February 2009 - Boost - lists.boost.org

Boost.Process 0.3 released
by Boris 14 Apr '09

14 Apr '09

I've released Boost.Process 0.3. Here's the documentation and a link to download the zip archive: Docs: http://www.highscore.de/boost/process/ Code: http://www.highscore.de/boost/process.zip It's a header-only library and thus pretty easy to use: Just copy the files to your Boost directory. In this release my main goal was to merge various snapshots: * There was my Boost.Process 0.2 version which was based on Boost.Process 0.1 from 2006. * There was a post-0.1 version of Boost.Process in SVN from 2007. * Chris Fairles had modified a Boost.Process snapshot for Unix platforms. * Ion Gaztañaga had also some ideas and bug fixes he sent to this mailing list recently. I just saw that Ilya Sokolov created another snapshot based on Boost.Process in SVN. That means we have again at least two different versions of Boost.Process. :-/ In my Boost.Process 0.3 version I concentrated on merging and overhauling code. I did not change the design but tried to make the code work: All the code which was written since 2006 should become usable. That's why I also concentrated a lot on test cases. There are quite a lot of test cases, and they all can be built and passed successfully on three platforms with four compilers. As it would be great if others run the test cases, too (ideally on new platforms), I'll send another message in a few minutes with a description how to run the test cases yourself. As the documentation was written in 2006 I also updated it. It's not yet really a good documentation: There are some files coming from 2006 while other files I wrote myself only last week. While the documentation can be improved it's at least up-to-date: The examples all work and can be compiled. As the documentation was not my priority for Boost.Process 0.3 it should be ok for now. Boris

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[filesystem] Version 3 request for comments
by Beman Dawes 12 Apr '09

12 Apr '09

A prototype implementation of version 3 of Boost.Filesystem is available for comment. The critical feature of this prototype is the replacement of the class basic_path template with a single class path that supports both narrow and wide character paths. It also supports user supplied types, and will support the new C++0x char16_t and char32_t character types as compiler and standard library support becomes available. There is still a lot of additional work before V3 could be added to the trunk and eventually released. For example, work so far has concentrated on the new functionality, and ignored breaking changes to existing code. But enough stuff is working to make requesting comments useful. See http://svn.boost.org/svn/boost/sandbox/filesystem-v3/libs/filesystem/doc/v3… for a fuller description of the prototype and links to the prototype implementation. I've got some specific issues I'd like opinions on, but would first like to hear comments from anyone interested. --Beman

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Final report of GSOC project 'Spatial Indexes'
by Federico J. Fernández 27 Mar '09

27 Mar '09

Hi List! I'm writing this email as a final report of my Google Summer of Code 2008 project for Boost. My project consist in adding some spatial indexing structures to Boost in the context of the Geometry proposal done by Barend Gehrels. Spatial indexes are data structures optimized for spatial oriented queries. The classic index structures (i.e. a binary tree) aren't spatially enabled, they have different ordering criteria but none of them relates to topological properties. The scope of these structures is really wide, from collision detection for games to geometry indexing for GIS software. The original project goals were: - Build a Quadtree. - Build an rTree. - Integrate some previous work from a former GSoC project of a k-d-tree. - Test and document everything. Both indexes are implemented now and everything is tested and documented. The only task that we didn't complete is the k-d-tree integration, because when we analyzed the code it was not ready, and we didn't have the time to finish it. About the results, we made several tests and benchmarks. We tested both indexes with 230.000 objects from GIS data to check the correctness of the implementation, and we made some benchmarks comparing the quadtree vs. rtree and comparing both of them to existing implementation (like GEOS) with very good results. We describe this benchmarks in the documentation offering this as a guide to choose the best index for each use. The code is still beta (or maybe alpha) and not recommended for production use because it is still not tested enough, but if you want to check the actual status you can find it in the following location: https://svn.boost.org/svn/boost/sandbox/SOC/2008/spacial_indexing/ And the docs are at: https://svn.boost.org/svn/boost/sandbox/SOC/2008/spacial_indexing/libs/spat… The future work now is huge. We have some ideas about integrating this in some way to multindexes, and we want to implement also a 'packed' version of the rtree to improve bulk-loading times among another things. Finally, I would like to thank to Boost for allowing me to be part of this year's SOC. And specially to my mentor Hartmut Kaiser for all his help during the program. -- federico j. fernandez

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[endian] superfluous boost::operators<> ?
by Roland Schwarz 26 Mar '09

26 Mar '09

I discovered, that the following will not compile: unsigned u; ulittle32_t u1; ulittle32_t u2; u = 1; u1 = 1; u2 = u1 + u; The compiler complains about not being able to resolve similar conversions. My guess is, that using boost::operators<> _and_ providing type conversion operators at the same time is causing this. I think it should be enough to define the essential operators in cover_operators template, and omit boost::operators<> at all. At least I am not able to find any problems with this, since the compiler adjusts the arguments (using the provided type conversion operators?) and calls the built in operators, thereby resolving ambiguity. Any thoughts? -- _________________________________________ _ _ | Roland Schwarz |_)(_ | aka. speedsnail | \__) | mailto:roland.schwarz@chello.at ________| http://www.blackspace.at

