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Boost Functionality question: Explicit dynamic library loading
by Sarbak, Joseph 01 Nov '09

01 Nov '09

Hello, I'm curious to know whether boost has support for explicitly loading shared libraries in a cross-platform fashion. I have done my own search of the 1.40.0 boost code base and could not find any abstraction around dlopen,dlsym,dlclose and their equivalents on windows. While it would be easy for me to write wrappers around this functionality, I would prefer to use something in boost if already available. Thank you and regards, Joe Sarbak ________________________________________ This E-Mail (including any attachments) may contain privileged or confidential information. It is intended only for the addressee(s) indicated above. The sender does not waive any of its rights, privileges or other protections respecting this information. Any distribution, copying or other use of this E-Mail or the information it contains, by other than an intended recipient, is not sanctioned and is prohibited. If you received this E-Mail in error, please delete it and advise the sender (by return E-Mail or otherwise) immediately. This E-Mail (including any attachments) has been scanned for viruses. It is believed to be free of any virus or other defect that might affect any computer system into which it is received and opened. However, it is the responsibility of the recipient to ensure that it is virus free. The sender accepts no responsibility for any loss or damage arising in any way from its use. E-Mail received by or sent from RBC Capital Markets is subject to review by Supervisory personnel. Such communications are retained and may be produced to regulatory authorities or others with legal rights to the information. IRS CIRCULAR 230 NOTICE: TO COMPLY WITH U.S. TREASURY REGULATIONS, WE ADVISE YOU THAT ANY U.S. FEDERAL TAX ADVISE INCLUDED IN THIS COMMUNICATION IS NOT INTENDED OR WRITTEN TO BE USED, AND CANNOT BE USED, TO AVOID ANY U.S. FEDERAL TAX PENALTIES OR TO PROMOTE, MARKET, OR RECOMMEND TO ANOTHER PARTY ANY TRANSACTION OR MATTER.

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Re: [Boost-users] Debugging memory corruption? (C++)
by Marshall Clow 01 Nov '09

01 Nov '09

On Nov 1, 2009, at 10:33 AM, Jean-Denis Muys wrote: > >> Followup on my memory corruption bug: >> >> I got a few suggestions (thanks everybody): >> >> - a memory watch point: I may be able to use that idea, but so far, I >> could not clearly identify a fixed location that's corrupted. >> - Guard Malloc: I have a machine that I started about 12 hours ago >> with Guard Malloc enabled. The host app hasn't finished launching >> yet. >> - Valgrind: I still have 10.5 running on a Mac mini, so I started the >> host app under Valgrind. It's veryyyy slow. Still running. >> - static analyzer: it doesn't detect anything wrong (but of course, >> my >> code is C++). >> >> I also wanted to report that I made some significant progress on how >> to call malloc heap checking facility at will. > > I managed to "fix" the memory corruption bug I had. Actually, I > still don't understand why it used to crash and not anymore. This is > a rather peculiar situation, that you might find interesting. > > The following idiom corrupted memory: > > long bad() > { > [...] > > sql::ResultSet *results = preparedStmt->executeQuery(); > > [...] > > delete results; > zoneCheck(); > > return result; > } > > While this one runs fine and nice: > > long good() > { > [...] > > std::auto_ptr<sql::ResultSet>results(preparedStmt->executeQuery()); > > [...] > > zoneCheck(); > > return result; > } > > > Since all std::auto_ptr does is to call delete on its internal > pointer when it goes out of scope (even in case of an exception), I > am still totally puzzled by this behaviour. > > As an aside, the library behind all this is mySQL's C++/Connector. > > I'd be interested by a possible explanation: my C++ is not sharp (no > pun, really) enough to grasp all the subtleties. Well, in the first case delete is called *before* zoneCheck, and in the second, it is called *after*. To me, that suggests that looking at the destructor for sql::ResultSet. -- Marshall

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[regex] Using Boost.Regex rather than std::regex with VC++
by Ahmed Charles 01 Nov '09

01 Nov '09

I'm using VC2010, which provides an implementation of std::regex/std::tr1::regex and boost gladly uses this implementation rather than it's own. I'd like to turn this off, so that I get the boost version when including: #include <boost/regex.hpp> Thanks in advance.

