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iostreams: streambuf class fails to compile on type check
by Dan Bloomquist 14 Mar '16

14 Mar '16

I'm trying to insert my own stream buffer into a boost stream. Here is the code <http://hostcode.sourceforge.net/view/5044> At the top are two arbitrary streambuf derived classes I copied from the web that are said to work with the std::stream. They don't work either. My work is in the rtf namespace. In main there is a test with my device, file_source, and std::ifstream derived, they all work. Then I've tried the likes of: rtf::basic_stream< char, char_array_buffer > io_4( input ); rtf::basic_stream< char, outbuf > io_4( input ); and the one I want to work: rtf::basic_stream< char, rtf::rtf_stream_buffer > io_4( input ); they all fail at: { BOOST_STATIC_ASSERT(is_std_io<T>::value); } line 66 in concept_adapter.hpp. All the classes are derived from std::basic_streambuf which is on the list #ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES And I could not find it defined with agent ransack So, I seem to be missing something fundamental and just don't know what it could be. Thanks. Dan.

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errors in polymorphic_iarchive_route.hpp:155 (boost version 1.60)
by Stack User 14 Mar '16

14 Mar '16

I get the following error when compiling code that uses boost version 1.60: In function `boost::archive::detail::polymorphic_iarchive_route<boost::archive::naked_binary_iarchive>::load(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&)': /usr/include/boost/archive/detail/polymorphic_iarchive_route.hpp:155: undefined reference to `boost::archive::basic_binary_iprimitive<boost::archive::naked_binary_iarchive, char, std::char_traits<char> >::load(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&)' Seems like the error is coming from polymorphic_iarchive_route.hpp at line 155: virtual void load(std::string & t){ ArchiveImplementation::load(t); } Can anybody point to a solution for this error? Thanks,

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[Fit] formal review ends today, 13th March.
by Vicente J. Botet Escriba 13 Mar '16

13 Mar '16

Hi, The formal review of Paul Fultz II's Fit library ends today, 13th March. If you had not time to do the review and you plan to do it, please let us know so that we see if the review can be extended. Up to now we had 3 formal review (2 for conditional acceptance and 1 against, not now). I have not done a review myself, but I have created a lot of issues on Github. Best regards, Vicente Fit is a header-only C++11/C++14 library that provides utilities for functions and function objects. Fit is: - Modern: Fit takes advantages of modern C++11/C++14 features. It support both `constexpr` initialization and `constexpr` evaluation of functions. It takes advantage of type deduction, varidiac templates, and perfect forwarding to provide a simple and modern interface. - Relevant: Fit provides utilities for functions and does not try to implement a functional language in C++. As such, Fit solves many problems relevant to C++ programmers, including initialization of function objects and lambdas, overloading with ordering, improved return type deduction, and much more. - Lightweight: Fit builds simple lightweight abstraction on top of function objects. It does not require subscribing to an entire framework. Just use the parts you need. Fit is divided into three components: * Function Adaptors and Decorators: These enhance functions with additional capability. * Functions: These return functions that achieve a specific purpose. * Utilities: These are general utilities that are useful when defining or using functions Fit has been tested on gcc 4.6-4.9, clang 3.4-3.7, and Visual Studio 2015. For more information see: Github:https://github.com/pfultz2/Fit/tree/boost Documentation:http://pfultz2.github.io/Fit/doc/html/ We encourage your participation in this review. At a minimum, kindly state: - Whether you believe the library should be accepted into Boost * Conditions for acceptance - Your name - Your knowledge of the problem domain. You are strongly encouraged to also provide additional information: - What is your evaluation of the library's: * Design * Implementation * Documentation * Tests * Usefulness - Did you attempt to use the library? If so: * Which compiler(s) * What was the experience? Any problems? - How much effort did you put into your evaluation of the review? More information about the review process can be found here:http://www.boost.org/community/reviews.html We await your feedback!

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boost karma qi: skipper concept
by Matwey V. Kornilov 13 Mar '16

13 Mar '16

Hello, I don't fully understand skip parser concepts. I would like to parse key-value list in bash style, like the following: KEY1=VAL1 KEY2="V A L 2" The pairs are separated by one or more space symbols. What is the supposed way to parse such constructions? 1. -(pair % (+space)) 2. *pair with skip=space 3. anything else?

