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Re: [boost] Meta State Machine (MSM) review
by Christophe Henry 12 Jan '10

12 Jan '10

Hi Barend, Sorry that I didn't have time to address earlier the questions in your review. >I would like to see a connection with Boost.Graph (I mean, see it in an >example or so, not within the kernel), to see what I'm doing with all >those transitions; I asked this on the list and this is possible, good. It is a good point and I'll try to provide this, at least for simple state machines. >1) the struct "Row" is written with a capital, this is unusual within >Boost. Words with a capital are normally template parameters. I >understand why it is done (there was already a row without a capital in >Msm 1.1), but I think it could have been solved differently (for >example: "transition", or if that is too long "tr" which could stand for >transition row or table row). I don't like to see Row where I expect to >see a normal classname. Conventions are always hard to define. I usually try to follow the following convention: - rows are usually not capitalized (a_row, g_row...) - except the row working with functors, like Row - eUML functors are also capitalized and finish with an underscore. - eUML functions are not capitalized and finish with an underscore. This tries to match the phoenix syntax. This allows differentiation between functors/non functors. I found this system practical but would not mind changing it if required. >The capitals are also used in the documentation and samples (struct >Empty) but there I've less problems with it. Maybe use of Capitals for >states is a state machine convention Yes, it is a common habit in UML to capitalize state names (though I am not aware of any written rules). >I noticed different conventions in >the source files. Many template parameters are completely capitalized. I >had done the same thing, earlier, but was hinted that this is unusual as >well. Just a matter of style (as long as library users normally don't >see it, it is less important) Yes, while the user doesn't see it, it is not very beautiful so I'll change this. >2) the class state_machine is quite long (in lines of code), containing >several sub-structs which maybe (don't know) could be moved to a >separate source file (detail). Yes, it became quite big, you're right. It's quite practical for me to have functions and helpers at the same place but some parts could be separated. >You have to call p.start() manually Yes. Calling start() will move the machine in its initial state and call on_entry on the machine and the initial state. You have to call it explicitly because sometimes you simply don't want on_entry to be called at the creation of the state machine. >Thanks for submitting this excellent library. I'm happy that you like it. Thanks for the great work you put on the review. Regards, Christophe

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[Polygon] "Ambiguous use of partial specialization" in CodeWarrior
by Kef Schecter 12 Jan '10

12 Jan '10

I'm using a special version of CodeWarrior for an embedded system, but I suspect that other versions of the software will show the problem. The problem is, basically, the compiler hates polygon_traits<T>. Here's an example from polygon_90_set_traits.hpp: template <typename T> struct traits_by_concept<T, polygon_90_concept> { typedef polygon_traits<T> type; }; It chokes on the typedef, saying "Ambiguous use of partial specialization". This is the complete text of the error message; it provides no other information. Most of the surrounding definitions are very similar, but only the ones that use polygon_traits<T> -- instead of, say, rectangle_traits<T> -- raise errors. Here's another example from polygon_traits.hpp: template <typename T> struct view_of<rectangle_concept, T> { typedef typename polygon_traits<T>::coordinate_type coordinate_type; [snip] }; It chokes on the typedef and any code that tries to use the typedef. The same problem happens with all the other view_of functions and a couple of others, but all the problems seem to deal with the use of polygon_traits<T> in a template. Unfortunately, I know very little about partial specialization, traits classes, or any advanced features of generic programming in C++. My understanding of templates is limited to stuff like making basic containers, generalized sorting functions, etc. -- the easy stuff. So I find the definition of polygon_traits too complicated and am unable to fully comprehend the essence of the problem, let alone how to fix or work around it. Since I need to get this to work, if a proper solution is not obvious, I'm willing to accept any kind of clumsy hack, including disabling parts of the library that I might not need. (I use very little of the Polygon library, but I have a hard time finding an alternative to the part I do use -- namely, finding the union of polygons while allowing for holes. Alternative suggestions in that area are welcome, but I can't use GPLed code, or code that I would need to pay a license for to use commercially.) Any ideas? - Kef

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[Archive] oserializer.hpp
by Richard Crossley 12 Jan '10

12 Jan '10

The following code from archive/detail/oserializer.hpp on head looks rather dubious... >line 394 // note:if this exception is thrown, be sure that derived pointer // is either registered or exported. if(NULL == true_type){ boost::serialization::throw_exception( archive_exception( archive_exception::unregistered_class, true_type->get_debug_info() // << Here ) ); } Regards, Richard.

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Re: [boost] [msm] eUML guard/action location
by Christophe Henry 12 Jan '10

12 Jan '10

>> You could declare those instances at namespace scope, in the same way >> most Proto terminals are declared, non? >The user could. But not the library writer AFAIU, since these state >types are created by the user. Exactly. Of course the library could predefine some state names (the way I understand arg1, arg2, etc. are defined) but I'm afraid it'd barely be an improvement. Christophe

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[persistent] Persistent library preview
by Stefan Strasser 12 Jan '10

12 Jan '10

Here's the current documentation of (Boost?).Persistent: https://svn.boost.org/svn/boost/sandbox/persistent/libs/persistent/doc/html… In short, it is a library that provides access to objects persistent on disk with an interface as close as possible to accessing regular objects in memory, and it introduces transactions to e.g. ensure consistency after a crash. See "Introduction" for more information. This is the version I plan to submit for a boost review, so if you are interested in that kind of library, please have a look at it now and don't wait for a formal review. The boost review queue has grown substantially, so it might be a long time until a formal review, which could be used for improvements based on your comments. Code will follow as soon as some issues are sorted out, especially porting the (few) platform dependent parts to windows. Regards,