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bad_any_cast being thrown but no idea why
by John Yamokoski 01 Nov '09

01 Nov '09

I have been pulling my hair out over this bug for a day or two now. Here's the synopsis. I have a boost::any object which is storing a std::string. Any test I do to check if indeed the any object is holding onto a std::string object verifies what I already know. For instance, the following function always returns true for my boost::any object: bool is_string(const boost::any& operand) { return ( operand.type() == typeid(std::string) ); } Also if I just print out the typeinfo information for the boost::any object is also shows that its holding onto a std::string: std::stringstream ss; ss << "any object: " << obj.type().name() << ", a string: " << typeid(std::string).name(); yields, any object: Ss, a string: Ss However, whenever I try and actually cast my object to a string (boost::any_cast<std::string>(...)), I always get "boost::bad_any_cast: failed conversion using boost::any_cast". Could this possibly be a compiler issue? I saw one other thread where "-fvisibility=hidden" was causing some problems for boost::program_options and std::string. In my situation, I have a library which is responsible for creating those boost::any objects. Then its in a separately compiled library where I am getting the problems.

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[Random] uniform_01
by Robert Patterson 01 Nov '09

01 Nov '09

Hi, I was looking at the docs for the uniform_01 distribution: http://www.boost.org/doc/libs/1_39_0/libs/random/random-distributions.html#… I read the following note "Note: The current implementation is buggy, because it may not fill all of the mantissa with random bits." I do not understand the problem. I looked at the code, which does what I expect. Why is it a problem if some of the mantissa bits are not 'random'? As I understand the requirement is the real numbers are uniformly distributed; the bit patterns should not matter provided they represent numbers with the right mathematical properties. Thanks Robert Patterson http://como.cheng.cam.ac.uk/index.php?Page=People&Section=riap2

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[interprocess] Best practice question on shared resources.
by Moritz 01 Nov '09

01 Nov '09

Hi there, I am writing a "server" that is capable of communicating data to many "clients". Because I am implementing different communication modes (async, sync), I need special methods to lock and unlock a managed shared memory segment. My question is how to store the mutex, semaphore and managed_shared_memory segment information that are required in the lock and unlock methods. I see different approaches to implement this on client side. 1. Open the resources in the constructor of the client. Save pointers to the resources as members. So it is possible to access the resources in every method of the client class without opening them every time. The problem is that I do not recognize if the resources were closed because they only throw on opening (using linux). 2. Open the resources in the functions. That means I have to create the resource objects every time the function is called. So I have a chance to recognize if the resources have been removed. But I think this will create some useless overhead. Has anybody implemented something similar to this. How would you handle the shared resources? Thanks in advance Moritz Illustration: 1. class client { client() { _mtx = new boost::interprocess::named_mutex(...); } void lock() { _mtx.lock() } boost::interprocess::named_mutex * _mtx; }; versus 2. class client { void lock() { boost::interprocess::named_mutex mutex(...); mutex.lock() } };

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Re: [Boost-users] building some boost libs for Windows ce
by Tom Aylesworth 01 Nov '09

01 Nov '09

> I want to build two libs, statechart and signals, for Windows CE using > MSVC 8.0. I have found suprisingly little info on how to accomplish this, > and I wonder if anyone has done this before and have any configuration > files I could refer to, to save some time (I really don't know much about > bjam)? We're not using statechart or signals, but we are using several of the other Boost libraries under Windows Mobile 5 with MSVC 9. Best info I found was here: http://cowo.supersized.org/archives/27-Compiling-BOOST-1.35.0-with-STLPort-… I had to make another change to use MSVC 9 but you shouldn't need to for 8. We're also using wcelibcex to provide C library routines that aren't provided by Microsoft. You may not need them for the statechart and signals libraries, but here's a link just in case: http://wcelibcex.sourceforge.net/ Thomas Aylesworth Senior Software Engineer RealityMobile http://www.realitymobile.com/