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[INTERPROCESS] Message queues with hex names - in Windows
by Davies, John 11 Mar '16

11 Mar '16

I'm refactoring some code that has a pretty good suite of unit tests. Or at least I think it does, since I wrote them<g>. I have a process that dispatches messages to one or more other processes that have their own message queues. It's just a switchboard. The refactored code works, and runs much faster than the test code I had written before. Much faster. And passes the unit tests. But in the process I see a bunch of stuff in the boost-interprocess folder with long hex names. They get cleaned up when the tests are done. It seems the long hex names come when I'm destructing the queues. So is it part of garbage collection? It only concerns me because other times I saw names like that it was because I was trying to make two input queues with the same name. Thanks, John ________________________________ The information contained in this message may be confidential and legally protected under applicable law. The message is intended solely for the addressee(s). If you are not the intended recipient, you are hereby notified that any use, forwarding, dissemination, or reproduction of this message is strictly prohibited and may be unlawful. If you are not the intended recipient, please contact the sender by return e-mail and destroy all copies of the original message.

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Trouble building boost with Visual Studio 2010 (32 vs 64 bit issue)
by David Aldrich 09 Mar '16

09 Mar '16

Hi I am trying to build Boost 1.60 with Visual Studio 2010 Professional on Windows 10. I use the command: b2 toolset=msvc-10.0 --with-python link=shared and get the following error: python34.lib(python34.dll) : fatal error LNK1112: module machine type 'x64' conflicts with target machine type 'X86' I guess this means I have a conflict of 32-bit and 64-bit libraries. I want to target 32-bit (X86). Do I need to install a 32-bit version of Python? I wonder if that can co-exist with the current version of Python? Best regards David

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Boost python - pointers
by Daniel Burchardt 09 Mar '16

09 Mar '16

Hi, I have problem with pointer in function return. My code: using namespace boost::python; v8::Platform* InitializePlatform() { v8::Platform* platform = v8::platform::CreateDefaultPlatform(); return platform; } BOOST_PYTHON_MODULE(hello) { def("InitializePlatform", InitializePlatform, return_value_policy<manage_new_object>()); } Python code: import hello x = hello.InitializePlatform() Building is ok, but when i try call InitializePlatform i have error: Segmentation fault gdb: (gdb) run test.py Starting program: /usr/bin/python test.py [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". [New Thread 0x7ffff45b8700 (LWP 21739)] Program received signal SIGSEGV, Segmentation fault. 0x00007ffff4924640 in __dynamic_cast () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6

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numeric_cast<float> throws for double infinity
by Dmitry Volosnykh 09 Mar '16

09 Mar '16

When I try to cast variable of type double (which is equal to std::numeric_limits<double>::inifinity()) to float I get exception: std::bad_cast: bad numeric conversion: positive overflow. I expected to get std::numeric_limits<float>::inifinity(). The same is true for negative infinity. Is it intended behavior or bug? In case this should be considered as bug, maybe it was fixed in more recent versions of Boost? PS. I am using stock Boost 1.54 on Ubuntu 14.04 Regrads, Dmitry.

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Re: [Boost-users] [boost] [Fit] formal review starts today
by Paul Fultz II 09 Mar '16

