May 2014 - Boost-users - lists.preview.boost.org

[Asio] async_read_until is passing no error and bytes_transferred of zero to handler
by Marcano, Gabriel E 08 May '14

08 May '14

I wanted to ask on the mailing list about an issue I'm having with Boost.Asio on Windows 7 before making a bug report. System information: Windows 7 64-bit Professional running on an Intel quad-core i7 with 4 GB of RAM, using Visual Studio 2012 for C++ development. Used VS2012 compiler to compile Boost 1.55 libraries by following instructions found in the documentation online. In case it matters, here are the C++ preprocessor defines I'm using: WIN32;_DEBUG;_CRT_SECURE_NO_WARNINGS;NOMINMAX;WIN32_LEAN_AND_MEAN; _WIN32_WINNT=0x0601; The project was compiled with the default debug settings for Visual Studio 2012, meaning no optimizations. The problem: While using Boost.Asio to communicate with a serial device (an Arduino, 250000 baud, 8n1), sometimes async_read_until would pass to the handler both a bytes_transferred of zero and an error condition indicating success. According to http://www.boost.org/doc/libs/1_55_0/doc/html/boost_asio/reference/ async_read_until/overload1.html, this should never occur (if I'm interpreting the documentation correctly). Specifically, under parameters, under handler: // The number of bytes in the streambuf's get // area up to and including the delimiter. // 0 if an error occurred. The odd thing about this problem is that it is not easily reproducible... I think it may be a race condition. The files I'm attaching include the wrapper class I made to access the serial port in Windows, with a small main function at the bottom of the implementation .cpp file. I almost couldn't reproduce the error with this setup-- it took me a few dozen runs to get it to manifest itself. I can guarantee that the problem does not lie with the Arduino or the UART communication-- I have been running USBPcap to make sure that USB communication is taking place. I can see all data travelling to and from the Arduino by analyzing the USBPcap output through Wireshark. The Arduino I have has a set of ASCII serial commands it supports. The only one I use in the included code is "?\r", which makes it return "ACK\r\nArduino\r\n". Based on my searching, the closest bugs to what I'm experiencing seem to be these ones: https://svn.boost.org/trac/boost/ticket/8933 https://svn.boost.org/trac/boost/ticket/8967 I considered disabling IOCP for testing, but serial port communication depends on IOCP in Windows. The original problem is far more reliably reproduced-- using Visual Studio's unit testing framework, I am running essentially the same code included in the main function of the included code. I'd say about one of every three or two runs results in the error using the unit testing framework. Running the code in the actual application I'm developing also reliably reproduces the problem (MFC application). The attached .zip file includes the stripped down version of the project used to reproduce the problem, the stack frame of the error as caught by the assert inside readUntilComplete, and a core dump with the heap for the stripped project when the error occurred. The debugging symbols for the core dump are also included in the top-most directory of the .zip file. I would greatly appreciate any input/suggestions on the issue. If people are having trouble reproducing the problem, I seemingly can occasionally reproduce it so I can do more analysis, if someone were to point me in the right direction. Thank you for your time! Sincerely, Gabriel E. Marcano

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Re: [Boost-users] [Asio] async_read_until is passing no error and bytes_transferred of zero to handler
by Marcano, Gabriel E 07 May '14

07 May '14

> The attached .zip file includes the stripped down version of the project used > to reproduce the problem I'm unsure if my .zip file made it through the mailing list (I don't think so, as best as I can tell). For the time being, I've uploaded the .zip to my Google drive. As a heads up, it's around 15 MB compressed due to the core dump. The link is found here: https://drive.google.com/file/d/0B6KwsUWQzY0NdVhIMDFLUWpPLTg/edit?usp=shari… Let me know if there is anything other information I can provide! Sincerely, Gabriel E. Marcano

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porting boost threads
by Jono Poff 07 May '14

