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

Boost.Log - textual format with severity
by Keith Bennett 12 May '14

12 May '14

Hello! I'm new to boost log (like many others, I imagine since it's only a relatively new library). I'm trying to specify a format textually (eg, keywords::format = "blahblah", instead of using a compiled expression). The idea is that the format can be reconfigured easily either through a command line parameter or through the configuration file without needing to recompile. However, it seems that anything specifying %Severity% when using a custom severity_level enum will simply not be output at all. Take the example from libs/log/example/keywords/main.cpp Simply changing line 86 to be: logging::add_console_log(std::clog, keywords::format = "%Severity% %TimeStamp%: %_%"); will exhibit the problem I believe I am trying to resolve. My suspicion is that the core doesn't know about the custom Severity attribute because it hasn't been registered and so is unable to parse %Severity% to any formatter. In contrast, the add_file_log below that does correctly output the severity level because it uses a compiled expression and is therefore able to deduce what needs to be done (am I correct in that assumption)? I seem to be unable to add an attribute to resolve this without rolling my own attribute class. How do I add an attribute or formatter related to the Severity which was declared with BOOST_LOG_ATTRIBUTE_KEYWORD? I think it's worth noting that if I remove the template parameter to severity_logger on line 123 so that it matches thus: src::severity_logger< > slg; It then devolves into a standard int instead of an enum and the output is "correctly" seen -- as an int and not as a human-readable string. While this is okay for now, I would of course want it to be human-readable if possible. This is as it is in the example in libs/log/example/settings_file/main.cpp. Any help would be appreciated. -- This message contains confidential information and is intended only for the individual named. If you are not the named addressee you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately by e-mail if you have received this e-mail by mistake and delete this e-mail from your system. If you are not the intended recipient you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited.

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Re: [Boost-users] [RFC] Modern CORBA C++ IDL Mapping and implementation
by Felipe Magno de Almeida 12 May '14

12 May '14

Sorry if this ends up duplicate. But I've sent it to the developer's list and it came back. Hello Boosters, Where I work we are implementing an open source, modern, CORBA implementation and IDL mapping. We want it to support C++ and C++11 IDL mapping, but we also want to create another IDL mapping. This new IDL mapping is being experimentated in the following url https://github.com/expertisesolutions/mORBid/tree/concepts It still has some very problematic issues (like compilation-time of generated code) and of course it is still far from completion. But, we would like to hear suggestions about this approach. What we did was that an IDL interface is mapped to a typedef for boost::type_erasure (I found the idea quite cool for the reasons that I'll mention below) with the requirements defined in the IDL, e.g. its operations. The IDL also emits a model for this type_erasure which is the actual stub class and is called remote_reference. It also emits a proxy_reference model for the same type_erasure typedef which receives a std::reference_wrapper and proxies the calls, this is needed because type_erasure can't switch between by-reference and by-value in runtime. Why I believe this approach is better than current IDL to C++11 mapping: Because the IDL to C++11 mapping is too intrusive. You can't really use normal classes you have written for use as servants in CORBA because you have to inherit from Skeletons classes *and* you have to use the *exact* same signature as defined in the mapping. This is *way too restricted*. This is also inerent to the OO paradigm that CORBA uses. But, we can mimic the same features using type-erasure instead of directly using dynamic polymorphism. This gives a much greater freedom to users. It might be that Boost.type_erasure is not the best tool here because of compile-time and compiler memory usage, but the idea surely is. We still haven't seriously profiled boost.type_erasure yet, but we will do so as soon as possible. I think it might be very interesting to experiment with lite concepts and Boost.concept_check as well. Also, we created a EDSL for GIOP and IIOP mapping based on the boost.spirit infrastructure. We use that to treat alignment and endianness automatically and to use the same grammar for generation and parsing of IIOP messages. The message header grammar is defined like this: start = "GIOP" & octet('\1') /* GIOP major version */ & octet('\0') /* GIOP minor version */ & endianness [ octet(MessageType) /* message_type */ & raw_size(ulong_)[body] ] ; Which is compiled to IIOP parser or generator through boost.spirit infrastructure of make_terminal, make_directive and etc. This works splendid well and is really easy to use, extend, is statically checked and has great performance. Whoever feel interested, please take a look and comments are highly appreciated. Regards, -- Felipe Magno de Almeida

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boost 1.55 build / install on OSX - why are aliases used instead of symlinks?
by Colby Boles 08 May '14

08 May '14

I recently installed and built boost 1.55 on an OSX machine of mine. With my current make system for my app (qmake) I needed to specify where the lib and include directories for boost were and thought the best thing to do would be to set them to \usr\local\lib \usr\local\include where I can see in the lib case there are links to the various library modules and in the include case there is a link to the boost include directories. The problem is that the boost installation makes these links using aliases instead of symlinks, so everything appears fine browsing in the Finder, but at the command line, the compiler can't see these directories. I'm able to change the aliases to symlinks, or point to the actual boost directories (e.g. \usr\local\Cellar\boost\1.55.0_1\*) and everything works, but it seems like the intention was to have symlinks at \usr\local\lib and \usr\local\include so that one can just point to these places and be version agnostic? Thanks, Colby

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Check if a type has a member function (inhrited member functions also) with Boost TTI
by Hijok Payne 08 May '14

08 May '14

Boost TTI has very convenient macros for checking if a type has a member function. See http://www.boost.org/doc/libs/1_55_0/libs/tti/doc/html/the_type_traits_intr… If I have not missing something BOOST_TTI_HAS_MEMBER_FUNCTION returns false for inherited member functions. Is there a convenient Boost solution for doing this? There is a SO<http://stackoverflow.com/questions/1966362/sfinae-to-check-for-inherited-me…> solution based on SFINAE. But I would like to avoid that and would prefer a Boost solution, since that way I am more sure it works on more compilers and I want avoid maintaining code for each such specific behavior.

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boost tti has_member_function
by Matei David 08 May '14

08 May '14

I'm trying to use boost tti has_member_function to test if a user-specified allocator has the expected methods. However, this fails with standard allocators. #include <iostream> #include <memory> #include <boost/tti/has_member_function.hpp> BOOST_TTI_HAS_MEMBER_FUNCTION(deallocate) typedef std::allocator< int > T; int main() { std::cout << has_member_function_deallocate< void (T::*) (T::pointer, T::size_type) >::value << "\n"; } I tried gcc-4.8.2 and clang-3.4. I'm compiling with: {g++|clang++} -std=c++11 -I${BOOST}/include -Wall -Wextra -pedantic -Wno-ignored-qualifiers -g3 -O0 In both cases, I get a 0. However, using "-E" and grep-ing for "\<deallocate\>", I see this signature: void deallocate(pointer __p, size_type) Shouldn't I be getting a 1? Am I using it the wrong way? Thanks

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[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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