April 2010 - Boost-users - lists.preview.boost.org

Overloading operators with multi index container?
by Paul Dovydaitis 29 Apr '10

29 Apr '10

We are using a multi index container to store some data indexed both by a text key and by a timestamp. For the text key index, we are using a non-unique ordering like below: boost::multi_index::ordered_non_unique< boost::multi_index::tag<tags::key>, boost::multi_index::identity<Transaction> > Sometimes we have an issue where we get duplicate keys for transactions that aren't actually duplicates (don't ask). In this case, we can tell them apart by looking at their timestamp and checking if both transactions occurred within a certain window. To do this, we tried to overload operator< in the following way: bool MyTransaction::operator<(const Transaction & rhs) const { const std::time_t WINDOW = 2; if (getHashKey() == rhs.getHashKey()) { if ((epochTime() - WINDOW) <= rhs.epochTime() && (epochTime() + WINDOW) >= rhs.epochTime()) { return false; } else { return (epochTime() < rhs.epochTime()); } } else { return (getHashKey() < rhs.getHashKey()); } } This ought to work, under the assumption that equality is determined by checking that (lhs < rhs) is false and (rhs < lhs) is false. This doesn't seem to be working correctly though. If we add some logging inside the operator overload, we see that it only gets called once, not twice, when we call find() on that keyed index. What is the logic behind find()? I tried to take a look but it's so heavily templated that I couldn't see much more than that it was doing a tree traversal and using a comp() method that's provided as a template argument. Also, I am testing this with just one item in the container. That item has a matching key, but the timestamps are not within the time window I'm using in the operator< overload. I have not checked to see if the behavior is different for a container with many elements. I also tried overloading all the other comparison operators for kicks, and none of them get called ever either. Ideas? Thanks, Paul ________________________________ Note: This email is for the confidential use of the named addressee(s) only and may contain proprietary, confidential or privileged information. If you are not the intended recipient, you are hereby notified that any review, dissemination or copying of this email is strictly prohibited, and to please notify the sender immediately and destroy this email and any attachments. Email transmission cannot be guaranteed to be secure or error-free. Jump Trading, therefore, does not make any guarantees as to the completeness or accuracy of this email or any attachments. This email is for informational purposes only and does not constitute a recommendation, offer, request or solicitation of any kind to buy, sell, subscribe, redeem or perform any type of transaction of a financial product.

4 3

issues with BOOST_CLASS_EXPORT
by Lukas Diduch 29 Apr '10

29 Apr '10

I'm serializing two different classes (fooA, fooB) using boost::any using a wrapper template class combined with a handmade NVP (for the type) under boost_1_42_0. Serializing every type multiple times works fine. However if i use BOOST_CLASS_EXPORT (fooA) to register the type, after the SECOND call that type (fooA) is not being serialized properly anymore. Any subsequent serialization fails. the (text)archive of the correct case: 22 serialization::archive 7 4 fooA 0 0 10 4 fooB 0 0 1.5 4 fooB 2.5 4 fooA 20 the (text)archive of the broken case: 22 serialization::archive 7 4 fooA 1 0 0 10 4 fooB 0 0 1.5 4 fooB 2.5 4 fooA 0 Does that make sense to anybody ? Maybe a bug ? Note also that in the 'broken' case the archive is split into three lines instead of one. Sorry for not posting the example code but it's quite lengthy. If neccesary i'll do so. To put you in a bigger context: i'd like to serialize types using sockets across different architectures (different typeids who'd have guessed). I don't know the order in which the types are sent, so i guess i should register the types upfront using BOOST_CLASS_EXPORT to make sure save and load are in sync on any arch at any time. Please correct me here if i'm wrong and don't need to use the export. Sincerely Lukas Diduch

2 4

AsIO daytime example needs terminate code
by Christopher Yeleighton 29 Apr '10

29 Apr '10

Regarding Daytime.3 - An asynchronous TCP daytime server: [1] There is no way to stop this server! I can kill it under Linux but then it aborts instead of exiting, which is in general not good. == My solution == Add a global quit event variable. Handle the QUIT signal by setting the quit event. Test for the quit event within the event loop. Thoughts? == References == [1] http://www.boost.org/doc/libs/1_42_0/doc/html/boost_asio/tutorial/tutdaytim…

2 10

Histogram
by David Doria 29 Apr '10

29 Apr '10

Does boost have a way to make a histogram of a vector? I want to be able to do queries such as: "Which numbers are in the 90th percentile?" Thanks, David

3 7

[numeric/interval/] Does Interval Arithmetic Library in Boost support Modal Intervals Arithmetic?
by yaoyansi 29 Apr '10

29 Apr '10

Hi, Could you tell me does Interval Arithmetic Library in Boost support Modal Intervals Arithmetic? If not, is there any C++ library support Modal Intervals Arithmetic? and which is best? Thank you. Cheers yaoyansi

