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Re: [boost] Mixing different versions of Boost libs in a single process
by Grund, Holger 27 May '11

27 May '11

Well, BoostCon is over. So let me try again focusing on some specific bits: > > So the next best thing would be the ability to mix different versions > of Boost in a single process. Today, linkage names will be identical > across versions, which is problematic for static libraries on Windows, > and static libs and DSOs on Linux. [..] > Also there's BCP, which supports renaming namespaces. That's great, but > I guess it could be even better -- e.g. on toolchains where we have > inline namespaces or __attribute__((strong)). On Linux targets, symbol > versioning via GNU LD version scripts might make things a bit better -- > specifically, in that things gone wrong fail earlier and with better > diagnostics. > So when I run BCP on the entire boost tree I still get linkage names that would seem to clash across versions. Specifically, there's the graphml_reader namespace in libs/graph/src/graphml.cpp. Boost.Python and Boost.MPI have symbols that could cause problems, though these would seems to come from external OpenMPI and Python headers. I haven't really looked but it seems these should be fine so long as we build against the same OpenMPI and Python versions with the same configuration. What's the policy here? Do we want BCP to address these things? Or do we want libraries to not use namespaces outside of ::boost (or use linkage/symbol visibility to hide symbols from other DSOs)? Are there any tools to detect this kind of problem? I have a few things check two binaries for potential conflicts by walking debug info and symbol tables -- it's far from perfect and I can't just upload this to Boost, but I'd be happy to help out, if there's interest to get something into the regression tests. Thoughts, anyone? Thanks! -hg -------------------------------------------------------------------------- NOTICE: Morgan Stanley is not acting as a municipal advisor and the opinions or views contained herein are not intended to be, and do not constitute, advice within the meaning of Section 975 of the Dodd-Frank Wall Street Reform and Consumer Protection Act. If you have received this communication in error, please destroy all electronic and paper copies and notify the sender immediately. Mistransmission is not intended to waive confidentiality or privilege. Morgan Stanley reserves the right, to the extent permitted under applicable law, to monitor electronic communications. This message is subject to terms available at the following link: http://www.morganstanley.com/disclaimers. If you cannot access these links, please notify us by reply message and we will send the contents to you. By messaging with Morgan Stanley you consent to the foregoing.

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[random] recent changes causing failures in accumulators tests
by Eric Niebler 27 May '11

27 May '11

Many accumulators tests are now failing on both trunk and release. I have tracked it down to recent changes in Boost.Random. I don't know for how long this has been happening. The accumulators tests use the lagged_fibonacci607 random number generator. The tests work by sending a large amount of random data through various statistical accumulators and checking that the results are within a certain tolerance of what they would be if the data were actually random. In Boost 1.45 and previous versions, this worked. (I haven't tested 1.46.) Trunk and release are hosed, leading me to suspect that this random number generator is no longer producing sufficiently random data. I have verified this by replacing boost/random on trunk with the one from 1.45. With this change, the accumulators tests pass. Steven, this seems like a regression. Can you look into this? -- Eric Niebler BoostPro Computing http://www.boostpro.com

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[pimpl] Modularity thoughts
by Gregory Crosswhite 27 May '11

27 May '11

Hey everyone, As I have stated I think that it pimpl is acceptable enough as is even though it might contain "too much" for advanced users. Nonetheless, having reflected on some of the other reviews I do have some thoughts on some changes that could be made to it to make it more modular, while still preserving a default "all-in-one" option for ordinary users. Take the pimpl struct: =========================== template<class Interface> struct pimpl { struct implementation; template<class> class value_semantics_ptr; template<template<class> class> class pimpl_base; typedef pimpl_base<value_semantics_ptr> value_semantics; typedef pimpl_base<boost::shared_ptr> pointer_semantics; static Interface null(); }; =========================== and replace it with something roughly like =========================== template<template<class> class> equality_ops; template<template<class> class> ordering_ops; template<template<class> class> null_ops; template<template<class> class> bool_ops; template<class Interface> struct pimpl { struct implementation; template<class> class value_semantics_ptr; template<template<class> class> class pimpl_base; typedef pimpl_base<value_semantics_ptr> value_semantics_base; typedef pimpl_base<boost::shared_ptr> pointer_semantics_base; struct value_semantics: public equality_ops<value_semantics_base>, public ordering_ops<value_semantics_base>, public null_ops<value_semantics_base>, public bool_ops<value_semantics_base> {}; struct pointer_semantics: public equality_ops<pointer_semantics_base>, public ordering_ops<pointer_semantics_base>, public null_ops<pointer_semantics_base>, public bool_ops<pointer_semantics_base> {}; static Interface null(); }; =========================== Now take out all of the operations from pimpl_base and put them in separate subclasses like so: =========================== template<typename pimpl_base_type> struct equality_ops : public virtual pimpl_base { bool operator==(equality_ops const& that) const { return (impl_ == that.impl_); } bool operator!=(equality_ops const& that) const { return !(impl_ == that.impl_); } }; template<typename pimpl_base_type> struct ordering_ops : public virtual pimpl_base { bool operator<(ordering_ops const& that) const { return pimpl_base_type::impl_ < that.pimpl_base_type::impl_; } }; template<typename pimpl_base_type> struct bool_ops : public virtual pimpl_base { operator safebool_type() const { return safebool(pimpl_base_type::impl_.get()); } }; template<typename pimpl_base_type> struct null_ops : public virtual pimpl_base { typedef typename pimpl_base_type::interface T; static T null() { return pimpl<T>::null(); } }; =========================== Now the user can mix and match whatever operations he or she likes like, or simply take the full package by default. Note that I have intentionally left out constructors in the above classes because they aren't needed: since we are using virtual inheritance, the user of this library will be calling the constructor of pimpl_base directly, so we don't even have to worry about generating lots of boilerplate to forward the constructor arguments up to the base. In fact, this actually makes using this library simpler in one respect: normally a downside of using virtual inheritance in general is that every derived class needs to call the constructors of all bases, but in the particular case of this library this turns out to be a feature rather than a bug! The documentation discussed how when initializing a derived class you essentially have to call the constructor of the immediate base class and then undo it by resetting the pointer and then filling it with the correct type, but since we are using virtual inheritance now we no longer need this awkward procedure since we can just skip over the constructor of the immediate base class and call the constructor of pimpl_base directly! This also further removes the need for implementations to support a "null" value. Finally, and most importantly, a strong advantage of this design is that it is extensible so users and library writers can define their own operation that they would like to add to classes and mix them right in. Anyway, these are just some thoughts that I had. :-) Cheers, Greg

