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

bad include guards
by Steven Watanabe 26 Jan '17

26 Jan '17

AMDG The following pairs of files have identical include guards ./boost/concept_check/general.hpp ./boost/concept/detail/msvc.hpp ./boost/concept_check/msvc.hpp ./boost/concept/detail/msvc.hpp ./boost/filesystem/cerrno.hpp ./boost/cerrno.hpp ./boost/interprocess/containers/tree.hpp ./boost/interprocess/containers/detail/tree.hpp ./boost/mpl/min_max.hpp ./boost/mpl/max.hpp ./boost/mpl/vector/aux_/front.hpp ./boost/mpl/list/aux_/front.hpp ./boost/multi_index/identity_fwd.hpp ./boost/multi_index/identity.hpp ./boost/python/pointee.hpp ./boost/python/detail/pointee.hpp ./boost/spirit/phoenix/closures.hpp ./boost/lambda/closures.hpp ./boost/xpressive/proto/v1_/proto_typeof.hpp ./boost/xpressive/proto/proto_typeof.hpp ./libs/config/test/boost_no_dep_nested_class.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/config/test/boost_no_mem_templates.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/config/test/boost_no_std_allocator.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/conversion/test.hpp ./libs/any/test.hpp ./libs/interprocess/example/print_container.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/interprocess/test/expand_bwd_test_template.hpp ./libs/interprocess/test/allocation_test_template.hpp ./libs/interprocess/test/printcontainer.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/interprocess/test/print_container.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/iostreams/test/detail/utf8_codecvt_facet.hpp ./boost/detail/utf8_codecvt_facet.hpp ./libs/regex/test/regress/test_regex_search.hpp ./libs/regex/test/regress/test_partial_match.hpp ./libs/serialization/test/C.hpp ./libs/serialization/test/A.hpp ./libs/xpressive/perf/regex_comparison.hpp ./libs/regex/performance/regex_comparison.hpp ./tools/inspect/time_string.hpp ./tools/common/time_string.hpp In Christ, Steven Watanabe

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Why no non-null smart pointers?
by Ross MacGregor 29 Apr '14

29 Apr '14

I just created a very small smart pointer libary for our project. It will contain two types of shared pointers: SharedHandle and NullableSharedHandle. SharedHandle will be a shared pointer that cannot be null by ensuring a non-null construction while NullableSharedHandle will basically be a typedef for boost::shared_ptr. I firmly believe that code can be made more reliable by minimizing the use of nullable pointers. To this end, I think it is important that we start using non-null pointer types. Ideally the compiler would be able to understand a non-null pointer and catch bugs at compile time, but I think we can still improve things with a few runtime checks. If we make sure that a shared pointer is constructed with a non-null pointer and ban any reset() type methods, we guarentee that it points to something. This can be beneficial for the following reasons: 1. Any function that uses this type will no longer be burdened with precondition checks to make sure variables of this type are not null. 2. It's type is simply more explicit and better explains its function. 3. Moving the non-null check to the creation phase will reduce the possibility of encountering null pointer exceptions at runtime (assuming there are many more pointer references than constructor calls). So my little pointer library seems to make a lot of sense, but if so why hasn't this simple smart pointer variation made it into boost yet? Has this been discussed somewhere already? My search on non-null smart pointers is not revealing much discussion on the topic. Regards, Ross

9 16

[interprocess] message_queue hangs when another process dies
by Sergei Politov 03 Nov '11

03 Nov '11

Hi, I have found the following problem with message_queue on win32 (MSVC 2008 + Windows Vista). Suppose we have 2 processes, one sends messages to queue, another reads them. When reading process dies (for instance using End process) during message_queue.receive the another process hangs in send. As I found during investigation, it tries to lock interprocess mutex, but it is already locked by dead process. So this message queue instance becomes unusable. I attached the example. Steps to reproduce: 1) Start "mq.exe s" (i.e. with argument s) It outs: sender: $PID 2) Start mq.exe without arguments. It outs: receiver: $PID 0 1 2 3 4 This time sender outs: send done: 3) At this point the message queue is empty and receiver waits for messages. End it with Task Manager. 4) Enter some number in sender console and press Enter. 5) The sender hangs in message_queue.send Best Regards, Sergei

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[asio] read_until -- possibly misleading documentation?
by Richard Smith 15 Apr '10

15 Apr '10

The documentation for Boost.ASIO (which is otherwise very comprehensive) says of the boost::asio::read_until set of overloads: | Read data into a streambuf until a delimiter is | encountered. <http://www.boost.org/doc/libs/1_35_0/doc/html/boost_asio/reference/read_unt…> What the function actually does is to read blocks of data into the streambuf, and stop when the delimiter is found. This means that frequently data beyond the delimiter will be read into the streambuf. (And this is elaborated in more detail on the individual function's pages, if a reader looks there.) I appreciate that this behaviour is compatible with the documentation, but someone less familiar with ASIO could easily assume that the function will read as far as the delimiter and no further. (And I have just spent a fair amount of time debugging a piece of code where the author had made this assumption.) Could we change the summary documentation to read something like: | Read data into a streambuf at least until a delimiter is | encountered. The implementation may read beyond the | delimiter, but will not block when doing so. While I'm on the subject of ASIO documentation, I can't see any documentation on whether the service_name parameters to the basic_resolver_query constructors are allowed to be port numbers (e.g. "80") or whether they have to be symbolic names (e.g. "http"). Port numbers work, at least on Linux, but it's not clear whether this is something that I should be relying on. Similarly for IPv4 and IPv6 addresses in the host_name parameter. Richard Smith

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Proposed addition to the iterator library for iterating over all tuples.
by Alex Mendes da Costa 19 Jun '09

19 Jun '09

Hi folks: I quite often have to write code to do the following: Given N sequences, generate all the N-tuples s.t. the i'th element in each tuple is drawn from the i'th sequence. For example, if sequence S1 is { 1, 2, 3 } and sequence S2 is { 10, 20 }, I need to generate these tuples: (1, 10), (2, 10), (1, 20), (2, 20). I think this problem could be solved elegantly with a iterator similar to zip_iterator. I have some questions: (1) Is there already a way to do this in boost? (2) If not, would this be a worthwhile addition to the iterator library? (3) If so, could I contribute code for this, or must the existing library owners write it? (4) If so, how would I go about getting my code added? Most of the docs seem to be about submitting entire libraries, rather than extensions to existing libraries. Thanks, Alex

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[mpl] is there a or_seq like logical metafunction?
by vicente.botet 17 Jun '09

17 Jun '09

Hello, I needs calculate the mlp::or_ of a sequence of nullary logical metafunction. This seams quite simple. I have do the following: <code> template <typename Seq> struct or_seq; template <typename Seq, long N> struct or_seq_aux : mpl::or_< typename mpl::front<Seq>::type, or_seq<typename mpl::pop_front<Seq>::type> > {}; template <typename Seq> struct or_seq_aux<Seq, 1> : mpl::front<Seq>::type {}; template <typename Seq> struct or_seq : or_seq_aux<Seq, mpl::size<Seq>::value> {}; </code> Is there a boost or_seq like logical metafunction? Is there a better way to do it? I would be extremely interested in any suggestions. Best regards --------------------------- Vicente Juan Botet Escriba

5 34

Proposed templated integer_sort
by Steven Ross 25 Apr '09

25 Apr '09

Would there be interest in an integer_sort call that is faster than std::sort? Spreadsort is an in-place hybrid radix-based and comparison-based algorithm with better worst-case and average-case (roughly 20-50%) performance than introsort on random integer data. The worst-case advantage is algorithmic, with Spreadsort taking the better of O(n(square_root(bit_sizeof(data) - log(n)))) and O(nlog(n)) time. For 32-bit integers, that's O(n(square_root(32 - log(n)))), so for a log(n) of 16 (65536 items), it's 4n (plus a small constant times n), vs 16n for introsort. For larger n, the advantage vs. pure comparison-based algorithms increases. In effect, Spreadsort smoothly transitions from pure MSB Radix sort to std::sort with its data cut up by a couple iterations of MSB Radix sort (reducing the size of the log(n) factor), depending upon the distribution and size of the data. I could write a templated version of Spreadsort for the Boost library if there is interest. It would work for anything that supports the << and - operators. It could also handle standard floats sorted as integers. Functors supporting << and - could make it more general. Multi-dimensional sorting is also sped up by Spreadsort. I could also write a similar string_sort, that should also be significantly faster than std::sort. This would look much like postal sort, just using introsort after a certain number of iterations. Is this of interest? http://sourceforge.net/projects/spreadsort