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date_time O/S conversion routine limitation
by Zachary Turner 01 Nov '09

01 Nov '09

Hello list, Apologies for the cross-post, this originally went to the boost-users list a day or so ago but it got no responses, and then I also realized it was actually more appropriate here. Suppose I have a cross-platform agent that communicates with a server. Agent from platform X sends a message to the server which contains a date/time. Server sends a message to another agent running platform Y with the same date/time. In practice X/Y are always either windows/linux or linux/windows. The server always tells the agent which platform's native format the time is represented in, so there should be no problem. Ideally I'd like to write the following code: ptime time; if (msg.is_from_windows()) { time = from_ftime<ptime>(msg.time()); } else { time = from_time_t(msg.time()); } But this doesn't work because from_ftime<> is not defined on linux. If from_ftime<> is already templated on the FILETIME type, is there any reason it needs to be #ifdef'd out on non-windows platforms? I mean, a FILETIME is really just a uint64, can't the templated function also just operate on a boost::uint64_t? Zach

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Bind to first available port
by Mathew Benson 31 Oct '09

31 Oct '09

I know how to do this with Windows sockets, but how do I bind a UDP listen socket to the first available port? I want to send a packet from client to the server to subscribe to data and tell the server what port to send the subscribed data to. I don't care what port the client listens to. If I hard code it, I can only run a single client on a PC. I want to bind to the first available one so I can run as many clients on the same PC as I want.

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Redirecting test output to an XML file
by Stephen Torri 31 Oct '09

31 Oct '09

I have the following code that I am using to regression test part of my library. The project uses automake and autoconf to build the Makefiles then runs the tests via 'make check'. I would like to see all the test result output written as XML files in the directory where the test files reside. That way I can use a script to gather them up and craft a web page off of them. My question: How to redirect Boost Test output to an XML file? I see I can use --log_format=XML to make an XML file but not quite sure how to incorporate that into automake and autoconf. Stephen ---------------------------------------- #include "Elf_arc_utils.h" #define BOOST_TEST_DYN_LINK #define BOOST_TEST_MODULE Suites #include <boost/test/unit_test.hpp> #include <string> BOOST_AUTO_TEST_SUITE(getType) BOOST_AUTO_TEST_CASE(getTypeMin) { using namespace libreverse::elf_module; BOOST_TEST_CHECKPOINT("getType minimum case"); std::string result = arc::ElfArcUtils::getType(arc::E_ARC_MACH_ARC5); BOOST_CHECK_EQUAL ( result, "R_ARC_NONE"); } BOOST_AUTO_TEST_CASE(getTypeMax) { using namespace libreverse::elf_module; std::string result = arc::ElfArcUtils::getType(arc::E_ARC_MACH_ARC8); BOOST_CHECK_EQUAL ( result, "R_ARC_B22_PCREL"); } BOOST_AUTO_TEST_CASE(expectedUnknown) { using namespace libreverse::elf_module; std::string result = arc::ElfArcUtils::getType(4); BOOST_CHECK_EQUAL ( result, "unknown"); } BOOST_AUTO_TEST_CASE(negativeValue) { using namespace libreverse::elf_module; std::string result = arc::ElfArcUtils::getType(-1); BOOST_CHECK_EQUAL ( result, "unknown"); } BOOST_AUTO_TEST_SUITE_END()

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Cross-platform date/time problems
by Zachary Turner 30 Oct '09

30 Oct '09

Suppose I have a cross-platform agent that communicates with a server. Agent from platform X sends a message to the server which contains a date/time. Server sends a message to another agent running platform Y with the same date/time. In practice X/Y are always either windows/linux or linux/windows. The server always tells the agent which platform's native format the time is represented in, so there should be no problem. Ideally I'd like to write the following code: ptime time; if (msg.is_from_windows()) { time = from_ftime<ptime>(msg.time()); } else { time = from_time_t(msg.time()); } But this doesn't work because from_ftime<> is not defined on linux. If from_ftime<> is already templated on the FILETIME type, is there any reason it needs to be #ifdef'd out on non-windows platforms? Or does someone maybe have another solution to being able to support the use-case I've mentioned above? Zach

