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tellg() not working for boost::iostreams::filtering_istream
by Roland Bock 30 Oct '08

30 Oct '08

Hi, tellg() member function is not working for boost::iostreams::filtering_istream (see attached example). Is this a bug or a necessity? Regards, Roland

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[serialization] Assertion failure with shared_ptr cycles
by Ult Mundane 30 Oct '08

30 Oct '08

Hi, I'm hitting an assert when I deserialize cycles of shared_ptr<>s. I have the following class hierarchy: Base <-- Derived Other Derived holds a shared_ptr<Other>, and Other holds a shared_ptr<Base>. I have an instance of Derived that points to an instance of Other, which in turn points back to the Derived instance (as a Base pointer). The serialization goes as expected. On deserialization, however, the Base::serialize() and Derived::serialize() are called repeatedly, crashing after the third time -- Other::serialize() is never called. This problem only happens when the cycle includes a pointer to a base class -- a straightforward a -> b -> a cycle works as expected. Has anyone else experienced this or found a workaround? It happens in both boost 1.36 and 1.37.0 beta1. I'm using gcc (3.3.5, 3.4.6, and 4.3.2). Thanks, Ult P.S. Attached is the source code illustrating the above example. Here is the output: Serializing... Derived Base Base done Other Other done Derived done Deserializing... Derived Base Base done Derived Base Base done Derived cycles: ./boost_1_37_0_beta1/libs/serialization/src/basic_iarchive.cpp:436: const boost::archive::detail::basic_pointer_iserializer* boost::archive::detail::basic_iarchive_impl::load_pointer(boost::archive::detail::basic_iarchive&, void*&, const boost::archive::detail::basic_pointer_iserializer*, const boost::archive::detail::basic_pointer_iserializer* (*)(const boost::serialization::extended_type_info&)): Assertion `new_cid == cid' failed. Aborted #include <fstream> #include <iostream> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/serialization/shared_ptr.hpp> #include <boost/serialization/is_abstract.hpp> #include <boost/serialization/export.hpp> // Forward declarations class Base; class Derived; class Other; typedef boost::shared_ptr<Base> BaseRef; typedef boost::shared_ptr<Derived> DerivedRef; typedef boost::shared_ptr<Other> OtherRef; // For debug output struct Debug { Debug(const char * name) : mName(name) { std::cout << std::string(++sIndentLevel, ' ') << mName << std::endl; } ~Debug() { std::cout << std::string(sIndentLevel--, ' ') << mName << " done" << std::endl; } static int sIndentLevel; char const * mName; }; int Debug::sIndentLevel = 0; // Base class Base { public: virtual ~Base() { } template<class Archive> void serialize(Archive & ar, const unsigned int) { Debug d("Base"); } }; // Derived class Derived : public Base { public: void setOther(OtherRef other) { mOther = other; } template<class Archive> void serialize(Archive & ar, const unsigned int) { Debug d("Derived"); ar & boost::serialization::base_object<Base>(*this); // This line is executed three times before a crash on deserialzation ar & mOther; // Code after here is never executed on deserialization } OtherRef mOther; }; // Other class Other { public: void setBase(BaseRef base) { mBase = base; } template<class Archive> void serialize(Archive & ar, const unsigned int) { Debug d("Other"); ar & mBase; } BaseRef mBase; }; BOOST_CLASS_EXPORT(Derived); // main int main(int /* argc */, char * /* argv */[]) { char const * fname = "cycles.text_archive"; std::cout << std::endl << "Serializing..." << std::endl << std::endl; { DerivedRef derived(new Derived()); OtherRef other(new Other()); derived->setOther(other); other->setBase(derived); std::ofstream ofs(fname, std::ios::out | std::ios::binary); boost::archive::text_oarchive oa(ofs); oa & derived; } std::cout << std::endl << "Deserializing..." << std::endl << std::endl; { Derived derivedCopy; std::ifstream ifs(fname, std::ios::in | std::ios::binary); boost::archive::text_iarchive ia(ifs); ia & derivedCopy; } }

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Bug or feature? date_time::microseconds limitations?
by athor 30 Oct '08