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[pimpl] Preliminary Review
by Gregory Crosswhite 27 May '11

27 May '11

Hey everyone, Here are my preliminary thoughts regarding the pimpl library. First, I like the idea of having it or something similar to it be part of Boost because the functionality seems like it would be useful in a lot of cases. One of the strengths of including such a library in boost in my opinion is that it will appear in the "Libraries" list, which means that more people will be exposed to the idiom and will think of it as a possible option than they would otherwise. Put another way, Boost is both a collection of libraries and of best practices, so a good pimpl implementation belongs in boost even if it is a relatively small one. Now the question is whether this particular implementation itself is good enough. Honestly, I have trouble figuring out exactly what it does except by reading through the code since the documentation itself doesn't say what it does behind the scenes except to say vaguely that it implements "pointer semantics" or "value semantics". So one thing that the documentation really needs (among the many others that have been mentioned) is a section that clearly lists the features that it offers. One objection that Artyom reasonably raised is that this implementation may try to do too much, and doesn't offer much in the way of customization. However, people like Artyom are most likely going to be rolling their own implementation of the pimpl idiom anyway. I think that it is sufficient that a implementation be "good enough" for an ordinary user's needs that they won't have to think about any of the ugly details since it does all of that work for them, and to the extent that this is true of the current implementation Now for my thoughts on the code itself. Two of the classes in the implementation should probably be reviewed separately and put in different Boost libraries rather than the Pimpl library, namely safebool and value_semantics_ptr. safebool is an interesting solution to the problem that implicit conversions to the "bool" type implies implicit conversions to hosts of other types such as integers which can result in all sorts of unexpected behaviors that will bite you when you least expect it. safebool solves this problem by providing a convenient way for you to implement an effective "bool()" by instead implementing an operator that returns a special function-pointer that is specialized to your class and thus is equal neither in type nor value to a safebool for any other class; a minor cost that is presumably incurred by this is that a small amount of code will be added to the binary for this special no-op function, since I don't see how this can be optimized away. The implementation looks straightforward and the comments contain good documentation explaining both the usage and the rationale. I would recommend that safebool be accepted into boost and added to the utilities library on its own merits. value_semantics_ptr is a class that contains a pointer to data (or possibly a null pointer) and has the semantics that upon assignment it copies the data from another pointer, allocating (or freeing) its internal pointer if necessary. I think that this is a good idea and that something like this belongs in boost, but I suggest that the current implementation should be changed at least as follows before being accepted: First, it should be taken out of the pimpl<> class and made independent. Second, the traits struct member should be changed from a derived class to a second parameter in the list of template arguments to the value_semantics_ptr type, with the deep_copy member being pulled outside and being made the default value of the new second template argument. Alternatively, a type function --- e.g., copy_traits<T> --- could be used instead. Third, if Boost::Move is going to be ready soon it would be ideal if this class could be modified to support it in order to potentially save some extraneous copies. Fourth, one of the methods confuses me and apparently also the author: bool operator<(value_semantics_ptr const& that) const { return this->impl_ < that.impl_; // Should it be "*this->impl_ < *that.impl_" instead? } so this should be finalized. Fifth, the implementation will need to be fleshed out. operators such as * (dereference) and -> will need to be added, as well as some additional typedefs such as value, pointer, reference, etc. Operator safebool() will also need to be added. In conclusion, if pimpl is accepted I think it would be better for there to be a polished value_semantics_ptr that we feel comfortable having be directly tested and exposed to users be the back-end of this class than something hidden away, so when value_semantics_ptr is ready I think that it should ultimately be accepted to the Smart Ptr library. So much for safebool and value_semantics_ptr, now on to pimpl itself. The code looks straightforward and the comments document it reasonably well --- in fact, the ratio of comments to code in the main pimpl class is roughly 2:1, and in that count I was lazily including whitespace and single { and } lines as code lines, so that gives you a sense of how heavily it is commented. I have only taken a quick glance through it since this is a pre-review, but it all looks simple and straightforward to me, and it does a good job of generating tedious boilerplate so the user doesn't have to, exactly as it claims. On a side note, one additional set of semantics that I would recommend adding is move semantics, which could be implemented using the Boost::Move library. In conclusion, I think that this library should be broken into parts with safebool being put in utilities, value_semantics_ptr (and we can bikeshed over the name here of course :-) ) being put in smart ptr, and pimpl being put in a separate library. After this is done pimpl will be quite small, but I think that it pulls enough weight that it is nonetheless useful. To repeat what I said earlier, boost is not just a repository of libraries but of C++ best practices, so even if pimpl is small if it does a good job of capturing the pimpl idiom I still think that it should be accepted into Boost. Cheers, Greg