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Profiling template instantiations
by Steven Watanabe 12 Feb '09

12 Feb '09

AMDG Over the last few days, I've been working on a tool that counts the number of class template instantiations in a translation unit. To use it from a jamfile import profile_templates : : directory of the tool ; template-profile result : some_file.cpp : <include>some_directories ; If everything works, this will create a file with the extension .tp which will contain the number of times each class template was instantiated, with the most common templates at the top. I've put a zip of a rough version in the vault. http://www.boost-consulting.com/vault/index.php?action=downloadfile&filenam… Caveats: I've only tested with Visual C++ 9.0 and gcc 3.4.4 on cygwin so far. Other compilers won't work, yet. Other versions of these compilers may or may not work. It may be necessary to add link=static to the bjam command line. In Christ, Steven Watanabe

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Re: [boost] Profiling template instantiations (Steven Watanabe)
by PORKOLAB Zoltan 12 Feb '09

12 Feb '09

Hi Steven, We have created a framework for debugging/profiling template metaprograms in 2006. It might give you a few tips. It works based on the same idea you have. We instrument all template codes, both at the begining and at the end of each template we insert a special piece of code emitting warning messages of a well-defined form. Before instrumentation we create an XML file to remember the template positions in the source file. When we parse the warning, using this information we can reconstruct the instantiation stack knowing the original line numbers, identifiers, etc.. At the end we produce another XML for possible front-ends. The framework uses boost::spirit and boost::wave. We have also implemented and tested a visual studio plug-in. An overview of the whole idea: http://gsd.web.elte.hu/templight/ There is also a GPCE article about the framework, you can find it here: http://portal.acm.org/citation.cfm?id=1173746&coll=portal&dl=ACM&CFID=47731… or here: http://gsd.web.elte.hu/contents/articles/gpce06.pdf You can download both the VS binaries and the source from: http://people.inf.elte.hu/pocok Please feel free to use the code or any of the ideas. For technical question you can find Jozsef: jmihalicza(a)gmail.com or me. Regards, Zoltan

4 3

[thread/interprocess] could we improve recursive_mutex constructor
by vicente.botet 24 Jan '09

24 Jan '09

Hi, the recursive_mutex constructor initialize/set/destroy the pthread_mutexattr_t every time. I'm wondering if we can improve the efficiency storing this on a static variable which will be initialized once. What could be the better way to initialize this static variable? Note: the same applies to interprocess mutexes. recursive_mutex() { // begin code that can be initialized only once pthread_mutexattr_t attr; int const init_attr_res=pthread_mutexattr_init(&attr); if(init_attr_res) { throw thread_resource_error(); } int const set_attr_res=pthread_mutexattr_settype(&attr,PTHREAD_MUTEX_RECURSIVE); if(set_attr_res) { throw thread_resource_error(); } // end code that can be initialized only once int const res=pthread_mutex_init(&m,&attr); if(res) { throw thread_resource_error(); } // begin code that can be removed BOOST_VERIFY(!pthread_mutexattr_destroy(&attr)); // end code that can be removed } Regards, Vicente

2 2

manipulators for filtering_stream s
by Roland Schwarz 22 Jan '09

22 Jan '09

Surprisingly I was not able to find on the net code that would give me a smart way to indent a stream. So I wrote a little filter based on the boost iostreams library. My first attempt was: boost::iostreams::filtering_ostream out; indent_filter ind(4); out.push(ind); out.push(std::cout); However trying to control it via e.g. ind.in() ind.out() turns out to be problematic interface since, 1) out.push() takes a copy of ind 2) the interface ind.in() is suboptimal. With my attached example it is possible to: #include "indent.hpp" ... boost::iostreams::filtering_ostream out; indent_filter::push(out,2); out.push(std::cout); ... And use it like so: out << "Hello Filter!\n" << indent_in << "this is\n" << "indented\n" << indent_out << "until here\n" ; Which will result in output: Hello Filter! this is indented until here The state is stored in the ios base class of the stream, by way of the pword mechanism. Consequently the filter stream even may be downcast to a basic_ostream, and the indenter will still work. E.g. with out defined as above: ... foo(out); ... void foo(std::ostream& out) { out << indent_in << "out is a downcast filter_stream\n" << indent_out << "end of indentation\n" ; } If you want to try it out, you just need to include the header indent.hpp. If someone thinks the snippet is usable either as an example for the iostreams library or the filter streams manipulator idea is worth generalizing to make it usable for other filters too, I would be glad to hear from you. -- _________________________________________ _ _ | Roland Schwarz |_)(_ | aka. speedsnail | \__) | mailto:roland.schwarz@chello.at ________| http://www.blackspace.at

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[thread] proposal to manage portable and non portable thread attributes
by vicente.botet 22 Jan '09

22 Jan '09

Hello, Boost.thread has already a non portable interface to get the thread handle class thread { public: ... typedef np_native_handle_type native_handle_type; native_handle_type native_handle(); ... }; Boost.Thread do not allow to pass thread attributes on the thread constructor. I supose that this is due to portable issues. Could we identifiy which attributes are portable and which one not? The portable attributes (as stack size, ...) can be grouped on a thread_attributes class. In order to be able to pass whatever attribute to the thread constructor we can add the setting of non portable attributes to this thread_attributes class, and making the thread constructor take a thread_attributes in addition to the existing parameters. class thread { public: class thread_attributes { // portable attributes public: // set/get of attributes // .. #if defined(BOOST_THREAD_PLATFORM_WIN32) // ... window version #elif defined(BOOST_THREAD_PLATFORM_PTHREAD) private: pthread_attr_t native_attributes; public: set_np_attributes(const pthread_attr_t* h); // ... other #else #error "Boost threads unavailable on this platform" #endif }; thread(const thread_attributes*p, F f,A1 a1); ... }; The portable application needing some specific configuration can construct portable threads using the following schema thread::thread_attributes attr; // set portable attributes // ... #if defined(BOOST_THREAD_PLATFORM_WIN32) // ... window version #elif defined(BOOST_THREAD_PLATFORM_PTHREAD) // ... pthread version pthread_attr_t native_attributes; pthread_attr_init(&native_attributes); pthread_attr_setstacksize(&native_attributes, 1000000); attr.set_np_attributes(&native_attributes); #else #error "Boost threads unavailable on this platform" #endif thread th(attr, f,ctx); What do you think? Vicente

3 3

[swap] How to fix ADL barrier for XL, Intel, GCC, Sun and Como?
by Niels Dekker - mail address until 2008-12-31 19 Dec '08

19 Dec '08

The boost::swap utility from Joseph Gauterin has an ADL barrier against infinite recursion or ambiguity, as recommended by Steven Watanabe and David Abrahams, last year at the mailing list: "Re: [boost] Koenig lookup swap." http://lists.boost.org/Archives/boost/2007/08/125938.php Last Friday I added "test_adl_barrier" to test this ADL barrier. Unfortunately it fails on many compilers, including XL (AIX), Intel (version 9 and 10), GCC, Sun and Como: http://www.boost.org/development/tests/trunk/developer/utility-swap_.html While I usually use MSVC, and for that specific compiler, the ADL barrier appears successful! Do you know how to fix the ADL barrier for the other compilers? I'm afraid we'll need to have #if BOOST_WORKAROUND statements in there... FYI, the boost::swap utility is at: http://svn.boost.org/svn/boost/trunk/boost/utility/swap.hpp The ADL barrier test is at: http://svn.boost.org/svn/boost/trunk/libs/utility/swap/test/test_adl_barrie… Kind regards, -- Niels Dekker http://www.xs4all.nl/~nd/dekkerware Scientific programmer at LKEB, Leiden University Medical Center

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[proto][design]why unary_expr,binary_expr; but no nullary_expr?
by Larry Evans 14 Dec '08

14 Dec '08

Although there's unary_expr<Tag,*>, binary_expr<tag.*,*> in traits.hpp there's no nullary_expr<Tag>. I realize this would be a replacement to the current terminal template but with a user specified tag. After all, if a user specified tag for n-ary (where n>0) expressions *is* desirable, why is a user specified tag for 0-ary expressions *not* desirable? On case where this would be useful is for algebraic morphisms where n-ary ops in a source algebra are mapped to n-ary ops in a target algebra. This *includes* 0-ary ops. An op would be the equivalent to proto tags. I think this could be done by another transform similar to the pass_through transform but allowing transformation of the tag. Currently pass_through just uses the source tag in the target expression. It seems like it should be pretty easy to allow transformation on the tag also.

