January 2008 - Boost - lists.preview.boost.org

[singleton] Design questions
by Peter Dimov 18 Jan '08

18 Jan '08

What is the reason to prefer the current instance/lease formulation instead of typedef ... instance_type; instance_type instance(); // automatically serves as a lease ? (Also, why mutexed_singleton? Mutexed is not a word; synchronized_singleton maybe?) Apologies if these have already been answered. I lost track of the thread. Appalling, I know.

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Bug with timer.hpp?
by Robert Dailey 18 Jan '08

18 Jan '08

Hi, I currently use the latest trunk version of boost. I have the following precompiled header: precompile.h: #include <boost/timer.hpp> When I compile using Visual Studio 2005 on Windows Vista x86, I get the following errors (Note that this is a very long list). I'm not sure why this is happening. If anyone could offer some advice I'd greatly appreciate it. Thank you. 1>c:\program files\microsoft visual studio 8\vc\include\cmath(18) : error C2039: 'acosf' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(18) : error C2873: 'acosf' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(18) : error C2039: 'asinf' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(18) : error C2873: 'asinf' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(19) : error C2039: 'atanf' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(19) : error C2873: 'atanf' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(19) : error C2039: 'atan2f' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(19) : error C2873: 'atan2f' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(19) : error C2039: 'ceilf' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(19) : error C2873: 'ceilf' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(20) : error C2039: 'cosf' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(20) : error C2873: 'cosf' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(20) : error C2039: 'coshf' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(20) : error C2873: 'coshf' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(20) : error C2039: 'expf' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(20) : error C2873: 'expf' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(21) : error C2039: 'fabsf' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(21) : error C2873: 'fabsf' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(21) : error C2039: 'floorf' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(21) : error C2873: 'floorf' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(21) : error C2039: 'fmodf' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(21) : error C2873: 'fmodf' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(22) : error C2039: 'frexpf' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(22) : error C2873: 'frexpf' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(22) : error C2039: 'ldexpf' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(22) : error C2873: 'ldexpf' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(22) : error C2039: 'logf' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(22) : error C2873: 'logf' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(23) : error C2039: 'log10f' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(23) : error C2873: 'log10f' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(23) : error C2039: 'modff' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(23) : error C2873: 'modff' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(23) : error C2039: 'powf' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(23) : error C2873: 'powf' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(24) : error C2039: 'sinf' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(24) : error C2873: 'sinf' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(24) : error C2039: 'sinhf' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(24) : error C2873: 'sinhf' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(24) : error C2039: 'sqrtf' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(24) : error C2873: 'sqrtf' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(25) : error C2039: 'tanf' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(25) : error C2873: 'tanf' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(25) : error C2039: 'tanhf' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(25) : error C2873: 'tanhf' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(27) : error C2039: 'acosl' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(27) : error C2873: 'acosl' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(27) : error C2039: 'asinl' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(27) : error C2873: 'asinl' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(28) : error C2039: 'atanl' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(28) : error C2873: 'atanl' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(28) : error C2039: 'atan2l' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(28) : error C2873: 'atan2l' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(28) : error C2039: 'ceill' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(28) : error C2873: 'ceill' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(29) : error C2039: 'cosl' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(29) : error C2873: 'cosl' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(29) : error C2039: 'coshl' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(29) : error C2873: 'coshl' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(29) : error C2039: 'expl' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(29) : error C2873: 'expl' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(30) : error C2039: 'fabsl' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(30) : error C2873: 'fabsl' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(30) : error C2039: 'floorl' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(30) : error C2873: 'floorl' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(30) : error C2039: 'fmodl' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(30) : error C2873: 'fmodl' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(31) : error C2039: 'frexpl' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(31) : error C2873: 'frexpl' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(31) : error C2039: 'ldexpl' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(31) : error C2873: 'ldexpl' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(31) : error C2039: 'logl' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(31) : error C2873: 'logl' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(32) : error C2039: 'log10l' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(32) : error C2873: 'log10l' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(32) : error C2039: 'modfl' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(32) : error C2873: 'modfl' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(32) : error C2039: 'powl' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(32) : error C2873: 'powl' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(33) : error C2039: 'sinl' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(33) : error C2873: 'sinl' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(33) : error C2039: 'sinhl' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(33) : error C2873: 'sinhl' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(33) : error C2039: 'sqrtl' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(33) : error C2873: 'sqrtl' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(34) : error C2039: 'tanl' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(34) : error C2873: 'tanl' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(34) : error C2039: 'tanhl' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(34) : error C2873: 'tanhl' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(36) : error C2039: 'abs' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(36) : error C2873: 'abs' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(37) : error C2039: 'acos' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(37) : error C2873: 'acos' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(37) : error C2039: 'asin' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(37) : error C2873: 'asin' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(38) : error C2039: 'atan' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(38) : error C2873: 'atan' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(38) : error C2039: 'atan2' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(38) : error C2873: 'atan2' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(38) : error C2039: 'ceil' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(38) : error C2873: 'ceil' : symbol cannot be used in a using-declaration 1>c:\program files\microsoft visual studio 8\vc\include\cmath(39) : error C2039: 'cos' : is not a member of '`global namespace'' 1>c:\program files\microsoft visual studio 8\vc\include\cmath(39) : fatal error C1003: error count exceeds 100; stopping compilation