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Library Review Tool (paging Jeff Garland) -- was : Re: [xint] Formal Review Result
by Michael Caisse 27 May '11

27 May '11

On 05/03/2011 09:12 AM, Matthew Chambers wrote: > On 5/3/2011 11:02 AM, Marsh Ray wrote: >> On 05/02/2011 03:04 PM, Barend Gehrels wrote (in another order): >>> >>> There was somebody who recently mentioned a scoreboard on this list >>> and I now think this is a good idea, because the review manager can >>> check if all reviews are taken into account. >> >> Yes, please. >> >> It would also make it more practical for an observer like me to sit >> down and simply read the reviews >> in an orderly way. >> >>> I understand that the traffic was really high, that review managers >>> do this voluntary, everybody don't have all the time, etc. >>> >>> Reviews are usually carefully written. People spend several hours on >>> it, sometimes days. Skipping these reviews is a sad thing. Writing a >>> library cost weeks, sometimes months or more. Forgetting reviews is >>> a very sad thing. >> >> Honestly, I would be more likely to help review libraries if I felt >> like it wouldn't be buried in >> the volume of the list. > > This where mailing lists fall to pieces. With proper forum software, > moderators could easily organize threads and change subject lines so > that it would be trivial to separate actual reviews from discussion. > And in fact, users would quickly adjust their behavior to fit the > paradigm. Instead, we have hundreds of messages with "review" in the > subject and only some of them are actual reviews, most being > discussion (like this one!). :( > > -Matt > _______________________________________________ Some time ago we all had a discussion like this and I believe Jeff Garland had mentioned Smart Bear's CodeCollaborator to aid in Boost Reviews. I used their product for a short time and was just taking a look at their web site again: <http://smartbear.com/products/development-tools/code-review/features/> I know there are other tools also (like Crucible) but CodeCollaborator also allows reviews of html docs which will obviously be handy. IIRC Jeff had mentioned that SmartBear might be willing to provide licensing for Boost (or opensource .. it is all fuzzy). I believe Jeff was in contact with them... but my memory might be failing (Jeff?? Are you there?) I would be willing to investigate this path further, including the administration and such of the tool, if it is of interest to the community. michael -- In the Sacramento/Folsom area? ** Profesional C++ Training mid-May ** http://www.objectmodelingdesigns.com/boostcon_deal.html Michael Caisse Object Modeling Designs www.objectmodelingdesigns.com

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[network] Review Manager - Volunteer
by Michael Caisse 27 May '11

27 May '11

Review Wizards - Dean Michael Berris and I spoke today about his Network library submission that is in the review queue. I am willing to act as Review Manager for the library which is also acceptable to Dean. If there are no objections, please sign me up. Thank you - michael -- Michael Caisse Object Modeling Designs www.objectmodelingdesigns.com

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Re: [boost] [Math and numerics] interest in Circular values math and statistics library ?
by Greg Rubino 26 May '11

26 May '11

I like that idea. An integer version of this lib would be a good start for a boost lib that supports arbitrary finite groups (you get cyclic and dihedral for free). I think such a thing would probably be more generally described in terms of permutations though. Greg Rubino On May 26, 2011 5:18 PM, "Krzysztof Czainski" <1czajnik(a)gmail.com> wrote:

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[pre-review] Pimpl submission in the review queue
by Vladimir Batov 26 May '11

26 May '11

I have a Pimpl generalization submission getting close to the top in the review queue. Rob Stewart suggested I'd post it to the new Boost Code Collaborator site for a pre-review. That's what I did with the following link to the pre-review (Review #5): http://demo.smartbear.com/boost/go?page=ReviewDisplay&reviewid=5 Your participation in that pre-review is most welcome. Best regards, Vladimir.

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[phoenix] conflicts between result_of namespace and result_of class.
by Vicente Botet 26 May '11

26 May '11

Hi, I have found an error when we define new phoenix expression inside boost namespace. The following #include <boost/phoenix/core/limits.hpp> #include <boost/phoenix/core/call.hpp> #include <boost/phoenix/core/expression.hpp> #include <boost/phoenix/core/meta_grammar.hpp> #include <boost/phoenix/object/detail/target.hpp> #include <boost/proto/transform/lazy.hpp> #include <boost/phoenix/core/is_actor.hpp> BOOST_PHOENIX_DEFINE_EXPRESSION( // line 19 (boost)(convert_to) , (proto::terminal<boost::phoenix::detail::target<proto::_> >) (boost::phoenix::meta_grammar) ) results in darwin.compile.c++ ../../../bin.v2/libs/conversion_ext/test/builtins.test/darwin-4.2.1/debug/builtins.o builtins.cpp:19: error: ‘namespace boost::result_of { }’ redeclared as different kind of symbol ../../../boost/utility/result_of.hpp:35: error: previous declaration of ‘template<class F> struct boost::result_of’ builtins.cpp:19: error: ‘template<class F> struct boost::result_of’ used without template parameters builtins.cpp:19: error: expected unqualified-id before ‘<’ token It seems that the Phoenix result_of protocol and the utility result_of conflicts. Is this a real issue? Best, Vicente -- View this message in context: http://boost.2283326.n4.nabble.com/phoenix-conflicts-between-result-of-name… Sent from the Boost - Dev mailing list archive at Nabble.com.