2 3

[integer] Promotion of endian library code from vault
by Neil Mayhew 01 Oct '08

01 Oct '08

On 2006-07-22 12:21:01, Beman Dawes wrote: > [boost] [integer] endian-0.6 posted w/ names changed > endian-0.6.zip has been posted in the integer directory of the file > vault at http://boost-consulting.com/vault/ This code is still in the vault, but I'd like to see it in the main part of boost. What needs to be done to make this happen? The endian library is exactly what I've been looking for, and I would really like to use it in my work, but I can't justify that to my colleagues if it's not an official part of boost. I would hate to become yet another person that reinvents this particular wheel. However, I notice there was a lot of discussion <http://lists.boost.org/Archives/boost/2006/07/108125.php> about PODs vs constructors, because of unions, so maybe not enough consensus was reached? There were some interesting proposals but no agreed-upon solution. In which case, I suspect that people will need to copy the code and each hack it to suit their own purposes, which is not what boost is all about. I have two use cases from my own work: TrueType fonts, and Mac HFS+ file systems. Both of these are big-endian file formats that need to be read into memory and processed, so (FWIW) I would support the POD approach. Currently, I can't use the code as-is because of the need to use the types in unions. References: http://lists.boost.org/Archives/boost/2000/03/2495.php http://lists.boost.org/Archives/boost/2006/05/105621.php http://lists.boost.org/Archives/boost/2006/06/105695.php http://lists.boost.org/Archives/boost/2006/06/105779.php http://lists.boost.org/Archives/boost/2006/06/105968.php http://lists.boost.org/Archives/boost/2006/06/106655.php http://lists.boost.org/Archives/boost/2006/07/108125.php http://lists.boost.org/Archives/boost/2006/07/108202.php --Neil

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[BENUM] Any interest in auto-generated enum-to/from-string functions, without longer/more-complex usage?
by Tony D 15 Sep '08

15 Sep '08

Anyone think this functionality belongs in boost? (I have working code) ENUM(X, B = N, C, D = B + C }; // or whatever X x1 = C; cout << x1 << '\n'; // outputs "C\n" X x2("D"); // construct from string... if (x2 == D) { will do } Tony __________________________________________________________ Sent from Yahoo! Mail. A Smarter Email http://uk.docs.yahoo.com/nowyoucan.html

4 3

[thread_pool]: formal review request
by Oliver Kowalke 12 Sep '08

12 Sep '08

Hello, I'd like to request a review of my thread_pool library - it is available at the boost vault/Concurrent Programming. The library provides: - thread creation policies: determines the managemnt of worker threads - fixed set of threads in pool - create workerthreads on demand (depending on context) - let worker threads ime out after certain idle time - channel policies: manages access to queued tasks - bounded channel with high and low watermark for queuing tasks - unbounded channel with unlimited numer of queued tasks - rendezvous syncron hand-over between producer and consumer threads - queueing policy: determines how tasks will be removed from channel - FIFO - LIFO - priority queue (attribute assigned to task) - smart insertions and extractions (for instance remove oldest task with certain attribute by newst one) - tasks can be chained and lazy submit of taks is also supported (thanks to Braddocks future library). - returns a task object from the submit function. The task it self can be interrupted if its is cooperative (means it has some interruption points in its code -> this_thread::interruption_point() ). Oliver -- GMX Kostenlose Spiele: Einfach online spielen und Spaß haben mit Pastry Passion! http://games.entertainment.gmx.net/de/entertainment/games/free/puzzle/61691…

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[spirt] question regarding BOOST_SPIRIT_THREADSAFE and BOOST_SPIRIT_SINGLE_GRAMMAR_INSTANCE
by Robert Ramey 05 Sep '08

05 Sep '08

I've just discovered the existence of these manifest constants in spirit and checked the documentation and code to determine what they do. Of course figuring what spirt code does and how it does is not easy to get right for the casual observer so feel free to correct and any mis-conceptions / conclusions that I 've got. My general conception is that parsing can be consider as various quasi - independent phases. a) specification of grammar - source code preparation b) compiliation c) instantiontion/construction of grammar definition d) usage of c) to parse a text string e) destruction of instance. >From this I want to conclude that phase d) does not change the grammar definition so so that in a multi-threading environment, the invocation of the scoped_lock would be limited to phases c) and e). That is, I want to believe that the following example adapted from the spirit documentation would work: const my_grammar g; // note addition of const if (parse(first, last, g, space_p).full) cout << "parsing succeeded\n"; else cout << "parsing failed\n"; The reason I ask is that the serialization library uses spirit to parse xml archives. Recently, I made changes to make the library thread-safe. I did this without using mutexes/locks by confine all non-const operations to construction and destruction and using static object constructed/destructed at pre-main and post main time time. Although the jury is still out on this, I believe it will make the serialization library thread safe without the need for using threading primitives and libraries. I never realised that spirt wasn't thread-safe. I would like this approach to include xml_archives. So my quesion is: Can I instantiate my xml grammar as a static variable at pre-execution time and permit it to be used by mulitipe threads without locking? Robert Ramey

7 13

Proto<markus>::review()(proto::accept);
by Markus Werle 30 Aug '08

30 Aug '08

Hi! I think Proto should be accepted for inclusion into boost. A general purpose Expression Template library is hard to write. Proto is the most sophisticated and closest approach to perfection available today. - What is your evaluation of the design? Proto is well-designed in many aspects, though I got the impression that some beauty and purity was sacrificed on the altar of compile-time efficiency, but that's OK. (And yes, I hate BOOST_PP_MACROS!) Proto catches the most important issues of a general purpose expression template library, I especially like the way how expression storage and expression evaluation is strictly separated and the way I can add my own functionality. Proto covers the most important aspects of an ET library, sometimes in very elegant ways. Proto's design adressed compile time issues. That's a value in itself. OTOH: Transforms leave me with mixed feelings. I am not very good at catching ideas without good step-by-step documentation and I got messed up with grammars vs. transforms. This part of proto is new and it looks like a candidate for rework. I'd like to have an extra review in half a year only on the grammar and transform part of proto (*)[comment below]. That's a DSEL all by itself and I guess that interface may have some pitfalls. Larry Evans has worked that out in detail. There may be issues in the naming convention used there, e.g. I am unsure whether and_ is the appropriate name for what it does. - What is your evaluation of the implementation? None. Not enough time. Steven Watanabe did it for us all. Code looks clean. For my taste too many levels of nested namespaces, but that's the boost trend at the moment. I may appreciate this style later in my life, once I understand why you need it. - What is your evaluation of the documentation? The quality varies from excellent to hard to read. I agree with all what David writes about the docs. There is some potential for improvement, but that should not hinder the inclusion into boost: we need a community effort here since Eric's skill level probably is way too high in order to have some feeling for why the unaware might have problems with parts of the doc. The teacher should be one step ahead, not too far ahead. - What is your evaluation of the potential usefulness of the library? We really, really need this. Better today than tomorrow. The whole world is waiting for this to come. And C++ again rocks - Did you try to use the library? A couple of hours, but only for some of the examples. - With what compiler? VC8, Intel 10.1 - Did you have any problems? Nope. Eric-faster-than-lightning fixed those before I could run into them ... - How much effort did you put into your evaluation? I read the docs three times and worked through some details. I investigated the type representation of expressions by reading purposely generated compiler error messages and tried to figure out the design. - Are you knowledgeable about the problem domain? I had several attempts to write some kind of ET library on my own, some parts published at daixtrose.sourceforge.net. I also planned to write something like proto myself, but due to lack of time and programming skills I lost the race before it began. (rm -rf /work/markus/ideas/expresion_templates_revisited) Eric, thanks for the time saved by the publication of proto. Markus P.S. This review is short, sorry. I had some unexpected tasks to do the last week which hindered further investigation. I'll put some more effort into this in the future. (*) I'd like to have an extra review on _every_ boost library in a 2-year-cycle. By this boost::multi_array could probably be forced to model assignable like any other STL container and ::_1 from boost::bind will move into its own namespace - just to mention my two favourite change requests ...

