October 2009 - Boost-users - lists.preview.boost.org

seg fault
by John Robertson 22 Oct '09

22 Oct '09

The following compiles and runs. typedef string Colour; struct edge_properties { vector < set< Colour > > eColours; } //get a reference to the vector of the sets of colours of some edge. vector < set<Colour> > & v_colour_outset = get(m_eColours_map,*out_iter); // Here *out_iter is some edge. //Add a set<Colour> to v_colour_outset ie. to get(m_eColours_map,*out_iter) . set<Colour> colour_set; v_colour_outset.push_back(colour_set); // get a reference to one of the set<colour> in get(m_eColours_map,*out_iter) . set<Colour> & outcset = v_colour_outset[1]; //or [0], or any elt. But when I try to add a new colour to this set outcset.insert("Blue"); I get segfault. My guess is that there is a predetermined size for colour_set, and when it is push_backed into v_colour_outset, a new colour cannot be added into it. I tried to create a vector of set<Colour> references as follows. struct edge_properties { vector < set< Colour > & > eColours; } But it did not compile. ( shouldn't it? ) Whats the best solution to this problem. Thanks - JR

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[fusion] is there anything resembling a joint_view of 2 maps?
by er 22 Oct '09

22 Oct '09

Hi All, I am wondering if anyone knows of anything that resembles a joint_view of a pair of maps. typedef mpl::int_<1> key1_; typedef mpl::int_<2> key2_; typedef pair<key1_,int> pair1_; typedef pair<key2_,int> pair2_; typedef map<pair1_> map1_; typedef map<pair2_> map2_; map1_ m1( make_pair<key1_>(1) ); map2_ m2( make_pair<key2_>(2) ); typedef joint_view< map1_, map2_ > jv_; // not supposed to compile (?), yet it does: jv_ view(m1,m2); // but not this: // at_key<key1_>(view) // I have no choice (?) but create a new map, // although view helps a bit for initializing it: typedef map< pair1_, pair2_ > map3_; map3_ m3 = fusion::as_map(view); int n1 = fusion::at_key<key1_>(m3); BOOST_ASSERT(n1 == 1); int n2 = fusion::at_key<key2_>(m3); BOOST_ASSERT(n2 == 2);

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[conversion] Release v0.3 : Changing the order of assign_to parameters + `tie' function
by vicente.botet 22 Oct '09

22 Oct '09

Hi, I have just released the version 0.3 of Boost.Conversion , which includes since my last publicly announced version 0.1: Version 0.3.0, Oct 22, 2009 Changing the order of to and from parameters on assign_to + Added `tie' function Incopatibility: * Changing the order of to and from parameters on assign_to. * Now boost/conversion/convert_to.hpp and boost/conversion/assign_to.hpp files are separated. New Features: * Added <boost/conversion.hpp> global file. * Added mca() function. * Added convert_to_via function. Test: * Added test for the new features Version 0.2.0, Mai 16, 2009 Adding array + fusion::tuples + Adaptation to Boost 1.39 New Features: * conversion between boost::array of explicitly convertible types. * conversion between Boost.Fusion sequences of explicitly convertible types. You can found all the detail for dowloading, documentation, ... in http://svn.boost.org/trac/boost/wiki/LibrariesUnderConstruction#Boost.Conve… I'd appreciate it if people could take a look, test it on their compiler and give me some feedback. Best regards, _____________________ Vicente Juan Botet Escribá

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[Asio] Any port with an endpoint
by Ryan McConnehey 22 Oct '09

22 Oct '09

In windows there is the capability to create a socket with an address but leave the port number up to windows to select. Is this possible with the asio endpoint or will I always need to define "some" port number? Ryan

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Re: [Boost-users] [signals2][review] The review of the signals2 library (formerly thread_safe_signals) begins today, Nov 1st
by Nat Goodspeed 22 Oct '09

