August 2009 - Boost - lists.preview.boost.org

[Endian] Version 0.10 available - Binary I/O added
by Beman Dawes 16 Sep '09

16 Sep '09

Version 0.10 of the Endian Integers library is available. Docs: http://mysite.verizon.net/beman/endian-0.10/libs/integer/doc/endian.html Zip: http://mysite.verizon.net/beman/endian-0.10.zip Sandbox: http://svn.boost.org/svn/boost/sandbox/endian This version adds binary I/O for both endian integers (<boost/integer/endian_binary_stream.hpp>) and C++ built-in types + std::string (<boost/integer/endian_binary_stream.hpp>). Support for C++0x features has also been added, ensuring that an Endian integer on C++0x is a POD. Comments appreciated! My Endian TODO list is pretty well cleared, so there are comments to the contrary, the library will be submitted for formal review in a few days. --Beman

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enabling/disabling floating point exceptions
by Gennadiy Rozental 15 Sep '09

15 Sep '09

Hi guys, I am looking to complete cross platform implementation of enabling/disabling logic in boost::execution_monitor. It looks like there is no standard interface available. I'm using _controlfp interface now on Windows. I also found these non-standard extensions: * feenableexcep/fedisableexcept available with glib 2.2 * fesettrapenable avaialble in Dinkumware (implementation of STL?) and HP * sun has something called fex_set_handling. not sure when it's available though * header fpu_control.h. Not sure where it's available though. * MAC OS X has something called _MM_SET_EXCEPTION_MASK in xmmintrin.h It also seems that in some cases the switch is compile time only (using compilation option). Would anyone care to extend this list/comment on it's applicability and/or correctness? Another change I am considering is to split floating point exception catching from other system exceptions. It seems perfectly valid scenario to set catch_system_error to false (thus avoid catching access violations etc) but still willing to catch and process floating point exception. What do you think? Gennadiy

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Build files locations, try 2
by Vladimir Prus 12 Sep '09

12 Sep '09

Some time ago, I have raised the concern that CMakeList.txt files violate directory structure requirements. See: http://thread.gmane.org/gmane.comp.lib.boost.devel/189496/ Back then, the discussion did not lead anywhere, and no further progress was made for 2.5 months. So, let me try to phrase this a bit differently. Is it fine with everybody if I move Jamfiles out of 'build' folder of every library one level higher? Thanks, Volodya

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Control of the file location for the boost::interprocess::managed_shared_memory object
by Michael Watkins 11 Sep '09

11 Sep '09

Is it possible to control the exact location of the file that is backing the shared memory created by boost::interprocess::managed_shared_memory? The issue occurs under Windows (it has not been tried yet under Linux). The problem is two processes attempting to connect to the same shared memory segment between two accounts, in specific from a program running as a service (using the system account) and a program running under a user account. The user account is running a program that needs to interface to the database that the service created. Everything seems to work fine, but the service will open the shared memory backing file in the global temp directory while the user account will open the file in their local settings temporary directory. Therefore two different segments are opened. The interim solution is to use boost::interprocess::managed_windows_shared_memory to create the shared memory, but the desire is to use the generic version for cross-platform compatibility. If the full file path could be specified when creating the memory segment, it would solve the problem. Michael Watkins _________________________________________________________________ Windows Live™: Keep your life in sync. http://windowslive.com/explore?ocid=PID23384::T:WLMTAGL:ON:WL:en-US:NF_BR_s…

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[unordered] please don't allocate memory in the default constructor
by Thorsten Ottosen 10 Sep '09

10 Sep '09

Hi Jeremy, I think this a really bad idea to allocate in the default construtor. The user can always call rehash() on the empty container, just like when we call reserve() for vector. Thanks -Thorsten

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Re: [boost] [serialization] Linker errors in trunk
by Hartmut Kaiser 08 Sep '09

08 Sep '09

> Sorry, resending as it ended up on the wrong list... > > ----------------------------- > > Since the latest changes in trunk I'm seeing linker errors while > linking with the serialization library (VS2005 SP1, > boost_serialization-vc80-mt-gd-1_40.lib): > > runtime_support.obj : error LNK2001: unresolved external symbol > "__declspec(dllimport) public: __thiscall > boost::archive::archive_exception::archive_exception(enum > boost::archive::archive_exception::_exception_code,char const *,char > const *)" > (__imp_??0archive_exception@archive@boost@@QAE@W4_exception_code@012@PB > D1@Z) > > (note the leading underscore in _exception_code) > > Which is really strange as this symbol is the only missing one. > > OTOH, the library exports the symbol: > > boost::archive::archive_exception::archive_exception( > enum boost::archive::archive_exception::exception_code, > char const *,char const *); > > (note the missing underscore in exception_code) > > If I change the first parameter of the archive_exception constructor to > be a 'int' everything builds fine. Ok, I solved it. The MS header file excpt.h has a #define exception_code _exception_code which leads to problems if not consistently included. Doh! What a mess. The bottom line is, that archive_exception.cpp needs to be compiled with exactly the same windows headers included (excpt.h gets included by windows.h) as any sources including archive_exception.hpp, which is generally not possible to ensure. The only fail-proof way I could see is to always have #if defined(BOOST_WINDOWS) #include <excpt.h> #endif inside archive_exception.hpp, globally mapping exception_code to _exception_code. Patch attached. Ok to commit? Regards Hartmut