3 3

Re: [boost] UTF-8 conversion etc. (Sebastian Redl) (Sebastian Redl)
by Graham 28 Aug '08

28 Aug '08

>> As I said to Phil, Rogier and I completed a Unicode character library >> for >> >> Release under boost, but never submitted it to Boost as we had intended >> to >> >> release it with a string library built on it, and never had time to do >> the >> >> second part of the work. >> >Post it, and we'll do the second part. It's open-source. > >Sebastian Sebasian, As requested, I have posted a Unicode character support library in the boost vault as Unicode_lib.zip. Please feel free to use this under the boost license. It would be great if somebody had the time to develop the existing character support to ad the string wrappers that we had intended to - but ran out of time doing. It should be well documented, but if you want any questions answered, please feel free to ask and I'll try and help! Thanks. Yours, Graham

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[smart_ptr] make_shared usage
by Daniel Frey 21 Aug '08

21 Aug '08

Hi, I have a question on make_shared. Consider a class which intends to force all instances to be handled via a shared_ptr. I used to do this by putting the ctors into the private section and adding static create()-methods in the public section. Example: class X { private: X( int, double ); public: static shared_ptr<X> create( int i, double d ) { return shared_ptr<X>( new X( i, d ) ); } }; Replacing the returned expression with make_shared<X>( i, d ) wouldn't work, since it requires a public ctor. Is there any solution to this or do I have to make a decision between efficiency and a safe interface for X? Regards, Daniel

7 17

[integer] Recent changes introduced failures on many platforms
by Markus Schöpflin 20 Aug '08

20 Aug '08

The two tests integer_mask_test and integer_test have been broken by the recent commits to integer on nearly all platforms. (Probably all but Windows) The error message is: In file included from ../libs/integer/test/integer_test.cpp:29: ../boost/integer.hpp:154:39: error: invalid suffix "ui64" on integer constant ../libs/integer/test/integer_test.cpp:115:39: error: invalid suffix "ui64" on integer constant ../libs/integer/test/integer_test.cpp:215:39: error: invalid suffix "ui64" on integer constant Regards, Markus

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[shared_ptr][exception] Support for disabled RTTI
by Daniel James 18 Aug '08

18 Aug '08

Using boost with RTTI disabled was recently discussed on the user list, and I had a quick look into it. It seems that shared_ptr added support for the BOOST_NO_TYPEID macro in 1.35: http://svn.boost.org/trac/boost/ticket/1108 But because it now depends on the new exception library, which requires RTTI, it no longer works. Would it be possible to support the macro in Boost.Exception? Daniel

5 8

[asio]: extending asio
by Andreas Pokorny 17 Aug '08

17 Aug '08

Hello, I would like to add more asynchronous event sources to asio, like: - input events for mouse, keyboard and joystick .. - window exposure, move, resize events in some generic form, - generic "quit" events - file alteration With directFB/X11/Unix/Linux most of that can be done directly through select or epoll. But since reading the message and parsing events is mostly done by a third party library, I would only need the reactor part for these. Is this possible with asio? According to msdn it seems to be possible to create so called event objects for direct input devices. I am no win32 expert so I do not know if one can combine that with completion ports? Regards Andreas Pokorny

7 16

contradictory information in FS docs?
by Noah Roberts 12 Aug '08

12 Aug '08

"Class basic_directory_iterator is an important component of the library. It provides an input iterator over the contents of a directory, with the value type being class basic_path." That seems to be correct. "The expression itr->path().leaf() == file_name, in the line commented // see below, calls the leaf() function on the path returned by calling the path() function of the directory_entry object pointed to by the iterator." But that claims the object pointed to the iterator is something other than basic_path and appears to be quite in error. itr->path() fails to compile. Documentation is same for both 1.34 and 1.35 - tested on 1.34. This appears in both the front page and the docs for directory iterator. The find_file function doesn't actually compile if copied verbatim. Need to remove all calls to path() on the iter and replace with "*itr".

2 2

proposal: interval containers; boost examples and more
by Joachim Faulhaber 11 Aug '08

11 Aug '08

Dear boost developers, after encouraging feedback by Paul A Bristow, Vicente Botet and Luke Simonson to my proposal on interval containers from end of May (http://lists.boost.org/Archives/boost/2008/05/137301.php) I started to boostify my interval template library (ITL). Even though there is a lot left to be done for the ITL to become fully boost compliant I'd like to report on some aspects of my current work. (1) As suggested by Paul A Bristow I have prepared some new examples that are using boost::date_time as instance types for the interval containers. * Example boost_party.cpp is a boostified instance of the introductory example party.cpp that demonstrates the 'aggregate on overlap' mechanism of interval maps (see: http://www.herold-faulhaber.de/itl/boost__party_8cpp.html) * Example month_and_weeks_grid.cpp demonstrates how different time grids can be merged in split_interval_sets by intersection (see: http://www.herold-faulhaber.de/itl/month__and__week__grid_8cpp.html) * Example man_power.cpp shows how calculations on interval_sets and maps can be obtained using set type operations. In the example the available man power in a small company is calculated accounting for weekends, holidays vacations etc. (see: http://www.herold-faulhaber.de/itl/man__power_8cpp.html) * Example user_groups shows how interval maps can be unified or intersected (see: http://www.herold-faulhaber.de/itl/user__groups_8cpp.html) (2) In the course of boostification of my code I have reviewed the design and completed the interval container classes as follows: * interval_set * split_interval_set * separate_interval_set (added) * interval_map (added) * split_interval_map You can see an overview these interval containers and some basic characteristics in the ITL's documentation here: http://www.herold-faulhaber.de/itl/interval__container__conduct_8h.html The major addition here is the class template interval_map. In contrast to a split_interval_map that preserves all interval borders that may emerge due to insertion and intersection operations, an interval_map keeps itself always minimal: Whenever two neighbouring interval-value pairs ([a,b), v), ([b,c),v) emerge, they will be joined to ([a,c),v). (3) Reviewing the overall design of the interval containers I have separated the meaning of insert/add and erase/subtract, which had been confounded in the previous version of the ITL. This has consequences especially for interval maps: As a design decision I'd like to choose that interval maps are addable and subtractable objects having operators += and -= that implement these properties. Addition and subtraction is then defined via element addition (add(value_type&)) and element subtraction (subtract(value_type&)). At a general level I can define add<inplace_op>(value_type&) and subtract<inplace_op>(value_type&)as member function templates, that implement aggregation on overlap (aggovering) not only for inplace_plus (+=) but also for arbitrary aggregate operations (inplace_op). It turned out, that function insert (std::insert semantics) can be expressed by the general add template (as well as erase can expressed by the subtract member function template): add<inplace_identity>(value_type&) is equivalent to insert(value_type&) subtract<inplace_erasure>(value_type&) is equivalent to erase(value_type&) In addition we can also define 'plain' element add and subtract by means of these templates: add(value_type&) can be defined as: add<inplace_plus>(value_type&) subtract(value_type&) can be defined as: subtract<inplace_minus>(value_type&) So for the ITL container classes I do provide now insert and erase that covers the std::semantics and I provide add and subtract that is the basis for addability and subtractability of itl::maps and itl::interval_maps. You can find an overview over all insert/erase and add/subtact functions and their relationships to std::semantics in the ITL's documentation here: http://www.herold-faulhaber.de/itl/interval__container__design_8h.html I find these design and semantical questions quite rich, and sometimes surprising ;-) and I have found many more aspects and properties while reviewing the ITL's design. I am planning to prepare a more detailed article about these topics in the next months to come. (4) I have prepared a new release 2.0.1 of the ITL for the current state that can be downloaded from: http://www.sourceforge.net/projects/itl Documentation is availabe online also from here: http://www.herold-faulhaber.de/itl The code is well tested using the Law Based Test Automaton (LaBatea) and is protabel for gcc 3.4.4 and msvc 8.0 sp1. I am sorry the ITL is still not in the boost standard directory structure. This will be one of the next steps on my todo list. (5) Concerning boostification of ITL there is still a lot to be done. Besides reviewing of the overall design reported above, I have removed virtual functions from all interval container classes using the curiously recurring template pattern (CRTP). To prevent you repeating advices that already found their way into my todo list I am listing it roughly as appendix to this posting. Cheers Joachim Faulhaber --- Boostification todo list: - Extracting a subset of the ITL as boost proposal - Providing the code in boost directory structure - Replacing own metaprogramming code by boost::mpl,fusion etc. - Using boost::value_initialized for generic initialisations - Further minimizing of class template interfaces and... - Providing more operators and functions as itl::global algorithms - Providing as much std::semantics as possible for interval containers (viewed as set<interval<T>> or map<interval<T>,U>) - Adapting testcode to boost testing standards - Improving documentation especially for issues of design and complexity - Providing boost style documentation - Preparing a proposal on the addition of open interval bounds to boost::interval

