pointer as well. And this would be overkill for objects that take up only a few bytes each! I could go on some more - I did think about it for quite some time. But I think I already gave you a notion of what to expect. Conclusion: consider what you would need a pool for in terms of individual object size, total size, fluctuation, and so on. Then check out the boost documentation on the four pool types it provides and check whether any of the four types would match your requirements in theory. Once you're there, think again, especially in light of the missing deallocation problem: can you afford to effectively keep a chunk of memory till the end of the program, a chunk that is big enough to store the maximum amount of pooled objects and probably quite a bit more? If you can, then give it a try. If not, ... HTH, Stefan -----Ursprüngliche Nachricht----- Date: Wed, 29 Oct 2008 15:34:53 +0200 From: "Roman Shmelev" <rshmelev(a)gmail.com> Subject: [Boost-users] [boost::pool] using many pools in the application To: boost-users(a)lists.boost.org Message-ID: <ca72680f0810290634y5be3b16fuaacfdb728c33bf6a(a)mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Hi, Are there any thoughts if using many boost::pool objects ( from 50 to 1000 to maybe 5000 ) in my application will be efficient or not? During the "long" run my program just allocates new chunks, and the deletion of them is done in the end of the program. The reason I use boost::pool is that my simple tests showed me that boost::pool allocates memory 10x faster than standard _new_ operator. But I'm suffering that 1000 pools will cause some kind of memory fragmentation or smth like that... so maybe it will be better to use _new_ operator? I can make some another test for multiple pools, but we know that real application will act in some other way, and I cannot make a decision. P.S.:MS VS2005, XpSp2_x86, boost 1.35 (if any ideas, I'll upgrade to the newest boost version) thank you! ------------------------------

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