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Arbitrary precision arithmetic
by Scott Johnson 07 Sep '09

07 Sep '09

Greetings. This is my first post to the mailing list, so I'll try not to act stupid. :) The recent release of Boost (1.39.0), in the boost::rational library documentation, broadly hints at (and expresses a fond wish for) an arbitrary-precision integer ("bignum") library; however none currently exists within Boost. There are numerous such libraries out in the wild (many targeted towards C); though some of them are under incompatible licenses. (One interesting starting point would be libtommath, by Tom St. Denis; it appears to be a pretty robust and functional C library; which now has a C++ wrapper--albeit one that doesn't meet boost standards. It also contains numerous other useful number-theoretic functions, many of which appear to not be dependeing on the underlying bigint type. And it's in the public domain, or at least appears to be...) Searching through the mailing list, I've seen numerous references to creating such a thing, some of them dating back nearly ten years--but none yet seems to exist. This is something, I think, which would be Really Useful to add to boost. I wasn't able to locate any current boost project or proposal to create such a thing--though it's certainly possible I looked up the wrong keyword(s). So, my possibly impertinent newbie question: Is anyone (seriously) working on such a thing, for inclusion in boost? Are there any nasty (political) obstacles to such a thing being added? Thanks! -- engineer_scotty (no, not that one) If life gives you lemons, drink Hefeweizen

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[ptr_container] Questionable strong guarantee of ptr_map::insert()
by Kazutoshi Satoda 05 Sep '09

05 Sep '09

Hi, With current implementation of ptr_map::insert(), if an exception is thrown, the objected pointed by the passed pointer is deleted. Is this really providing strong guarantee as documented? I understand strong guarantee as described here. http://www.boost.org/community/exception_safety.html > The strong guarantee: that the operation has either completed > successfully or thrown an exception, leaving the program state exactly > as it was before the operation started. I think ptr_map::insert() doesn't provide this guarantee because deleting the object is a change of the program state. As more concrete problem, see the attached code. I couldn't find any way to provide strong guarantee for delayed_inserter::insert_ready() using ptr_map. I want ready_value unchanged if an exception is thrown during the insertion. Looking for a solution on a similar situation, I found constructors of shared_ptr. Its documentation clearly says that "If an exception is thrown, delete p is called". And for auto_ptr version, it provides strong guarantee by taking the auto_ptr as non-const reference. I think ptr_map::insert() should follow this manner; document the deletion on exception for raw pointer version, and provide strong guarantee with insert(const key_type& key, std::auto_ptr<U>& x) . The the auto_ptr& version can be a better replacement of the raw pointer version. The required temporary of auto_ptr, instead of key_type, is more expressive (about the purpose of the temporary), and matches the Best Practices shown in the documentation of shared_ptr. http://www.boost.org/libs/smart_ptr/shared_ptr.htm#BestPractices But, introducing the auto_ptr& version seems to cause some change of behavior in client codes using the current pass-by-value version. Is it valid to request (create a ticket) for strong guaranteed (taking auto_ptr&) version while having this compatibility concern? Regards. -- k_satoda #include <memory> #include "boost/ptr_container/ptr_map.hpp" namespace ptr_map_insert_strong_guarantee_demo { class value { public: explicit value(int source); // ... }; class delayed_inserter { public: // ... // This is called from context that knows key and source of value, // but doesn't know the time of insertion. void ready_new(int key, int source) { // OK. // This implementation offers strong guarantee for this call. std::auto_ptr<value> new_value(new value(source)); ready_key = key; ready_value = new_value; } // This is called from context which doesn't know key and value, // but knows the time of insertion. void insert_ready() { if (ready_value.get() != 0) { // I want to offer strong guarantee for this call, // but boost::ptr_map deosn't provide the way to do that; // *** ready_value is deleted when an exception is thrown. *** map.insert(ready_key, ready_value); } } // ... private: int ready_key; std::auto_ptr<value> ready_value; boost::ptr_map<int, value> map; // ... }; }