07 May '14

Hi, this is my first post. I'm experimenting with boost 1.55.0 having last used version 1.3.mumble. I'm porting some old classes to see what changes there are and it has been quite smooth, with spirit stuff coming over easily using the classic namespace. One of my old wrapper classes typedefs boost::detail::thread::scoped_lock<boost::recursive_mutex> which seems to be missing from the latest version. Replaced with boost::mutex::scoped_lock perhaps? I expect to find other changes i thread... Can anyone point me to an explanation of changes to Boost thread that would help smooth this transition. Cheers, Jono -- ------------------------------ This email, including any attachments, is only for the intended recipient. It is subject to copyright, is confidential and may be the subject of legal or other privilege, none of which is waived or lost by reason of this transmission. If you are not an intended recipient, you may not use, disseminate, distribute or reproduce such email, any attachments, or any part thereof. If you have received a message in error, please notify the sender immediately and erase all copies of the message and any attachments. Unfortunately, we cannot warrant that the email has not been altered or corrupted during transmission nor can we guarantee that any email or any attachments are free from computer viruses or other conditions which may damage or interfere with recipient data, hardware or software. The recipient relies upon its own procedures and assumes all risk of use and of opening any attachments. ------------------------------

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[PropertyTree] read_json() followed by write_xml produces invalid XML
by Marcel Loose 07 May '14

07 May '14

Hi all, Last week I posted the message below to the Boost Users group. One of the posters suggested that I stumbled upon a bug in Boost.PropertyTree. So, the question is: am I doing something wrong, or is this is a bug in Boost.PropertyTree? Best regards, Marcel Loose. ---- Start of message ---- I was quite surprised and disappointed to find out that I was unable to convert a simple JSON file into XML, using the Boost PropertyTree. As input I used the example JSON file from the documentation (see example.json below). I wrote a small program (see example.cc below) that reads in this JSON file, writes it to disk as XML file, and finally tries to read back this XML file. This last operation fails with an exception (see output below); the XML file that is produced (see example.xml below) is invalid, because it contains empty tags (<>). Am I doing something wrong? Best regards, Marcel Loose. $ cat example.json { "menu": { "foo": true, "bar": "true", "value": 102.3E+06, "popup": [ {"value": "New", "onclick": "CreateNewDoc()"}, {"value": "Open", "onclick": "OpenDoc()"} ] } } $ cat example.cc #include <boost/property_tree/ptree.hpp> #include <boost/property_tree/json_parser.hpp> #include <boost/property_tree/xml_parser.hpp> #include <fstream> using namespace std; using namespace boost::property_tree; int main() { ptree pt; { read_json("example.json", pt); ofstream ofs("example.xml"); write_xml(ofs, pt, xml_writer_make_settings(' ', 2)); } { ifstream ifs("example.xml"); read_xml(ifs, pt); } return 0; } $ ./example terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::property_tree::xml_parser::xml_parser_error> >' what(): <unspecified file>(7): expected element name Aborted $ cat example.xml <?xml version="1.0" encoding="utf-8"?> <menu> <foo>true</foo> <bar>true</bar> <value>102.3E+06</value> <popup> <> <value>New</value> <onclick>CreateNewDoc()</onclick> </> <> <value>Open</value> <onclick>OpenDoc()</onclick> </> </popup> </menu> ---- End of message ----

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Boost PropertyTree: read_json() followed by write_xml() produces invalid XML
by Marcel Loose 07 May '14