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Re: [boost] [serialization] failures of test_exported* tests with gcc 4.1 and higher
by Boris Gubenko 18 Jan '08

18 Jan '08

The situation is that with polymorphic base class, serialization library throws an exception. With non-polymorphic base class, the program succeeds. You are, probably, right that while x.cpp in my previous mail and test_exported.cpp throw the same exception, the cause may be different. I tried x.cpp (with polymorphic base class) with aCC instead of gcc and got: aCC runtime: Uncaught exception of type "boost::archive::archive_exception". At the same time, test_exported succeeds with aCC. I'll try serialization library at rrsd.com when I have a chance. In the meantime, do you have any idea why the program might be throwing exception with 1.35? Thanks, Boris Robert Ramey wrote: > One can't invoke any function of the derived class through a base class > pointer unless the base class is polymorphic - that is has at least one > virtual function. > > Serialization is no different in this regard. > > I would not expect the behavior of the program below to > change between version. > > The error message is the same as those failures in test_export > but the cause isn't necessarily the same. > > I would be curious of the version 1.36 serialization library > at rrsd.com would pass tests with gcc 4.1 and higher. > > Robert Ramey > > Boris Gubenko wrote: > > x.cpp below reproduces failures of test_exported* tests on > > several platforms using gcc 4.1 and higher. The tests fail with: > > > > terminate called after throwing an instance of > > 'boost::archive::archive_exception' > > what(): unregistered void cast > > > > When compiled with macro WORKS defined, i.e. when destructor of > > the base class is removed, reproducer succeeds. Does it give any > > clue? > > > > Thanks, > > Boris > > > > x.cpp > > ----- > > #include <fstream> > > #include <boost/archive/binary_oarchive.hpp> > > > > struct polymorphic_base > > { > > template<class Archive> > > void serialize(Archive&, const unsigned int) {} > > #ifndef WORKS > > virtual ~polymorphic_base(){} > > #endif > > }; > > > > struct polymorphic_derived : polymorphic_base > > { > > template<class Archive> > > void serialize(Archive&, const unsigned int) {} > > }; > > > > int main() > > { > > std::ofstream os("x.x"); > > boost::archive::binary_oarchive oa(os); > > polymorphic_base *rb = new polymorphic_derived; > > oa << BOOST_SERIALIZATION_NVP(rb); > > } > > > >

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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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Re: [boost] [interest] Egg, function object builders and adaptors
by dan marsden 18 Jan '08

