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Boost::asio, set tcp_nodelay, bad file descriptor?
by Alex Black 08 Aug '09

08 Aug '09

I'm experimenting with turning off the Nagle algorithm to possibly improve the performance of my socket server, I'm processing lots of small requests and I'd like as little latency as possible. Here is a code snippet: void CBaseWebServer::StartAccept() { try { shared_ptr<tcp::socket> pSocket(new tcp::socket(m_IoService)); boost::asio::ip::tcp::no_delay option(true); pSocket->set_option(option); m_pAcceptor->async_accept(*pSocket, bind(&CBaseWebServer::HandleAccept, this, pSocket, boost::asio::placeholders::error)); } catch ( ... ) { cout << "Unexpected exception caught in " << BOOST_CURRENT_FUNCTION << endl << boost::current_exception_diagnostic_information(); } } I'm getting an exception on the set_option line: Unexpected exception caught in void CBaseWebServer::StartAccept() Throw in function (unknown) Dynamic exception type: N5boost16exception_detail10clone_implINS0_19error_info_injectorINS_6syst em12system_errorEEEEE std::exception::what: Bad file descriptor What am I doing wrong here? Thanks! - Alex

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[BGL] Bug - Can't correctly copy bundled data
by Caligula 08 Aug '09

08 Aug '09

Hi, I've been working on this bug for a few weeks now. Its sort of a show stopper for me. I'm not able to copy a simple string datum from one element in a bundled property struct to another such element. Just go to http://pastebin.org/7125 And see pastebin references. I have found an ugly workaround for now, but I would really like it to work properly. Hope someone can/will help me with this. I'm also having trouble with copy_graph. I think people should be able to store and retrieve high level elements such as graphs, subgraphs, vertices, adges and their data. BGL seems to be deficient in this regard. Thanks Caligula

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[Singals]problem about add a new connection in slot callback
by mos 08 Aug '09

08 Aug '09

Hi! I'm afraid i can't discribe the problem very well, so please see the code: #include <boost/signal.hpp> #include <iostream> using namespace std; typedef boost::signal<void ()> signal_t; typedef boost::signals::connection connection_t; signal_t g_signal; void test_b() { cout << "b" << endl; } void test_a() { cout << "a" << endl; g_signal.connect(test_b); } int _tmain(int argc, _TCHAR* argv[]) { connection_t t = g_signal.connect(test_a); g_signal(); t.disconnect(); g_signal(); return 0; } int the function test_a , I perfer call test_b next signal that mean output is "a b" but test_b is called immediately and the output is "a b b" how can I solve the problem? mos.

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question about multi_array use
by Alle Meije Wink 08 Aug '09

08 Aug '09

Hello, I would like to use the multi_array container to handle imaging data. The image data can be anything up to 8-dimensional (usually up to 4) and dimension information is found in records that accompany the binary data. Would it be possible to create an image class that takes the dimensionality and extents list as parameters, so that images of all dimensionalities can be treated as one class? For example, could the dimensionality be passed as a size_t argument? What I understand from the multi_array paper is that the extents list would only be required whan the array is initialised. Best wishes Alle Meije

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[BGL] Bug - Can't correctly copy bundled data.
by Caligula 07 Aug '09

07 Aug '09

Hi all, Been working on this bug for a few weeks now. Its sort of a show stopper for me. Not able to copy a simple string datum from one element in a bundled property struct to another such element. See attachment. Hope someone can/will help me with this. Thanks -Caligula

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[boost-users]Shared_ptr and std::find
by Ryan McConnehey 07 Aug '09

07 Aug '09

Is it possible to have std::find compare the class that the shared_ptr is pointing too? I have a list of shared_ptr of a class called FundamentalTypes. The class has it's own operator==. I'd like to search the list with std::find using the class's operator==. I've included the class with the key elements I'm referring too. Ryan class FundamentalTypes { public: FundamentalTypes(std::string const& name) : m_name(name) bool operator==(FundamentalTypes const& rhs) { return (rhs.m_name == m_name) ? true : false; } std::string m_name; }; template<typename T> class Type : public FundamentalTypes { Type(std::string const& name) : FundamentalTypes(name) }; //main typedef shared_ptr<FundamentalTypes> sharedTypes typedef std::list<sharedTypes> TypesList sharedTypes value = sharedTypes(new Type<short>("bob")); TypesList m_list; TypesList::iterator itor = std::find(m_list.begin(), m_list.end(), value);

