- Boost - lists.boost.org

smart_ptr doesn't work when built with gcc on AIX
by Florent Guiliani 03 Sep '13

03 Sep '13

Hi, The Boost 1.54 smart_ptr atomic API code only supports the IBM xlC compiler under AIX. The attached patch make it also support the gcc compiler. I wanted to fill in a ticket for it on https://svn.boost.org/trac/boost/newticket but for some reason the ticket was classified as a spam by Trac. Anyone could help me here? One issue is the _sync*() APIs doesn't work when built optimized with GCC 4.8.0 on AIX 6.1 and 7.1 (and so the patch assume they don't work with all versions of GCC on AIX), so the patch undefine BOOST_SP_HAS_SYNC to prevent using those APIs. Another issue is the builtins.h file that Boost uses is missing, because it is installed as part of xlC. Under gcc, this patch will define assembly versions of the 2 builtins that are used in sp_counted_base_aix.hpp. Hope this gets through, -- Florent

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[git] b2 headers not producing headers
by Ahmed Charles 02 Sep '13

02 Sep '13

I've tried following the instructions here: https://svn.boost.org/trac/boost/wiki/TryModBoost The 'b2 headers' command doesn't see to actually produce a boost directory. Is this supposed to work or is it just too soon?

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[smart_ptr] Proposal to extract intrusive_ref_counter from Boost.Log
by Andrey Semashev 01 Sep '13

01 Sep '13

Hi, I'd like to move intrusive_ref_counter class from Boost.Log to Boost.SmartPtr. The class is intended to be used as a base class for a user's class that is intended to be used with intrusive_ptr. The class implements a reference counter and the related intrusive_ptr_add_ref/intrusive_ptr_release operations, so the user doesn't have to do that himself. Usage example: class my_class : public intrusive_ref_counter { }; intrusive_ptr< my_class > p = new my_class(); Besides just simplifying intrusive_ptr usage, the base class can be used as a sort of "void" as in shared_ptr< void >. I.e. intrusive_ptr< intrusive_ref_counter > can refer to object of any class that follows this protocol. Implementation: boost/log/utility/intrusive_ref_counter.hpp

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Re: [boost] [utility] Proposal to extract some components from Boost.Log
by Daryle Walker 01 Sep '13

01 Sep '13

I don’t think you need a “constexpr_if.” You can unconditionally put BOOST_CONSTEXPR in the definition. This will unconditionally add “constexpr” to the member operator (for C++11 systems), which will be ignored if the compiler determines that the attached function (or a particular call) is disqualified from being used in constant expressions. So any extra preprocessor work, or a variant macro, is unnecessary. Sent from Windows Mail From: Andrey Semashev Sent: ‎Sunday‎, ‎September‎ ‎01‎, ‎2013 ‎4‎:‎40‎ ‎AM To: boost(a)lists.boost.org On Sunday 01 September 2013 03:27:06 Daryle Walker wrote: > > Date: Wed, 28 Aug 2013 12:14:51 +0400 > > From: andrey.semashev(a)gmail.com > > > > 1. BOOST_EXPLICIT_OPERATOR_BOOL() macro for defining explicit operator > > bool() for a class. > > a. It isn't marked "constexpr." I can add that myself before using > "BOOST_EXPLICIT_OPERATOR_BOOL" in "boost/rational.hpp," but what happens if > someone corrects it in "explicit_operator_bool.hpp"? Will the (temporary) > double definition cause an error? Well, since there isn't a constexpr_if or something, I don't see a way to add it to BOOST_EXPLICIT_OPERATOR_BOOL. I could add BOOST_EXPLICIT_OPERATOR_BOOL_PP(pre, post), which would add pre() and post() before and after the operator signature. For example:

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[multimethods] Proposal: Open Multi-Methods
by Jean-Louis Leroy 01 Sep '13