18 Jan '08

Giovanni Piero Deretta wrote: >> Kirit Sælensminde wrote: >> >> >> If interested enough, it might be enqueued to the review queue. >> >> Anyway, comments are most welcome. >> > >> > I do hope so. I'm surprised that nobody has replied to queue it up >> > already :( >> >> For the record, I and a couple more, have expressed interest already >> in a previous thread. > >I didn't reply to this specific thread, but yes, count me definitely interested. > Just to make sure, I'm definitely interested as well. Looks excellent. Cheers Dan ___________________________________________________________ Support the World Aids Awareness campaign this month with Yahoo! For Good http://uk.promotions.yahoo.com/forgood/

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[serialization] failures of test_exported* tests with gcc 4.1 and higher
by Boris Gubenko 18 Jan '08

18 Jan '08

x.cpp below reproduces failures of test_exported* tests on several platforms using gcc 4.1 and higher. The tests fail with: terminate called after throwing an instance of 'boost::archive::archive_exception' what(): unregistered void cast When compiled with macro WORKS defined, i.e. when destructor of the base class is removed, reproducer succeeds. Does it give any clue? Thanks, Boris x.cpp ----- #include <fstream> #include <boost/archive/binary_oarchive.hpp> struct polymorphic_base { template<class Archive> void serialize(Archive&, const unsigned int) {} #ifndef WORKS virtual ~polymorphic_base(){} #endif }; struct polymorphic_derived : polymorphic_base { template<class Archive> void serialize(Archive&, const unsigned int) {} }; int main() { std::ofstream os("x.x"); boost::archive::binary_oarchive oa(os); polymorphic_base *rb = new polymorphic_derived; oa << BOOST_SERIALIZATION_NVP(rb); }

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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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interprocess
by Jan 17 Jan '08

17 Jan '08

Hi, I noticed the documentation has been updated in the last few months. How close is interprocess to been included in a release of boost? Thanks

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Wiki Defaced
by Joel 17 Jan '08

17 Jan '08

Folks, A spammer just defaced the front of the wiki... http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl Joel

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Attention gmane users
by Phil Endecott 17 Jan '08

17 Jan '08

I know that some people read this list via the gmane web interface, and I thought I ought to point out that http://news.gmane.org/gmane.comp.lib.boost.devel has been missing some messages recently; in particular it has none of the singleton review thread after the announcement. It is visible at http://blog.gmane.org/gmane.comp.lib.boost.devel, however. Phil.

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Facebook update.
by Jan 17 Jan '08

17 Jan '08

We now have 80 members on facebook, this can serve as a good recruiting ground for new C++ talent. Boost/C++ group on facebook: http://www.facebook.com/group.php?gid=4200526117 Thanks

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[Accumulators] Documentation
by Edward Diener 17 Jan '08

17 Jan '08

Attempting to build accumulators documentation from the latest SVN head by executing bjam from the /boost/libs/accumulators/doc directory yields: error: Unable to find file or target named error: 'object(file-target)@476' error: referred from project at error: /E:/Programming/VersionControl/Subversion/Boost/tools/quickbook'

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Boost.Tests: Unit test defines own main() function, why?
by Jens Seidel 17 Jan '08

17 Jan '08

Hi, I would like to know why Boost's unit test framework requires that the user defines init_unit_test_suite(int, char**) (or with char *[] argument???) instead of main(). I recently had again some trouble because of it: * It broke the general autoconf test in boost.m4 as the existance of a Boost library can normally easily be tested by using boost code in main() and not init_unit_test_suite(). (Will probably be fixed soon in boost.m4.) * According to http://lists.boost.org/Archives/boost/2007/05/121601.php linkers don't look into libraries (either static or dynamic) to find main so that unit tests cannot be cimpiled as shared library. * I noticed that Debian's Boost library doesn't work for me as main() is not found in the shared library (but in the static one). I found now beside my bug report http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=456863 also http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=432921 which mainly refers to the link above. I'm not sure whether my problem is an error in Debian's packages or not but I ask why is main handled differently in Boost.test? Wouldn't it be sufficient to ask the user simple to start init_unit_test_suite() from a user specified main() to make most problems go away? Maybe it would be even OK to just start init_unit_test_suite() in the constructor of a static variable (yes, I know that the initialisation order may cause trouble with other static data). http://www.boost.org/libs/test/doc/faq.html doesn't explain it! I will now use ifdef's to easily allow using boost/test/included/unit_test.hpp as alternative to the library. Jens

