December 2014 - Boost-users

double free when both shared library and executable linked to boost libraries
by Eric Roller 09 Jan '15

09 Jan '15

I've run into a run-time error (double free) with my software which uses a plug-in architecture. The main executable (a.out) uses dlopen to load a shared library (mylib.so). Both a.out and mylib.so utilize the boost libraries (version 1.54) and are therefore linked separately to them. Depending on whether I use static or dynamic linking to the boost libraries I encounter the double free error as confirmed by address sanitizer using gcc 4.9.2 on linux x86_64. Here is a summary of the results: a.out link mylib.so link double free? static dynamic YES static static NO dynamic dynamic NO dynamic static NO So you can see, only when the main executable used static linking to boost and the shared library used dynamic linking to boost is when I saw the double free error at run time. My question is, why is the error only triggered under that condition and what is the recommended link configuration when using boost libraries for both a shared library and an executable. Ideally, the shared library plug-in should be free to use any boost version with either static or dynamic linking, and it should be independent from (i.e. not conflict with) the main executable's boost version and link type. What compiler/link settings would be necessary to achieve this, if it is even possible at all? -- Eric Roller

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Using static code checkers against the Boost code base
by Hickman, Steve (AdvTech) 08 Jan '15

08 Jan '15

I don't know if there is a policy yet on using static code checkers on the Boost code base as part of the release cycle. Given that the Visual Studio 2012 Analyzer tool I'm using just picked up 3 issues in the 1.57 release (I've posted TRAC items on them already), I suspect not. I would like to encourage such a policy. Boost is, among other things, about quality. This is a way to enhance quality. For people like me who work in safety critical fields, it is vital. I cannot use Boost libraries if they can't be certified. Static analyzers can help insure quality, which makes it easier to qualify these tools. There are many tools available. Some, like CppCheck, are open source. Others are built into development environments (aforementioned VS Analyzer, Clang tools, etc.). Further, I suspect that tool vendors could be convinced it would be good PR to have their tools used by Boost, so I suspect even those with paid licenses can be made available for free. Steve Hickman System Architect, Flight Deck of the Future 480-236-8367

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pass asio socket to another class
by cap 05 Jan '15

05 Jan '15

I have two classes SslHandshake and SslRequest with according to names functionality. After client and server handshakes are done in the SslHandshake, I pass both sockets to SslRequest and start transferring data from server to client. 1. If I is not waiting for finishing of transferring, instance of SslHandshake will be destroyed automatically (in the ~SslHandshake I will destroy both socket objects and transferring in the SslRequest will be aborted). 2. If I start transferring with waiting, after a few iterations SslRequest::ReadSocketOut will be called successfully, but the readSocketHandle will not be called (so, will be called but with timeout error). So, I need to handshake in one class and transfer data into another class. How to prevent destroying instance of SslHandshake until data transferring will be done into SslRequest or how to fix socket reading without callback calling after a few iterations? void SslHandshake::HandshakeInHandle(const bSystem::error_code &error) { TRY { CHECK_BOOST_ERROR { LOG_MSG_DEBUG_KEYWORD(KEYWORD_INCOMING, << "Handshake done"); // --- Transfer with waiting of mutex //IoServicePtr servicePointer((IoService *)&m_SocketIn->get_io_service()); //boost::thread serviceThread(boost::bind(&IoService::IO_SERVICE_THREAD_VOID, servicePointer)); //SslRequest::SharedPtr sslRequest(new SslRequest(m_SocketIn, m_SocketOut)); //sslRequest->Transfer(); SslRequest::SocketPtr socketIn(m_SocketIn); SslRequest::SocketPtr socketOut(m_SocketOut); // --- Transfer with waiting of thread //IoServicePtr servicePointer((IoService *)&m_SocketIn->get_io_service()); //servicePointer->SessionIndex = IndexThis; //boost::thread serviceThread(boost::bind(&IoService::IO_SERVICE_THREAD_VOID, servicePointer)); //SslRequest::SharedPtr request = SslRequest::CreateInstance(m_SocketIn, m_SocketOut); //request->Transfer(); //serviceThread.join(); // --- Transfer with waiting of IO_SERVICE_THREAD_VOID IoServicePtr servicePointer((IoService *)&m_SocketIn->get_io_service()); servicePointer->SessionIndex = IndexThis; SslRequest::SharedPtr request = SslRequest::CreateInstance(/*m_SocketIn, m_SocketOut*/socketIn, socketOut INDEX_THIS_PASS); request->Transfer(); servicePointer->IO_SERVICE_THREAD_VOID(); } } CATCH_LOG_STD CATCH_LOG_ANY } void SslRequest::ReadSocketOut(TransferringBuffer &buffer, SimpleSocketCallback readSocketHandle) { bAsIO::async_read( *m_SocketOut, bAsIO::buffer(buffer), boost::bind( readSocketHandle, SHARED_FROM_THIS, baPlaceholders::error, baPlaceholders::bytes_transferred)); } -- View this message in context: http://boost.2283326.n4.nabble.com/pass-asio-socket-to-another-class-tp4670… Sent from the Boost - Users mailing list archive at Nabble.com.