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Re: [boost] [ICL] some improvement proposals. Making selectors return const reference
by Joachim Faulhaber 26 May '11

26 May '11

Hi Denis, list, thanks for your interest in Boost.ICL and for your input. First a side note on the subject line: You did what is stated in the boost discussion policy http://www.boost.org/community/policy.html which says: Put the Library Name in the Subject Line [ICL] some improvement proposals. Actually as you can see on the list the convention that is actually established is [boost][Libraryname] bla bla for the developers list and [Boost-users][Libraryname] bla bla for the user's list. *Would someone update the web page accordingly?* Next I'd like to refer to a suggestion you've sent in off-list: 2011/5/16 Denis <denis(a)camfex.cz>: > Hi Joachim > > I also think that the functions upper() lower() first() last() have to > return const reference to domain_type instead of domain_type. > It is the same for int/double/time but has sense for my blobs. > Returning domain_type implies copying. > Same logic as std::vector's at(). This is interesting. With first() and last(), I don't think it is possible, because, dependent on the type of interval, we may generate a local temporary object via increment (++) or decrement (--), which can not be referred to. On the contrary for upper() and lower(), we should always be able to pass the constant reference of the member variables of the interval as return value. As you say, this avoids copying operations that might decrease efficiency, if domain_type objects are large. I think a modification to the code can be done without breaking existing code, at least I hope so. We could use typedef boost::call_traits<domain_type>::param domain_return_type as return type of lower() and upper(), so pass by value can be kept for built in types. Still I am kind of reluctant when I think of implementing this optimization: (1) Return by value works well and fast for the majority of applications where domain_type is built-in or small (2) Return by value allows for compiler optimizations that are taking care for copy elision in many cases. (3) It would be nicer if all selectors had the same signatures (simplicity). (4) Customization of intervals will become more obscure, less understandable by the new domain_return_type. (5) We'd increase expert-friendliness for a concern that is relatively local: Using ICL::intervals and interval_containers with large domain objects is unfavorable anyway. If efficiency is a mayor issue, we would have to consider not using the large objects directly in intervals but introducing a level of indirection. We may refer to them through (smart)pointers or iterators which are small and use an induced ordering for the interval containers for the Compare template parameter. x < y <=> (*x) < (*y) So I'm not shure what to do. Currently I tend to consider an implementation of the proposal. Thoughts? Joachim -- Interval Container Library [Boost.Icl] http://www.joachim-faulhaber.de

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Re: [boost] [Boost-commit] svn:boost r72166 - trunk/libs/thread/src/pthread
by Juergen Hunold 26 May '11

26 May '11

Hi Anthony, On Wednesday, 25. May 2011 23:19:01 anthony(a)justsoftwaresolutions.co.uk wrote: > Author: anthonyw > Date: 2011-05-25 17:18:59 EDT (Wed, 25 May 2011) > New Revision: 72166 > URL: http://svn.boost.org/trac/boost/changeset/72166 > > Log: > extern "C" functions are static > > Text files modified: > trunk/libs/thread/src/pthread/once.cpp | 4 ++-- > 1 files changed, 2 insertions(+), 2 deletions(-) > > Modified: trunk/libs/thread/src/pthread/once.cpp > =========================================================================== > === --- trunk/libs/thread/src/pthread/once.cpp (original) > +++ trunk/libs/thread/src/pthread/once.cpp 2011-05-25 17:18:59 EDT > (Wed, 25 May 2011) @@ -22,12 +22,12 @@ > pthread_key_t epoch_tss_key; > pthread_once_t epoch_tss_key_flag=PTHREAD_ONCE_INIT; > > - extern "C" void delete_epoch_tss_data(void* data) > + extern "C" static void delete_epoch_tss_data(void* data) At least gcc-4.5.2 does not like this combination and bails out with: error: invalid use of 'static' in linkage specification gcc version 4.5.2 (Ubuntu/Linaro 4.5.2-8ubuntu4) Please find a patch fixing this attached. Okay to commit? Yours, Jürgen -- * Dipl.-Math. Jürgen Hunold ! Ingenieurgesellschaft für * voice: ++49 511 262926 57 ! Verkehrs- und Eisenbahnwesen mbH * fax : ++49 511 262926 99 ! Lister Straße 15 * juergen.hunold(a)ivembh.de ! www.ivembh.de * * Geschäftsführer: ! Sitz des Unternehmens: Hannover * Prof. Dr.-Ing. Thomas Siefer ! Amtsgericht Hannover, HRB 56965 * PD Dr.-Ing. Alfons Radtke !

