February 2007 - Boost-users

signals newbie
by V12 20 Feb '07

20 Feb '07

hi ppl, i am new to using boost signals lib and have the following doubts: i have an event manager class which has a member function loadmap(). this class also has a signal s_ChangeMap to connect to the above function . now when i tried to do: s_ChangeMap.connect(&LoadMap); i get the following error: error C2276: '&' : illegal operation on bound member function expression the same error also occurs when i try to connect the signal to a function of a different class what should i do to get rid of this. am i missing on some understanding of the working of the signals system or is it something related to the scope of a connection?? please help me , thanx -- View this message in context: http://www.nabble.com/signals-newbie-tf3257471.html#a9056554 Sent from the Boost - Users mailing list archive at Nabble.com.

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Re: [Boost-users] [program options] some docs suggestion
by Ovanes Markarian 20 Feb '07

20 Feb '07

On Tue, February 20, 2007 13:18, Vladimir Prus wrote: > Ovanes Markarian wrote: > >> It would be really helpful to know that varaibles map is a derivative of std::map<...>. > > I recall I was going to document this, but don't see it :-( > I'll add this to my TODO. > > - Volodya > > > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users > The varaible_map class has double colons after its name. http://www.boost.org/doc/html/variables_map.html class variables_map : : public boost::program_options::abstract_variables_map { ... }; May be something was stripped off during documentation generation? With Kind Regards, Ovanes Markarian With Kind Regards, Ovanes Markarian

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[multi_array] suggestion
by Николай Широковский 20 Feb '07

20 Feb '07

Hello. I`ve been using Boost.MultiArray for a while and found that next features for MultiArray concept would be usefull. 1. Index permutations, which result is multiarray again. Most encontered in 2d dimential arrays used as matrices, and feature become matrix transposition. 2. This feature is possibly less agreed with Boost.MultiArray concept, nevertheless. It would be useful to have an iterator over all elements, not subcontainers, possibly with custom ordering differ from that used on construction for memory layout. Than i can easily use an STL algorithms on iterators. Having operation of creating subarray and array views i can manage wich part of multi_array object is exposed to algorithm. I hadly see an using of this iterator with stl::adjacent_difference as it interpret iterator as "really sequence", but in my work i will have some code look better using std::transform with such iterator.

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Fwd: [bimap] Review of the Bimap library begins today Feb 15
by Matias Capeletto 20 Feb '07