4 6

web service client based on boost?
by Gregory Dai 09 Aug '08

09 Aug '08

Anyone tried building a web service client based on existing boost library components such as asio? Like to share, or brag :-) about your experience? A web service server is probably more involved. Doing a client should be a nice first step, and helps build a common foundation forward. Thanks, Greg

5 10

Re: [boost] data_binding
by Brian Davis 06 Aug '08

06 Aug '08

>Stjepan Rajko writes: > I have tried to tackle the value/domain transformation problem a while > back, inspired by Brook Milligan's (CC-d) probability library (which > can nicely transition probability values between linear and log > domains). > Brook Milligan also worked on a generic domain transformation library, > so he might comment on this as well. There is also the Boost.Units > library which might offer transformations for some cases. >Thanks, Stjepan. I've continued to refactor that, actually, to make >it support the more generic problem under discussion here. So far it >is mostly done. I think the only issues are some silly overloading >resolution issues that have little to do with the basic ideas. For >the discussion I'll outline my approach. The goal I have/desire is to preform type transformations and allow the programmer to specify these transformations in a generic way For type T1 and T2 allow the programmer to specify f(T1 t1, T2 t2 ) and g(T1 t1, T2 t2 ) where f and g are transformation functions from T1 -> T2 and T2->T1 respectively. Overloading operator= and specifying f(T1 t1, T2 t2 ) := t2 = t* 1/2 and g(T1 t1, T2 t2 ):= t1 = t2*2 allowing the programmer to type float t1; float t2; bind_values<float ,float > t1t2ValueBinder( t1, t2 ); t1 = 12; printf( "%f", t2 ); // produces output of 6 Transformations shall allow chaining/cascaded to be specified. int a; int b; float c; boost::uint32_t d; bind_values<int,int> abBinder( a, b ); bind_values<int,float> abBinder( b, c ); bind_values<float,boost::uint32_t> abBinder( c, d ); // a->b->c->d a = 12; printf( "%f", d ); // produces output of 6 Transformations shall allow for fanout int a; int b; float c; boost::uint32_t d; boost::uint32_t e; boost::uint32_t f; bind_values<int,int> abBinder( a, b ); bind_values<int,float> abBinder( a, c ); bind_values<float,boost::uint32_t> abBinder( c, d ); bind_values<float,boost::uint32_t> abBinder( c, e ); bind_values<float,boost::uint32_t> abBinder( c, f ); // a-+->b // | // +->c-+->d // | // +->e // | // +->f // a->b->c->d a = 12; printf( "%f", f ); // produces output of 12 as f and g default to 1 to one mapping a = 12; printf( "%f", f ); // produces output of 12 as f and g default to 1 to one mapping printf( "%f",e); // produces output of 12 as f and g default to 1 to one mapping f=32; printf( "%f", a ); // produces output of 32 as f and g default to 1 to one mapping printf( "%f",f ); // produces output of 32 as f and g default to 1 to one mapping printf( "%f",c ); // produces output of 32 as f and g default to 1 to one mapping Transformations shall support bidirectional and unidirectional updates. >The basic observation that motivates this is that in some (many?) >situations there exist a group of related types that clearly have >common semantics in the application domain but may impose different >constraints in their implementation. Yes. Agreed >Indeed, some operations may not >be practical or feasible for some of the types but could be for others >and there may exist transformations from one to another. Where if there exists no clear transformation... the programmer shall be allowed to specify one. >In the case >of probabilities think of two types, one for a probability and one for >its logarithm with appropriate operators defined for each domain and > the interconversions. Another example involves the representation of > polynomials, which can be in terms of coefficients or in spectral > terms that ease their multiplication. In this case, it may be > completely undesirable to implement a polynomical multiplication for > the coefficient representation. Yes so some types can not be automatically transformed. My example provides absolutely no support for this except for 1 to 1 translation... for disparate types it is... well... compiler errors waiting to happen if no translation functions are supplied. > Conceptually then, the Domain library seeks to create a framework for > implementing sets of such types that work smoothly together, and > enable the compiler to make choices about how to handle mixed domain > operations (e.g., adding a probability and a log probability) or > operations that must be performed in another domain (e.g., multiplying > two polynomials represented as coefficients). I think these are most > of the salient points, all of which are currently supported. The software engineer shall be allowed to specify a transform is the compiler cannot automatically figure it out. How difficult is it to specify new types and tranforms.... Are we talking about the types like thoes defined by the section titled "A Deeper Look at Meatafunctions - 3.1 Dimensional Analysis" in "C++ Template Metaprogramming" by David and Aleksey? If so ... ouch... could be quite painful to specify new types and conversions... What is your approach? > - Allow definition of families of types (domains) based upon each > member of a family sharing common semantics in the application > domain. Providing type conversions across known domains where they exist. Yes sounds great. > - Allow implementation (or not) of any within-domain operators that > make sense in the application domain. Yes sounds great with the exception of the "operators portion"... like every one in boost using operators for new purposes (think Spirit - and I don't mean this in a bad way) we are running out of operators which provide meaningful schematics... Food for thought: Wouldn't it be nice if we had our compilers be able to compile unicode source files ... call them .ucpp... and define new operators in the C++ language... then we would be able to utilize these new operators to write code which looks ascetically pleasing and readable. Another benifit could be easier support internationalization of software. I'll digress. > - Allow implementation (or not) of any appropriate interdomain type transformations. > - Decouple the domain type information from the value types used to > represent the internal domain-specific information. This I also provided for in my simple example. Though kinda a cheesy example as "domain" is completely specified by the programmer and there is no automatic domain logic . > - Allow specification of a default value type for any domain type so > that unspecified templates (i.e., T<>) provide meaningful results. > - Allow specification of which domains are interconvertible as a > series of pairwise conversions. so you have a chain a->b->c->d change a and b, c, and d are changed... correct? This was in my example Should also allow for fanout // a-+->b // | // +->c-+->d // | // +->e // | // +->f and avoid recursion. a->b->c->a->a->b->c->a... you get the idea > - Allow specification of which domains support which operations so > that the compiler can seek an appropriate domain for arguments that > may (or may not) be directly usable. What happens when and operation cannot be found in a domain, but the programmer can or needs to specify one? Is it extensible? > The goal is to clearly define all these points of extension so that > the "real" types (e.g., probabilities or polynomials) can be > constructed on top of the Domain library, thereby simplifying the > specification of domain families for any application or library. The easier it is to provide new specifications for types and their transformations the better.... you'll never think of every domain and translation. Need to supply a clear path to adding new types, domains, and translations. > I have been using this to refactor the Probability library as a proof > of concept. As mentioned, most of what the old version could do, the > new one will also do. > There are a few issues with overloads that are > confusing to me, so help is welcome. How do I obtain the code and where is the problem? > Thus, I am certain that there is > some merit in this approach to a generic domain solution. However, I > am also certain that there are other ideas out there that could > improve this. Gerneric domain is exactly what I am after. We have type T1, T2, T3,....TN and we have to translate between them... What's the easiest way to specify this for the programmer? > Because of the interaction in development between the two libraries > (Domain and Probability) I haven't quite finished everything. I'll > try to roll them up for viewing shortly, though. > I look forward to continuing discussion, receiving input, and > discovering how these ideas might be put to use in other contexts. Context.... Let me speak to context... Let's say your one of thoes down to earth engineer types... you got to get your product out... you have all this incoming and out going data at multiple layers of the software form hardware<->driver<->user space lib<->executable<->network<->client and you have to translate between types for each interface... Bitfields... don't get me started on bit fields... Why is a bit such a degenerative type in C++ (try typeid(bit.in_a_bitfield).name() and wonder why you get back unsigned... would be nice to get the position info of where the bit or bits are withing a bit field) ... I'll digress again... any way you want to easily specify type conversions at each layer. You've received the event in the past and called the appropriate conversion routine after conversion routine and thought to yourself.. Hey is there any way to get rid of all of these calls to conversion functions in my callback routine... they're kinda making the code messy. Sure would be nice if I had a data_binding library where I could specify the types and specify the conversion functions and when the value arrives just set it and have the conversion take place bidirectionally. Then you write it up... think to yourself who might be able to use this... maybe those boost guys :-) Hope my input is helpful. Brain