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[interest] Egg, function object builders and adaptors
by shunsuke 17 Jan '08

17 Jan '08

Hi, all. In a recent discussion, a library named Egg possibly left a good impression on boosters, so I propose it. Introduction: It is not so easy to define FunctionObjects especially if you want to support Boost.ResultOf and Boost.Lambda. Therefore, as Boost provides iterator_facade and iterator adaptors, Egg provides function_facade and function adaptors. Egg provides the following features: * Helpers to build FunctionObject: * egg::function and egg::function_facade provides the way to build FunctionObject which supports Boost.ResultOf and Lambda. * FunctionObject Adaptors(in other words, higher-order functions): * egg::curryN supports the currying. * egg::pipable emulates extension methods(C#). * egg::fuse emulates variadic templates in very limited way. * etc... The zipped source code is in Vault/FunctionObjects: http://tinyurl.com/34lgda The document is on line: http://p-stade.sourceforge.net/boost/libs/egg/ svn repository: https://p-stade.svn.sourceforge.net/svnroot/p-stade/trunk/boost Tested under: trunk and Boost1.34.1. An example of currying in Egg: int plus(int x, int y) { return x + y; } typedef result_of_curry2<int (*)(int, int)>::type T_curried_plus; T_curried_plus const curried_plus = BOOST_EGG_CURRY2(&::plus); void test() { BOOST_CHECK( curry2(&::plus)(4)(9) == 13 ); BOOST_CHECK( curried_plus(4)(9) == plus(4, 9) ); BOOST_CHECK( uncurry(curry2(plus))(4, 9) == 13 ); } If interested enough, it might be enqueued to the review queue. Anyway, comments are most welcome. Regards, -- Shunsuke Sogame

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Re: [boost] Boost.Tests: Unit test defines own main() function, why?
by Vectra17 17 Jan '08

17 Jan '08

This code needed #define BOOST_TEST_DYN_LINK and now works perfectly. Well almost perfectly, before I realised something rather strange: the compiler ask for a .LIB as well. I am sure it exectues the DLL because when I erase it, the program crashes(.dll not found). So why is the compiler still asking for a .LIB file when I specifeid DLL linking? -- View this message in context: http://www.nabble.com/Boost.Tests%3A-Unit-test-defines-own-main%28%29-funct… Sent from the Boost - Dev mailing list archive at Nabble.com.

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Re: [boost] Is there any interest in a template geometry library?
by artemp 17 Jan '08

17 Jan '08

Barend Gehrels wrote: > > Is there any interest in a template geometry library? > I'm very interested! --Artem http://mapnik.org -- View this message in context: http://www.nabble.com/Is-there-any-interest-in-a-template-geometry-library-… Sent from the Boost - Dev mailing list archive at Nabble.com.

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wave lexed_tokens sample gives an unexpected answer
by Leo Davis 17 Jan '08

17 Jan '08

Hello, I built the Wave preprocessing lib out of CVS head today using GCC 4.2.1 on Linux x86 box (openSUSE 10.3). I then built the lexed_tokens sample and ran it on the attached header file. The unexpected answer was how the 'defined' keyword was treated. I expected it to treat it as T_DEFINED, but it seems to return T_IDENTIFIER as shown by this output fragment: ... PP_IF (#370) at foo.h ( 4/ 1): >#if< SPACE (#393) at foo.h ( 4/ 4): > < IDENTIFIER (#381) at foo.h ( 4/ 5): >defined< SPACE (#393) at foo.h ( 4/12): > < IDENTIFIER (#381) at foo.h ( 4/13): >BAR< NEWLINE (#395) at foo.h ( 4/16): >\n< ... Leo #ifndef FOO_H #define FOO_H #if defined BAR #define BAZ #endif #endif /* FOO_H */