07 May '14

Hi all, Last week I posted the message below to the Boost Users group. One of the posters suggested that I stumbled upon a bug in Boost.PropertyTree. So, the question is: am I doing something wrong, or is this is a bug in Boost.PropertyTree? Best regards, Marcel Loose. ---- Start of message ---- I was quite surprised and disappointed to find out that I was unable to convert a simple JSON file into XML, using the Boost PropertyTree. As input I used the example JSON file from the documentation (see example.json below). I wrote a small program (see example.cc below) that reads in this JSON file, writes it to disk as XML file, and finally tries to read back this XML file. This last operation fails with an exception (see output below); the XML file that is produced (see example.xml below) is invalid, because it contains empty tags (<>). Am I doing something wrong? Best regards, Marcel Loose. $ cat example.json { "menu": { "foo": true, "bar": "true", "value": 102.3E+06, "popup": [ {"value": "New", "onclick": "CreateNewDoc()"}, {"value": "Open", "onclick": "OpenDoc()"} ] } } $ cat example.cc #include <boost/property_tree/ptree.hpp> #include <boost/property_tree/json_parser.hpp> #include <boost/property_tree/xml_parser.hpp> #include <fstream> using namespace std; using namespace boost::property_tree; int main() { ptree pt; { read_json("example.json", pt); ofstream ofs("example.xml"); write_xml(ofs, pt, xml_writer_make_settings(' ', 2)); } { ifstream ifs("example.xml"); read_xml(ifs, pt); } return 0; } $ ./example terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::property_tree::xml_parser::xml_parser_error> >' what(): <unspecified file>(7): expected element name Aborted $ cat example.xml <?xml version="1.0" encoding="utf-8"?> <menu> <foo>true</foo> <bar>true</bar> <value>102.3E+06</value> <popup> <> <value>New</value> <onclick>CreateNewDoc()</onclick> </> <> <value>Open</value> <onclick>OpenDoc()</onclick> </> </popup> </menu> ---- End of message ----

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Boost pool and move constructor
by Bruno Sanches 06 May '14

06 May '14

I am trying to create a object using boost object_pool, but trying to use the move constructor of the desired object, but on Visual 2013, I am always getting: error C2664: 'MyObject::MyObject(const MyObject &)' : cannot convert argument 1 from 'MyObject (__cdecl &)(void)' to 'MyObject &&' The error happens because boost pool construct method always assume a const parameter. Sample code: #include <boost/pool/object_pool.hpp> class MyObject{ public: MyObject(): m_iData(0) { } MyObject(MyObject &&other): m_iData(std::move(other.m_iData)) { other.m_iData = 0; } MyObject(const MyObject &rhs) = delete; MyObject &operator=(const MyObject &rhs) = delete; private: int m_iData;}; int main(int, char**){ boost::object_pool<MyObject> pool; MyObject obj; MyObject *pObj = pool.construct(std::move(obj));} Is there any way to invoke the move constructor using boost::object_pool? Thanks Bruno Sanches ======================== http://www.pontov.com.br

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Sequence of boost::logic::tribools - let indeterminate entries inherit from their neighbours
by Jens Müller 06 May '14

06 May '14

Hi, I have a sequence of tribools and I want element with a indeterminate value to inherit from their neighbours. Does such an algorithm exist already in Boost? If not, do you think it would be a useful addition? BR, Jens

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[range] can't use boost::any_range with RTTI disabled due to boost::polymorphic_downcast
by Adam Romanek 06 May '14

06 May '14

Hi! I'd like to draw your attention to an issue with boost::any_range that prevents it from being used with RTTI disabled. The problem is that boost::any_range indirectly uses boost::polymorphic_downcast which in turn uses dynamic_cast. Note that the dynamic_cast is only used to ensure the requested cast is valid and it's done only in non-release builds. It would be great if the check was simply skipped in RTTI-disabled environments, as it is done in release builds. This would result in loss of safety that boost::polymorphic_downcast provides but the pieces that use it would at least compile in RTTI-disabled environments. Would it be possible to fix this problem? If you wish I could create a ticket for this issue. BTW, there's a typo in the documentation of boost::any_range [1]. It mentions boost::forward_pass_traversal_tag, which does not exist. It should rather be boost::forward_traversal_tag. WBR, Adam Romanek [1] http://www.boost.org/doc/libs/1_55_0/libs/range/doc/html/range/reference/ra…