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wait-free fast-pathed, bounded-time, 100% starvation-free rw-mutex...
by Chris M. Thomasson 04 Sep '09

04 Sep '09

I was wondering if the following invention of mine might be of use to Boost: http://software.intel.com/en-us/forums/intel-threading-building-blocks/topi… (please __read_all__; thank you) Here are some performance numbers wrt my algorithm versus NPTL on Linux (fedora 10), and OpenSolaris: http://groups.google.com/group/comp.programming.threads/msg/3e7531657a11baf0 My invention has some very interesting properties that simply do not exist for 99% of all the other rw-mutex algorithms I have seen to date. It's 100% starvation free and has bounded wait time for readers and writers. Heck, even the Microsoft rw-mutex algorithm in Vista does not come close to that: http://msdn.microsoft.com/en-us/library/aa904937(VS.85).aspx They clearly state that their algorithm is not fair. The algorithm I have observed in OpenSolaris does not meet this goal as well. Another nice property is that the algorithm has wait-free fast-paths. If readers hit a fast-path, then they are going to get wait-free access to the protected data-structure. The same goes for writers. The underlying operation is a single atomic fetch-and-add operation: http://software.intel.com/en-us/forums/intel-threading-building-blocks/topi… In fact, the algorithm only needs fetch-and-add; no stupid CAS-loops are required. Please take not that there are absolutely no loops in the algorithm; this is one reason why it's bounded time and starvation free. Also, it has conditional reader-to-writer upgrades and non-conditional writer-to-reader downgrade capabilities. This is something that does not exist in the Microsoft implementation, or even the OpenSolaris, or basically any Linux implementation I have observed. Same goes for OSX. Therefore, I think this particular algorithm might be of use to Boost. Any thoughts? Thank you all for you're valuable time; I really do appreciate it! :^)

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[date_time, Boost 1.40.0]
by Christoph 03 Sep '09

03 Sep '09

including boost/date_time/posix_time/posix_time.hpp or boost/date_time/gregorian/gregorian.hpp gives lots of warning for the following line(s): (boost/date_time/gregorian/conversion.hpp; posix_time, tooo) line 44 std::tm datetm = {}; // zero initialization is needed for extension members, like tm_zone I admit I don't understand the comment. Is it possible to fix that (correctly) such that including the header does not produce like 20 warnings in each .cpp file including the header? (I am using linux running gcc 4.1.2) Best regards Christoph

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[pool] patch to make pool support zero sized allocations.
by Steven Watanabe 02 Sep '09

02 Sep '09

AMDG The patch at https://svn.boost.org/trac/boost/attachment/ticket/386/pool.patch allows the pool classes to support zero sized allocation, by returning a null pointer. std::vector sometimes allocates a zero sized block, so this is necessary for pool_allocator. Returning a null pointer is the simplest solution and I'm that the standard allows an allocator to return the null pointer when asked for a block of zero elements. Okay to commit? In Christ, Steven Watanabe

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windows timeout implementation
by Gennadiy Rozental 01 Sep '09

01 Sep '09

Hi, I have windows timeout support implemented for boost::execution monitor. It requires multithreading and thus introduces additional dependencies. I am thinking of making it available with compile time flag. Any comments/suggestions are welcome. Gennadiy

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[polygon] examplefile compilation failed
by Joachim Faulhaber 31 Aug '09

31 Aug '09

Hi Luke and polygonists! I had problems compiling the example files from the doc's main page with msvc-9. None of custom_p*.cpp examples compiled. Also the connectivity_extraction_usage.cpp example failed. (1) connectivity_extraction_usage.cpp: #include <boost/gtl/gtl.hpp> must be replaced by #include <boost/polygon/polygon.hpp> namespace gtl = boost::polygon; has to be added. (2) custom_point.cpp: compilation yields: 1>.\custom_point.cpp(75) : error C2757: 'gtl' : a symbol with this name already exists and therefore this name cannot be used as a namespace name 1>.\custom_point.cpp(77) : error C2143: syntax error : missing ';' before '<' 1>.\custom_point.cpp(77) : error C2913: explicit specialization; '::geometry_concept' is not a specialization of a class template and many errors more after replacing gtl:: by boost::polygon:: and namespace gtl { ... } by namespace boost { namespce polygon { ... } } and adding typedef int coordinate_type; to struct CPoint the code finally compiled. Are these examples intended to be excercises ;) HTH Joachim

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C++ MapReduce performance - compared to C Phoenix
by Jose 31 Aug '09