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[review][autoindex] AutoIndex review result
by Daniel James 25 May '11

25 May '11

The AutoIndex reviews were unanimously in favour of inclusion so it has been accepted into Boost. Reviews were submitted by: Edward Diener, Paul A. Bristow, Barend Gehrels and Hartmut Kaiser. Artyom also took part. Some of the general issues that were raised: The name should be more consistent. There was a little confusion about installation, but this should be easier once it's part of boost. Since it works at the docbook level it can be a bit confusing for a pure quickbook user. We might need to add extra support to quickbook - possibly in the form of a template library. There was some confusion about the integration of the different documentation tools, e.g. the use of <quickbook-define> to optionally include content in quickbook, using 'xinclude' to include doxygen documentation in quickbook. I think this is more of a weakness of the quickbook documentation. A few reviewers wanted finer grained control over where index terms are inserted. It isn't clear how this could be done without adding too much complexity. Adding processing instructions to the xml is one possibility. The C++ header scanner picks up too many symbols for spirit (and will possibly do so for other libraries), some kind of annotation or configuration might help. Thanks to everyone who participated in the review, and to John Maddock for developing AutoIndex, Daniel James

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Boost.Conversion: functors namming
by Vicente BOTET 25 May '11

25 May '11

Hi, during the Boost.Convert after review discussion there were some proposals to use Boost.Phoenix to build the functors. My question is what should be the name of the function that builds the functor. Some possibilities: short s=1; long l=3; using boost::phoenix::placeholders::_1; A- Use a different name: make_converter_to? s=boost::make_converter_to(*short*)(_1)(l) ; B- Use the same name in a different namespace. What about using "fp" as namespace (functional programming). s=boost::conversion::fp::convert_to(*short*)(_1)(l) ; C- Use the same name in the same namespace and use SFINAE/enable_if to select the correct implementation depending on the parameter. s=boost::convert_to(*short*)(_1)(l) ; Which are your preferences? Best, Vicente

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[type traits] issue with operator traits and volatile qualifier
by Frédéric Bron 25 May '11

25 May '11

Sorry for being absent during the last month but it was very hard to find any time to work on the addition of the operator traits. I have not yet had the time to deal with the naming issue... But I found something more tricky while trying to solve the issue of reference types (& was just ignored). I never used the volatile qualifier but I found that the following behaviour breaks the code that detects if an operator returns void or not. Could someone tell me why the following code does not compile? bool f() { } void g(const volatile bool &) { } int main() { g(f()); return 0; } Many thanks, Frédéric

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Re: [boost] [Lambda] Handling Bind/Lambda name clashes.
by Max Sobolev 25 May '11

25 May '11

On 25.05.2011 15:49, Eric Niebler wrote: > (fixing attribution...) > > On 5/23/2011 11:42 PM, Robert Jones wrote: >> On Thu, Apr 7, 2011 at 3:01 PM, Steven Watanabe wrote: >>> At some point in time, Eric Niebler wrote: >>>> And what is wrong with leaving bind in the boost namespace as I was >>>> suggesting and define boost::function like this: >>>> >>>> namespace boost { >>>> namespace function_adl_block { >>>> template<class Sig> >>>> struct function {...}; >>>> } >>>> using function_adl_block::function; >>>> } >>>> >>>> Now the "boost" namespace is no longer associated with >>>> boost::function, >>>> and boost::bind won't be found by ADL. > > It's probably a good general policy to move most/all types in Boost into > ADL-blocking namespaces like above, except those for which there is > reason to keep boost as an associated namespace. cool technique (for building more modular software / libs)!

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[chrono, trunk] linux compile fix
by Tim Blechmann 25 May '11

25 May '11

today's trunk does not compile correctly. this trivial patch fixes the issue: thanks, tim Index: boost/chrono/detail/inlined/posix/thread_clock.hpp =================================================================== --- boost/chrono/detail/inlined/posix/thread_clock.hpp (revision 72154) +++ boost/chrono/detail/inlined/posix/thread_clock.hpp (working copy) @@ -21,6 +21,7 @@ thread_clock::time_point thread_clock::now( ) { + struct timespec ts; #if defined CLOCK_THREAD_CPUTIME_ID // get the timespec associated to the thread clock if ( ::clock_gettime( CLOCK_THREAD_CPUTIME_ID, &ts ) ) @@ -31,7 +32,6 @@ clockid_t clock_id; pthread_getcpuclockid(pth, &clock_id); // get the timespec associated to the thread clock - struct timespec ts; if ( ::clock_gettime( clock_id, &ts ) ) #endif { @@ -49,6 +49,7 @@ } thread_clock::time_point thread_clock::now( system::error_code & ec ) { + struct timespec ts; #if defined CLOCK_THREAD_CPUTIME_ID // get the timespec associated to the thread clock if ( ::clock_gettime( CLOCK_THREAD_CPUTIME_ID, &ts ) ) @@ -59,7 +60,6 @@ clockid_t clock_id; pthread_getcpuclockid(pth, &clock_id); // get the timespec associated to the thread clock - struct timespec ts; if ( ::clock_gettime( clock_id, &ts ) ) #endif {

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Re: [boost] [pre-review] Pimpl submission in the review queue
by Sean Chittenden 25 May '11