20 Feb '07

---------- Forwarded message ---------- From: Matias Capeletto <matias.capeletto(a)gmail.com> Date: Feb 18, 2007 2:39 PM Subject: Re: [Boost-users] [bimap] Review of the Bimap library begins today Feb 15 To: boost(a)lists.boost.org On 2/18/07, Gottlob Frege <gottlobfrege(a)gmail.com> wrote: > On 2/15/07, Ion Gaztañaga <igaztanaga(a)gmail.com> wrote: > > Hello everyone, > > > > The review of the proposed Boost Bimap library written by Matias > > Capeletto starts today (February 15th, 2007) and ends after 10 days > > (February 25, 2007). Hi Gottlob, > So far: > A: namespace: > --------------------- > > from the 'One Minute Tutorial': > > That is more or less all that is needed to start using the > bidirectional map. The following two lines must also be added: > > #include <boost/bimap/bimap.hpp> > using namespace bimap; > > 2 points: > - I prefer not to use 'using'. I know I don't have to, but I don't > like that the docs imply that I do. Ok, the "must" in the docs is maybe to strong. I can reword that. > more importantly: > - is it going to be in 'bimap' or in 'boost'? We have to put everything inside a namespace, I do not want to pollute the boost namespace. > B: 'relation' > ---------------- > > I think I understand the philosophical reasoning for preferring > 'left/right' over 'first/second', and thus the impetuous for creating > 'relation'. However... Two issues to talk about here. 1) The new notation left/right used instead of first/second. 2) A new name for 'relation'. We have to introduce the new notation. In the context of maps, the notation first/second is used in places where the first element has different meaning than the second one. left/right is symmetrical and implies that both sides are at the same level, that there is no special side.This is the key point to grasp. This is explained here: http://cablemodem.fibertel.com.ar/mcape/boost/libs/bimap/boost_bimap/the_tu… > - I think 'relation' is too generic a word to abscond. >From the dictionary: "A logical or natural association between two or more things" I like 'relation'. But we can talk about other names. > - how about: > - couple > - duo The thing is that these words are very similar to "pair" and the idea is to mark the difference. > - or probably just 'bipair' That was my original choice. 'relation' sounds better to me but let see what other people think about this. > - or maybe even consider that std::pair, although not perfect, might > make things easier: Using left/right instead of first/second is an important design decision. Here is where things start mixing up. > - it can be used in other algorithms The new notation is used in very different contexts. The algorithms written for first/second has no sense in the contexts where left/right are used. If you want to use algorithms that works with map/pair notation you have to pass one of the side views to it. > - it is already well known That is true and in the context of maps it have a very established meaning different from what we want to express with left/right. This is a point for the new notation. > - the nature of typing code forces order - ie note that bimap<X, Y> > is different than bimap<Y, X> (although philosophically the same). (Side Note: Using tags they are exactly the same.) > Even with 'left/right' you still have order - left corresponds to the > *first* type listed in the bimap, 'right' corresponds to the *second* > type passed in. Or is it bimap<Right, Left>? I don't think so. You still have order. The important thing to understand is that we are not looking to eliminate that order. We want to express that the two things are equally important. > But other than that, so far so good. Looks like something I'd use. > And the docs are snazzy. Thanks! Matias

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[program options] some docs suggestion
by Ovanes Markarian 20 Feb '07

20 Feb '07

It would be really helpful to know that varaibles map is a derivative of std::map<...>. I was wondering where the variables_map::count(...) come from in getting started example... if (vm.count("help")) { cout << desc << "\n"; return 1; } Only after looking into the source of variables_map helped :( With Kind Regards, Ovanes Markarian

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[program_options] unknown options in config files
by Sebastian Weber 20 Feb '07

20 Feb '07

Hello! I'm using program_options to parse command line options and configuration files. I absolutley need the unknown option feature. For the command line options this works fine. However, the configuration file parsing always throws an option unknown exception when I parse cfg-files with non-registered options. Right right I circumvent this by catching the corresponding exception. But this is not very nice and I can as well not be sure that all options have been parsed in the cfg-file, depending upon the first occurence of an unknown option, right? So, is there a possibility to process unknown options in cfg-files? Thanks a lot in advance. Greetings, Sebastian

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Boost in embedded systems
by Peter Poulsen 20 Feb '07

20 Feb '07

I know this sounds insane, but our developers are very happy with boost (who can blame them :-)), and want to have boost available on our embedded systems. We only have 64 mb of flash memory available for the entire system (OS, hardware monitoring and applications) and I simply cannot get boost down to a reasonable size. Am I trying to do an impossible task, or can somebody give me some good advice on how to build boost so it has a more reasonable size? Of course what should be done is removing some of the features, and I can probably negotiate with developers about what features we can provide and which have to go. Which one should I try to get rid of first? /peter -- A: Because it messes up the order in which people normally read text. Q: Why is it such a bad thing? A: Top-posting. Q: What is the most annoying thing on usenet and in e-mail?

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Updated date_time_zonespec.csv for 2007?
by Brendon Oliver 20 Feb '07

20 Feb '07

Does anybody have a date_time_zonespec.csv file updated for the US DST changes this year? I've googled the mailing lists & looked at sourceforge (I see there was a bug raised 5 Feb, but no responses since). I also downloaded a 1.34 alpha tarball but there's no date_time_zonespec.csv file in there :-( . I've looked at updating the file myself (the syntax is pretty straight-forward), I'm just worried about missing particular zones. Cheers, - Brendon. -- Conversation, n.: A vocal competition in which the one who is catching his breath is called the listener. 10:19:19 up 61 days, 19:45, 2 users, load average: 0.34, 0.26, 0.25