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Globally Unique Identifier library by Andy Tompkins ?
by Janek Kozicki 16 Jan '08

16 Jan '08

Hello, I wasn't following boost development for about 8 months, now I'm slowly getting back on track (about 4000 unread emails had accumulated in my inbox, gotta look through them ;) I just looked at http://www.boost.org/more/formal_review_schedule.html and I didn't see any information about the mini review for Andy's library. Is it scheduled, was it already done, is it accepted? What's the status? best regards -- Janek Kozicki |

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Re: [boost] Terminology:Type Unification? (was Re: RFC Generic data structure traversal / manipulation library
by dan marsden 16 Jan '08

16 Jan '08

Larry Evans wrote: >Page: > >http://spirit.sourceforge.net/dl_docs/traversal/html/traversal/quick_start_… > >contains a section titled: > >Type Unification > >however, it appears like what it describes is more like the stl's >accumulate or mpl's fold. Could you explain the reason for the >title and why a title using accumulate or fold wouldn't be >more intuitive to readers? The terminology is taken from the paper by Ren and Erwig, in the references section. I've borrowed a lot of the naming conventions and terminology from this paper. In the original there are 2 traversal types, type preserving which return a result of the same type as their input argument, and type unifying, which take all input types to the same (fixed) output type. In my library, I've currently replaced the type preserving traversals with inplace traversals, as C++ suits modification in place better than large amounts of copying. The 2 numbered points at the start of the Type Unification section attempt to explain this, but obviously this could be clearer. I'll have a look at rewording things. The operation is certainly not a fold, so I think it would be misleading to associate the example with fold like terminology. Cheers Dan ___________________________________________________________ Yahoo! Answers - Got a question? Someone out there knows the answer. Try it now. http://uk.answers.yahoo.com/

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[utility] initialized_value - a convenience class for value_init.hpp
by Niels Dekker - mail address until 2008-12-31 16 Jan '08

16 Jan '08

For the convenience of the end users, I would like to add a little class to value_init.hpp, called initialized_value, having a conversion operator as its one and only member. Because it's just an extra feature of value_init, and Fernando Cacciola (the owner of value_init) already agrees that this class is a useful addition, I don't think an officially review of the class is necessary. But please tell me if you think otherwise. Details: The following syntax should initialize an object in a generic way, assuming that its type T is CopyConstructible: T obj1 = T(); Unfortunately this object may *not* be initialized properly, because of value-initialization related compiler issues of various C++ implementations, including MSVC, Borland, and GCC. (Boost ticket #1217, #1459, and #1491.) Fernando Cacciola and I have recently reimplemented boost::value_initialized, to work around those issues. (value_init.hpp, release branch, changeset [42501].) So the next release version of boost::value_initialized can be used to properly initialize an object, even in the presence of those compiler issues, as follows: T obj2 = get( value_initialized<T>() ); Still this way of initializing an object is rather verbose, and it has a form of code duplication, because it mentions the type of the object (T) twice. Within user code, the type may of course look more like Namespace::Template<Arg>::Type. Therefore I would like to add a class, boost::initialized_value, supporting the following: T obj3 = initialized_value(); The class would be implemented as follows: namespace boost { class initialized_value { public : template <class T> operator T() const { return get( value_initialized<T>() ); } }; } Its conversion operator would provide an appropriate value-initialized object for any CopyConstructible type T. Any comments are welcome. If it's okay, I would like to add it to the trunk version of value_init.hpp, next week. Kind regards, -- Niels Dekker http://www.xs4all.nl/~nd/dekkerware Scientific programmer at LKEB, Leiden University Medical Center