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Anyone care if I merge Boost.Array fixes to the release branch?
by Marshall Clow 12 Jan '10

12 Jan '10

Since no one is maintaining Boost.Array (as far as I know), and there is at least one bug fix on the trunk that hasn't been merged to the release branch, I propose merging: boost/array.hpp libs/array/doc/array.xml to the release branch. Any objections?? If not, I'll do it about midnight EST tonight. -- Marshall

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[asio] Pass some parameter to io_service::run
by Dmytro Ovdiienko 11 Jan '10

11 Jan '10

Hello All, I'm new in boost asio. I'm trying to adapt this library to my existent network application. There is a problem with current application's architecture. I see no way to pass some parameter to the completion routine from the io_service::run calling thread. Below brief application description. Hope this will help: 1. It is *low-latency* network application 2. Application processes incoming multicast UDP messages. 3. Number of multicast groups/ports is *unlimited*. Technical details: 1. Application encapsulates udp::sockets subscribed to multicast group 2. udp::socket::async_receive method used to receive data 3. io_service::run is used in the thread pool to call socket's complete routine. 4. Every thread of the pool encapsulates some object for messages processing. I need to pass reference to this object to the socket::async_receive complete routine to complete message processing. This object allocates a lot of memory and I cannot create it for every socket. It is possible to create but there is no sense. It is very important to avoid thread_local_storages and null_buffers to make application as simple as possible without performance gaps. I believe it is possible because POSIX and Windows I/O allow it. Please help with advise. Thanks. Dima

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[asio] streambuf example wrong
by Michael Caisse 11 Jan '10

11 Jan '10

The example section in the documentation for boost::asio::streambuf indicates you can: boost::asio::streambuf::const_buffers_type bufs = b.prepare(512); The compiler (gcc) thinks not. You can however: boost::asio::streambuf::const_buffer_type bufs( b.prepare(512) ); Regards - michael -- ---------------------------------- Michael Caisse Object Modeling Designs www.objectmodelingdesigns.com

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Regression testing on win32 platforms
by Arash Partow 11 Jan '10

11 Jan '10

Hi all, With regards to regression testing of boost libraries on the win32 platform using MSVC versions post introduction of checked iterators, are any of the regression tests compiled with the following defines? _SCL_SECURE_NO_WARNINGS _SECURE_SCL=0 As I've noticed MSVC installs with SP1 that have had patches included from the last month or so are causing this failure. #include <cstddef> #include <iostream> #include <string> #include <boost/regex.hpp> int main() { using namespace boost; std::string s = "(1)(23)(456)(7890)"; regex expr("\\(.*?\\)"); sregex_iterator itr(s.begin(),s.end(),expr); sregex_iterator it_end; std::string token; std::size_t match_count = 0; while (it_end != itr) { ++itr; ++match_count; } std::cout << "Match count: " << match_count << std::endl; return 0; } ************************************************** example.exe!_crt_debugger_hook(int _Reserved=3619112) Line 65 C example.exe!_invalid_parameter(const wchar_t * pszExpression=0x00000000, const wchar_t * pszFunction=0x00000000, const wchar_t * pszFile=0x00000000, unsigned int nLine=0, unsigned int pReserved=0) Line 112 + 0x7 bytes C++ example.exe!_invalid_parameter_noinfo() Line 125 + 0xc bytes C++ example.exe!boost::match_results<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> >,std::allocator<boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > > > >::set_size() + 0x5b bytes C++ example.exe!boost::re_detail::perl_matcher<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> >,std::allocator<boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > > >,boost::regex_traits<char,boost::w32_regex_traits<char> > >::find_imp() + 0xc9 bytes C++ ************************************************** Removing SP1 or applying SP1 with patches up until mid nov '09 slip-streamed seems to work fine, this is just a heads up for people using this particular environment. Initially I was using the BOOST Pro distribution, with static linking (1.39 and 1.40) MT and single modes, I've also done clean builds just in case something was wrong with the distrib, same problem observed in all cases. I've tested the above code on linux with gcc 4.4 and intel v11 runs fine and valgrind checks-out ok (as expected). BTW I've gone here http://www.boost.org/development/testing.html looking for any kind of documentation relating to the types of settings used, is there a more up-to-date location? Kind regards, Arash

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[bloom_filter dynamic_bitset] Serialization support
by Paul Fee 11 Jan '10

11 Jan '10

I've been looking at the Bloom filter implementation in the sandbox area: https://svn.boost.org/trac/boost/browser/sandbox/bloom_filter A previous email thread implied serialization was available, but I don't see it in svn. http://lists.boost.org/Archives/boost/2009/06/152731.php Is the serialization code available somewhere? I've made an attempt at implementing this myself. In doing so I had to implement serialization for boost::dynamic_bitset. The dynamic_bitset serialization code may be useful independent of Bloom filters. The Bloom filter serialization in turn makes use of dynamic_bitset serialization. I've uploaded my implementation to the boost vault: http://www.boostpro.com/vault/index.php?directory=serialization Perhaps I should supply tests, example usage and documentation, but I'm hoping to get advice on Boost best practise before going too far in the wrong direction. I'd like to see dynamic_bitset serialization in Boost proper and bloom_filter serialization alongside the existing code in the sandbox area. Can I request a sandbox account to upload code there? All comments welcomed. Thanks. Paul Fee

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