22 Oct '09

[Sorry, I know I'm replying to a very old post, but this IS continuing the same exchange.] Frank Mori Hess wrote: > > On Wednesday 18 February 2009, Nat Goodspeed wrote: >> [snip - talking about boost::signals2::signal::connect() accepting a boost::bind expression containing a boost::shared_ptr] >> the >> shared_ptr copy stored in the boost::bind() result makes the referenced >> object effectively immortal. >> >> To my surprise, I find that it's not destroyed even when I explicitly >> disconnect the resulting connection. > It will get destroyed eventually. The signal cleans up its slot list little > by little during connect/invoke. It doesn't immediately remove disconnected > slots from the slot list since other threads might be using the same slot > list concurrently. It might be possible to make it immediately reset the > shared_ptr owning the slot though, leaving an empty shared_ptr in the slot > list, since that wouldn't invalidate any iterators. Frank, has this logic changed at all since Boost 1.39? I've bumped into a situation where the lazy cleanup is causing a crash. We've got a DLL containing a slot stored in a signal used by the main program. Before attempting to unload the DLL, we disconnect the slot -- but the signal retains a reference to memory invalidated by the departure of the DLL, resulting in badness. Would updating to Boost 1.40 solve this problem? Or is there some explicit cleanup call we could/should make with a 1.39 boost::signals2::signal? Or could you suggest how to patch the logic as you describe above? Many thanks.

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shared_ptr and inheritance
by Daniele Barzotti 22 Oct '09

22 Oct '09

Maybe this is a simple question but... Suppose to have: template<typename T> class Base {...}; template<typename T> class Derived : public Base<T> {...}; and shared_ptr< Base<T> > BasePtr; shared_ptr< Derived<T> > DerivedPtr; How can assign BasePtr to DerivedPtr? Thanks Daniele.

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using pairs with boost.foreach
by Sean Farrow 22 Oct '09

22 Oct '09

Hi: Is it possible to use an std::pair with boost.foreach? I'm getting all sorts of errors when trying to do this. Any help appreciated.

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need help using boost bzip2 filter on Windows (or zlib filter)
by ChristinaDRS 22 Oct '09

22 Oct '09

Hello all, I have the following code simple code to compress/uncompress a string: #include <iostream> #include <boost/iostreams/copy.hpp> #include <boost/iostreams/device/back_inserter.hpp> #include <boost/iostreams/filter/bzip2.hpp> #include <boost/iostreams/filtering_stream.hpp> using namespace std; int main() { string message = "this is a test message!"; cout << "message: " << message << endl; string compressed; boost::iostreams::filtering_streambuf<boost::iostreams::output> out; out.push(boost::iostreams::zlib_compressor()); out.push(boost::iostreams::back_inserter(compressed)); boost::iostreams::copy(boost::make_iterator_range(message), out); cout << "compressed message: " << compressed << endl; boost::iostreams::filtering_streambuf<boost::iostreams::input> in; in.push(boost::iostreams::zlib_decompressor()); in.push(boost::make_iterator_range(compressed)); string decompressed; boost::iostreams::copy(in, boost::iostreams::back_inserter(decompressed)); cout << "decompressed message: " << decompressed << endl; } but I get the following linking error: 1>------ Build started: Project: bzip2_compression_test, Configuration: Debug Win32 ------ 1>Compiling... 1>bzip2_test.cpp 1>Linking... 1>LINK : fatal error LNK1104: cannot open file 'libboost_bzip2-vc90-mt-gd-1_39.lib' 1>Build log was saved at "file://d:\compression\BoostCompression2\Debug\BuildLog.htm" 1>bzip2_compression_test - 1 error(s), 0 warning(s) ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== I tried following the instructions on this page: http://www.boost.org/doc/libs/1_40_0/libs/iostreams/doc/installation.html so I defined these environment variables: BZIP2_BINARY = libbz2.lib BZIP2_INCLUDE = D:\bzip2-1.0.5 BZIP2_LIBPATH = D:\bzip2-1.0.5\Debug BZIP2_SOURCE = D:\bzip2-1.0.5 I also tried a similair example with zlib and I get the same error: 1>------ Build started: Project: libz_compression_test, Configuration: Debug Win32 ------ 1>Compiling... 1>zlib_test.cpp 1>Linking... 1>LINK : D:\Debug\libz_compression_test.exe not found or not built by the last incremental link; performing full link 1>LINK : fatal error LNK1104: cannot open file 'libboost_zlib-vc90-mt-gd-1_39.lib' 1>Build log was saved at "file://d:\\compression\libz_compression_test\Debug\BuildLog.htm" 1>libz_compression_test - 1 error(s), 0 warning(s) ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== Any ideas how I can fix this? Thanks! Christina -- View this message in context: http://www.nabble.com/need-help-using-boost-bzip2-filter-on-Windows-%28or-z… Sent from the Boost - Users mailing list archive at Nabble.com.