4 12

[1.36.0 beta] Beta release available on SourceForge
by Beman Dawes 06 Aug '08

06 Aug '08

New libraries: Accumulators, Exception, Units, Unordered. Updated Libraries: Assign, Foreach, Interprocess, Intrusive, Math, Multi-index Containers, PtrContainer, Spirit, Thread, Xpressive, plus a bunch more. Many thanks to Daniel James, Rene Rivera, Marshall Clow, Eric Niebler, the testers, and all the others who helped to get this beta release together. The beta period will be approximately one week. Please post bug reports here, but also let us hear about success stories too! --Beman

3 3

[sandbox][move] Regular requirement
by Michael Marcin 06 Aug '08

06 Aug '08

I'm using the current move library in the sanbox by daniel james (which I believe is the 4th move emulation library I've used now). It seems to be very good so far and makes writing code that handles both move and copy a breeze. I hope this gets finalized and ready for review soon because a consistently used move emulation library would be a great aid to writing efficient libraries that work well together. However the documentation says that objects have to model the Regular concept in order to model the Movable concept. This seems unfortunate as Regular puts a lot of requirements on types that don't seem necessary to gain moving. It requires Assignable which requires a copy constructor and it requires EqualityComparable which seems unnecessary. As a matter of fact I'm currently using the library with types I derive from boost::noncopyable on msvc 2008 and it is working wonderfully. Can the Movable concept be relaxed to require only what is truly necessary? Thanks, Michael Marcin

3 3

fixed pt binary lib
by Neal Becker 06 Aug '08

06 Aug '08

I have the beginning of a fixed-pt binary lib. Fixed-pt is popular in DSP applications. It is integer arithmetic, but keeping track of the binary pt. It is built on top of constrained_value. It is small, so I include it here:

8 22

variant invariant
by Emil Dotchevski 05 Aug '08

05 Aug '08

Reading boost::variant's documentation: "If any bounded type is nothrow default-constructible (as indicated by boost::has_nothrow_constructor), the library guarantees variant will use only single storage and in-place construction for every bounded type in the variant. Note, however, that in the event of assignment failure, an unspecified nothrow default-constructible bounded type will be default-constructed in the left-hand side operand so as to preserve the never-empty guarantee." Do I read correctly that in an attempt to assign one variant object to another, the left-hand object _might_ silently change its type? This makes it very difficult for the user to enforce some useful invariants for types that have boost::variant members, which in my mind is very important. Wouldn't it be better to guarantee that operator= either succeeds or doesn't change the observable state of the left-hand side operand, even at the cost of memory allocation? In that case the other behavior may still be provided through a separate function. Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode

7 18

Why I hate subversion
by Eric Niebler 02 Aug '08

02 Aug '08

U boost/indirect_reference.hpp U boost/parameter.hpp svn: In directory 'boost' svn: Can't move 'boost/.svn/tmp/foreach.hpp.2.tmp' to 'boost/foreach.hpp': Permission denied ericne@ericne-xps ~/boost/org/trunk $ svn up svn: Checksum mismatch for 'boost/.svn/text-base/enable_shared_from_this.hpp.svn-base'; recorded: '12d8c5183a709a7699c13b312073c36c', actual: 'c89a6b23045ff8c89d2de74213d1649a' Does this ever happen to anybody else? I get this random corruption of my local subversion repository about once a month. -- Eric Niebler Boost Consulting www.boost-consulting.com

11 15

[unnullable_ptr] Proposal for a new library
by Angel Tsankov 02 Aug '08

02 Aug '08

Hello, Is there any interest in a class template which acts like a pointer and guarantees at compile time and at no CPU or memory cost (except when a call to any of its methods is not inlined) that the pointer is not null? One of the applications that I have found for this template is in defensive programming to eliminate the chances that dereferencing a pointer will result in undefined behaviour (when the pointer is null). Using this template is superior to any alternative method (that I know) to achieve the same result, since: (*) it consumes no CPU (in contrast to null checks); (*) the class template instances are copy constructible and copy assignable (in contrast to references which can also be used to guarantee unnullability); (*) it is natively supported by the language and provides a 'real' guarantee (in contrast to 'design by contract'); (*) supports the natural syntax for access to the wrapped resource (in constrast to boost::ref). Regards, Angel Tsankov

13 35

[shifted_ptr] STL support works at 90% (...!)
by Phil Bouchard 02 Aug '08

02 Aug '08

I've finalized the ad extremum idea of STL support of smart pointers such as shifted_ptr which is a good example to use because of the distinct types it is using as pointer types (T *, shifted<T> *, shifted_allocator::pointer, etc.). I have 2 patch files that can be used as an example to add support for real smart pointers using Gcc's STL. These are located in the bits/ folder. These are Gnu related but I wanted to share this here for objectivity. I have added special contructors in shifted_ptr that takes raw pointers (T *) instead of the type safe shifted<T> *. This is temporary until I add the proper casts inside the STL code. What else? I simplified shifted_allocator and fixed abominable bugs in shifted_ptr created by these temporary constructors added. Now I'm pretty dang happy about it... There are still some I need to fix and some more are yet to be found but it should be much easier now. Once again I am using shifted_ptr_test2.cpp as my main test application. Later, -Phil

1 2

Possible library submissions: fuzzy logic library, new container
by Alex Shafir 01 Aug '08