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[MPI] GCC 4.4.1 Compilation errors
by joel 30 Oct '09

30 Oct '09

I upgraded to gcc 4.4 and got the following error when compiling Boost MPI ./boost/mpi/detail/mpi_datatype_oarchive.hpp: In member function ‘void boost::mpi::detail::mpi_datatype_oarchive::save_enum(const T&, mpl_::true_)’: ./boost/mpi/detail/mpi_datatype_oarchive.hpp:64: error: expected primary-expression before ‘enum’ ./boost/mpi/detail/mpi_datatype_oarchive.hpp:64: error: expected ‘;’ before ‘enum’ Is it a known bug ? -- ___________________________________________ Joel Falcou - Assistant Professor PARALL Team - LRI - Universite Paris Sud XI Tel : (+33)1 69 15 66 35

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[program_options] Custom validate for asio endpoints
by Ryan McConnehey 30 Oct '09

30 Oct '09

I'm trying to validate an ip address and port that is being passed in through the command line arguments. I could retrieve the string and do the validation outside program options. I thought it would be better to use the custom validate function shown in the documentation. I'm trying to retrieve the information as a boost::asio::ip::udp::endpoint. Even after creating the validate function the compiler is complaining that there is no user defined function or stream operator. I've include some code to show what I'm doing. Any help would be great. Ryan class CommandLine { static void validate(boost::any & v, std::vector<std::string> const& values) { using namespace boost::program_options; // Make sure no previous assignment to 'v' was made. validators::check_first_occurrence(v); // Extract the first string from 'values'. If there is more than // one string, it's an error, and exception will be thrown. std::string const& s = validators::get_single_string(values); // Do regex match and convert the interesting part to int. if (validIPandPort(s)) { v = boost::any(createEndpoint(s)); } else { throw validation_error("invalid value"); } } static ApplicationArguments process(const int argc, char * argv[]) { ApplicationArguments returnApplicationArguments; //Create an options menu with all parameters allowed, to be passed in through the command line arguments. boost::program_options::options_description menu("Usage: program.exe -a ip:port,ip:port -r ip:port,ip:port\nOptions:"); menu.add_options() ("ip1,a" , boost::program_options::value<boost::asio::ip::udp::endpoint>() , "description") ("ip2,r" , boost::program_options::value<boost::asio::ip::udp::endpoint>() , "description") ; //Process the command line arguments and place them in a map. boost::program_options::variables_map vm; boost::program_options::store(boost::program_options::parse_command_line(argc, argv, menu), vm); boost::program_options::notify(vm); return returnApplicationArguments; } }; static void validate(boost::any & v, std::vector<std::string> const& values, boost::asio::ip::udp::endpoint * target_type, int) { CommandLine::validate(v, values); }

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Change return type automatically
by Surya Kiran Gullapalli 30 Oct '09

30 Oct '09

Hello, I've a class with multiple boost signals like this class A { private: boost::signal<void()> m_voidSignal ; boost::signal<void (const string&)> m_stringSignal ; public: boost::signal<void()>& voidSignal() { return m_voidSignal ; } boost::signal<void (const string&)>& stringSignal { return m_stringSignal ; } } ; when i'm connecting signals to slots, I do some thing like this. A a; a.voidSignal().connect (...) ; This works fine. But I've many signals with different signatures. what I want to achieve is a single interface where I want to map every signal to enums and access signal from the enums like this. class A { public: typedef enum { VoidSignal, StringSignal ... } ; SignalIds ; // return type should be deducted automatically from the enum ReturnType& getSignal (SignalId) ; ... } ; So that I can do some thing like this A a; a.getSignal (A::VoidSignal).connect (...) ; a.getSignal (A::StringSignal).connect (...) ; Basically with a single interface, I want to change the return type automatically. Can I achieve something like this with any of the boost libraries (mpl, fusion etc) ? Any pointers on this would be of great help. Thanks, Surya

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building some boost libs for Windows ce
by Frank Black 30 Oct '09

30 Oct '09

Hi, I want to build two libs, statechart and signals, for Windows CE using MSVC 8.0. I have found suprisingly little info on how to accomplish this, and I wonder if anyone has done this before and have any configuration files I could refer to, to save some time (I really don't know much about bjam)? Thanks!

