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Distinct elements in a std::vector<T>
by Hicham Mouline 10 Apr '10

10 Apr '10

Hello, Given a std::vector<T> and a Compare<T> comparator, how can I: 1. determine the number of different elements in the vector? 2. get iterators to the list of distinct elements in the vector? My naive implementation for 1 is: /// v is const-ref to a std::vector<T> std::vector<T>::size_type distinct = v.empty()? 0: 1; std::vector<T>::const_iterator j; for (std::vector<T>::const_iterator i = v.begin()+1; i!=v.end(); ++i) { j = std::find(v.begin(), i, *i, Compare<T>()); if (j!=i) ++distinct; } Obviously, this is of worst order n*(n+1)/2. I'm sure a better order can be achieved. I don't quite see how to do 2. Does anything in the C++ std lib or boost facilitate this? Regards,

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Re: [Boost-users] [boost][serialization] Binary portable archive (eos implementation in Vault)
by Marc Perso 10 Apr '10

10 Apr '10

> De : Pfligersdorffer, Christian [mailto:Christian.Pfligersdorffer@eos.info] > Hi Marc, Hi Christian, Thank you for considering my post. > since I do not always monitor the boost users list it is good you > contacted me in this issue. Your problem is almost certainly VC7.1 since > that is unfortunately not tested and not supported by me. We use VC8 > here and is to be considered outdated ;-) > I succeeded in building and running your example using me setup: > - VC8 > - boost 1.41 > - XP 32-bit > I am not sure where VC7.1 fails but it might be some template stuff that > was not fully supported then... Is upgrading your compiler an option for > you (and your team)? We are going to upgrade from VC7.1 to VC9 in few weeks or few months but for the moment nothing was confirmed administratively speaking so I'm not very confident right now about this upgrade. And this upgrade will be consequent in term of workload for us and we can assume that it will take few days to be completed. I will prefer to integrate your "portable archive" before this migration but I'm not able to identify the workload for tweaking your source code for VC7.1. I'm sure that a lot of Boost experts can be very helpful for finding this tweaking: maybe Robert Ramey? Any helps from Boost experts to have this nice tool running under VC7.1 will be greatly appreciated! Best regards, Marc Viala

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[Date_Time] Visual Studio 8 debugger visualizer
by Bruno Durin 10 Apr '10

10 Apr '10

Hi, This is my second post in a mailing list and my first on boost-users so I apologize for the naive style and for my English (I am not a native English speaker). I would like to give a solution to a problem that kept annoying me for a long time when debugging code using Boost.Date_Time in Visual Studio 8. The library is based on an int representation of datetime and this int is displayed by the debugger, which gets hard to understand if it's the correct datetime or not. The solution, as already explained in http://www.virtualdub.org/blog/pivot/entry.php?id=120, is to customize Visual Studio debugger. I have found a solution in boost documentation section, provided by filip dot konvicka at logis dot cz, but you have to click refresh to get the info displayed. I thus suggest a partial brute force solution for boost::gregorian::date, boost::posix_time::time_duration and boost::posix_time::ptime (the only objects I use, but extension to local time zone should be easy). This solution simply recodes the conversion functions available in Boost.Date_Time, adding some formatting. I included it as an attachement because of the length of some lines is very long. As an example boost::posix_time::ptime a_time(boost::gregorian::date(2010, Apr, 7), boost::posix_time::hours(22)) would display instantaneously in the preview area in the debugger as a_time 2010-4-7 22h0m0s (0us) Note: us is microseconds. If you work with nanosecond resolution, you have to change the visualizer definition. In order to get it work, backup the file autoexp.dat (it's in the installation directory of Visual Studio), and add the content of the attachement in the [Visualizer] section. It should work without even restarting Visual Studio. I have only tested under Visual Studio 8 2005, but it should work as well with Visual Studio 9 2008. Hope that will help! Bruno Durin.

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[program_options] Clearing variables_map
by Jason Reich 10 Apr '10

10 Apr '10

Hello, I'm using boost::program_options to parse an command line within a running program (i.e. not just at startup, whenever a new command comes in), and am trying to avoid memory deallocation/reallocation. Is there any way reuse a variable_map that has already had options stored into it? If I use the std::map<>.clear() it seems to clear the stored values, but when I next try to parse, the results are still empty. I think this is happening because the m_final variable (as far as I can understand). Is there some reason why the variables_map can't be cleared and reused? thanks in advance for any insight you can provide, Jason.

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[boost-users][program_options] How can I restrict possible values?
by Germán Diago 10 Apr '10

10 Apr '10

Hello. I'm using boost.program_options and I want to know if I can restrict the possible values for an option. I couldn't find an obvious way in the documentation. Thanks.

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Boost.Test - Advice needed on structuring tests
by pholding 10 Apr '10

10 Apr '10

I'm looking for some advice/recommendations on how I should structure a suite of unit tests for a project I've been working on. The code uses exceptions rather than return codes. Essentially the code is a wrapper around a C database library. In the future the code will grow into a full application, but I'm taking small steps at the moment. As I'm new to unit testing I'm unsure the tests should be structured and am keen to follow good practice. I'm thinking of structuring the unit tests as follows Unit test 1 - connect to database Unit test 2 - create table Unit test 3 - insert record into table Unit test 4 - select record from table Unit test 5 - (perform some other SQL statements) Unit test 6 - disconnect from database Some of these tests could be considered as setup and teardown code, but I want the unit tests to cover all code in my wrapper. What I'm unsure about is whether it's considered good practice for one unit test to depend upon a previous unit test creating something in order to allow the test to be performed. The other issue I've got is whilst the function may not have thrown an exception it doesn't necessary mean the function did what its supposed to do. For example unit test 2 might not throw an error, but the only way I'll know if the function worked correctly is to query the database metadata or do unit test 3. Should unit test 2 only check that an error was not thrown or should it also call another function to query the metadata and then check the result of that function before marking unit test 2 as a success? -- View this message in context: http://old.nabble.com/Boost.Test---Advice-needed-on-structuring-tests-tp281… Sent from the Boost - Users mailing list archive at Nabble.com.