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Re: [boost] [review] Fast track review of Boost.Utility/Singleton
by Tobias Schwinger 16 Jan '08

16 Jan '08

Nat, thanks for your very positive review. Nat Goodspeed wrote: > John Torjo wrote: > >> Today starts the formal Fast-Track review of the Boost.Utility/Singleton >> library. >> >> What to include in Review Comments >> ================================== >> >> Here are some questions you might want to answer in your review: >> >> * What is your evaluation of the design? > > Very strong. I like it! > I've implemented CRTP Singleton templates a few times before -- > highlighting the need for a Boost library. ;-) I'm pleased with the > deluxe functionality: >> * What is your evaluation of the documentation? > > Very clear, though not entirely complete, as described below. The > organization and style is excellent, and when polished, this > documentation will be exemplary. I like the examples. Pointing out the > ability to bind() instance and/or lease, and the semantics of each, is > great. Also the multiple-inheritance example to graft Singleton behavior > onto an existing class. > I didn't fully understand the thrust of the example described as: "We > might as well have a static facility use the Singleton internally, by > using non-public inheritance". A few more words about that example would > be useful; maybe a bit of the implementation of static void message(). I might have kept it so brief since I'm not too sure it's good practice. I think I'll better just remove it. > It appears that the third template parameter SubsystemTag was a > recent introduction. The documentation (especially the reference > material) doesn't describe it enough, and often fails to mention it > entirely. Yes. > The first paragraph under > http://torjo.com/tobias/index.html#boost_utility_singleton._singletons_and_… > seems to want to be a bullet list that got flowed instead. Yes. > Very little is said about BOOST_SINGLETON_PLACEMENT and > BOOST_SINGLETON_PLACEMENT_DECLARATION. The reference material mentions > them without any explanation. That "Singletons and dynamic libraries" section explains their purpose. What exactly is missing? I'm not too fond of specifying what those macros expand to and I don't really want to mention them in the introductory section either, as for me they are kind-of workarounds for the imperfect ABIs we have to deal with. > The example > http://torjo.com/tobias/index.html#boost_utility_singleton._singletons_and_… > appears to be inconsistent: shouldn't mylib_tag and library_tag be the > same, one way or the other? They should. My head must had been on vacation revising the docs. > Also, that example combines three different > mechanisms: BOOST_SINGLETON_PLACEMENT, destroy_singletons() and > SubsystemTag. More explanation of the role of each (why are we using > that mechanism here?), and how they interact -- or remain orthogonal -- > would clarify. Yes. Regards, Tobias

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RFC Generic data structure traversal / manipulation library
by dan marsden 15 Jan '08

15 Jan '08

Hi All I'm posting an early version of a library for manipulating hierarchical data structures, for example the parse trees that are produced by Spirit2. The library enables traversals, and local modifications of complex data structures, without the need to implement large amounts of repetitive traversal code. The library is in a very early state, but has a pretty large introduction and quick start guide, which (hopefully) will help get people started with the library. Formal documentation is unfortunately non-existent at this point. The library is based on techniques from the Haskell community, links to relevant papers are provided in the documentation. The library is intended to play well with the rest of Boost, it already contains support for structures built with Boost.Optional and Boost.Variant, and Boost.Fusion, and will support other Boost libraries in future releases. The library makes heavy use of function objects, and is intended to work with Boost.Lambda, Phoenix, and other function object libraries in Boost. Online documentation can be found at: http://tinyurl.com/2eyjeh A gzip copy of the latest source is available for download at. http://tinyurl.com/2h2tb6 I've also detailed some of the directions that future implementations of the library make take. Any feedback gratefully accepted. Thanks Dan ___________________________________________________________ Yahoo! Answers - Got a question? Someone out there knows the answer. Try it now. http://uk.answers.yahoo.com/

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[result_of][borland-5.9.2] BOOST_NO_RESULT_OF
by Jonathan Turkanis 15 Jan '08

