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[Boost.accumulators] Immediate variance
by Milosz Marian Hulboj 18 Jan '08

18 Jan '08

Hello, I was looking through the documentation of boost.accumulators for calculating the variance in one pass. It seems that for so called 'immediate variance' some approximation is being introduced. However I think that it is not necessary (unless there is a hidden purpose?) and incremental calculation can be done according to the substitution schema described here: http://planetmath.org/encyclopedia/OnePassAlgorithmToComputeSampleVariance.… Regards, Milosz

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[Fwd: Re: [Boost-announce] [review] Fast track review of Boost.Utility/Singleton begins today] (on behalf of Ingolf Steinbach)
by John Torjo 18 Jan '08

18 Jan '08

[on behalf of Ingolf Steinbach] -------- Original Message -------- Subject: Re: [Boost-announce] [review] Fast track review of Boost.Utility/Singleton begins today Date: Mon, 14 Jan 2008 22:46:54 +0100 From: Ingolf Steinbach <ingolf.steinbach(a)googlemail.com> To: John Torjo <john.groups(a)torjo.com> References: <478B978A.6090503(a)torjo.com> Hi, John. 2008/1/14, John Torjo <john.groups(a)torjo.com>: > * What is your evaluation of the design? Some questions: 1. Shouldn't there be a protected d'tor in singleton in order to reduce the chance of mis-use (deletion via pointer to singleton)? 2. Why does instance have pointer-like (rather than reference-like) syntax? I know that GoF use pointers, but references typically make me feel better than pointers (or something that looks like one) which might be 0. 3. Is a private (or protected) my_singleton destructor supported without 'verbose "template...friend-making"'? > * What is your evaluation of the implementation? Not evaluated. > * What is your evaluation of the documentation? Not evaluated. > * What is your evaluation of the potential usefulness of the library? I'd very much like to see this kind of library in boost. This one looks promising. > * Did you try to use the library? With what compiler? > Did you have any problems? No. N/A. N/A > * How much effort did you put into your evaluation? A glance only due to lack of spare time. Sorry . > * Are you knowledgeable about the problem domain? A little: I have written some template based singleton code myself and have read Andrei's MCPPD. > * Do you think the library should be accepted as a Boost library? I'd like to see the above issues addressed in some way. Apart from that, I have no objections. Kind regards Ingolf -- http://John.Torjo.com -- C++ expert ... call me only if you want things done right

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[Boost String Algorithms library] ireplace_all bug with character arrays
by Richard Turrin 18 Jan '08

18 Jan '08

Hi, I've encountered a bug with ireplace_all from the Boost String Algorithms library for version 1.35. If I pass a character array for the Format argument, the function ignores the null terminator and instead uses the entire array minus the last character to replace the occurrences of the Search string in the Input parameter. However, if I provide a pointer to a character array, the string replacement is done as expected. When I stepped into the code, I came across the following lines (excerpt from /trunk/boost/range/as_literal.hpp): template< class Char, std::size_t sz > inline iterator_range<const Char*> as_literal( const Char (&arr)[sz] ) { return boost::make_iterator_range( arr, arr + sz - 1 ); } There is no check for a null terminator. Nor did I find one after this function returned. I think the author here assumed that a caller would always pass in a character array of the right size. I've attached a sample that demonstrates the problem. I performed the test in Visual Studio 2008. Let me know if you need more information. Thanks. Rich Turrin

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the Switch library by Steven Watanabe has been accepted provisionally
by Stjepan Rajko 18 Jan '08