25 May '11

> I have a Pimpl generalization submission getting close to the top in the review > queue. Rob Stewart suggested I'd post it to the new Boost Code Collaborator site > for a pre-review. That's what I did with the following link to the pre-review > (Review #5): > > http://demo.smartbear.com/boost/go?page=ReviewDisplay&reviewid=5 > > Your participation in that pre-review is most welcome. Fantastic! I signed up and am anxious to see this library accepte^Wreviewed^Waccepted. I've been using the Boost.Pimpl interface for nearly a year now and have been very successful and happy with its use in my projects. Second to ASIO, Boost.Pimpl has done more to impact the design, structure and maintenance of my projects than any other library (the benefits of a stable ABI are understated). Its use in maintaining clean interfaces and projects can't be understated. Historically I'd always saved implementing Pimpl for external facing bits and had always rolled my own interface, now I use it for everything internal or external because of how easy it is to thump out a Boost.Pimpl based interface. As I said on the review site, I've moved the Pimpl implementation in to "boost/pimpl" directory with success, though was not able to move the Pimpl library under the boost namespace. Actually... let me post a quick example that I wrote to both learn and quickly teach how to use Pimpl: https://github.com/sean-/Boost.Examples/tree/master/pimpl It takes about 60sec-3min for most people to have their "ah ha!" moment with that example (those unfamiliar with Pimpl would be wise to check it out, imnsho). I didn't dive in to the why, but in the implementation it is necessary open your namespace after you have defined your private implementation (see pimpl/pimpl_example_pointer_impl.cc:35). It would be nice to know why this is the case (or if it's a bug). Pre-review feedback: The examples used in the Pimpl unit tests are very very good, but it takes a few minutes to wade through the polymorphism and to tease out the most basic requirements for starting to use Pimpl. Walking through 1K of code to do something very simple is a bit daunting despite the obvious and nearly immediate dividends. Whenever I started using this, it was one of the best few hours I've ever spent learning something new. I'm very pleased to see this library move forward and look forward to its formal review. -sc -- Sean Chittenden sean(a)chittenden.org

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Re: [boost] [date_time] Time zone improvements
by Rutger ter Borg 25 May '11

25 May '11

Jeff Garland wrote: > Very cool :-) One question -- is there a portable solution where a user > could deploy a files onto a Windows system or is it a Unix only solution? > I'm fine with incorporating a *nix only solution because what your > suggesting will be a nice solution for *nix platforms, but it will need to > be clear that it's not portable. I don't see why it wouldn't be possible to deploy the (big-endian) binary files to any platform. Getting it into this binary form (using zone info compiler zic) may be harder to do cross-platform, but cygwin may help here. [snip] > As the primary maintainer of Boost date-time I can say with certainty that > there is interest in this functionality -- it's long been on my todo list > and I haven't had time to get to it. You can email me privately and we > can discuss all the details of how to get your code incorporated. I'll do! Regards, Rutger

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Re: [boost] [ICL] some improvement proposals
by Joachim Faulhaber 25 May '11

25 May '11

Hi Denis, thanks for your input again. You're a good analyzer of code. Maybe you want to consider writing a code review for libraries that are submitted for formal review on the boost developer's list from time to time :) 2011/5/19 Denis <denis(a)camfex.cz>: > Hi > > 1. (questionable because it changes the visible interface): rename > `left_open` and `right_open` to `right_closed` and `left_closed`. > > Reason: interval_bounds is used in bitwise operations with bit=1 means > `closed`. (1) I tried to consider common usage of naming of intervals that is known from math. There seems to tendency to assume closedness as default, while openness is indicated by naming: [x, y] an interval (also closed interval) [x, y) a right open interval (x, y] a left open interval (x, y) an open interval. (2) The bits are chosen so closedness is indicated by 1 and openness is indicated by 0 11 [x, y] an interval (also closed interval) 10 [x, y) a right open interval 01 (x, y] a left open interval 00 (x, y) an open interval. > `left_closed() | open()` resulting in `left_closed()` is more readable than > `right_open() | open()` resulting in `left_closed()`. > > Also, there are checkers `is_left_closed()` and `is_right_closed()` but not > for *_open ... again following common usage [see (1)]. > I had to use `class bounded_value` in my program (as in Icl details: > calculating lower and upper bound of interval separately, then constructing > the interval, bitwise or'ing bounds) > and I commented every usage of `right_open()` as `left closed` in order to > explain why I use `interval_bounds::right_open()` in constructing the left > `bounded_value` of the interval. > This resulted in the idea of renaming. > > Maybe making bit=1 mean `open` would be less painful for other users ? You see me inconsolable to hear that you are suffering pain from my library =( There is an concept "interval_bound" http://svn.boost.org/svn/boost/trunk/boost/icl/concept/interval_bounds.hpp that allows you to combine and-ing or-ing etc. of interval_bounds directly. I think that'll reduce your suffering, at least I hope so. Yes, it's missing from the docs. Would you create a ticket? BTW, you may locally extend the concepts in the way you desire and add functions according to you naming rational. > 2. define `contains(interval, elt)` as `!below(interval, elt) && > !above(interval, elt)` allowing the user to use `below()` and `above()`. > Sometimes it is useful. (3) Thanks for this suggestion. The design of the icl::interval's interface is done under the general requirement of minimality. The concept approach allows you always to add own function templates locally to the concept if you need them. > Anyway, all the versions of `contains()` are made of checking for both > bounds. If you found a suboptimal function implementation, please refer them specifically. I'd appreciate a suggestion for an optimization. You can also create a ticket. > 3. It would nice if the functions taking two intervals will have versions > taking an element as second argument. > I mean functions like `left_subtract`, `operator &`, etc. (I cannot tell all > the list at the moment) > Constructing temporary `close_interval` object in order only to pass it into > those functions is cheap with ints but would be expensive with > heap-allocated domains (blobs, strings, etc). This is worth considering. In my own use of intervals within the implementation of interval containers I never encountered the need for such functions ... yet they may be useful in other situations. What do others think? Best regards, Joachim -- Interval Container Library [Boost.Icl] http://www.joachim-faulhaber.de