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Re: [Boost-users] [interprocess]files locations for mutex and named shm
by Mike Spertus 07 Aug '09

07 Aug '09

I'm being bitten by the surprise discovery that different Windows users can't(?) communicate via named shared memory using Boost Interprocess as in the post below from 2008-09-18 (Changing all processes to use the same TMP directory is not an option for us due to interoperability requirements). Is there a workaround? Was anything ever done about the proposed solution below? Another alternative would be to make it possible to specify the "Boost Interprocess temp directory". Mike Eugen Stoianovici wrote: > > Ion Gaztañaga wrote: > > Eugen Stoianovici wrote: > >> Ion Gaztañaga wrote: > >>> You can't, unless you modify the code in: > >>> > >>> boost/interprocess/detail/temp_dir_helper.hpp > >>> > >>> Why do you want to change the location of those files? > >>> > >>> Ion > >> This is only a problem if you run processes with different users. Ex: > >> if you're using shared memory between an user app and a service, the > >> service will look for the segment in C:\Windows\Temp\ and the user > >> app will look for it in C:\Documents and settings\user\local > >> settings\etc. > >> My changes should go in the temp_dir_helpers.hpp file, right? > > > > Good point. I'll try to see if I can unify this when I have a bit of > > time. Maybe we can find a common directory for all processes. Any hint > > or suggestion? > > > On XP C:\Windows\Temp would be a good idea but i don't know if it is > writable by all users. I'm going to look into it when i get the chance, > but for now, changing the "TMP" env to something else is enough for me. > > Thanks again, > Eugen Stoianovici

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[Serialization] Zero-sized arrays
by Roland Kaminski 07 Aug '09

07 Aug '09

Hi, i am planning to use the boost serialization library to implement checkpointing for an ASP/Sat solver. Unfortunately, the solver implements one (very special) optimization that makes use of a zero-sized array at the end of a class. I have found no way to store something like this using the library. There is a small program in the attachment that contains data structures similar to the ones used in the solver code. This would need a mechanism to control the allocation of memory during deserialization. Do you see any possibility do serialize something like this? Regards and thanks, Roland

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Parsing Sparse Matrix to Get JA, IA, A Vector
by Peverall Dubois 07 Aug '09

07 Aug '09

Does boost has a library to parse a sparse matrix to get the index the non-zero element value? E.g. given this matrix: 1 2 0 0 0 3 9 0 0 1 4 0 We hope it to return A = [ 1 2 3 9 1 4 ] IA = [ 1 3 5 7 ] JA = [ 1 2 2 3 2 3 ] Let NNZ denote the number of nonzero entries of Matrix. The first array is A, which is of length NNZ, and holds all nonzero entries of M in left-to-right top-to-bottom order. The second array is IA, which is of length m + 1 (i.e., one entry per row, plus one). IA(i) contains the index in A of the first nonzero element of row i. Row i of the original matrix extends from A(IA(i)) to A(IA(i+1)-1). The third array, JA, contains the column index of each element of A, so it also is of length NNZ. Is there any implementation for handling such a large matrix to give us A, IA and JA, without having have to slurp all the files into RAM? Because the actual dimension is very large 10^6 to 10^7. Regards, G.V.

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Inconsistent behavior of fusion::find with vector and adapted struct.
by Mike Tegtmeyer 06 Aug '09