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boost 1.38 to 1.42 upgrade problem
by DE COCK Gregory 09 Apr '10

09 Apr '10

Hello, I'm using successfully boost library (interprocess part mainly) since a long time (ver 1.38) But when I try to upgrade to newer version (any version higher than 1.38), compilation is failing (using VC++ express 2008)... here is the error msg from compiler : d:\svn\fbistudio\dep\boost_latest\boost/preprocessor/iteration/detail/lo cal.hpp(37) : error C2664: 'helpdesk::objects::shm::shared_data::shared_data(helpdesk::objects::shm ::sharedmemory_type &) throw()' : cannot convert parameter 1 from 'const helpdesk::objects::shm::sharedmemory_type' to 'helpdesk::objects::shm::sharedmemory_type &' 1> Conversion loses qualifiers 1> d:\svn\fbistudio\dep\boost_latest\boost/preprocessor/iteration/detail/lo cal.hpp(37) : while compiling class template member function 'void boost::interprocess::detail::Ctor1Arg<T,is_iterator,P0>::construct(void *,boost::interprocess::detail::false_)' 1> with 1> [ 1> T=helpdesk::objects::shm::shared_data, 1> is_iterator=false, 1> P0=helpdesk::objects::shm::sharedmemory_type 1> ] 1> d:\svn\fbistudio\dep\boost_latest\boost/preprocessor/iteration/detail/lo cal.hpp(37) : see reference to class template instantiation 'boost::interprocess::detail::Ctor1Arg<T,is_iterator,P0>' being compiled 1> with 1> [ 1> T=helpdesk::objects::shm::shared_data, 1> is_iterator=false, 1> P0=helpdesk::objects::shm::sharedmemory_type 1> ] 1> ..\src\objects\shareddata.cpp(181) : see reference to function template instantiation 'T *boost::interprocess::detail::named_proxy<SegmentManager,T,is_iterator>: :operator ()<helpdesk::objects::shm::sharedmemory_type>(const P0 &) const' being compiled 1> with 1> [ 1> T=helpdesk::objects::shm::shared_data, 1> SegmentManager=boost::interprocess::segment_manager<char,boost::interpro cess::rbtree_best_fit<boost::interprocess::mutex_family>,boost::interpro cess::iset_index>, 1> is_iterator=false, 1> P0=helpdesk::objects::shm::sharedmemory_type 1> ] Any idea ? Thanks Greg

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asio flushing a buffer
by Lloyd 09 Apr '10

09 Apr '10

Hi, I went through the documentation of boost::asio::read_until() function. It says that if some data left in the stream after a read_until() operation, it will be available in the next "read" opration from the stream. Is there any way to "flush" (simply remove) the unwanted data from the stream so as to receive entirely new data than the old "useless" data left in the stream? Thanks, Lloyd ______________________________________ Scanned and protected by Email scanner

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Re: [Boost-users] serialization unordered_map
by alev mutlu 09 Apr '10

09 Apr '10

Hi Daniel, It gives the following compile time error: /boost/include/boost-1_37/boost/serialization/unordered_map_mod.hpp:49: error: redefinition of ‘template<class Archive, class Container, class InputFunction> void boost::serialization::stl::load_hash_collection(Archive&, Container&)’ /boost/include/boost-1_37/boost/serialization/hash_collections_load_imp.hpp:33: error: ‘template<class Archive, class Container, class InputFunction> void boost::serialization::stl::load_hash_collection(Archive&, Container&)’ previously declared here how should I proceed? _alev On Sat, Apr 3, 2010 at 8:52 PM, Daniel F. Savarese <dfs(a)savarese.org> wrote: > > In message <m2pd23942591004020904y909f9116x83d9b14ad2124bdf(a)mail.gmail.com>, > al > ev mutlu writes: > >I could not find any library for unordered_map? > >Is there one? > > No. This is what my company has been using for the past four years: > http://www.savarese.com/software/wispers/api/a00254_source.html > > daniel > > >

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[test] Problem with Boost.Test command-line parameters in 1.42.0
by Florian Winter 09 Apr '10

09 Apr '10

Hi, We have recently upgraded our unit test suite from Boost 1.35.0 to 1.42.0. Now we have the following problem: Some of our unit test applications take command-line parameters of their own, and there seem to be name conflicts with command-line options of Boost.Test. For example, some of our test applications accept a command line parameter "-f", which takes no arguments. However, Boost.Test also accepts a "-f" parameter, which takes 1 argument. So whenever we specify our "-f" option when running a test, we get an error message from Boost.Test similar to the following: "Invalid output format: -L" We don't like the idea of changing our own command-line interface, because some tests take a lot of command-line parameters with short names, and there are likely to be new name conflicts with future Boost versions. Is there an easy way to disable or bypass the command-line parser of Boost.Test, or at least to disable parsing of short options? -- Florian Winter Senior Software developer Motama GmbH Lortzingstraße 10 · 66111 Saarbrücken · Germany tel +49 681 940 85 50 · fax +49 681 940 85 49 mlohse(a)motama.com · www.motama.com Companies register · district council Saarbrücken · HRB 15249 Law registered office · Saarbrücken CEOs · Dr.-Ing. Marco Lohse, Michael Repplinger This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden.

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