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[Iterator] Constness of transform_iterator's dereference operator
by Michel MORIN 24 May '11

24 May '11

(In the previous mail, "function call operator" should be "dereference operator". Sorry for this, I fix it and resend a mail.) A long-standing request that transform_iterator should use boost::result_of will be resolved in Boost 1.47. This is really nice news, but I have a concern related to this. In the new code, transform_iterator uses result_of<UnaryFunc(typename std::iterator_traits<Iterator>::reference)> to determine the return type of a functor. However, since transform_iterator's dereference operator is const, result_of<const UnaryFunc(typename std::iterator_traits<Iterator>::reference)> should be used instead. There is a patch for this fix in #5127: https://svn.boost.org/trac/boost/ticket/5127 Alternatively, to remove this inconsistency, we can strip the constness of transform_iterator's dereference operator by either A. Make UnaryFunc member data mutable as suggested in #4969: https://svn.boost.org/trac/boost/ticket/4969 or B. Add non-const overloads to - transform_iterator's dereference() function - iterator_core_access' dereference() function - iterator_facade's operator*() Patches for A (make_mutable.patch) and B (add_nonconst_overloads.patch) are attached in this mail. Comments? Regards, Michel

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Re: [boost] [pre-review] Pimpl submission in the review queue
by Jeff Garland 24 May '11

24 May '11

Mostafa wrote: >> If you want to use the Code Collaborator site to examine the library, you must create an account. The good news is that there are other libraries there that you can review, too. If you wish to avoid creating an account, then you can follow the link on the review schedule to the code in the sandbox. > > Some may just want to follow a review without necessary participating in one. Requiring a user account discourages such activity, and in my opinion, creates an artificial barrier to further engagement between newcomers, or even existing Boost watchers, and Boost, even if it is a one-sided engagement. > > My thoughts, > > Mostafa This is all getting a bit ahead of my post-boostcon report on the library in a week review activities, but to answer this particular issue I'd say 1) you need a login to participate in the mailing list, 2) it's essential for spam prevention, and 3) data can be periodically put to the list to mitigate this issue. Below is a report (minor formatting tweaks) of the pimpl review generated from code collaborator. I think in all likelihood using one of the modern review tools is going to create a better environment overall. Jeff ************* Overview ID: 5 Status: Inspection Title: Pimpl idiom generalization. Creator: Vladimir Batov Created On: 2011-05-23 15:13 Finished On: 2011-05-24 11:55 Total Person Time: 01:27:06 Wall-Clock Time: 20:34:38 Total Reviewer Time: 00:46:00 LOC All Versions (Uploaded/Changed): 2997/0 LOC Final Versions (Uploaded/Changed): 2997/0 Document Pages (All): 0 Document Pages (Final): 0 Number of Defects: 16 Number of Comments: 8 ************* Overview: Support for value and pointer semantics. Support for boost::serialization. Support for separate -- interface and implementation -- class hierarchies (the Bridge pattern in GoF). Support for internal (implementation-only) run-time polymorphism (Non-Virtual Interface Idiom). Support for delegating constructors. Tutorial. Doxygen-generated docs. Linux and VS2008. ************* Participants Name Role Person-Hours Vladimir Batov Author 00:13:17 Robert Stewart Reviewer 00:46:00 Sean Chittenden Observer 00:06:13 ************* Defect Log ID Creator File Location Type Severity Text D22 Robert Stewart pimpl.hpp Line 25 Interface Major Names with two consecutive underscores are reserved for the implementation D23 Robert Stewart pimpl.hpp Line 25 Style Minor This macro name should start with "BOOST_PIMPL_" D24 Robert Stewart pimpl.hpp Line 54 Interface Minor pimpl<T>::xxxx_semantics is interesting, but xxxx_pimpl<T> is simpler and more direct. D25 Robert Stewart pimpl.hpp Line 157 Interface Major Names with double underscores are reserved for the implementation D26 Robert Stewart pimpl.hpp Line 158 Interface Major Names with double underscores are reserved for the implementation D27 Robert Stewart pimpl.hpp Line 159 Interface Major Names with double underscores are reserved for the implementation D28 Robert Stewart pimpl.hpp Line 160 Interface Major Names with double underscores are reserved for the implementation D29 Robert Stewart pimpl.hpp Line 244 Interface Major Names with double underscores are reserved for the implementation D30 Robert Stewart pimpl.hpp Line 49 Interface Minor What about Pimpl support for classes with a base class? Your design requires multiple inheritance. You could, instead, do the following: class Book : public value_pimpl<Book, Base> { }; template <class T, class Base = null_type> class value_pimpl : public Base { }; template <class T> class value_pimpl<T,null_type> { }; D31 Robert Stewart pimpl.hpp Line 291 Interface Minor This exposes too much of the implementation to the user. A construct() member function set, like the set of constructors your macro now generates, with perfect forwarding (and variadic support, when available), would be better. construct() can call the new operator and save the pointer, thereby hiding those details from the user. D32 Robert Stewart pimpl.hpp Line 57 Interface Minor This exposes the pseudo-smart pointer semantics. It shouldn't be public and it should probably be named "nil" rather than "null." The idea is that nil() returns an object with no implementation rather than a null pointer. D33 Robert Stewart pimpl-use-cases.html Line 346 Documentation Minor "It is not but not a 100% kosher" is nonsensical. Presumably, you mean something like, "This design has some problems." D35 Robert Stewart pimpl-use-cases.html Line 357 Documentation Minor s/nut shell/nutshell/ D36 Robert Stewart pimpl-use-cases.html Line 364 Documentation Minor s/More,/What's more,/ D37 Robert Stewart pimpl-use-cases.html Line 385 Documentation Minor s/for vast majority/for the vast majority/ D38 Robert Stewart pimpl-use-cases.html Line 386 Documentation Minor You can avoid the subsequent "he/she" awkwardness by rephrasing this sentence: "However, putting both <i>book1</i> and <i>book2</i> in a <i>std::set</i> results in two elements rather than one, despite the fact that they are supposed to represent the same <i>Book</i>." Overall Review Conversation Sean Chittenden I've been using Boost.Pimpl for almost a year now with great success (using it in conjunction with MSM, ASIO and Spirit). This has been an incredibly useful library for minimizing the interfaces exposed across components. There are three things that I'd like to see but are largely trivial: 1) a set of clean-room examples of the two implementations (i.e. split out the unit tests from a set of examples for pointer and value semantics), and an example of how to use Pimpl once it has been moved in to the boost namespace (I took a crack at this and was never successful at moving Pimpl in to the boost namespace).