06 Aug '09

I seem to have found an inconsistency in how fusion::find works with fusion::vector and an adapted struct. Basically, attempting to find a non-const type on a const vector with a non-const member works but requires a const-member find for an adapted struct. (See code below). Is this something that was just overlooked or there a technical reason for this behavior. In any case is there some way to identify a adapted struct in the general case (as apposed to the tag of the specific type) that can be used for a workaround? Thanks in advance, Mike #include <boost/fusion/adapted/struct/adapt_struct.hpp> #include <boost/fusion/container/vector/vector.hpp> #include <boost/fusion/algorithm/query/find.hpp> #include <boost/type_traits.hpp> #include <string> #include <iostream> namespace b = boost; namespace bf = boost::fusion; namespace demo { struct employee { std::string name; int age; }; } // demo::employee is now a Fusion sequence BOOST_FUSION_ADAPT_STRUCT( demo::employee, (std::string, name) (int, age)) int main(void) { typedef bf::vector<int,float> V1; // Find against non-const V1 V1 v1(1,2.0); BOOST_MPL_ASSERT_NOT(( b::is_same<bf::result_of::find<V1,int>::type,bf::result_of::end<V1>::type> )); assert(*bf::find<int>(v1) == 1); // Find against const V1 const V1 const_v1(3,4.0); BOOST_MPL_ASSERT_NOT(( b::is_same<bf::result_of::find<const V1,int >::type,bf::result_of::end<const V1>::type> )); assert(*bf::find<int>(const_v1) == 3); // Find against non-const employee demo::employee e1 = {"Foo",18}; BOOST_MPL_ASSERT_NOT(( b::is_same<bf::result_of::find<demo::employee,int>::type,bf::result_of::end<demo::employee>::type> )); assert(*bf::find<int>(e1) == 18); // Find against const employee const demo::employee const_e1 = {"Bar",21}; #if 0 BOOST_MPL_ASSERT_NOT(( b::is_same<bf::result_of::find<constdemo::employee, int>::type,bf::result_of::end<const demo::employee>::type> )); assert(*bf::find<int>(const_e1) == 21); #else // note that the find key is a const int for this to work and is inconsistent with fusion::vector BOOST_MPL_ASSERT_NOT(( b::is_same<bf::result_of::find<constdemo::employee, const int>::type,bf::result_of::end<const demo::employee>::type> )); assert(*bf::find<const int>(const_e1) == 21); #endif return 0; }

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[mpi] irecv / send problem
by Nick Collier 06 Aug '09

06 Aug '09

I running into an issue where an irecv followed by a send results in deadlock. A simple test case, class Item { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive& ar, const unsigned int version) { ar & val; } public: int val; Item() : val(1) { } }; struct Receipt { boost::mpi::request request; std::vector<Item> items; }; int main(int argc, char **argv) { mpi::environment env(argc, argv); mpi::communicator world; Receipt receipt; vector<Item> msg(100000); int other = world.rank() == 0 ? 1 : 0; cout << world.rank() << " irecv from " << other << endl; receipt.request = world.irecv(other, 0, receipt.items); cout << world.rank() << " sending to " << other << endl; world.send(other, 0, msg); receipt.request.wait(); cout << "Done" << endl; } Run with mpirun -np 2, this never completes. It does complete with vector<Item> msg(10) however. Nick

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[lambda] Help figuring out variable substitution, lazy functions, etc.? Should I be looking at Phoenix
by Jesse Perla 06 Aug '09

06 Aug '09

I have been trying to prevent variable substitution with boost::lambda and cannot figure out how to prevent variable substitution. Here is a (simplified) version: double first_moment(double x) { return x; } //And create a function auto myfunc = first_moment(_1); cout << myfunc(2.0); ... This doesn't compile, and every permutation I can think of using protect, etc. fails as well. Now I realize that this looks like a job for "bind" (which works fine of course) but this is a simplified pattern of the notation I want. Is there any way to do this with protect, unlambda, etc. around the _1? Are other libraries like Phoenix a better place to look for this kind of functionality? Do people see Phoenix as the evolution of boost lambda or are these likely to remain in parallel? Should I stick with C++0X lambdas? Thanks, Jesse

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Terminate an io_service properly
by Robert Gruendler 06 Aug '09

06 Aug '09

Hi, i'm trying to create a simple socket server wich should be able to shut down when receiving a specific message. I've tried to alter the blocking tcp echo server example of the boost::asio library, but i'm not sure how to properly end the main "listening" loop from within the session thread. here's the modified asio example. when i try to close the acceptor from within the session thread, i get an exception "*The file handle supplied is not valid". *i assume this is the wrong place to close the acceptor / stop the io_service, but i don't know where else i can do this: using boost::asio::ip::tcp; const int max_length = 1024; typedef boost::shared_ptr<tcp::socket> socket_ptr; boost::asio::io_service io_service; tcp::acceptor* acceptor; void session(socket_ptr sock) { try { for (;;) { char data[max_length]; boost::system::error_code error; size_t length = sock->read_some(boost::asio::buffer(data), error); if (error == boost::asio::error::eof) break; // Connection closed cleanly by peer. else if (error) throw boost::system::system_error(error); // Some other error. std::string message = data; if (message.compare("SHUTDOWN") == 0) { //how to terminate the server through an incoming message ? acceptor->close(); io_service.stop(); } boost::asio::write(*sock, boost::asio::buffer(data, length)); } } catch (std::exception& e) { std::cerr << "Exception in thread: " << e.what() << "\n"; } } void server(boost::asio::io_service& io_service, short port) { acceptor = new tcp::acceptor(io_service, tcp::endpoint(tcp::v4(), port)); std::cout << "server started" << std::endl; for (;;) { if (acceptor->is_open()) { socket_ptr sock(new tcp::socket(io_service)); acceptor->accept(*sock); boost::thread t(boost::bind(session, sock)); } else break; } std::cout << "server stopped"; } int main(int argc, char* argv[]) { try { server(io_service, 22222); } catch (std::exception& e) { std::cerr << "Exception: " << e.what() << "\n"; } delete acceptor; return 0; }