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[Spirit] Grammar rule problem
by Dylan Klomparens 30 Oct '09

30 Oct '09

Hello, I'm writing a configuration file parser with boost::spirit, and have encountered some strange errors. The errors are: 1) error C2078: too many initializers (in file assign_actor.hpp, line 62) 2) error C2440: 'initializing' : cannot convert from 'const iterator_t ' to 'value_type' (in file assign_actor.hpp, line 62) The line that's causing the error is identical (in concept) to the one above. Why is it generating an error? The code I'm using is below. Rule "two" is generating the error. #include <iostream> #include <boost/spirit.hpp> using namespace std; int main() { using namespace boost::spirit; const int UnsignedCharacterMaximum = (numeric_limits<unsigned char>::max)(); const int UnsignedShortMaximum = (numeric_limits<unsigned short>::max)(); rule<> octet_p = limit_d(0, UnsignedCharacterMaximum)[int_p]; rule<> ip_address_p = octet_p >> ch_p('.') >> octet_p >> ch_p('.') >> octet_p >> ch_p('.') >> octet_p; rule<> network_port_p = limit_d(0, UnsignedShortMaximum - 1)[int_p]; string s; int i; rule<> one = ip_address_p[assign_a(s)]; rule<> two = network_port_p[assign_a(i)]; // Commenting this line gets rid of the error. // But this line should work. It is identical (in conecpt) to the previous line. cout << parse("192.168.0.1", one).full << endl; return 0; }

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BGL - VertexList of adjacency_list = boost::setS?
by Ondrej Sluciak 30 Oct '09

30 Oct '09

Is there some reason why the vertexlist parameter of adjacency_list cannot be of "setS" type? If I do something like: typedef boost::adjacency_list<boost::listS,boost::setS> Graph; Graph g; boost::add_edge(0,1, g); I always get this error: Error 1 error C2664: 'std::pair<_Ty1,_Ty2> boost::add_edge<boost::detail::adj_list_gen<Graph,VertexListS,OutEdgeListS,DirectedS,VertexProperty,EdgeProperty,GraphProperty,EdgeListS>::config>(void *,void *,boost::directed_graph_helper<Config> &)' : cannot convert parameter 2 from 'int' to 'void *' c:\mycode\boosttest\boosttest\boosttest.cpp 18 If I change it to vecS, then it works. I know the std::set is somehow different from vector or list, but since I don't understand it so well, I don't know why the vertexList cannot be setS, and for example OutEdgeList (1st parameter of adjacency_list) can. Thanks for clarifynig.

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[REGEX] seg fault
by John Robertson 30 Oct '09

30 Oct '09

When running the credit_card snippet in gdb I get. Program received signal SIGSEGV, Segmentation fault. 0x00002ac3263b38f2 in boost::re_detail::cpp_regex_traits_implementation<char>::lookup_classname_imp () from /usr/lib64/libboost_regex.so.2 I'm using BOOST_VERSION 103900 Thanks -JR

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program_options wchar_t support (again)
by Yang Zhang 30 Oct '09

30 Oct '09

Last mentioned I could find was 5 years ago: http://lists.boost.org/Archives/boost/2004/02/61057.php Has this been fixed? -- Yang Zhang http://www.mit.edu/~y_z/

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Incorrect parameters problem
by Mathew Benson 30 Oct '09

30 Oct '09

My project was compiling and executing, but I get an error now. I'm not sitting at my desk right now, but I think it said "Incorrect parameters" when I examine the error. Here's the offending code: boost::asio::io_service io_service; using boost::asio::ip::udp; udp::socket s(io_service, udp::endpoint(udp::v4(), 0)); udp::resolver resolver(io_service); udp::resolver::query query(udp::v4(), "127.0.0.1", 606); try { udp::resolver::iterator iterator = resolver.resolve(query); s.send_to(boost::asio::buffer(buffer, size), *iterator); } catch ( std::exception& e ) { std::cout << e.what() << std::endl; } The first line in the try block is what causes the exception. I thought I backed out all my changes, but I still can't get it to work. Can somebody tell me what obvious dumb mistake I made?