30 Oct '08

The boost::date_time::microseconds(...) constructor overflows the int64 size limits in intermediary calculations. The code below will reproduce the error (using VC++ 2008 and boost 1.36). ptime start(boost::gregorian::date(2000, 1, 1)); ptime end(boost::gregorian::date(2000, 5, 1)); time_duration td = end - start; ptime wrongEnd = start + microseconds(td.total_microseconds()); BOOST_CHECK_EQUAL(end, wrongEnd); The microseconds constructor takes an int64 as input and the total_microseconds is well within its range. Inside the date_time::subsecond_duration<time_duration, 1000000> the internal duration is calculated as ss*traits_type::res_adjust()/frac_of_second Since the both res_adjust() and frac_of_second have the value 1000000, the result should be ss*1 but... the intermediary value ss*res_adjust overflows the int64 causing a negative number to be returned. Question is, is this by design or is it a bug? I'm rather new to boost::date_time and was hoping to replace our current datetime types with it. We are using millisecond timestamped data over long time series (years). I guess the simple solution would be to add parentheses around (res_adjust()/frac_of_second) assuming frac_of_second always divides res_adjust. However, there are similar issues when adding 200 years worth of seconds which overflows the int32 argument (but that's not of my immediate concern). -- View this message in context: http://www.nabble.com/Bug-or-feature--date_time%3A%3Amicroseconds-limitatio… Sent from the Boost - Users mailing list archive at Nabble.com.

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boost.python / bjam
by Mark Williams 30 Oct '08

30 Oct '08

Hi, is it possible to build boost.python such that the python version gets embedded in the .so name along with the compiler name, version, multithread flags, etc? For example, "libboost_python25-gcc41-mt-1_35.so" instead of "libboost_python-gcc41-mt-1_35.so" Alternatively, is it possible to build it without the embedded SONAME so that it can be renamed afterwards? Thanks in advance, Mark

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Using Asio's ICMP support
by David Smith 30 Oct '08

30 Oct '08

Hi, Sorry if this is a silly question, but in Asio's ICMP support, what portion of an ICMP packet will an application supply when sending? What portion of an ICMP packet will an application retrieve when receiving? I get the impression that the whole body of the ICMP packet is supplied/retrieved (only an IP header with the ICMP protocol is prefixed). Is that the right impression? Thanks, David

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Please define _WIN32_WINNT or _WIN32_WINDOWS appropriately
by Jean-Sebastien Stoezel 30 Oct '08

30 Oct '08

Hi, I am compiling Boot 1_35_0 with Visual Studio 2008 under Windows XP, and at compile time I get the following message: Please define _WIN32_WINNT or _WIN32_WINDOWS appropriately Assuming _WIN32_WINNT=0x0501 (i.e. Windows XP target) Following the advice, I then defined the following macro: _WIN32_WINNT=0x0501 However now I get the following errors: d:\program files\microsoft visual studio 9.0\vc\atlmfc\include\afxdlgs.h(235) : error C2504: 'IFileDialogEvents' : base class undefined d:\program files\microsoft visual studio 9.0\vc\atlmfc\include\afxdlgs.h(244) : error C2061: syntax error : identifier 'FDE_SHAREVIOLATION_RESPONSE' d:\program files\microsoft visual studio 9.0\vc\atlmfc\include\afxdlgs.h(246) : error C2061: syntax error : identifier 'FDE_OVERWRITE_RESPONSE' d:\program files\microsoft visual studio 9.0\vc\atlmfc\include\afxdlgs.h(249) : error C2504: 'IFileDialogControlEvents' : base class undefined What macros do really need to be defined? What values should be assigned for Windows XP? Thanks, Jean

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mutex Locks!
by Wesley Khandavalli 29 Oct '08

29 Oct '08

Dear all, i am new to threading. i want to know the following. Given a shared object which is accessed by more than one process, where should we implement the mutex locking? Is it in the shared object or in the critical section of the Processes? If locking is done in process, will it work having different names for the locks in the processes? class A { .......... ........ public: execute() { ......... lock(mutex1) //write data to shared object unlock(mutex1) ......... } }; class B { .......... ........ public: execute() { ......... lock(mutex2) //write data to shared object unlock(mutex2) ......... } }; SharedObject { ........... .......... }; -- Wesley K

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compile problem?
by Wenhao Xu 29 Oct '08