18 Jan '08

The Switch library, submitted by Steven Watanabe, has been accepted provisionally pending a mini-review to be scheduled when possible. The purpose of the mini-review will be to assure that the suggestions outlined below have been adequately addressed. I would like to again thank Steven for submitting a very useful library, and for diligently working with the reviewers on improving its design. I would also like to thank Tobias Schwinger, Joel de Guzman, Darren Cook, Daniel (dherring@...), Felipe Magno de Almeida, and Paul Bristow for providing reviews, votes and half votes. Finally, thanks also to Dan Marsden, Larry Evans, Alexander Nasonov, Richard (legalize@...) and Mathias Gaunard for contributing to the discussion. SUMMARY OF VOTES: Tobias Schwinger and Joel de Guzman have submitted full reviews with positive votes: http://article.gmane.org/gmane.comp.lib.boost.user/32637 http://article.gmane.org/gmane.comp.lib.boost.user/32634 (Joel eventually converted his vote to "yes") One "yes" (half) vote was submitted by Paul Bristow: http://article.gmane.org/gmane.comp.lib.boost.devel/170069 One "no" (half) vote was submitted by Felipe Magno de Almeida: http://article.gmane.org/gmane.comp.lib.boost.devel/170051 Another "no" came privately - the point there was that the library didn't undergo enough scrutiny before submission, and that it should be resubmitted. Another privately submitted "no" came soon after the review opened, stating that the reviewer was not able to deduce any usability/usefulness from the library documentation, and suggested there should be a motivating example on the first page. RATIONALE FOR ACCEPTANCE: I believe the low number of full, positive reviews is justified by the relatively narrow scope that this library covers. Within that scope, however, reviewers indicated that the library is extremely useful. Also, the reviewers submitting positive votes have indicated (and proven) significant expertise in the area, leading me to place much weight on their votes. On the other hand, the negative votes did not point out any concrete flaws in the library itself that would merit rejection. RATIONALE FOR REQUIRING A MINI-REVIEW The "no" votes did, on the other hand, indicate some skepticism of the quality of the library/documentation as submitted, and the progress of the redesign that was happening during the review. Also, as a result of the review, the potential scope of the library has expanded significantly from what was originally proposed (which mostly focused on the ability to choose the number of cases at run-time). I believe that a combination of these two give sufficient reason for a mini-review - doubts about the library can be resolved, and those that might become prospective users of the library under the expanded scope will get a chance to give their opinion. I volunteered to manage the mini-review, so once the library is ready it will hopefully not remain in the review queue for too long (as it seems that finding review managers is the biggest problem ATM). To keep the burden on the community low, I propose to treat the mini-review as a partial continuation of the current review - I will consider the "yes" votes by Tobias and Joel to be left standing unless they state otherwise, and will require any "no" votes to be (re)justified given the new condition of the library. SUGGESTED CHANGES TO THE LIBRARY: * Documentation All reviewers have noted that the documentation could be improved. Specific suggestions were: * motivating example on the first page * additional examples * performance stats * more explanation of the types involved and how they are used. As the scope for the library has increased as a consequence of the review, a gentler, more detailed documentation approach might benefit the library - I believe that many people might find the new library useful, given the right motivation and examples in the documentation. * Return type Tobias Schwinger suggested that the return type should be specified explicitly in the switch_ call, rather than inferring it from the function object, and this seems to be the status quo in the newer designs. Joel de Guzman also suggested that if a version of switch_ should infer the return type, that return type should be a Boost.Variant of the types returned by each of the cases. * Default default behavior If the default behavior is left unspecified, switch_ should invoke the default constructor of the return type in the default case, rather than throwing an exception. This was suggested by Tobias Schwinger after the issue was raised by Dan Marsden. Alexander Nasonov has also indicated that a throwing default case can cause inefficiency, even when it is guaranteed not to be invoked. * Fall-through Alexander Nasonov pointed out the lack of fall-through capability in the submitted implementation. Fall-through has been incorporated into the recent designs being discussed. * Allowing void-returning function objects for the default case with a non-void returning switch Tobias Schwinger mentioned the possibility of allowing default case function objects of void return type even when the switch return type is non-void, as long as the function object call does not return. This would be useful, for example, if the function object is guaranteed to throw. After some discussion on whether determining if the return type is void can be done efficiently, it looks like the proposed solution is to use a special return type that indicates that the call will not return. Since Tobias indicated that this feature is a minor point, it could be implemented or not, depending on how well it fits into the final design. * Design There has been a lengthy discussion on the underlying design of the library, what it should offer, and whether the name of the library is appropriate. There are two types of designs that have been put forward as being appropriate and/or necessary for a Boost.Switch library. On one hand, there is the submitted design (labeled "A" in recent postings), which takes the switch cases in an MPL sequence and a single function object containing implementations of all cases. Joel de Guzman has proposed another design (labeled "B"), in which the switch cases are specified separately and allow a different function to be used for each case. Design "A" is better suited for situations in which the number of cases is determined by a compile time constant, while "B" is more appropriate for many use cases, and provides more flexibility and a more familiar syntax. The result of the discussion was that the Boost.Switch library should cover both situations, and an interface is now being developed that can be used in different ways for different uses (based on a common concept capturing case sequences). Thanks again to all that have contributed to this review, and congratulations to Steven for the accepted library. As others have stated, there is much confidence that Steven will meet the challenges successfully for the mini-review, which we will schedule as soon as the library is ready. Regards, Stjepan