09 Mar '16

On Monday, March 7, 2016 at 2:52:09 AM UTC-6, Edward Diener wrote: > > On 3/7/2016 12:15 AM, Paul Fultz II wrote: > > > > > > On Sunday, March 6, 2016 at 9:42:19 PM UTC-6, Edward Diener wrote: > >> > >> On 3/3/2016 6:43 AM, Vicente J. Botet Escriba wrote: > >>> Dear Boost community, sorry for the late anounce > >>> > >>> The formal review of Paul Fultz II's Fit library starts today, 2nd > March > >>> and ends on 13th March. > >>> > >>> Fit is a header-only C++11/C++14 library that provides utilities for > >>> functions and function objects. > >> > >> These are some comments/queries about the Fit documentation. > >> > >> Introduction > >> > >> The introduction says that Fit "provides utilities for functions and > >> function objects." But it seems as if Fit works only with lambda > >> functions and function objects. > > > > > > Fit works with any generalized Callable: > > > > http://en.cppreference.com/w/cpp/concept/Callable > > Please document this. A generalized Callable is a much bigger set of > functionality than just lambda functions and function objects. > > > > > > >> The term 'function' normally encompasses > >> a much larger definition in C++ which includes global functions, static > >> functions, member functions, and lambda functions. > > > > > > Which is what Callable encompasses, but I used "function" since more > > people are familiar with that than Callable. > > A 'function' and a Callable in C++ are two entirely different things. > Use the one that is precise and don't worry what people are familiar > with. Explain what a Callable is early on ( I know you explain it later > ) if you feel that people do not know what it means. > > > > > > >> Fit needs to be more > >> precise in what it says it works with. It repeatedly refers to function > >> objects and lambda functions as 'functions'. I think this vagueness of > >> terminality is really confusing in the documentation. > >> > > > > Perhaps, I should refer to the Callable concept early on then. > > See above. > > > > > > >> > >> Quick Start:Function Objects > >> > >> "We can make it behave like a regular function if we construct the > class > >> as a global variable." > >> > >> What about a non-global > >> > >> sum_f sum = sum_f(); > >> > >> makes 'sum' not behave like a regular function other than the fact that > >> the variable 'sum' may eventually go out of scope ? > >> > > > > In C++, a regular function is always global, there is no such thing as > local > > function(sans gcc extensions). > > My point is that the non-global 'sum' in my example above behaves just > as much like a regular function as your global 'sum'. You may want to > promote the idea of global function objects but I think that this is > personally a bad idea. IMO global variables of any kind are to be avoided. It is quite common in several modern C++ libraries to declare functions as global objects. There are many advantages to this. Why do you believe it should be avoided? Especially since it has the same effect as a free function. DO you believe free function should be avoided as well? > > > > > > > >> > >> Quick Start:Lambdas > >> > >> Why do we need both BOOST_FIT_STATIC_LAMBDA and > >> BOOST_FIT_STATIC_LAMBDA_FUNCTION ? I would seem that > >> BOOST_FIT_STATIC_LAMBDA_FUNCTION would be adequate and > >> BOOST_FIT_STATIC_LAMBDA is just redundant, mimicking lambda syntax to > no > >> purpose. > >> > > > > BOOST_FIT_STATIC_LAMBDA_FUNCTION and BOOST_FIT_STATIC_FUNCTION both > define a > > function at global scope, and can only be used at global scope, whereas > > BOOST_FIT_STATIC_LAMBDA can be used to constexpr initialize local > variables > > as > > well. > > It might be good to add that when the end-user first encounters > BOOST_FIT_STATIC_LAMBDA, because the name does not suggest > initialization of local objects. Furthermore I cannot imagine why one > would want to use it to initialize a local object, Really? You just said that you would prefer avoiding global functions. > so you might want to > explain the benefit of doing so as opposed to the normal syntax for > creating a lambda function. > Maybe the quick start guide isn't the place for this in the first place. > > > In fact, BOOST_FIT_LIFT uses this since it is not always clear what > > context the user might call BOOST_FIT_LIFT. > > > > > >> > >> Quick Start:Overloading > >> > >> The overloading adaptors show two or more lambda functions. Can they > >> also work with function objects ? Or a mix of lambda functions and > >> function objects ? In fact all the reamining Quick Start topics show > >> examples with lambda functions. Do they also work with function objects > ? > >> > > > > Yes it can be used with function objects. I probably should show an > example > > of > > that as well. I used the lambdas because of the terseness of them. > > Evidently the adaptors can be used with any Callable. I think you should > make that point very strongly and show that in examples also. > Agreed. > > > > > > >> > >> Quick Start:Variadic > >> > >> I do not understand what 'We can also make this print function > varidiac, > >> so it prints every argument passed into it.' means ? > >> > > > > I'll try to explain that better, but basically it will print each > argument, > > so: > > > > print("hello", 5); // Will print "hello" and 5 > > I wouldn't associate that with the word 'Variadic' but I do think you > need to explain that more clearly. > I always understood variadic to mean taking a variable number of arguments. What do you understand variadic to mean? > > > > > > >> > >> I do not think the Quick Start explains very much since it is dealing > >> with adaptors of which we know almost nothing and the explanation for > >> these adaptors and what they actually do is very terse. > > > > > > Probably can expand the explanation of adaptors a little more. > > Good idea. What do adaptors create ? They create a function. > Different function objects I would > imagine ? In that case how about the explanation that adaptors take > Callables as input and generate function object types that adapt the > original functionality of one or more Callables to some other purpose. > The examples are already show taking Callables. Are you suggesting I show an example taking a member function or something? > > > > >> > >> In the 'Signatures' section of the Overview I read: > >> > >> "All the functions are global function objects except where an explicit > >> template parameter is required." I honestly don't know what this is > >> supposed to mean. Does this refer to when function objects are referred > >> to as parameters to the adaptors, functions, and utilities of the > library > >> ? > >> > > > > I don't understand what you are asking. It means that the function is > > written > > like this in the documentation: > > > > template<class IntegralConstant> > > constexpr auto if_(IntegralConstant); > > > > But its actually a function object like this in the code: > > > > struct if_f > > { > > template<class IntegralConstant> > > constexpr auto operator()(IntegralConstant) const; > > }; > > const constexpr if_f if_ = {}; > > > > However, `if_c` is written like this in the documentation: > > > > template<bool B, class F> > > constexpr auto if_c(F); > > > > It requires the bool `B` template parameter explicity. So in the code it > is > > written as a function and not as a function object. > > I don't understand to what you are referring when you say 'function'. > Are you talking about adaptors in your library, functions in your > library, or what ? I am talking about all functions that are defined in the library, that includes adaptors as well. I am not sure how to make that clearer. > Please try to understand that your use of the word > 'function' is very broad but that the word 'function' in C++ has a much > narrower meaning. > By function, I mean something like in the example: template<class IntegralConstant> constexpr auto if_(IntegralConstant); I think everyone agrees that is a function in C++.