3 2

Boost Software License implications for derivative works
by Naik, Roshan 06 Aug '09

06 Aug '09

The Boost Software License (BSL) requires derivative works to include the text of the Boost License itself. I am considering the use of the Boost preprocessor library (only) to implment certain parts of Castor <http://www.mpprogramming.com/cpp> (an open source C++ library) which is already covered under the MIT license. My real concern is, by including the BSL text in Castor, I dont want it to look as if Castor is covered by BSL when it is actually covered by MIT license. As Boost::pp would be used internally it would be shipped as part of the library. Would it suffice if boost::pp headers were simply bundled as-is, along with the licensing text that appears at the top each header ? That way it would appear as if only those headers are covered by BSL and the rest of Castor is covered by MIT. - Roshan

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Why does auto_link.hpp assume that debug versions of STLPort are built with _STLP_DEBUG?
by Max Motovilov 06 Aug '09

06 Aug '09

Subj. Is there a [relatively non-invasive] way to break this dependency? As far as I can tell, STLPort itself makes no such assumption and builds in non-_STLP_DEBUG mode by default. I cannot use _STLP_DEBUG mode for other reasons... The platform is Windows Mobile 5, Visual Studio 2008 (VC9) Regards, ...Max...

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Why is size param required for BOOST_PP_TUPLE_TO_LIST(size, tuple) ?
by Mathieu Malaterre 06 Aug '09

06 Aug '09

Hi there, I am looking at: http://www.boost.org/doc/libs/1_39_0/libs/preprocessor/doc/ref/tuple_to_lis… Just ouf of curiosity why is size required ? Can't the number of argument be deduced using the preprocessor ? Eg.: http://groups.google.com/group/comp.std.c/browse_thread/thread/77ee8c8f92e4… Thanks, -- Mathieu

2 1

[program options] the default value is to long.
by W Eryk Wolski 06 Aug '09

06 Aug '09

At runtime I am getting the following error: Assertion failed: line_length > first_column_width, file libs\program_options\src\options_description.cpp, line 460 It's due to a quite long default value (path to file) ("input-baf" , po::value<std::string>()->default_value(filename),"\t baf file to process") Is there a way to increase first_column_width? Thanks in advance. -- Witold Eryk Wolski Heidmark str 5 D-28329 Bremen tel.: 04215261837

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bjam options
by mike_wilson 06 Aug '09

06 Aug '09

Hi, Was wondering if anyone know how to use the bjam options just to build the multi thread library? Thanks. -- View this message in context: http://www.nabble.com/bjam-options-tp24845152p24845152.html Sent from the Boost - Users mailing list archive at Nabble.com.

2 1

boost.array query
by Sean Farrow 06 Aug '09

06 Aug '09

Hi: I'm using boost.array in a call (waitForMultipleObjects) to be specific. I am passing the c_array() (i.e void const *) if I do this do I need to use 0 or can I still use 1-based indices for my switch statement.Any help appreciated. Sean.

2 1

[coroutine] Stack corruption?
by Pavel Shevaev 06 Aug '09

06 Aug '09

Guys, I'm playing around with Boost.Coroutine experimental package[1] and it looks like it's corrupting the stack. I can't say for sure if it's a stack corruption, however, my application produces a seg.fault when running acceptance tests and gdb can't fully show the core dump backtrace saying "Backtrace stopped: previous frame inner to this frame (corrupt stack?)". If there are any coroutine users around, could you please give any tips on proper usage of this package, its limitations, etc? I had really high hopes for this package and really don't want to go back to the ugly non-coroutine logic. Thanks P.S. I'm using gcc-4.3.3 on linux x86(_64) [1] http://www.crystalclearsoftware.com/soc/coroutine/index.html -- Best regards, Pavel