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Error using native_file_string()
by Eswar K 17 Jan '08

17 Jan '08

Hi, I am newbie to boost. I was earlier using boost-1.33.1 and my code was working fine. In FC6 i am compiling my code and shows me the following error. * error: âclass boost::filesystem::basic_directory_entry<boost::filesystem::basic_path<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::filesystem::path_traits> >â has no member named ânative_file_stringâ* Is there any difference in the libraries ? Am I missing something? My function is something like this. *void recurse_directory( const boost::filesystem::path& directory ) { boost::filesystem::directory_iterator end; for( boost::filesystem::directory_iterator dir_itr( directory ); dir_itr != end; ++dir_itr ) { if( boost::filesystem::is_directory( *dir_itr ) ) { try { recurse_directory( *dir_itr ); } catch (boost::filesystem::filesystem_error &e) { std::cerr << "Error recursing directory: " << (*dir_itr).native_file_string() << " (" << e.what() << ")" << std::endl; continue; } } else { add_file( (*dir_itr).native_file_string() ); // Get error here.... } } } * I am getting the error on the highlighted line. I am stuck here. Any help would be deeply appreciated. Thanks in advance. Regards, Eswar

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Examples of boost::thread?
by Robert Dailey 17 Jan '08

17 Jan '08

Hi, I want to make a simple worker thread in my WTL application. However, looking through the boost::thread documentation, I don't see any samples of how to create a thread. Would anyone be so kind as to point me in the right direction? Thank you.

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Boost.regex :: u32regex does not compile with latest STLPort
by Amit 17 Jan '08

17 Jan '08

Hi, Not sure if this is an issue on boost side or STLPort side, but compiling u32regex match givess an error in v4/perl_matcher.hpp, line 85. the call is essentially vector<int>::assign(int, int) since char type is int for ICU strings. This is being resolved to template<iter> assign(iter, iter) member, hence the error. I have fixed it in my local copy by changing the line to s1.assign(static_cast<std::size_t>(1), col); But don't know if this is a good fix. This used to work on Dinkum STL, so I am guessing STLPort is messing up somewhere. Do I need to build regex libraries again after this change? Thanks Amit

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MinGW Build Issues
by Chris Miller 17 Jan '08