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Boost.DateTime library to synthesise time-series data?
by Riskybiz 05 Jan '15

05 Jan '15

Dear boost-users, It's my first time trying this and hope that someone may be able to enlighten me about which aspects of the Boost.DateTime library will help solve this problem... I have some time-series data which is time stamped with boost::posix_time::ptime values. From this base-series I would like to synthesise higher interval time-series. For example, a base-series of 1 second time-series data could be used to synthesise a time-series of any greater interval; 2 seconds, 5 seconds, 86400 seconds (1 day) etc. Or 1 minute base-series data could be used to synthesise, 2 min, 15min, 60 min time-series etc. It is entirely possible that any given base-series time point could be absent i.e. there could be time gaps in the base-series. I have an idea to use boost::posix_time::time_period to create regularly temporally spaced 'buckets' of the required time interval; into which the base-series data elements would accumulate and thus allow the synthesising of the higher interval time-series. Each 'bucket' represents one higher interval time-series data element. It is important that the 'buckets' are aligned with natural multiples of the time interval for which they are accumulating. So for example a 10 second synthesised time-series would have boost::posix_time::time_period 'buckets' like so at: 1-10, 11-20, 21-30, 31-40, 41-50 & 51-60 seconds time_periods. The first data element of the base-series could fall at any time, it could be on the 7th second of a minute, equally it could be on the 59th minute of an hour. Somehow the first boost::posix_time::time_period 'bucket' for a particular synthesised interval must be set such that it spans the correct period of time and ends on a multiple of the time-series interval which is being synthesised. Put simply, that first base-series data element needs to fall into a correctly aligned time_period 'bucket'. Using Boost.Date_Time how could the boost::posix_time::ptime of the first data element of the base-series be examined and the first time_period 'bucket' be correctly aligned to the relevant begin and end times for the synthesised time-series? I envisage subsequent 'buckets' will be created by incrementing forward in time from the datum of the first. With grateful thanks for any assistance, Riskybiz.

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How to build Boost with VC++ 2013 to target XP/2003 platform?
by Caroline Beltran 01 Jan '15

01 Jan '15

Programs written in VC++ 2012 or 2013 will only run on Windows XP or Windows 2003 when you choose the 'Windows XP (v120_xp)' toolset option in the IDE. Is there some way to set this option from Bjam? P.S. A Stack Overflow user indicated that he got Boost to build under VC++ 2012. I tried his solution under VC++ 2013 but it did not work for some reason completely unknown to me. http://stackoverflow.com/questions/27695187/modify-visual-c-vcvars32-bat-to… Apparently, VC++ 2012/2013 use the Windows 8 SDK and the solution above causes you to use the Windows 7 SDK which is compatible with XP and Windows 2003. Please help me