31 Aug '09

I wanted to share some performance numbers to encourage others to write examples or applications using the C++ multi-core mapreduce library being developed by Craig H. I ran some tests comparing the C++ version to the C version, for the word_count example. The tests are run on a X86_64 linux Fedora 10 with 2 cores. The results below show that the C++ MapReduce (mr) has very similar performance to the C version (mr-c). The tests start running phoenix first. Run 3 and 4 show that c++ mr is slightly faster. When using 1MB MR_L1CACHESIZE (which should be the best comparison) shows that mr-c is a little bit faster but not much. 1-mr-c 0m18.077s 2-mr 0m13.818s 3-mr-c 0m14.828s 4-mr 0m14.148s 5-mr-c-1MB 0m14.006s 6-mr-c-2MB 0m14.084s Note: The C++ version uses a chunk size of 1MB while the C version uses by default a chunk size of 64KB (which can be changed with the variable MR_L1CACHESIZE) regards jose

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Boost.MapReduce: what next?
by Craig Henderson 31 Aug '09

31 Aug '09

I am thinking now about how to progress my MapReduce library that is in the Boost SandBox. I have completed the single-machine implementation; it's performance is comparable to other libraries such as Phoenix (http://mapreduce.stanford.edu) and has been tested by a few people on this list. There has, however, been little interest in the library so far from Boost users/developers which surprises me. I don't know if that is because of the single-machine limitation and people don't see any value that MR can bring to multi-threaded programming? So where do I go next with the library? Options that I see are: 1. Complete the documentation and submit the current library to Boost for a formal review. I'm not clear there is sufficient interest, though. 2. Continue to develop the library in the sandbox to multi-machine implementation and work towards submitting that for formal review. Is there interest for this? 3. Accept that Boost is not an appropriate forum for a MapReduce library and find an alternative community to develop the library. Looking at the download figures from the Vault, there has been a reasonable number of downloads; Of course there is no way to tell the number of people looking at the sandbox implementation. Perhaps the library has some silent interest? Please let me know your thoughts. Thanks -- Craig Craig Henderson <http://craighenderson.co.uk/> http://www.craighenderson.co.uk http://www.siteupdatenotification.com

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factory.hpp missing
by Felipe Magno de Almeida 31 Aug '09

31 Aug '09

Hi, AFAIK, the functional/factory.hpp was accepted in boost a long time ago. But never seem to have made into svn. Does anybody know why? Regards, -- Felipe Magno de Almeida Sent from my Nokia E71

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Re: [boost] Proposal: MapReduce library (single machine)
by Mateusz Berezecki 31 Aug '09

31 Aug '09

Hi , I've just joined this mailing list because of this particular discussion :-) >> 2) have a plan so that the library can eventually range from >> working on 1 multi-core system to distributed >This is the eventual goal, and I have designed the library to be extensible >to be able to do this in the future. With the policy based designed, making >use of the open source projects that you mention should be non-intrusive; >the library allows the user to supply a handler for the intermediate files >(to use kosmosfs or hypertable, for example) I'm going to give it a spin as it happens I'm already having a half-baked distributed backend lacking a mapreduce library for both hypertable and KFS and report back. But this is interesting! Can't stop thinking about it now :-) best, Mateusz

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Help with Boost Preprocessor
by Emil Dotchevski 30 Aug '09

30 Aug '09

Let's say I have a class template functor like this: struct func { typedef void result_type; template <class A1,class A2,class A3> void operator()( A1, A2, A3, int x ) { } }; Given a list of types, I want the function instantiated and called for all permutations of the types in the list; the additional argument(s), x, just need to be forwarded the same for all instances. Actually I got it working, see http://codepad.org/tnYTy9Iw. I don't think that my solution is very good though. First, it has some run-time overhead due to the use of boost::bind in fwd1 and fwd2 (see link above.) Second, I'd like the macro that defines the type list not to be hard-coded in fwd1 and fwd2. Is this possible? Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode

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[1.40.0] Release candidates available
by Beman Dawes 30 Aug '09

30 Aug '09

The 1.40.0 release candidates are available. See http://boost.cowic.de/rc/ Please download, give it a try, and then report back either success or failures. These will get pushed out to SourceForge once we've had enough reports to be sure the packages are good. TIA, --Beman

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[1.40] Release of PDF docs for Boost-1.40 now available.
by John Maddock 29 Aug '09