01 Sep '13

Hi, I am working on library that pretty much implements what Pirkelbauer, Solodkyy and Stroustrup describe in their paper "Open Multi-Methods for C++" - although there are some divergences. I have posted it on GitHub: https://github.com/jll63/multimethods. Please examine the files in the "examples" directory to get an idea of how to use it. Salient features are: * syntax: is relatively uncluttered. There are no limitations on the number of virtual arguments. Virtual and non-virtual arguments can be arbitrarily mixed. Multiple inheritance is supported, with some limitations - see below. * speed: close to a virtual function call when the hierarchies involved in the virtual arguments collaborate with the library. Calling a method that does nothing, with a single virtual argument in a single inheritance hierarchy is 33% slower than the equivalent virtual function call. The difference becomes unnoticeable if the functions perform a few simple maths operations. See tests/benchmarks.cpp. * size: the dispatch table is constructed in terms of class groups. This results, most of the time, in a table devoid of redundancies. The size is bounded by the product of the number of specializers - not classes - in each dimension. * support for "foreign" class hierarchies: the library can be used without modifications to existing classes, at the cost of lower performance. Collaborating and foreign arguments can be freely mixed. Performance is still quite good, see the benchmarks. * next: a pointer to the next most specialized method is available inside method specializations - see examples/next.cpp. Alternatively, it is possible to call a specialization directly. Current limitations are: * restrictions on hierarchy: the classes involved in a method call must have a single root. Repeated inheritance is not supported. Multiple inheritance is supported, provided that the two conditions above are respected. * no overloading: multi-methods are implemented as constexpr function objects. This does not allow for overloading. This restriction can be easily side-stepped by wrapping multi-methods with different names in a set of overloaded functions. I know how to make multi-methods functions instead of objects, at the cost of a slightly less nice syntax for specializers. This is open to discussion. Besides, the library differs from Stroustrup et al's paper on the following points: * a specializer specializes only one multi-method: what would "next" mean otherwise? What would its static type be? * pure multi-methods are allowed: if called, an exception is thrown. This seems a better choice given that most of the time the declared virtual arguments will be abstract classes anyway. The library is essentially feature complete (if anything ever is). I am now going to work on the documentation, a build system, some clean up and compatibility (I tested it only with g++ 4.7.2 only so far). Is there interest in the Boost community for this stuff? If yes, I will adapt it to the guidelines and submit it for formal review. Of course, suggestions are welcome. Thank you for your time, Jean-Louis Leroy

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[thread] MinGW/gcc compile error in thread.cpp
by Emil Dotchevski 01 Sep '13

01 Sep '13

Building the trunk version, I get this on MinGW: gcc.compile.c++ ..\..\..\bin.v2\libs\thread\build\gcc-mingw-4.7.2\debug\link-sta tic\threading-multi\win32\thread.o ..\..\..\libs\thread\src\win32\thread.cpp: In member function 'bool boost::threa d::start_thread_noexcept()': ..\..\..\libs\thread\src\win32\thread.cpp:238:9: error: reference to 'uintptr_t' is ambiguous In file included from c:\mingw\bin\../lib/gcc/mingw32/4.7.2/include/stdint.h:3:0 , from c:\mingw\bin\../lib/gcc/mingw32/4.7.2/../../../../include/ wchar.h:479, from c:\mingw\bin\../lib/gcc/mingw32/4.7.2/include/c++/cwchar:4 6, from c:\mingw\bin\../lib/gcc/mingw32/4.7.2/include/c++/bits/pos types.h:42, from c:\mingw\bin\../lib/gcc/mingw32/4.7.2/include/c++/bits/cha r_traits.h:42, from c:\mingw\bin\../lib/gcc/mingw32/4.7.2/include/c++/string:4 2, from ..\..\../boost/date_time/c_time.hpp:18, from ..\..\../boost/date_time/time_clock.hpp:16, from ..\..\../boost/thread/thread_time.hpp:9, from ..\..\../boost/thread/win32/thread_data.hpp:10, from ..\..\../boost/thread/thread_only.hpp:15, from ..\..\..\libs\thread\src\win32\thread.cpp:17: Emil

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[gil::io] clang compiler error
by Christian Henning 31 Aug '13

31 Aug '13

Hi all, I'm trying to fix some compiler errors with clang and the new gil::io. The following trivial code just wont compile: extern "C" { #include <stdio.h> #include <jpeglib.h> } int main() { jpeg_create_compress(NULL); return 0; } The error is: undefined reference to `jpeg_CreateCompress' I guess it's a very simple solution but I'm not much experienced with clang and gcc. Thanks, Christian

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[cpo-proposal] presentation of the idea
by Santiago Tapia 29 Aug '13

29 Aug '13

Hi everyone, I would like to make a proposal for a new library. I only have a draft without documentation but I would like to know people’s opinion about the idea before making a formal proposal. The library will be named CPO (containers for polymorphic objects) and it will provide containers to store dynamic allocated objects from a class hierarchy. I have drafted one container and I have two more in process. The cpo library could be an alternative solution for boost pointer container library or some other solutions that use pointers. In order to understand the idea, I think that the following example of the use of the library might be better than a long explanation: #include <boost/cpo/classifier.hpp> #include <iostream> using namespace boost::cpo; class base { public: virtual int do_something(int a) const = 0; }; class derived_A : public base { public: derived_A(int b) : data(b) {} virtual int do_something(int a) const { return a + data; } protected: int data; }; class derived_B : public base { public: derived_B(int b) : data(b) {} virtual int do_something(int a) const { return a - data; } protected: int data; }; int main(int argc, char** argv) { classifier<base, std::allocator> collection; collection.insert( derived_A(21) ); collection.insert( derived_B(40) ); classifier<base, std::allocator>::iterator i, e = collection.end(); for ( i = collection.begin(); i != e; ++i ) { const base& x = *i; std::cout << x.do_something(6) << std::endl; } return 0; } ---- Program output: 27 -34 ---- Some details and advantages must be remarked in the provided example: - There are not any pointers in the client code (the example). - The container's name is classifier because it classifies objects internally using the RTTI. - The container classifier is _not_ a sequence. - Any iterator of the classifier dereferences to the base class. - The allocator argument in the classifier will be applied to every object added to the classifier. Thus, the allocator is provided without its argument. The std::allocator is the default argument. - The classifier uses continuous storage in memory for objects of the same type, therefore it is expected to improve cache efficiency with respect to solutions that use pointers (and new to allocate objects), especially if the client code uses some cache-aware allocator. I think that the idea will be interesting and useful. Although I have registered a project in sourceforge, classifier_container, I must insist: the library is under development and without documentation. I look forward to your comments and I thank you for them in advance. Best Regards, Santiago Tapia CITEF CENTRO DE INVESTIGACIÓN EN TECNOLOGÍAS FERROVIARIAS | RAILWAY TECHNOLOGY RESEARCH CENTRE UNIVERSIDAD POLITÉCNICA DE MADRID ESCUELA TÉCNICA SUPERIOR DE INGENIEROS INDUSTRIALES Santiago Tapia Fernández José Gutiérrez Abascal, 2 | 28006 Madrid TEL + 34 91 336 4267 | FAX + 34 91 561 8618 E-MAIL stapia(a)etsii.upm.es; www.citef.industriales.upm.es