29 Oct '08

Hi everyone, I am a new to boost. When I compile the example of asio_timer, I have a compile error: " g++ -o test_timer test_timer.cpp -I /peter/boost/boost_1_36_0 -lboost_thread-gcc42-mt-1_36 -lboost_system-gcc42-mt-1_36 In file included from /usr/include/c++/4.2/iostream:44, from test_timer.cpp:11: /usr/include/c++/4.2/i486-linux-gnu/bits/c++config.h:149: error: expected constructor, destructor, or type conversion before ‘namespace’ Compilation exited abnormally with code 1 at Tue Oct 28 00:04:58" My compile command is: g++ -o test_timer test_timer.cpp -I /peter/boost/boost_1_36_0 -lboost_thread-gcc42-mt-1_36 -lboost_system-gcc42-mt-1_36 I cannot find the reason. Could you help me? Thanks very much. Best wishes, Wenhao // // time_t_timer.cpp // ~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2008 Christopher M. Kohlhoff (chris at kohlhoff dot com) // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // #include <boost/asio.hpp> #include <ctime> #include <iostream> struct time_t_traits { // The time type. typedef std::time_t time_type; // The duration type. struct duration_type { duration_type() : value(0) {} duration_type(std::time_t v) : value(v) {} std::time_t value; }; // Get the current time. static time_type now() { return std::time(0); } // Add a duration to a time. static time_type add(const time_type& t, const duration_type& d) { return t + d.value; } // Subtract one time from another. static duration_type subtract(const time_type& t1, const time_type& t2) { return duration_type(t1 - t2); } // Test whether one time is less than another. static bool less_than(const time_type& t1, const time_type& t2) { return t1 < t2; } // Convert to POSIX duration type. static boost::posix_time::time_duration to_posix_duration( const duration_type& d) { return boost::posix_time::seconds(d.value); } }; typedef boost::asio::basic_deadline_timer< std::time_t, time_t_traits> time_t_timer; void handle_timeout(const boost::system::error_code&) { std::cout << "handle_timeout\n"; } int main() { try { boost::asio::io_service io_service; time_t_timer timer(io_service); timer.expires_from_now(5); std::cout << "Starting synchronous wait\n"; timer.wait(); std::cout << "Finished synchronous wait\n"; timer.expires_from_now(5); std::cout << "Starting asynchronous wait\n"; timer.async_wait(handle_timeout); io_service.run(); std::cout << "Finished asynchronous wait\n"; } catch (std::exception& e) { std::cout << "Exception: " << e.what() << "\n"; } return 0; }

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program_options: one-of-set option format
by Ivan Godard 29 Oct '08

29 Oct '08

The boost::program_options library appears to lack the capability for one-of-set options, i.e. one of -a, -b, or -c, but not more than one, returned as an enumeration value in a common result for all the options. Currently I have a function: template<typename T> options_description& oneOf(options_description& od, std::vector<std::string>& names, T& t); which adds options for all the names to "od", with notifiers that update "t" with the "T" enumeration value corresponding to the particular option that the parser finds present using the ordinal position in "names" as a value. However, this is somewhat unsatisfying because detected errors (missing or too many choices) don't feed into the program_options reporting system. It also does not fit with the rather nice syntax used by the program_options library for option declarations. I also looked at using an external parser as supported by program_options, but this seems low-level overkill - you get a raw string to parse, but none of the nice facilities for abbreviation, long or short forms, etc. are usable. Lastly, I considered adding the capability as a native feature of program_options, but while the library is reasonably clean it doesn't seem to be designed to support any inter-option linkages as required for reporting the result and verifying that only one of the set was present. So the question for this list: am I reinventing the wheel here and this oneOf capability already exists somewhere? If not, is there a better approach than my present purely extra-library solution? Thank you Ivan

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boost bind conflicting with socket bind
by Sharad Mittal 29 Oct '08