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Boost support of MinGW
by Kosta Zertsekel 05 May '14

05 May '14

Hi guys, It is said that MinGW is not supported by Boost because it is not fully POSIX compatible: http://www.boost.org/doc/libs/1_55_0/more/getting_started/windows.html#pch Excerpt: "A note to Cygwin and MinGW users If you plan to use your tools from the Windows command prompt, you're in the right place. If you plan to build from the Cygwin bash shell, you're actually running on a POSIX platform and should follow the instructions for getting started on Unix variants. Other command shells, such as MinGW's MSYS, are not supported-they may or may not work." Does it mean that is some program that uses Boost was compiled with MinGW, then it can randomly crash or has some stability issues? Thanks in advace, --- Kosta

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[TypeIndex 3.0] Review Manager's Report
by Niall Douglas 04 May '14

04 May '14

Dear Boost, The second round of peer review of proposed Boost.TypeIndex finished on Wed 30th, and here is the review manager's report. My thanks to the five reviewers who took the time and trouble to submit full reviews, plus to everyone else who commented. Votes regarding acceptance: 4 voted to accept TypeIndex into Boost immediately. 1 voted to accept into Boost with conditions. Overall: I recommend immediate acceptance into Boost. Conditions: 1. No one liked the present boost::typeind namespace, almost anything else would be better. I see the namespace has already changed in the develop branch to boost::typeindex, so I think this is already solved. Other common comments: * More than one reviewer mentioned how they liked the docs. * More than one reviewer expressed a desire for an ability to programmatically parse through type specifier strings. I agree with Antony that that is another library which isn't TypeIndex (something Boost.Spirit based which works directly with mangled symbol string representations, representing them as a partial AST - preferably also with a libclang compatible backend - would be great, but that is a totally different library and TypeIndex 3.x provides extensibility for such an additional function). * More than one reviewer sought some method of preventing link if you mix up incompatible uses of TypeIndex and/or with RTTI. Niall -- Currently unemployed and looking for work in Ireland. Work Portfolio: http://careers.stackoverflow.com/nialldouglas/

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What's wrong with my code?
by Bill David 04 May '14

04 May '14

Hi all, I meet a problem with some code with boost and want to ask for some help here. To the following code: #include <list> using namespace std; #include "boost/function.hpp" #include "boost/foreach.hpp" #include "boost/bind.hpp" using namespace boost; void InsertItemHelper(list<int>& inContainer, list<int>::iterator& ioPosition, const list<int>::value_type& inItem) { ioPosition = inContainer.insert(ioPosition, inItem); } void WorkerFunction(const list<int>& inContainer, boost::function<void(int)> const& inAddItemCallback) { BOOST_FOREACH(auto item, inContainer) { inAddItemCallback(item); } } void Print(const list<int>& inContainer) { BOOST_FOREACH(auto item, inContainer) { std::cout << item << endl; } } int main() { list<int> sourceContainer; sourceContainer.push_back(1); sourceContainer.push_back(2); sourceContainer.push_back(3); list<int> targetContainer; list<int>::iterator pos = targetContainer.end(); boost::function<void(int)> addItemCallbackFxn(boost::bind(& InsertItemHelper, targetContainer, pos, _1)); WorkerFunction(sourceContainer, addItemCallbackFxn); return 0; } When I run it on Windows with VS2012, I always get a “list insert iterator outside range” error with: inContainer.insert(ioPosition, inItem); It seems targetContainer I passed to boost::bind is copied so that the following debug error of STL is hit: #if _HAS_ITERATOR_DEBUGGING if (_Where._Mycont != this) _DEBUG_ERROR("list insert iterator outside range"); #endif /* _HAS_ITERATOR_DEBUGGING */ But I am passing targetContainer as a reference and after the error, I can correctly get data in it. Does anybody know what’s wrong behind? Thanks, BD

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