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[Boost::Interprocess] access violation when function returns a pointer to shared memory object
by BaDBuTz 22 Oct '09

22 Oct '09

hi, I want to synchronize multiple Processes with boost::Interprocess. For the start I implemented a simple Synchronisation Class (with some mutexes) in my test program that will be stored in the Shared Memory. The first call of print() (in function getSyncObject) returns the correct output. But why do I get an access violation, when I call the function again (the pointer is the same!) in main()? I am using WINXP, msvc 7-1 and mingw44 (with both compilers I get the same error) Thanks in advance Martin (compilable) Code: #include <iostream> #include <boost/interprocess/managed_shared_memory.hpp> #include <boost/interprocess/allocators/allocator.hpp> #include <boost/interprocess/containers/string.hpp> typedef unsigned long U32; class SyncObject { public: SyncObject(std::string aId) : id(aId), locAddrSp0Range(0), locAddrSp0Remap(0), locAddrSp1Range(0), locAddrSp1Remap(0), usbInterfaceOwner(0), useCounter(0) {}; ~SyncObject() {} ; void print() { std::cout << id << " locAddrSp0Range = " << locAddrSp0Range << " locAddrSp0Remap = " << locAddrSp0Remap << " locAddrSp1Range = " << locAddrSp1Range << " locAddrSp1Remap = " << locAddrSp1Remap << " usbInterfaceOwner = " << usbInterfaceOwner << " useCounter = " << useCounter << "\n"; }; std::string id; boost::interprocess::interprocess_mutex mtxReadWrite; boost::interprocess::interprocess_mutex mtxFunction; U32 locAddrSp0Range; U32 locAddrSp0Remap; U32 locAddrSp1Range; U32 locAddrSp1Remap; U32 usbInterfaceOwner; U32 useCounter; }; class SharedMemory { public: SharedMemory(); ~SharedMemory(); SyncObject* getSyncObject(std::string id); }; using namespace boost::interprocess; const char* MANAGED_SHARED_MEMORY_NAME = "sharedMemoryMapTest17"; SharedMemory::SharedMemory() {} SharedMemory::~SharedMemory() {} SyncObject* SharedMemory::getSyncObject(std::string id) { managed_shared_memory segment(open_or_create, MANAGED_SHARED_MEMORY_NAME, 65536); SyncObject* ptr = segment.construct<SyncObject>(anonymous_instance)(id); ptr->print(); //works! return ptr; } int main() { SharedMemory shm; SyncObject* ptr = shm.getSyncObject("idName"); ptr->print(); //Application crashes here with an access violation return 0; }

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multiple or single joins on asio socket
by Lee MacDonald 22 Oct '09

22 Oct '09

Guys, I have a application running on Linux using boost 1.35, that receives packets to several different multicast addresses, but on the same port and interface. For each different multicast address I perform the following: // create a new socket socket_(ioService) // set the listen end point to that of the multicast address and port boost::asio::ip::udp::endpoint listenEndPoint(multicastAddress.to_v4(), port); // we need to be able to reuse the underlyling socket created as more than one asio socket will share it. socket_.set_option(boost::asio::ip::udp::socket::reuse_address(true)); socket_.bind(listenEndPoint); // perform the actual join to the multicast group socket_.set_option(boost::asio::ip::multicast::join_group(destAddress.to _v4(), interfaceAddress.to_v4())); So I bind to a seperate asio socket instance for each multicast address and then perform a join to that address, hence each asio socket only has a single join associated with it. Is a better approach to have a single asio socket instance and perform a join for each multicast address that shares the port & interface? If so, how would I set listenEndPoint? Is there any performance differences between the two? Are there better approaches? Thanks. Lee MacDonald Schneider Trading 4th Floor, 25 Copthall Avenue London EC2R 7BP -------------------------------------------------------- Message from: lee.macdonald(a)schneidertrading.com Message to: boost-users(a)lists.boost.org Attached files: 0 This e-mail and any files transmitted with it are confidential, may be legally privileged, and are for the sole use of the intended recipient. Copyright in this e-mail and any accompanying document created by us is owned by us. If you are not the intended recipient of this e-mail or any part of it please telephone our IT Department at the number shown above or by e-mail at info(a)schneidertrading.com. You should not use or disclose to any other person the contents of this e-mail or its attachments (if any), nor take copies. This e-mail is not a representation or warranty and is not intended nor should it be taken to create any legal relations, contractual or otherwise. Schneider Trading Associates Ltd (Registration No. 3692131) is incorporated in England and Wales and the registered office is at 25 Copthall Avenue, London EC2R 7BP. The company is authorised and regulated by the Financial Services Authority

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