1 0

Re: [Boost-users] [Bind] Unexpected behavior when binding constchar* to function
by Pete Bartlett 29 Apr '10

29 Apr '10

Piotr Jachowicz wrote: >"Cases like that promote stereotype "It's >better to avoid Boost because it contains many traps" Hi Piotr, I hope that when you have absorbed the comments of others, and understood that a const char* is a pointer and a std::string is object and so of course they have behave differently under copying, then you will come back and disown the above comment. Otherwise a false "slur" against Boost will remain on the internet forever, which is unfair to its authors. Pete

5 7

ptime::time_period without the date
by Patrick Loney 29 Apr '10

29 Apr '10

Hello, Just wondering if there is a boost class similar to boost::posix_time::time_period but where you don't need to tie the time period to a particular date? Thanks, Patrick ****************************************************************************** "This message and any attachments are solely for the intended recipient and may contain confidential and privileged information. If you are not the intended recipient, any disclosure, copying, use, or distribution of the information included in this message and any attachments is prohibited. If you have received this communication in error, please notify us by reply e-mail and immediately and permanently delete this message and any attachments. Thank you." Interactive Transaction Solutions Ltd (2473364 England) Registered Office: Systems House, Station Approach Emsworth PO10 7PW ********************************************************************** This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________

1 0

Invitation to connect on LinkedIn
by Hitesh Dhiman 29 Apr '10

29 Apr '10

LinkedIn ------------Hitesh Dhiman requested to add you as a connection on LinkedIn: ------------------------------------------ Hermann, I'd like to add you to my professional network on LinkedIn. - Hitesh Accept invitation from Hitesh Dhiman http://www.linkedin.com/e/vyhGWmEqB2IKeRN9DMTel5y44rvJcs9rKs7Z6xxi13/blk/I2… View invitation from Hitesh Dhiman http://www.linkedin.com/e/vyhGWmEqB2IKeRN9DMTel5y44rvJcs9rKs7Z6xxi13/blk/I2… ------------------------------------------ Why might connecting with Hitesh Dhiman be a good idea? Hitesh Dhiman's connections could be useful to you: After accepting Hitesh Dhiman's invitation, check Hitesh Dhiman's connections to see who else you may know and who you might want an introduction to. Building these connections can create opportunities in the future. ------ (c) 2010, LinkedIn Corporation

1 0

64 bit Project
by Christoph Rabel 29 Apr '10

29 Apr '10

Hi! I am trying to build a project here with Visual Studio 2008 for a 64 bit platform, but I get a lot errors like the following (building it 32 bit works fine) 1>boosttest.obj : error LNK2001: unresolved external symbol "private: class boost::basic_regex<char,struct boost::regex_traits<char,class boost::w32_regex_traits<char> > > & __cdecl boost::basic_regex<char,struct boost::regex_traits<char,class boost::w32_regex_traits<char> > >::do_assign(char const *,char const *,unsigned int)" (?do_assign@?$basic_regex@DU?$regex_traits@DV?$w32_regex_traits@D@boost@@@boost@@@boost@@AEAAAEAV12@PEBD0I@Z) Here is what I did to build the libs: bjam msvc architecture=x86 address-model=64 stage bjam msvc architecture=x86 address-model=64 install I tried various versions of the above lines, with other parameters, or written differently e.g. (--toolset=msvc) but the end result did not change. Then I added the c:\boost\include\... and c:\boost\lib dir to (Tools -> Options -> VC++ Directories -> Platform x64 Include and Library files) To simplify the problem I created a new project and created a new Configuration for x64 ----- #include "stdafx.h" #define BOOST_LIB_DIAGNOSTIC #include <boost/regex.hpp> #include <string> int main() { boost::regex pat( "bla" ); } ----- I can build above fine in 32 bit mode, using the same(!) lib folder. So I assume, the created libs are 32 bit. (Can I check that somehow?) Any ideas what I might do wrong? Or what I might do to find out where the problem lies? Thanks, Christoph

5 10

[BGL] Filtered_graph edgepredicate
by Line Blander Reinhardt 29 Apr '10

29 Apr '10

Hi all I need to make a filtered graph for each color. I have a graph where the edges are assigned a color (there are many colours). I want to make a filtered graph (for each colour) given a colour. I am a little lost with the filtered graph and edge predicates and do not know how to make one with a colour and a colour-edge map. In the examples I have found it is only the map that is needed in the edgepredicate. I have made something like ... template <typename Colour, typename EdgeColourMap > struct same_edge_colour { same_edge_colour(): t_colour(){ } same_edge_colour(Colour a, EdgeColourMap m) : t_colour(a),m_colours(m){ } template <typename Edge> bool operator()(const Edge& e) const { return boost::get(m_colours,e)==t_colour; } Tag t_colour; EdgeAgentMap m_colours; }; I am not able to make my filter and the filtered graph. Can someone help me?? Tell me if you need more information. Thanks Line

3 3