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[signals] thread_safe_signals feature-complete
by Frank Mori Hess 20 Feb '07

20 Feb '07

Hi all, I've finished thread_safe_signals. To get thread safety you have to include an additional header file thread_safe_signals/multi_threaded.hpp and set the last template parameter to boost::signals::multi_threaded. I've done a little benchmarking. With thread-safety off and connecting 10 slots, it appears to have about the same overhead as cvs boost.signals (which is much less than the latest release of boost.signals). When 1 slot is connected, it has more overhead, a little less than a factor of 2 when running a single empty slot. Turning thread-safety on increases overhead by about 50% for the 1 slot case and 100% for the 10 slot case. It is able to invoke slots concurrently though, which should be a win if the slot is non-trivial. -- Frank

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any boost library for referring a portion of the container ?
by abir basak 19 Feb '07

19 Feb '07

Hi, I am having a few containers whose some portion I want to refer to another class (sometime I need to refer to a continuous portion, while sometime need a non-continuous portion) . At present I have written all of these myself. But wondering if a few portion can be substituted by some boost library. Just to make the concept clear, I am elaborating the structure and why it is done in that way. In the program it takes the user handwriting (as entered using digital pen etc) and analysis them. as user writes, I register points (x,y coord) and put them in an deque (in actual case I am using boost::circular_buffer_space_optimized ). Now, a second deque (or other container) stores another structure Trace, which has 2 index pointing start & end of that continuous writing until pen up occurs. These have to be 2 index rather than iterator, as iterator may get (and usually gets ) invalidated while more points are added in the point deque. Thus Trace refers deque<Point> Now from the trace structure I return the points for the trace (boost::sub_range ) using the 2 index and the deque (i.e from deque<Point> get iterator, add index as offset , make sub_range and return). Now these are the continues portions , referred by 2 index. Next, some such things can be even not continuous. In that case I store all index to which it points (in a vector ) and return a sub_range kind of structure (named index_range ) which takes these index and a container, and iterates over it jumping by those specific offsets. Example can be a Character class which refers some of those traces , not necessarily continuous (like user writes a dot much later than the i , thus Character i contains index of the vertical stroke of the i & dot ) Similarly more hierarchy are constructed, like Trace => Page, and Character => Word => Line => Paragraph => Page etc. Most of them contains 2 index and with the help of the container returns a boost sub_range , while some contains a vector of index (size_t) and returns index_range (created by me) . So far I found it is the ONLY way to create a level of hierarchy/ view from different set of dynamic data. (The other can be storing everything as a pointer in the container, and creating by new, in that case no problem arises as the objects are not movable, but in C++ it is quite bad solution) A Graphical representation is like, =============== deque<Point> ===================== <=remove old data => add new data | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | =============== deque<Trace> ==================== | 1 | 2 | =============== deque<Page> ===================== These are for continuous data (i.e 2 index struct & boost::sub_range ) ================ deque<Trace> ==================== |1,3,4| 2 | 5,6 | 7,9 | 8 | ... ================== deque<Character> =============== | 1,2,4, 5 | 3 | .... ================== deque<Word> ===================== | 1 | 2 | 3 | .... (assuming past a line user doesn't correct word, they can be made a pair of index ! ) ================== deque<Line> ===================== .... ================== deque<Paragraph> ================ etc... My question , 1) had anyone faced these kind of design , where a class referrers a portion of STL container ? and multiple view from same set of data exists (otherwise I could had Trace contains the points , instead of having index of the portion, if Trace is the only view for the points ) 2) Any boost library / other library is there to help these kind of design ? I had posted a same kind of topic in C++ newsgroup also, but it seems their people are more concerned with answering C++ standard based question . I think, boost may be the better news group to ask this question, as boosters work in a broader area. Thanks to all, esp to those who share their thought on it ... abir -- Abir Basak, Member IEEE B. Tech, IIT Kharagpur email: abir(a)abirbasak.com homepage: www.abirbasak.com

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