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Writing custom allocator for use with extended boost vector
by Olumide 31 Dec '14

31 Dec '14

I am considering using boost::container::vector as an alternative to std::vector because std::vector moves when its capacity is exceeded. This is a problem because I am using a lean stack-like allocator that acquires a pool of memory from the heap and manages it my incrementing or decrementing a pointer to the available memory; and automatically moving the vector in the pool is a big no-no for several reasons chief of which is that such moves invalidate the above pointer. My allocator does not use a header block in order to delineate subsequent allocations. This approach works because my application is recursive i.e. objects are allocated and deallocated in a strict LIFO order. Furthermore allocations are typically small (but not constant size) and and are routinely smaller than the size of the canonical header block consisting of a forward and backward pointer. To use such a header block would IMHO be a waste. I'd like to port this allocator to for use with boost::container::vector but I'm not sure entirely sure how much of the boost::container::allocator interface that I need to implement, or if perchance there is already an allocator that does what I am trying to do. Please advise. Regards, - Olumide

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nowide
by Colin Humphries 30 Dec '14

30 Dec '14

Artyom, Please ignore my request for wifstream and wofstream constructors. I see now that these are not needed: windows accepts UTF-16 filenames so of course I just needed to use widen. I am however surprised that your fstream constructors do not directly accept std::string? I feel that the required .c_str() call should be incorporated. Regards, Colin Humphries

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nowide
by Colin Humphries 29 Dec '14

29 Dec '14

Hello Artyom, Please provide wifstream and wofstream constructors. I realise this request may seem contrary to the spirit of your very useful library but wide streams are required by boost::serialize to output to XML (i.e. UTF-8) (Yes, I agree it might be more sensible to update Boost::Serialize). Regards, Colin Humphries

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[filesystem] ISO TS 18822, Technical Specification - File System
by Beman Dawes 29 Dec '14

29 Dec '14

The filesystem TS has been unanimously approved by ISO. 32 countries voted. The document has been forwarded to the ISO Central Secretariat for publication. The current working draft, which is technically the same as the TS but may have editorial corrections, is available at http://cplusplus.github.io/filesystem-ts/working-draft.html Many thanks to all the Boost folks who contributed so much to the Boost library that became the ISO TS! The C++ standards committee Filesystem Study Group will continue to operate, and will issue further TSes as further proposals dictate, and will continue to publish a working paper as issues for the TS are corrected. Happy Boost New Year, --Beman

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[Serialize] Conflict between Serialize and PIMPL?
by Merrill Cornish 28 Dec '14

28 Dec '14

In a normal PIMPL structure, the visible class is responsible for instantiating the private implementation class when the visible class is instantiated. However, when serialization is restoring objects, /it/ thinks it is responsible for instantiating all classes, including the private implementation classes of a PIMPL structure. Who wins? Do I end up with /two/ instances of the private implementation class, one of which is just hanging in mid-air? If you need a more solid background, here is what I'm doing: _Visible class header_: struct Foo_Private; class Foo { public: Foo(); . . ./other//stuff/ . . . . . . /data member-free serialization//code/ . . . private: *const std::unique_ptr< Foo_Private() > d_ptr**;* }; _Visible class code_: Foo::Foo() : *d_ptr(std::make_unique< Foo_Private >())* {...code to initialize Foo_Private data members...} _Private Implementation class header_: struct Foo_Private{ Foo_Private(); . . . /data member declarations/ . . . . . . /data member serialization code/ . . . }; Private implementation class has no code file. It is a header-only class. One alternative I thought of was to /not/ serialize the private implementation class, even though it contains all of the data member that need serializing. Instead, if the private class has data members, say, bar and baz, then the /visible/ class would have a serialize() function that "reached into" the private object using its d_ptr: template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & d_ptr->bar; ar & d_ptr->baz; } So, the visible class (which has no data members of its own) is serialized using data extracted from/inserted into the private class object. Would serialization-by-proxy work?

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