01 Aug '08

I am trying to determine if there might be any interest in a couple of possible library submissions. Both ideas were very useful and instrumental for many C++ development projects that I was doing for the last years. The fuzzy logic library is a simple, pure C++, optimized for speed, practical implementation of the fuzzy logic calculations that DOES NOT attempts to comply with the FCL(Fuzzy Control Language) standard (like IEC 1131). It CANNOT load FCL files. Instead similar to the Boost Spirit framework it provides a syntax that enables fuzzy logic rules to be written exclusively in C++. Compiled fuzzy model specifications are immediately executable. A snippet of what this syntax currently looks like is at the end of this message. The other idea is the “sparse array” container. Working for securities trading industry I used it innumerable number of times. It is useful in situations where there is a set of entities identified by integer(unsigned) numbers. Most often the numbers are identity keys in a database, a protocol field ids, etc. The potential range of the numbers makes it impractical to use a C++ array or the STL <vector>. On the other hand the average percentage of the keys that are really used in an application relative to the potential range is often less then 5% and there are huge holes of unused keys between zero and max(used key). The data elements or pointers to objects are kept in a structure similar to a balanced B-tree. Elements are directly accessed by an index operator. Access involves only a few arithmetic and redirection operations. When storing a new element that is outside of the range provided by exiting data structure the structure bilds itself up extending the indes range enough to accommodate a new index value. Existing data are never physically moved like in the STL vector. So, all references/pointers/iterators referencing existing elements are never invalidated. Feel free to comment. Fuzzy model syntax sample: ======================================== #include "TestModel.h" using namespace Fuzzy; // test model definition TestModel::TestModel(string file): Model(file), angle(-1), velocity(-1), speed(-1) { // fuzzy variables definitions created by the base class (Fuzzy::Model) // Input/Output methods; Input/Output arguments are refs // to double scalar variables Var& Angle = Input(angle); Var& Vlcty = Input(velocity); Var& Speed = Output(speed); // membership functions definitions created by fuzzy variables // Term method; Term method takes curve name as an argument; // cureve names are defined in the Fuzzy::Model curve definition // file MemFun& AngleNegHigh = Angle.Term("AngleNegHigh"); MemFun& AngleNegLow = Angle.Term("AngleNegLow"); MemFun& AngleZero = Angle.Term("AngleZero"); MemFun& AnglePosLow = Angle.Term("AnglePosLow"); MemFun& AnglePosHigh = Angle.Term("AnglePosHigh"); MemFun& VlctyNegHigh = Vlcty.Term("VelocityNegHigh"); MemFun& VlctyNegLow = Vlcty.Term("VelocityNegLow"); MemFun& VlctyZero = Vlcty.Term("VelocityZero"); MemFun& VlctyPosLow = Vlcty.Term("VelocityPosLow"); MemFun& VlctyPosHigh = Vlcty.Term("VelocityPosHigh"); MemFun& SpeedNegHigh = Speed.Term("AngleNegHigh"); MemFun& SpeedNegLow = Speed.Term("AngleNegLow"); MemFun& SpeedZero = Speed.Term("AngleZero"); MemFun& SpeedPosLow = Speed.Term("AnglePosLow"); MemFun& SpeedPosHigh = Speed.Term("AnglePosHigh"); // these are the model rules; syntax is pretty strightforward; // rules look like operator >> where lhs is the condition and // rhs is the conclusion; // lhs and rhs have to be in parens if they contain more then // one term because of the c++ operators precedence rules; // conclusion may be a comma separated list of output terms // in parens ((AngleZero and VlctyZero)or(AnglePosLow and VlctyNegLow)or(AngleNegLow and VlctyPosLow)) >> SpeedZero; ((AngleZero and VlctyNegLow)or(AngleNegLow and VlctyZero)) >> SpeedNegLow; ((AnglePosLow and VlctyZero)or(AngleZero and VlctyPosLow)) >> SpeedPosLow; ((AngleZero and VlctyNegHigh)or(AngleNegHigh and VlctyZero)) >> SpeedNegHigh; ((AnglePosHigh and VlctyZero)or(AngleZero and VlctyPosHigh)) >> SpeedPosHigh; } TestModel::~TestModel() { } void TestModel::run(double a, double v, double &s) { // we assign scalar variables to class members angle = a; velocity = v; speed = s; // then run the model // it should be pretty fast as it all designed to preallocate // all the needed large objects in the model constructor Model::run(); // and assign the values of output variables s = speed; }

3 2

dll-path feature
by brook＠biology.nmsu.edu 01 Aug '08

01 Aug '08

It seems that I need to use the dll-path feature to add an -rpath directive to the linker when my boost libraries are installed. This seems to be described (mostly) fairly clearly at http://www.boost.org/boost-build2/doc/html/bbv2/faq/dll-path.html What is not clear is where the feature should be invoked. My attempt to modify Jamroot to add <dll-path> to the boost-install rule failed in the sense that not rpath information makes it into the installed libraries. (The rest of this snippet is the original.). rule boost-install ( libraries * ) { package.install install : <dependency>/boost//install-headers $(install-requirements) : # No binaries : $(libraries) : # No headers, it's handled by the dependency ; install stage : $(libraries) : <location>$(BOOST_STAGE_LOCATE) <dll-path>/path/to/add/via/rpath ; local c = [ project.current ] ; local project-module = [ $(c).project-module ] ; module $(project-module) { explicit stage ; explicit install ; } } So, how is one supposed to invoke the <dll-path> feature in order to have -rpath added to the linking of libraries during their installation? Thanks for your help. Cheers, Brook

3 4

[release] xpressive bug fix
by Eric Niebler 01 Aug '08

01 Aug '08

What are the chances that I'll be able to merge a bug fix to the release branch? This one: http://svn.boost.org/trac/boost/ticket/2157 just came in, and I've already fixed it on trunk. Assuming that the next cycle of the trunk tests don't show anything amiss, would I be permitted to merge the fix? The bug will not cause crashes, but it will lead to incorrect results when matching the end-of-line assertion ($) against internal line breaks, which is fairly common usage scenario. I have high confidence in the fix. These are the relevant changesets: http://svn.boost.org/trac/boost/changeset/47899 http://svn.boost.org/trac/boost/changeset/47901 -- Eric Niebler BoostPro Computing http://www.boostpro.com

2 3

1.36 documentation
by Daniel James 01 Aug '08

01 Aug '08

Hello everyone, Since the generated documentation isn't currently included in the snapshots, I've temporarily made it available here: http://www.calamity.org.uk/1.36/ Hopefully, the documentation should be integrated with the beta site soon after the beta release. Daniel

9 19

[swap] End-user allowed to add overloads to boost namespace?
by Niels Dekker - mail address until 2008-12-31 31 Jul '08

31 Jul '08

Is any end-user allowed to add her own overloads of existing Boost functions to the boost namespace? The boost::swap utility from Joseph Gauterin (recently moved to the trunk) allows the user to customize boost::swap for her class, by providing a swap function for her class within the namespace of the class. Internally boost::swap does the idiomatical "using std::swap; swap(left,right);", to allow finding such a user-provided swap function by argument-dependent lookup (ADL) <svn.boost.org/svn/boost/trunk/boost/utility/swap.hpp> Unfortunately some compilers don't fully supported ADL, as is shown by the mixed test results of swap/test/specialized_in_global.cpp and swap/test/specialized_in_other.cpp, at http://www.boost.org/development/tests/trunk/developer/utility-swap_.html ADL failures appear to occur for GCC 3.3.1 (PathScale), Intel C++ 8.1, MSVC 7.1 (2003), and Borland (up to 5.9.3). Once the boost::swap utility would be used by other Boost libraries, end users might want to add a custom overload of swap for their classes to the boost namespace. Especially when users would have to deal with lacking ADL support of their compiler. Would it be okay for them to do so? Or are there some moral objections, or technical issues, regarding a user-provided overload within the boost namespace? Kind regards, Niels PS Volodya, thanks for fixing swap/Jamfile.v2! -- Niels Dekker http://www.xs4all.nl/~nd/dekkerware Scientific programmer at LKEB, Leiden University Medical Center