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Implicit cast rules
by Gregory Crosswhite 24 May '11

24 May '11

Hey everyone, Would someone please explain to me the implicit cast rule that prevents the following from compiling, and/or if there is a way around it? #include <boost/optional.hpp> #include <iostream> using namespace boost; using namespace std; struct C { operator optional<int>() { return none; } }; int main() { C c; cout << static_cast<optional<int> >(c) << endl; return 0; } Error message: In file included from /usr/include/boost/optional.hpp:15, from cast-to-optional.cpp:1: /usr/include/boost/optional/optional.hpp: In member function ‘void boost::optional_detail::optional_base<T>::construct(const Expr&, const void*) [with Expr = C, T = int]’: /usr/include/boost/optional/optional.hpp:262: instantiated from ‘boost::optional_detail::optional_base<T>::optional_base(const Expr&, const Expr*) [with Expr = C, T = int]’ /usr/include/boost/optional/optional.hpp:559: instantiated from ‘boost::optional<T>::optional(const Expr&) [with Expr = C, T = int]’ cast-to-optional.cpp:13: instantiated from here /usr/include/boost/optional/optional.hpp:392: error: cannot convert ‘const C’ to ‘int’ in initialization I can tell what is happening; it would seem that the implicit cast rule selects the optional() constructor before it even looks at my more specific cast operator. I'm just confused about why this should be, since I see no reason why constructor casts should be prioritized over operator casts. Is this just the way it is, a GCC quirk, something I'm doing wrong, etc? Thanks! Greg

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Towards a plan to reduce active tickets
by Vicente BOTET 24 May '11

24 May '11

Hi, I've inspected the number of tickets since the las Bug Sprint and we ca see that we are having a mean of 18 additional active tickets each month. month created closed diff 01/05/10 99 107 8 01/06/10 122 316 194 // Bug Sprint 01/07/10 103 56 -47 01/08/10 115 120 5 01/09/10 85 34 -51 01/10/10 105 91 -14 01/11/10 109 80 -29 01/12/10 83 92 9 01/01/11 98 79 -19 01/02/11 98 71 -27 01/03/11 161 107 -54 01/04/11 105 145 40 MEAN 106,2 87,5 -18,7 * MEAN is calculated since the last Bug Sprint, that is for the last 10 months. I don't know what could be done to instead of having more active tickets each month having less. While the Bug Sprints are useful I think that we need to have a plan to reduce them is a regular way. I know that a lot of people would be at BoostCon. It would be great if this subject could be discussed in one of the general sessions. if you have any suggestion, please replay to this post and share your view with the Boost community. Best, Vicente

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[Iterator] Constness of transform_iterator's function call operator
by Michel MORIN 24 May '11

24 May '11

A long-standing request that transform_iterator should use boost::result_of will be resolved in Boost 1.47. This is really nice news, but I have a concern related to this. In the new code, transform_iterator uses result_of<UnaryFunc(typename std::iterator_traits<Iterator>::reference)> to determine the return type of a functor. However, since transform_iterator's function call operator is const, result_of<const UnaryFunc(typename std::iterator_traits<Iterator>::reference)> should be used instead. There is a patch for this fix in #5127: https://svn.boost.org/trac/boost/ticket/5127 Alternatively, to remove this inconsistency, we can strip the constness of transform_iterator's function call operator by either A. Make UnaryFunc member data mutable as suggested in #4969: https://svn.boost.org/trac/boost/ticket/4969 or B. Add non-const overloads to - transform_iterator's dereference - iterator_core_access' dereference - iterator_facade's operator() Patches for A (make_mutable.patch) and B (add_nonconst_overloads.patch) are attached in this mail. Comments? Regards, Michel

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BoostCon 2011 in German IT news
by Boris Schaeling 24 May '11

24 May '11

I got BoostCon 2011 into the German IT news on http://www.heise.de/developer/artikel/developer_artikel_1247894.html. If someone wants to contact IT websites in other countries (after all as a C++ developer I want to read about things like BoostCon), have a look at the article. This should give you an idea how you could get in contact with websites and provide them the kind of news they want to publish. As the conference ended last week, it maybe makes sense to send out "press articles" again when the videos of the presentations are online. Boris

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