May 2012 - Boost-users - lists.preview.boost.org

asio async_read_some handler called but has bad data
by Matt Fair 08 May '12

08 May '12

Hello, I have client/server code similar to the chat server, but I am using async_read_some/async_write_some. I am having a problem with my client when the server sends a bunch of data to it at one time. What happens is that it works for a while then readComplete is called with a full buffer and no error set, but my buffer has garbage and eventually causes my socket to crash. I wanted to check with everyone to see if they have seen this problem before, and if there is anything glaring that I'm doing wrong here with boost::asio. I noticed that in the http server it is using shared_from_this, is this necessary? If the server is sending the client data with async_write faster than I can processes it with async_read, could it cause some buffer overrun? Thanks, Matt My buffer is defined as a private array: static const unsigned int m_maxReadLength = 1024; // maximum amount of data to read in one operation char m_readBuffer[m_maxReadLength]; The client starts to read the socket with: void TCPSocket::readStart() { if(isOpen()) { // Start an asynchronous read and call read_complete when it completes or fails m_pSocket->async_read_some( boost::asio::buffer(m_readBuffer, m_maxReadLength), boost::bind( &TCPSocket::readComplete, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); } } My readComplete method is: void TCPSocket::readComplete(const boost::system::error_code& error, size_t bytes_transferred) { // the asynchronous read operation has now completed or failed and returned an error if(!error && bytes_transferred <= m_maxReadLength) { //convert to string const string buffer(&m_readBuffer[0], &m_readBuffer[bytes_transferred]); //buffer eventually becomes junk ..... } else { //handle error } readStart(); //read some more data }

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boost graph: isomorphism SIGSEGV
by Vömel Christof (vome) 08 May '12

08 May '12

Hi, when testing boost graph 1.46 isomorphism on two graphs of size 11869 on x86_64-suse-linux, g++ 4.6.2, compiled at various levels of optimization, I consistently get the following error. (on very small graphs, everything seems to work) Could this be due to a problem of recursion/stack size due to the size of the graph? Up to what size of graph is the isomorphism program sure to work? Thanks, Chris Program received signal SIGSEGV, Segmentation fault. 0x00000000004099a6 in boost::iterator_core_access::equal<boost::detail::out_edge_iter<__gnu_cxx::__normal_iterator<boost::detail::sei_<unsigned long, std::_List_iterator<boost::list_edge<unsigned long, boost::no_property> >, boost::no_property>*, std::vector<boost::detail::sei_<unsigned long, std::_List_iterator<boost::list_edge<unsigned long, boost::no_property> >, boost::no_property>, std::allocator<boost::detail::sei_<unsigned long, std::_List_iterator<boost::list_edge<unsigned long, boost::no_property> >, boost::no_property> > > >, unsigned long, boost::detail::edge_desc_impl<boost::undirected_tag, unsigned long>, long>, boost::detail::out_edge_iter<__gnu_cxx::__normal_iterator<boost::detail::sei_<unsigned long, std::_List_iterator<boost::list_edge<unsigned long, boost::no_property> >, boost::no_property>*, std::vector<boost::detail::sei_<unsigned long, std::_List_iterator<boost::list_edge<unsigned long, boost::no_property> >, boost::no_property>, std::allocator<boost::detail::sei_<unsigned long, std::_List_iterator<boost::list_edge<unsigned long, boost::no_property> >, boost::no_property> > > >, unsigned long, boost::detail::edge_desc_impl<boost::undirected_tag, unsigned long>, long> > (f1=..., f2=...) at /usr/include/boost/iterator/iterator_facade.hpp:535 535 return f1.equal(f2);

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Aspen Meadows Resort suite available for up to 4 nights of C++Now Conference
by Pdruck 08 May '12

08 May '12

Hi. I reserved a suite at Aspen Meadows Resort for 4 nights, for the C++Now conference; Sunday night, May 13 – Wed night, May 16, leaving Thurs. May 17. But due to last minute pressing events in the office, I have to cancel my registration. Propose to switch my reservation to whomever might be attending. Win-win. I don’t lose a heft cancellation fee. You get a beautiful suite (having been there previously) and conveniently located to the conference at Physics Center. Regards. Phil

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Re: [Boost-users] Updating filesystem to V3 (boost 1.49) - normalize deprecated
by Shai Shasag 08 May '12

08 May '12

Thanks, Lars I defined the macros only for my code and now everything compiles. I have a question regarding the deprecated function path::normalize(). Before moving to V3 I used this function to resolve paths containing "..". For example: path myPath("/Dir_A/Dir_B/a.txt/.."); myPath->normalize(); now myPath is: "/Dir_A/Dir_B" Can this be done using V3 code? Thanks, Shai

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Use boost::object_pool can not quit clearly. Am I misusing?
by 文凯 08 May '12

08 May '12

I use boost::object_pool in my program, but I found some problems, it can not quit. Below is the code. Don't suggest me use boost::pool. The boost::pool is no problem, just discuss the boost::object_pool. Could anybody help me? #include <iostream> #include <boost/pool/object_pool.hpp> int main(void) { boost::object_pool<int> p; int count = 1000*1000; int** pv = new int*[count]; for (int i = 0; i < count; i++) pv[i] = p.construct(); for (int i = 0; i < count; i++) p.destroy(pv[i]); delete [] pv; return 0; } This program can not quit normally. Why? http://stackoverflow.com/questions/10491649/use-boostobject-pool-can-not-qu… -- Cheers & KaiWen