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Compiling With Boost’s UBlas Numeric Binding Library to Solve Ax=b Linear System
by Peverall Dubois 06 Aug '09

06 Aug '09

I am using Numeric Library Bindings for Boost UBlas to solve a simple linear system: __BEGIN__ #include<boost/numeric/ublas/matrix.hpp> #include<boost/numeric/ublas/io.hpp> #include<boost/numeric/bindings/traits/ublas_matrix.hpp> #include<boost/numeric/bindings/lapack/gesv.hpp> #include <boost/numeric/bindings/traits/ublas_vector2.hpp> namespace ublas = boost::numeric::ublas; namespace lapack= boost::numeric::bindings::lapack; int main() { ublas::matrix<float,ublas::column_major> A(3,3); ublas::vector<float> b(3); for(unsigned i=0;i < A.size1();i++) for(unsigned j =0;j < A.size2();j++) { std::cout << "enter element "<<i << j << std::endl; std::cin >> A(i,j); } std::cout << A << std::endl; b(0) = 21; b(1) = 1; b(2) = 17; lapack::gesv(A,b); std::cout << b << std::endl; return 0; } __END__ I tried compiling it with the following command: g++ -I/home/foolb/.boost/include/boost-1_38 -I/home/foolb/.boostnumbind/include/boost-numeric-bindings solve_Axb_byhand.cc -o solve_Axb_byhand but fail with the following error: media/disk/tmp/ccbd973l.o: In function `boost::numeric::bindings::lapack::detail::gesv(int, int, float*, int, int*, float*, int, int*)': solve_Axb_byhand2.cc:(.text._ZN5boost7numeric8bindings6lapack6detail4gesvEiiPfiPiS4_iS5_[boost::numeric::bindings::lapack::detail::gesv(int, int, float*, int, int*, float*, int, int*)]+0x59): undefined reference to `sgesv_' collect2: ld returned 1 exit status __END__ What's wrong with my approach? - G.V

1 0

Xpressive Character Literals
by Etienne Philip Pretorius 05 Aug '09

05 Aug '09

Hello List, Just a quick question; Xpressive seems not to compile when I use 0x?? instead of 'a' for regular expressions. Eg. sregex characters = +(set=0x20,0x0A,0x0D,0x20,0x33); Is there perhaps a way to accomplish this in Xpressive? Thank you, Etienne

2 2

Boost example programme compilation error (Sun C++5.8 on Solaris 5.8)
by Bernd Zwatschka 05 Aug '09

05 Aug '09

Hi, we're new to Boost and trying to compile the example programme from the getting started page (compiler version: Sun C++ 5.8 2005/10/13, OS: Solaris 5.8) with Boost release 1_39. I'm getting the following error upon compilation: "/finag/ZwatschB/boost_1_39_0/boost/lambda/detail/operator_lambda_func_base.hpp" , line 212: Error: Initializing std::ostream & requires an lvalue. "test.cc", line 12: Where: While instantiating "std::for_each<std::istream_iterator<int, char, std::char_traits<char>, int>, boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda:: bitwise_action<boost::lambda::leftshift_action>, boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::lam According to the release notes, Boost has been tested on C++ 5.8 on Solaris 5.10, so I'm assuming our configuration of compiler / OS is to blame? Is there a way of getting the 1_39 release working on Solaris 5.8 or do we have to switch to an earlier version of Boost? Or could there be another reason for the compilation error? Any pointers on this would be much appreciated. Thanks, Bernd

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Help in altering SSL example
by Ed Curren 05 Aug '09

05 Aug '09

Hello everyone, First, please excuse me if this question has already been asked and addressed. I searched what I was able to of the list and did not find information helpful to me. I am using the boost asio SSL examples as my starting point. At the moment the example simply takes a chunk of the overall data sent to the server and writes it back to the client, (simple echo). My goal is to have the server collect the entire message then move onto a message parsing routine that I will write. I have read through the code of many of the examples, and tried an endless combination of ideas in the code, but all have failed to read the entire message and then move onto a parsing function. Would someone please be kind enough to show me how to accomplish this? Thanks very much.

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Important: Boost server downtime on August 5, 2009
by Doug Gregor 05 Aug '09

05 Aug '09

The Boost mailing lists, web server, and Subversion server will be offline tomorrow (Wednesday, August 5th) from 8:00AM EDT to 9:00AM EDT while we upgrade the mailman software. My apologies for the late notice. - Doug

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