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about serialization
by lz＠sina 29 Aug '13

29 Aug '13

hi! I'm wonding if I can change the in "interface_oarchive.hpp": template<class T> Archive & operator<<(T & t){ this->This()->save_override(t, 0); return * this->This(); } to template<class T> Archive & operator<<(const T & t){ this->This()->save_override(t, 0); return * this->This(); } and in "polymorphic_oarchive_route.hpp" template<class T> polymorphic_oarchive & operator<<(T & t){ return polymorphic_oarchive::operator<<(t); } to template<class T> polymorphic_oarchive & operator<<(const T & t){ return polymorphic_oarchive::operator<<(t); } , so I can write code like this: enum E {}; class C { private: E e; public: E getE() const; void setE(const E e); }; template<class Archive> inline void save_construct_data(Archive & ar, const C * t, const unsigned int file_version) { // save data required to construct instance ar << t->getE(); // without changing the liberary code, I'll have to write like this: //int x = t->getE(); //ar << x; } I'm not sure about the changes, can anybody verify it? -------------- lz@sina

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FW: [cfe-dev] Documenting Clang: question about how best to deliver the doc
by Paul A. Bristow 29 Aug '13

29 Aug '13

I've copied the posting below because it shows that Doxygen comments syntax are being even more widely used to add documentation of code (as opposed to writing tutorial and other descriptive text). Doxygen comments are post-processed to produce a C++ Reference section in many Boost program docs prepared using Quickbook. I suggest that this is a good method for future proposed libraries. In case you are not familiar with Doxygen, http://www.stack.nl/~dimitri/doxygen/manual/index.html here is a silly example to give the flavour of the comments (they start with the backslash trip character and are within C/C++ comments with an added !). template <typename T> int donowt(int I, char j) { /*! The ! shows that this is a Doxygen-syntax comment. Non-member free function that does nowt useful at all describing the function. \tparam T unused template parameter. \param i is an argument that is ignored completely. \param j Another argument. \pre No preconditions. \post No side effects. \returns -1 always. \throws std::exception if the unthinkable happens. \sa See also another function. */ return -1; } // int donowt(int i) Of course, the value from all this comes from the quality of the *information provided as comments*, describing the use of the parameters, templates, pre and post conditions (documenting but not enforcing concepts) and returns... Doxygen also analyses the code (now optionally using the Clang compiler - it used to get confused by some code, especially code that didn't compile!) and provides many cross-referencing links automatically, a great benefit to the authors and the readers. Doxygen remains under active development thanks to <http://www.stack.nl/%7Edimitri/doxygen/index.html> Dimitri van Heesch. It is Open-Source and entirely free and very widely used for several languages. Paul --- Paul A. Bristow, Prizet Farmhouse, Kendal LA8 8AB UK +44 1539 561830 07714330204 pbristow(a)hetp.u-net.com From: cfe-dev-bounces(a)cs.uiuc.edu [mailto:cfe-dev-bounces@cs.uiuc.edu] On Behalf Of Morrison, Michael Sent: Tuesday, August 27, 2013 10:40 PM To: cfe-dev(a)cs.uiuc.edu Subject: Re: [cfe-dev] Documenting Clang: question about how best to deliver the doc Thanks to everyone on this thread who replied to our query about what approach to take for our Clang documentation. Your thoughtful comments were very helpful to our understanding of the issues and of the preferences of the community. We’ve reviewed your responses to the options that we proposed, and we’ve decided to pursue the following option: > 1a) Maintain the documentation in Doxygen. Any other formats required (HTML, XML, reST/Sphynx, and so on) can be generated on-the-fly from the Doxygen comments as needed. We have a good idea about how to proceed with this option, and we expect that we can begin submitting our updated Doxygen documentation later this summer. Cheers, Michael

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