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Technical Question
by Erwin C. 07 May '12

07 May '12

Hey Boost! I plan on using Boost for the first time for our school project during our third year. I am using Visual Studio 2010 (windows) as the only member in the project to use Boost with. I added the root of the boost folder as additional include directory which turns out to be the correct way for the includes to work. But when i build i get the following error. 1>LINK : fatal error LNK1104: cannot open file 'libboost_system-vc100-mt-gd-1_49.lib' I searched thoroughly on google but i did not know what to do with the information... Kind Regards. Erwin

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Forwarding ctor calls in fusion sequence
by Joel Falcou 07 May '12

07 May '12

Say I have a fusion vector of different types with a constructor taking an int. eg: fusion::vector< std::vector<double>, std::vector<int> > and I have such a type as a member of a class foo. Now class foo has a constructor taking an int and I want to forward this parameter to all constructor of my fusion sequence member. Is there a C++03 way to do this with minimal amount of copying ?

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[asio] Connection not ending
by Markus Bonk 07 May '12

07 May '12

Hi, I have a server and connection originally based on the http server 3 example. I am calling io_service::stop which results in the server run() being ended. Currently, though, I am not seeing the connection being ended, or the destructor being called. I interpret this as being because the shared_ptr to the connection instance is still being held by the async_read_some() callback functor. I was expecting the stop() to result in the async_read_some() exiting/aborting. Should it or do I need to do something specific to get rid of the connection? I am using boost 1_44 Markus ________________________________ Markus Bonk Senior Software Engineer [cid:imagee211e8.GIF@21ba809e.4bbea53b] 3Dconnexion GmbH Clarita-Bernhard-Str. 18 81249 München Germany Tel: +49 (89) 897 45 42 - 70 Fax: +49 (89) 897 45 42 - 50 markus_bonk(a)3dconnexion.com<mailto:markus_bonk@3dconnexion.com> Kennen Sie schon die NEUE SpaceMouse Pro? Hier klicken um mehr zu erfahren!<http://www.3dconnexion.de/products/spacemousepro.html?3dxcp=signature_mail> Geschäftsführer: Antonio Pascucci Sitz der Gesellschaft: München Registergericht: München HRB 99232

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boost::function and cross dll call issue
by ariasgore＠gmx.de 07 May '12

07 May '12

Hello, I have a weird access violation when using boost::function which is passed from one DLL to another. At work we use an engine that loads libraries at runtime. One of those libraries provides a class, that looks like that: class CLib { public: LIB_API CLib(void); typedef boost::function<void ()> Func; LIB_API void virtual Invoke(Func * func); }; Another library tries to make use of this lib by void freedummy() { int x = 0; } CLib::Func f = freedummy; f(); // testinvoke locally c.Invoke(&f); // passing to dll The invocation fails hard with Visual Studio 2008 SP1 (Windows 7 64bit, application as 32 bit) when passing to the other dll. The result is a call to a function address that points to nomans-land (c.Invoke()), whereas the direct f() call invokes the freedummy correctly. I have tried to create a very basic reproducer for this case and I could not make it crash. I tried to track down the execution of freedummy in the disassembler. The f-Pointer remains the same all the time but when boost::function0<void>::operator()() gets called on the lib the ptr to f remains correct but the inner function_ptr pointing to freedummy gets corrupted and pointing into garbage. Since I could NOT reproduce it with a simple test setup and I actually am not very sure why this fails I am a bit out of ideas. Can there be somehow a misalignment or different assembler (The dlls may have been compiled with different settings, not sure). I just remembered that this line: vtable_type* get_vtable() const { return reinterpret_cast<vtable_type*>( reinterpret_cast<std::size_t>(vtable) & ~static_cast<size_t>(0x01)); } (in function_template.hpp on 678) looked different in the disassembler when called f() in the main executable compared to the invocation in CLib in the external dll. Can I somehow get a better grip on what's happening? My assembler is not that strong that I could understand all those calls when journeying down the boost call stack. Any hint appreciated, Sam -- Empfehlen Sie GMX DSL Ihren Freunden und Bekannten und wir belohnen Sie mit bis zu 50,- Euro! https://freundschaftswerbung.gmx.de

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Using boost interprocess features from inside Class member functions
by Achuth Sankar 06 May '12

06 May '12

Hi All Am facing a lot of issue while using interprocess features inside my class file. I am pasting my class file below: class MyClass{ Ref* ref; public: MyClass(); void initializeBuffers(); void processMessage(); ~MyClass(); }; void MyClass::createBuffer() { shared_memory_object::remove("test"); shared_memory_object shm(open_or_create, infoBufferName, read_write); shm.truncate(sizeof(ServerDetails)); mapped_region region(shm, read_write); void* addr = region.get_address(); ref=new (addr) Ref; ref->value=50; } void MyClass::processMessage() { printf("%d",ref->value); //I get a segmentation fault in here. } int main() { MyClass c(); c.createBuffer(); c.processMessage(); } When I execute this I am getting segmentation exception. If I merge processMessage and createBuffer under same function it starts working. But if in any case I change the function signature to have an argument again this issue starts. Am not sure if I am doing some thing wrong above. Please do help me on this. Error I get is: Program received signal SIGSEGV, Segmentation fault. 0x77d41df8 in ntdll!RtlGetCompressionWorkSpaceSize () from C:\Windows\system32\ntdll.dll -- Achu

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