15 Jan '08

Hi, I make one fairly modest use of result_of in Boost.Iostreams. My initial implementation included result_of.hpp and guarded the use of result_of with the macro BOOST_NO_RESULT_OF. I then discovered that Borland 5.9.2 and Borland 5.9.3 don't support result_of well enough for my needs, but that result_of.hpp header doesn't set BOOST_NO_RESULT_OF for these toolsets (since they supposedly support SFINAE). So I added checks for Borland version to the guard around result_of. This worked until yesterday. Now it seems that simply including the result_of header fails on Borland (see std_test_result_of_header: http://tinyurl.com/26umcr) I'd like to patch Iostreams as soon as possible, so I'm wondering whether this regression will be resolved by making the header includable by Borland or by marking std_test_result_of_header as an expected failure. It seems to me that result_of.hpp either has to be unconditionally includable, or BOOST_NO_RESULT_OF has to be defined in boost/config.hpp so I can tell whether to include it. If result_of is now really unusable on Borland (and if late model Borland really supports SFINAE), then it's no longer true that BOOST_NO_RESULT_OF is simply the disjunction of two existing config macros, and so it seems natural to define it in config.hpp instead of in result_of.hpp. (It could be defined in config/compiler/borland.hpp and also in config/suffix.hpp if BOOST_NO_SFINAE or BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION is defined.) Thanks, -- Jonathan Turkanis CodeRage http://www.coderage.com

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Re: [boost] [Spirit-devel] RFC Generic data structure traversal / manipulation library
by dan marsden 15 Jan '08

15 Jan '08

Eric Niebler wrote: >dan marsden wrote: >> Hartmut Kaiser wrote: >>> Is the used concept extensible in a way allowing for _structural_ >>> changes of the traversed data structure? This would make it usable >>> for tree transformations, which would be especially interesting if >>> used with Spirit.Qi (parsing) and Spirit.Karma (generation). ><snip> >> As for arbitrary transforms from type A to type B, this is probably >> the biggest open question for the library (IMO). > >This is the sort of thing that Proto's tree transformations handle >naturally, but Proto transforms only work when the tree nodes can be >differentiated at compile time. Perhaps there is some synergy between >these two libraries. > >I'm working on the documentation for Proto's new tree transformation >framework right now. Dan, we should talk. Yes, from what I understand of Proto, it is basically providing case analysis on the parse trees for expression template expressions. Its also nicely composable, it's that sort of case analysis type structure that I had in mind. I'd be glad to discuss whether possibly synergies between the 2 approaches. Cheers Dan __________________________________________________________ Sent from Yahoo! Mail - a smarter inbox http://uk.mail.yahoo.com

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Re: [boost] [Spirit-devel] RFC Generic data structure traversal / manipulation library
by dan marsden 15 Jan '08

15 Jan '08

Hartmut Kaiser wrote: >IIUC, the traversal library is designed to help traversing arbitrary data >structures and to apply local _value_ changes. My question is: >Is the used concept extensible in a way allowing for _structural_ changes of >the traversed data structure? This would make it usable for tree >transformations, which would be especially interesting if used with >Spirit.Qi (parsing) and Spirit.Karma (generation). Currently, the most straightforward way to make structural changes to the tree is at nodes where variants are present. Obviously then switching to a subtree of a different type is straightforward. Optional and pointers provide limited scope for eliminating subtrees in a similar way. As for arbitrary transforms from type A to type B, this is probably the biggest open question for the library (IMO). Currently local value changes are pretty well supported within a framework of standard traversals which can be tweaked for certain types. To what extent the library can / should support traversals in which custom behaviour is required at the majority of the nodes is an area I'm currently giving thought to. Ideally I'd like to support at lot more use cases than this first iteration can manage, as things mature, and I incorporate feedback. Cheers Dan __________________________________________________________ Sent from Yahoo! Mail - a smarter inbox http://uk.mail.yahoo.com

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