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[Serialization] XML serialization of class with abstract template ancestors
by Terry Roberts 30 Oct '09

30 Oct '09

Hi, I'm having some trouble using the Serialization library with a class derived from an abstract template (example code below). What I'd like to do is serialize instances of the derived type through a base class pointer (polymorphic) using the XML archive. The code below works fine using both the text and binary archives, but fails at runtime with the XML archive. The exception thrown is boost::archive::xml_archive_exception with the message "uninitialized exception". My environment: GCC 4.1.2 on RHEL 5.3 Boost v1.37 I've also attempted to use Boost 1.40 (although I didn't see anything to suggest relevant changes), which results in link errors (undefined references to members of boost::archive::detail::archive_serializer_map<boost::archive::xml_iarchive> and boost::serialization::void_cast_detail::void_caster among others). Any help would be appreciated. Thanks. #include <iostream> #include <string> #include <sstream> #include <boost/serialization/serialization.hpp> #include <boost/archive/xml_iarchive.hpp> #include <boost/archive/xml_oarchive.hpp> #include <boost/serialization/export.hpp> class AbstractBase { public: AbstractBase(const std::string& n):name(n) {} virtual ~AbstractBase() {} virtual std::ostream& print(std::ostream& os) const = 0; protected: AbstractBase():name("UNKNOWN BASE") {} friend class boost::serialization::access; template<class Archive> void serialize(Archive& ar, const uint32_t version) { ar & BOOST_SERIALIZATION_NVP(name); } std::string name; }; template <class T> class AbstractTemplate : public AbstractBase { public: AbstractTemplate(const std::string& n):AbstractBase(n) {} virtual ~AbstractTemplate() {} virtual void doSomething(const T& t) = 0; protected: AbstractTemplate():AbstractBase("UKNOWN TEMPLATE") {} friend class boost::serialization::access; template<class Archive> void serialize(Archive& ar, const uint32_t version) { ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(AbstractBase); } }; class Derived : public AbstractTemplate<std::string> { public: Derived(const std::string& n):AbstractTemplate<std::string>(n) {} virtual ~Derived() {} std::ostream& print(std::ostream& os) const { return os << "Derived name: " << name << std::endl; } void doSomething(const std::string& str) { print(std::cout << str << ": "); } protected: Derived():AbstractTemplate<std::string>("UNKNOWN DERIVED") {} friend class boost::serialization::access; template<class Archive> void serialize(Archive& ar, const uint32_t version) { ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(AbstractTemplate<std::string>); } }; BOOST_CLASS_EXPORT(Derived) namespace boost { template <> struct is_abstract<AbstractBase > { typedef mpl::bool_<true> type; BOOST_STATIC_CONSTANT(bool, value = true); }; template<class T> struct is_abstract<AbstractTemplate<T> > { typedef mpl::bool_<true> type; BOOST_STATIC_CONSTANT(bool, value = true); }; } // namepsace boost int main(int argc, char** argv) { static const char XML_NAME[] = "Stuff"; Derived* d = new Derived("test 1"); AbstractTemplate<std::string>* at = d; AbstractBase* ab = d; std::cout << "before serialization:" << std::endl; d->doSomething("something"); at->print(std::cout); ab->print(std::cout); /* serialization */ std::stringstream ss; { boost::archive::xml_oarchive xmlOut(ss); xmlOut << boost::serialization::make_nvp(XML_NAME, ab); } delete ab; ab = NULL; std::cout << "Serialization:" << std::endl << ss.str() << std::endl; /* deserialization */ { boost::archive::xml_iarchive xmlIn(ss); xmlIn >> boost::serialization::make_nvp(XML_NAME, ab); } at = dynamic_cast<AbstractTemplate<std::string>*>(ab); d = dynamic_cast<Derived*>(ab); if ((ab == NULL) || (at == NULL) || (d == NULL)) { std::cout << "deserialization failed" << std::endl; return EXIT_FAILURE; } std::cout << "after deserialization:" << std::endl; d->doSomething("something"); at->print(std::cout); ab->print(std::cout); delete ab; return EXIT_SUCCESS; }