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Command Line Options Questions
by Jon Lederman 09 Mar '16

09 Mar '16

Hi, I have two questions re: the boost command line options library: 1) I am compiling a dynamic library that links to the boost command line options library as a shared library. When I try to unload the dynamic library, I find that it isn’t properly unloaded and the boost library seems to be causing the issue. I did find that things were helped somewhat when I linked to the boost static libraries. However, it still feels unstable. Are there any particular things I should know about in this context in terms of how my makefile should be linking to boost? Or are there other things I should look at. 2) When using program options, I am getting the following error. For some reason this seemed to work with the dynamic libraries (or it may be a coincidence). Am I required to implement the << and >> operators? It had been compiling previously and stopped. After googling this issue there seems to be a lot of confusion. Any help would be greatly appreciated. in file included from /usr/include/boost/any.hpp:27:0, from /usr/include/boost/program_options/value_semantic.hpp:12, from /usr/include/boost/program_options/options_description.hpp:13, from /usr/include/boost/program_options.hpp:15, from /usr/local/src/freeswitch/src/mod/applications/mod_sc_dsp/mod_sc_dsp.cpp:23: /usr/include/boost/lexical_cast.hpp: In instantiation of 'struct boost::detail::deduce_target_char_impl<boost::detail::deduce_character_type_later<dsp_type> >': /usr/include/boost/lexical_cast.hpp:415:89: required from 'struct boost::detail::deduce_target_char<dsp_type>' /usr/include/boost/lexical_cast.hpp:674:92: required from 'struct boost::detail::lexical_cast_stream_traits<std::basic_string<char>, dsp_type>' /usr/include/boost/lexical_cast.hpp:2363:19: required from 'static Target boost::detail::lexical_cast_do_cast<Target, Source>::lexical_cast_impl(const Source&) [with Target = dsp_type; Source = std::basic_string<char>]' /usr/include/boost/lexical_cast.hpp:2543:50: required from 'Target boost::lexical_cast(const Source&) [with Target = dsp_type; Source = std::basic_string<char>]' /usr/include/boost/program_options/detail/value_semantic.hpp:89:38: required from 'void boost::program_options::validate(boost::any&, const std::vector<std::basic_string<charT> >&, T*, long int) [with T = dsp_type; charT = char]' /usr/include/boost/program_options/detail/value_semantic.hpp:170:55: required from 'void boost::program_options::typed_value<T, charT>::xparse(boost::any&, const std::vector<std::basic_string<charT> >&) const [with T = dsp_type; charT = char]' /usr/local/src/freeswitch/src/mod/applications/mod_sc_dsp/mod_sc_dsp.cpp:484:1: required from here /usr/include/boost/lexical_cast.hpp:388:13: error: static assertion failed: Target type is neither std::istream`able nor std::wistream`able BOOST_STATIC_ASSERT_MSG((result_t::value || boost::has_right_shift<std::basic_istream<wchar_t>, T >::value), desc.add_options() ("help", "Generates help message") ("dsp_type", po::value<dsp_type>(&params.dsp_type)->required(), “") where dsp_type is this: struct dsp_type { dsp_type() {} dsp_type(std::string const& val): value(val) { } std::string value; }; and I have a validator defined as this: void validate(boost::any& v, std::vector<std::string> const& values, dsp_type* /* target_type */, int) { using namespace boost::program_options; //namespace po = 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); if (s == "ladspa" || s == "audioweaver" || s == "gstreamer" || s == "lv2") { v = boost::any(dsp_type(s)); } else { throw validation_error(validation_error::invalid_option_value); } } /usr/local/src/freeswitch/build/modmake.rules:214: recipe for target 'mod_sc_dsp.lo' failed make[1]: *** [mod_sc_dsp.lo] Error 1

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