17 Jan '08

Why on earth I try and support Windows is beyond my comprehension. It's just something I do. I'm having some massive difficulties making Boost build with MinGW so I can start using it from Code::Blocks. I've tried using Boost's native Jam system, but first I have to build that. And that doesn't work. It keeps telling me this: C:\USERS\LORDSA~1\DESKTOP\BOOSTJAM>build.bat mingw ### ### Using 'msvc' toolset. ### C:\Users\LORDSA~1\DESKTOP\BOOSTJAM>rd /S /Q bootstrap C:\Users\LORDSA~1\DESKTOP\BOOSTJAM>md bootstrap C:\Users\LORDSA~1\DESKTOP\BOOSTJAM>cl /nologo /GZ /Zi /MLd /Fobootstrap/ /Fdboot strap/ -DNT -DYYDEBUG kernel32.lib advapi32.lib user32.lib /Febootstrap\jam0 co mmand.c compile.c debug.c execnt.c expand.c filent.c glob.c hash.c hdrmacro.c he aders.c jam.c jambase.c jamgram.c lists.c make.c make1.c newstr.c option.c outpu t.c parse.c pathunix.c regexp.c rules.c scan.c search.c subst.c timestamp.c vari able.c modules.c strings.c filesys.c builtins.c pwd.c class.c w32_getreg.c nativ e.c modules/set.c modules/path.c modules/regex.c modules/property-set.c modules /sequence.c modules/order.c 'cl' is not recognized as an internal or external command, operable program or batch file. C:\USERS\LORDSA~1\DESKTOP\BOOSTJAM>g++ G++: no input files C:\USERS\LORDSA~1\DESKTOP\BOOSTJAM> It keeps trying to use the MSVC toolset, even though I'm telling it not to. Any help here would be nice! I'm putting this all into an instruction set for potential programmers on my project here: http://www.fsdev.net/index.php?option=com_openwiki&Itemid=22&id=code:kw_pro… -- Registered Linux Addict #431495 http://profile.xfire.com/mrstalinman John 3:16! If Microsoft is the Wal*Mart of the Software World, then Linux is the Home Depot

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ms vc80 works well but intel compiler10 fail
by 杨留安 17 Jan '08

17 Jan '08

here I have some class to test the boost::any_cast,usually I use intel compiler 10.0,but I got a message the application must be close. but the ms vc 8.0 compiler works well. My operator is windows xp,and I use vs2005 with inter compiler 10.0 here is my code: ----------------------------------------------------------------------------------------------------------------------------------------- class CA{public: void tellme() { cout<<"I am ca"<<endl; }}; class CB{public: void tellme() { cout<<"I am cb"<<endl; }}; class CC{public: void tellme() { cout<<"I am cc"<<endl; }}; class dotellme{public: void operator()(boost::any& ra) { if(CA* p = boost::any_cast<CA>(&ra)) { p->tellme(); } else if (CB* p = boost::any_cast<CB>(&ra)) { p->tellme(); } else if (CC* p = boost::any_cast<CC>(&ra)) { p->tellme(); } else if(string* p = boost::any_cast<string>(&ra)) { cout<<*p<<endl; } else { int a; try { a = boost::any_cast<int>(ra); cout<<"it's int:"<<a<<endl; } catch (boost::bad_any_cast& e) { cout<<"OOPS"<<endl; } } }}; //void tellme(boost::any& ra)//{// dotellme()(ra);//}int _tmain(int argc, _TCHAR* argv[]){ vector<boost::any> va; va.push_back(CA()); va.push_back(CB()); va.push_back(CC()); va.push_back(string("haha,it a string")); va.push_back(dotellme()); va.push_back(5); dotellme dt; for_each(va.begin(),va.end(),dotellme()); va.clear(); return 0;} _________________________________________________________________ 手机也能上 MSN 聊天了，快来试试吧！ http://mobile.msn.com.cn/

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Boost 1.35 Release Date
by Chauhan, Vikas 17 Jan '08

17 Jan '08

Hello all, Following on the original post. Does anybody have anymore updates on BOOST 1.35 (rc1) release date? Is there a location on Boost website where I can get this information? Thanks and regards, Vikas > Message: 6 > Date: Wed, 28 Nov 2007 16:37:43 +0100 > From: "Tarjei Knapstad" <tarjei.knapstad(a)gmail.com> > Subject: Re: [Boost-users] Boost 1.35 release date > To: boost-users(a)lists.boost.org > Message-ID: > <ff5e09cc0711280737g1a1b919cw9633f00e0a1346de(a)mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1 > > On 26/11/2007, Chauhan, Vikas <Vikas.Chauhan(a)anritsu.com> wrote: > > > > Hello, > > > > Can you please advise the planned release date for BOOST > 1.35 version. > > > > >From Beman's post on the main Boost list: > <quote> > * Merge for release complete: Sunday, November 25th. > * Start testing release candidate build process: Monday, December 3rd. > * Release Candidate 1: Monday, December 10th. > </quote> > > So I'm guessing early next year if there's not too much > trouble with the RC's. My guess is as good as yours though :) > > -- > Tarjei >

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