29 Oct '08

Hello, My Socket code that contains call to "bind" to a port is conflicting with boost::bind in 1.36. It compiles fine under boost 1.34 and 1.35. Interestingly, nothing is included from boost in that file. I am using boost with mingw on Win Xp. The code snippet is as follows: int Socket::BindPort(int family, int address, int port) { sockaddr_in sa; int dwError = RERROR_SUCCESS; memset(&sa, 0, sizeof(sa)); sa.sin_family = family; sa.sin_addr.s_addr = address; sa.sin_port = htons(port); if (bind(s_, (sockaddr *)&sa, sizeof(sockaddr_in)) == SOCKET_ERROR) { dwError = RERROR_SOCKET_BIND_ERROR; LOG (LOG_ERR, "Could not bind socket to port %u", port); BAIL_ON_ERROR (dwError); } error: return dwError; } Here is what I am getting... [g++] [Socket.o]<-[Socket.cpp] E:/msys/1.0/boost/boost_1_36_0/boost/bind.hpp: In instantiation of `boost::_bi::result_traits<boost::_bi::unspecified, unsigned int>': E:/msys/1.0/boost/boost_1_36_0/boost/bind/bind_template.hpp:15: instantiated from `boost::_bi::bind_t<boost::_bi::unspecified, unsigned int, boost::_bi::list2<boost::_bi::value<sockaddr*>, boost::_bi::value<unsigned int> > >' Socket.cpp:98: instantiated from here E:/msys/1.0/boost/boost_1_36_0/boost/bind.hpp:67: error: `unsigned int' is not a class, struct, or union type E:/msys/1.0/boost/boost_1_36_0/boost/bind/bind_template.hpp: In instantiation of `boost::_bi::bind_t<boost::_bi::unspecified, unsigned int, boost::_bi::list2<boost::_bi::value<sockaddr*>, boost::_bi::value<unsigned int> > >': Socket.cpp:98: instantiated from here E:/msys/1.0/boost/boost_1_36_0/boost/bind/bind_template.hpp:15: error: no type named `type' in `struct boost::_bi::result_traits<boost::_bi::unspecified, unsigned int>' E:/msys/1.0/boost/boost_1_36_0/boost/bind/bind_template.hpp:18: error: no type named `type' in `struct boost::_bi::result_traits<boost::_bi::unspecified, unsigned int>' E:/msys/1.0/boost/boost_1_36_0/boost/bind/bind_template.hpp:24: error: no type named `type' in `struct boost::_bi::result_traits<boost::_bi::unspecified, unsigned int>' E:/msys/1.0/boost/boost_1_36_0/boost/bind/bind_template.hpp:30: error: no type named `type' in `struct boost::_bi::result_traits<boost::_bi::unspecified, unsigned int>' E:/msys/1.0/boost/boost_1_36_0/boost/bind/bind_template.hpp:36: error: no type named `type' in `struct boost::_bi::result_traits<boost::_bi::unspecified, unsigned int>' E:/msys/1.0/boost/boost_1_36_0/boost/bind/bind_template.hpp:45: error: no type named `type' in `struct boost::_bi::result_traits<boost::_bi::unspecified, unsigned int>' E:/msys/1.0/boost/boost_1_36_0/boost/bind/bind_template.hpp:51: error: no type named `type' in `struct boost::_bi::result_traits<boost::_bi::unspecified, unsigned int>' E:/msys/1.0/boost/boost_1_36_0/boost/bind/bind_template.hpp:59: error: no type named `type' in `struct boost::_bi::result_traits<boost::_bi::unspecified, unsigned int>' E:/msys/1.0/boost/boost_1_36_0/boost/bind/bind_template.hpp:65: error: no type named `type' in `struct boost::_bi::result_traits<boost::_bi::unspecified, unsigned int>' E:/msys/1.0/boost/boost_1_36_0/boost/bind/bind_template.hpp:74: error: no type named `type' in `struct boost::_bi::result_traits<boost::_bi::unspecified, unsigned int>' E:/msys/1.0/boost/boost_1_36_0/boost/bind/bind_template.hpp:80: error: no type named `type' in `struct boost::_bi::result_traits<boost::_bi::unspecified, unsigned int>' E:/msys/1.0/boost/boost_1_36_0/boost/bind/bind_template.hpp:87: error: no type named `type' in `struct boost::_bi::result_traits<boost::_bi::unspecified, unsigned int>' E:/msys/1.0/boost/boost_1_36_0/boost/bind/bind_template.hpp:93: error: no type named `type' in `struct boost::_bi::result_traits<boost::_bi::unspecified, unsigned int>'

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