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Compile warnings
by HT4N - 30 Oct '09

30 Oct '09

When I compile the boost spirit with VisualStudio I got the following warnings. Is this a known issue/bug? /* c:\src\indexserve2\private\shared\boost\spirit\tree\impl\tree_to_xml.ipp(66) : warning C4996: 'std::ctype<wchar_t>::wide Function call with parameters that may be unsafe - this call relies on the caller to check that the passed values are correct. To disable this warning, use -D_SCL_SECURE_NO_WARNINGS. See documentation on how to use Visual C++ 'Checked Iterators' */ #pragma warning(disable:4996) /* c:\src\indexserve2\private\shared\boost\spirit\tree\parse_tree.hpp(213) : warning see reference to class template instantiation 'boost::spirit::skip_parser_iteration_policy<ParserT>' being compiled c:\src\indexserve2\private\shared\boost\spirit\core\scanner\skipper.hpp(147) : warning C4512: 'boost::spirit::skip_parse r_iteration_policy<ParserT>' : assignment operator could not be generated */ #pragma warning(disable:4512) _________________________________________________________________ Windows 7: It helps you do more. Explore Windows 7. http://www.microsoft.com/Windows/windows-7/default.aspx?ocid=PID24727::T:WL…

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[lambda] delayed assignment to a member
by Igor R 29 Oct '09

29 Oct '09

Hello, How can I create a functor, which would assign to a member variable, when invoked? I mean, something like this: int member_; //... lambda::bind(my_obj::member_, this, 5); The above bind itself compiles, but if I try to invoke it or to assign to a function<void()>, it doesn't compile. Thanks.

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[getting IP-header]How do I get the IP-header information
by Mats Carlsson 29 Oct '09

29 Oct '09

Hello, I'm trying to get the IP-header information from an IP-message sent using boost. I can get the message itself by using: void Receiver::wait_for_packet() { socket.async_receive_from(boost::asio::buffer(receive_buffer), remote_endpoint, boost::bind( &Receiver::handle_packet, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); } void Receiver::handle_packet(const boost::system::error_code& error, int bytes_transferred) { if (error) { //throw boost::system::system_error(error); } std::string message; for (int i = 0; i < bytes_transferred; i++) { message += receive_buffer[i]; } std::string payload(message); Packet packet; packet.set_payload(payload); listener->new_packet_received(packet); wait_for_packet(); } Where "message" is the body of the sent stuff. But how do I get to the IP-header things? I've been looking in doc/html/boost_asio/example/serialization/connection.hpp, but do not really get what to do. BR, /Mats Carlsson

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asynch_write fails when used to write long data
by A.Agrawal＠patrick.com.au 29 Oct '09

29 Oct '09

Hi, I have a Client (windows) - server (linux) program which uses boost::asio asynch methods. I am getting error when server writes to client using asynch_write and data is large with size greater than a particular value. ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// std::vector<boost::asio::const_buffer> _buffers; _buffers.push_back(boost::asio::buffer(outbound_header)); _buffers.push_back(boost::asio::buffer(outbound_message)); _buffers.push_back(boost::asio::buffer(outbound_data)); boost::asio::async_write(_socket, _buffers, boost::bind(&ClientSession::handle_write, this, boost::asio::placeholders::error)); ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// here outbound_header is of type string of length 8 and has value " 202e5" outbound_message is of type string of length 8 and has value " 2" outbound_data when of length 131813. I get error with error_code - val = 14 (Bad Address) If I reduce the outbound_data size to 130812, everything is fine. I am unable to figure out the problem, I thought I can send unlimited size data in a single call. Please advise if you have any idea. I will be more than happy to provide you with information that you may need. Regards, Anil Agrawal PTS

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