29 Aug '09

For those who prefer printable docs, PDF builds of the docs from Boost-1.40 are now available from the usual sourceforge download site: https://sourceforge.net/projects/boost/files/ (look under the boost-docs subtree). Direct links are as follows: zip (19.2Mb): https://sourceforge.net/projects/boost/files/boost-docs/1.40.0/boost_pdf_1_… tgz (19.7Mb): https://sourceforge.net/projects/boost/files/boost-docs/1.40.0/boost_pdf_1_… 7z (17.9Mb): https://sourceforge.net/projects/boost/files/boost-docs/1.40.0/boost_pdf_1_… Please note that not all libraries have documentation suitable for automatic PDF generation yet, libraries covered are: Accumulators Any Array Asio Bimap Bjam Boost.Build Range Boostbook TR1-complex number algorithms Concepts Config Conversion Date_time Foreach Function FunctionTypes Fusion Hash Interprocess Intrusive Iterator Lambda Math (special functions and distributions) Math-gcd MPI Octonion Optional Phoenix ProgramOptions Proto Python tutorial Quaternion Quickbook Ref Regex ScopeExit Signals Signals2 StaticAssert StringAlgo Thread TR1 Tribool TypeTraits Typeof Units Unordered Variant Xpressive Enjoy! John Maddock.

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RFC - Updated MapReduce library
by Craig Henderson 29 Aug '09

29 Aug '09

I have considerably revised and updated my MapReduce library and committed the changes to the Sandbox. I've also uploaded to the Vault for easy access http://www.boostpro.com/vault/index.php?action=downloadfile <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=mapred uce_0_3.zip&directory=&> &filename=mapreduce_0_3.zip&directory=& Library documentation to date is available along with the code, or on my site at http://craighenderson.co.uk/mapreduce/ I am very interested to hear any comment on design, code, performance or any other area. Regards -- Craig Craig Henderson <http://craighenderson.co.uk/> http://www.craighenderson.co.uk http://www.siteupdatenotification.com

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Boost.Multimethod proposal
by Nicholas Howe 29 Aug '09

29 Aug '09

I have written a C++ Multimethod library and propose adding it to Boost. I see that the addition of such a library to Boost has been proposed in the past, and been met with relative enthusiasm. However, it has not been done. Does anyone know why previous attempts were aborted? I want to be sure there is a demand before starting the somewhat daunting task of boostifying and documenting my library. The library works by requiring clients to register user types of interest, and specify their public base classes. This allows traversing class hierarchies at run-time. A multimethod uses this information to perform run-time overload resolution on registered methods to determine the best implementation based on the type-id of each parameter. There are no restrictions on the types of a multimethod's parameters, although only single indirections to user types will behave polymorphically. The library is designed to behave well when used by other libraries. To declare a new method, the client is required to derive a new type from the multimethod type. This allows multiple multimethods with the same parameters in different libraries. It also allows encapsulation of each multimethod implementation within each library, reducing the chance of conflict between different libraries that were compiled with different versions of the multimethod library. Is there any interest in including my library in Boost? Nick

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Boost C++ Math Toolkit
by Paul A. Bristow 29 Aug '09

29 Aug '09

I am pleased to announce publication of the Boost Math Toolkit PDF documentation as a book (in CD format initially). Boost C++ Math Toolkit, ISBN 0-9504833-2-X John Maddock, Paul A. Bristow, Hubert Holin, Xiaogang Zhang, Bruno Lalande, Johan Råde, Gautam Sewani, Thijs van den Berg Publisher: hetp Publication date: 1 Sep 2009 Suggested Classification 519.2-dc22 If you are using this software, and writing academic or scholarly articles, you can reference it as above. (If you an author you can add it to your CV ;-) In the unlikely event that anyone would like this as a CD, I can of course provide it (at a modest cost) - but then you can download everything for free from www.boost.org or www.sourceforge.net. The CD also includes a Windows Installer program for the Distribution Explorer (but you can also download from http://distexplorer.sourceforge.net/) Please tell me if you would like to be able to buy a printed version. Thank you. Paul --- Paul A. Bristow Prizet Farmhouse Kendal, UK LA8 8AB +44 1539 561830, mobile +44 7714330204 pbristow(a)hetp.u-net.com

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[mpl] minor typo in for_each documentation
by Emil Dotchevski 29 Aug '09

29 Aug '09

See http://www.boost.org/doc/libs/1_39_0/libs/mpl/doc/refmanual/for-each.html, the example at the bottom: shouldn't the 'n' be '\n'? Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode

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GTL Questions
by Tom Brinkman 28 Aug '09

28 Aug '09

Just to get things rolling, a few softball questions. Could you give a short history of this library? How long has it been in development? Is it in current use? If so, how and where. Does this library have any affiliation with Intel? Thanks for submitting this greatly needed library. A lightweight, boost friendly geometry library would be very useful. Tom

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