6 14

boost versus Apple's gcc 4.2
by Mat Marcus 31 Jul '08

31 Jul '08

On the boost users list, there was a discussion about some issues arising with boost versus gcc-4.2 on Apple systems. One interesting issue arises from the fact that Apple decoupled the gcc compiler version from the lib version. They "own" libstdc++, which they've kept at version 4.0 even when the 4.2 compiler. This breaks some assumptions in boost headers. I am reposting on the main developer list: ### Peter Dimov wrote: > Is the new Apple GCC documented somewhere? I wasn't able to find anything > related to a new assembler syntax or -fasm-blocks. Can you ask Apple to > explain the issue? Stock g++ 4.2.x compiles the code, so the problem must be > Apple-specific. Ok, I've got a little bit more information on the Apple gcc 4.2 situation. Here is a snippet from an email dialog between a user and an apple compiler engineer: user appears below with with prefix ">>" apple compiler engineer appears below with with prefix ">" >> Thank you very much for the detailed reply. >> Based on your information I deduce: >> >> 1) Using gcc 4.2 with 4.0 (c++) libraries is a supported >> configuration by Apple > > Right. > >> I then conclude that the C++ ABI is fully compatible between 4.0 and >> 4.2 > > Right. [snip, then user hypothesizes as to why there are problems with boost under gcc 4.2/libstdc++ 4.0 on current Apple systems] >> This is the case because boost assumes that a 4.2 compiler implies >> 4.2 libraries in flies such as boost/detail/atomic_count_gcc.hpp: >> >> #if (__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 2)) >> # include <ext/atomicity.h> >> #else >> # include <bits/atomicity.h> >> #endif > > Yes, this is a bug or faulty assumption in boost. [snip] > The 4.2 library issue is a bug in Boost, not a problem with > our compiler. I'd suggest raising the issue on one of the boost > mailing lists and see what they say. Comments? Mat

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[1.36 beta] Beta release candidate available
by Beman Dawes 31 Jul '08

31 Jul '08

Release candidate tarballs for the 1.36 beta are available at http://boost.cowic.de/rc/ Special thanks to Daniel James for generating the docs. Hopefully we can get the doc generations problems fixed quickly so that we can get back on a nightly release snapshot generation running again. I'd like to get feedback before uploading these to SourceForge. Please post a reply indicating success or problems encountered, being sure to indicate your platform and which file you downloaded. Thanks, --Beman

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The --toolset option
by Vladimir Prus 31 Jul '08

31 Jul '08

Okay, now it's my turn to propose something to sneak into 1.36.0 at the last minute. Fortunately, it's only documentation change. For quite a while, both getting-started, and bjam --help mentioned --toolset option. This in practice, resulted in folks getting wrong analogy and trying to use --variant=debug --link=shared, etc. We agreed (on Boost.Build list), in principle, that we better remove --toolset from documentation, and use 'toolset=' instead -- which has exactly the same effect. So, I would like to commit the following Jamroot change to HEAD and merge to release branch. Any objections? I also would like to see the issue filed against getting-started: http://svn.boost.org/trac/boost/ticket/2050 fixed, and can provide a patch assuming release manager is fine with having this doc tweak merged into release branch, too. Opinions? Thanks, Volodya

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range_ex: status?
by Mathias Gaunard 30 Jul '08

30 Jul '08

I'm writing some piece of software working that does a lot of data structures traversal and that really needed filtering of traversal etc. I thought I'd get that from Boost.Range, but I was surprised to see Boost.Range provides very little: all the good stuff (the range-based algorithms and adaptors) are in another library, range_ex, which isn't in the main distribution yet. Will this library be included in Boost soon? It's really great. As for the open issues, here are my opinions: - Output ranges: don't adaptors already output ranges? - Two input ranges, or a range and an iterator?: two ranges can do more - For any algorithm foo(container, args...), if foo(args...) is valid then it should be called - Null-termination of C-style strings: Isn't that up to Boost.Range to decide whether it's a range or not?

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add new category in libs/libraries.htm
by Emil Dotchevski 30 Jul '08

30 Jul '08

Any opinions on adding a new category in libs/libraries.htm, Error Reporting, containing static_assert and the exception lib? Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode

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[getting started][1.36] Please rebuild and merge.
by Daniel James 30 Jul '08

30 Jul '08

Please can somebody rebuild the getting started guide in trunk? Beman, is it be okay to merge this into the release branch? I've only updated the version numbers: http://svn.boost.org/trac/boost/changeset/47870/ I've also added a note to the release procedure wiki pages so hopefully this won't be missed in the future. thanks, Daniel

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[hash] Broken link in docs
by John Maddock 30 Jul '08

30 Jul '08

While building the docs in /doc/ I see: Writing unordered/buckets.html for section(unordered.buckets) ID recommended on table: Methods for accessing the hash and equal... Writing unordered/hash_equality.html for section(unordered.hash_equality) ID recommended on table: Interface differences. Error: no ID for constraint linkend: unordered.rationale.equality_operator. ID recommended on table: Complexity Guarantees Writing unordered/comparison.html for section(unordered.comparison) Writing unordered/rationale.html for section(unordered.rationale) Looks like a broken link? John.

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remove_pointer and pointers to members?
by John Maddock 29 Jul '08

29 Jul '08

Folks, I'm trying to decide how to fix this bug report: https://svn.boost.org/trac/boost/ticket/2011 Basically what should: remove_pointer<int (foo::*)>::type be? Should it produce an int, or have no effect? TR1 explicitly says that it has no effect, so I guess I vote to stick with that behaviour. In which case, anyone object to a remove_member_pointer trait that transforms: int (foo::*) --> int int (foo::*)(double) --> int (double) etc. It's also tempting to add a "member_object" trait at the same time that transforms: int (foo::*) --> foo int (foo::*)(double) --> foo thoughts? Thanks, John.

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Test machines available
by Ruediger Berlich 29 Jul '08

29 Jul '08

Hi there, I was wondering whether there would be a need for additional systems for automated, nightly builds. My employer would agree to make a few (3-4) machines available, with Linux-based operating systems. This would be a VMWare ESX-based setup, although on high-performance hardware (8-core blades). I would personally be most interested in a test environment with the OpenSUSE 11 64 bit / g++ 4.3.1 combo. It might be possible to also have an OpenSolaris/Intel installation there, or an installation with Intel's C++ compiler. A pre-condition would be that no external access to the machines is needed, i.e. it would not be possible for Boost members to log in. Instead, I would set up the test environment as needed, and of course it would be possible for these machines to contact the outside world and transmit test results. Thus my question, what needs to be done to set up such a test environment. Note that I cannot give a guaranty for long-term availability, as a) I do not know how much work is involved in running such an environment and b) it might become necessary for the systems to be used in other contexts. If this turns out to be pretty much self-hosting (i.e. the build-environment is self-sustained on a normally configured Linux system), I would aim to ensure that the systems are available for a longer period. Best Regards, Ruediger /*************************************************************************/ The Steinbuch Centre for Computing of Karlsruhe Institute of Technology (the Cooperation of Forschungszentrum Karlsruhe GmbH and Universitaet Karlsruhe TH) will run its annual GridKa School from September 8th to 12th, 2008. Please find further information at http://www.fzk.de/gks08 . /*************************************************************************/ Forschungszentrum Karlsruhe GmbH Sitz: Weberstraße 5 76133 Karlsruhe Amtsgericht Mannheim HRB 100302 Vorsitzende des Aufsichtsrats: Baerbel Brumme-Bothe Vors. der Geschäftsführung: Prof. Dr. Eberhard Umbach

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[1.37] When this will start?
by vicente.botet 29 Jul '08

29 Jul '08

Hi, Release 1.36 will have soon 2 weeks behind schedule. In order to maintain a quarterly release, when do you plan to start the 1.37 release? IMO it is time to start with it (1/08/2008), but without a named branch by release this is impossible. Could you share with us which is the plan to avoid that the quarterly release become a wish? Vicente

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