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[C++0x] The cpp0x branch has been merged into trunk
by Beman Dawes 21 Mar '09

21 Mar '09

The cpp0x branch has been merged into trunk, enabling a bunch of BOOST_NO_* macros for C++0x feature tests. This should have no impact on existing code, so be sure to let me know if it causes any problems. --Beman

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[fusion] C++0x support?
by Ein Held 17 Mar '09

17 Mar '09

Hello is there any chance for c++0x support (rvalue forwarding for the containers' constructors and operator=s' in particular) for fusion in 1.39? If noone is up to adding support for this to fusion, my collegues and me would love to implement it. Thank you

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Boost.Chrono where we are?
by vicente.botet 16 Mar '09

16 Mar '09

Hi, In November 2008, Beman said: "The Chrono library in the sandbox is now more-or-less feature complete." This library is esential to conform some boost libraries implementing standard libraries as Boost.Thread and Boost.Future as much as possible to the standard. It will be used also on the Boost.ThreasPool library and I would like also to use it on my AsynchronousExecutors library. Can we expect to have Boost.Chrono for review soon? Thanks, Vicente

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request for discussion - yet another approach to automated memory management that solves the cycles problem and is very efficient
by Achilleas Margaritis 16 Mar '09

16 Mar '09

Dear boost members, The file 'mm2.zip' (in boost vault/memory) contains yet another solution for automatic memory management. The solution has the following attributes: 1) it solves the problem of cycles. 2) it releases resources deterministically. 3) it does not scan the graph of objects for reachability. It uses simple numeric values (i.e. keys) to determine if an object can be collected or not. The idea is very simple: pointers obtain keys during their construction (a simple global variable that is incremented). The key remains constant throughout the lifetime of a ptr. During pointer release, the pointers that point to an object are scanned: if there is no pointer that points to the object that has a lower key from the key of the releasing pointer, then the object can be deleted. The pointer semantics are normal C pointer semantics, except for the construction: the solution requires that pointers that are lvalues should obtain a key before the heap object that they will be assigned to. i.e. you can't do this: ptr p1 = new object; You have to do this: ptr p1; p1 = new object; All the operations have O(1) complexity, except the release operation, which has O(N) complexity, whereas N is the number of pointers that point to an object. Practically, the complexity is minimal, because it is rare to have that many different pointers to a single object (I think :-)). I have no idea if it works for all cases. The file 'main2.cpp' contains a lot of tests, which all pass. I have also included the benchmark of the Boehm GC modified to use my special ptr classes. In my machine, an Athlon 64 2.2 GHz, the benchmark is executed, using boost pools, at roughly 1900 milliseconds, whereas the Boehm gc benchmark, using the Boehm gc collector, is executed at roughly 1200 milliseconds (and the Java benchmark at roughly 600 milliseconds). The amazing thing is that it looks like it works, but I am not sure. I am sure there is a catch :-).

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Re: [boost] [Boost-users] Maintenace Guidelines wiki page
by vicente.botet 15 Mar '09

15 Mar '09

----- Original Message ----- From: "Tomas Puverle" <Tomas.Puverle(a)morganstanley.com> To: <boost-users(a)lists.boost.org> Sent: Sunday, November 23, 2008 4:31 AM Subject: Re: [Boost-users] Maintenace Guidelines wiki page > >> I have started the Maintenace Guidelines wiki page. >> >> You can access it directly >> https://svn.boost.org/trac/boost/wiki/Guidelines/MaintenanceGuidelines >> >> or via https://svn.boost.org/trac/boost/wiki >> >> Guidelines >> * Maintenance Guidelines >> >> There page need to be completed and surely reworked but this is an starting >> point. >> >> Please be free to improve the page directly or post your comments or > suggestions to this list. >> >> Hopping this goes on the right direction, > > Vincente, > > A few ideas: How will you evaluate that your proposal is actually successful > and being followed by the boost developers? Hi, First this is proposal for guidelines. So people will be after all free to follow some of them or not. I'm expecting from people like you to improve it so it could be followed by more people. > Also, check out Daniel Walker's idea in the Boost.Range thread on boost.devel > about not having the engineers in charge of their own QA. Daniel Walker's idea " Perhaps a procedural solution that could avert this problem in the future is to quarantine the test cases. Authors can maintain commit privileges to their libraries on trunk, but only a select group of independent guardians have commit privileges to the test cases. That way there is a guarantee that libraries pass the same tests from one release to another. If an author would like to make a change that would break a test case, he or she would need to present the change to the list and submit a patch to the test case sentinels. This would be a fairly simple quality assurance protocol: engineers aren't allowed to do their own QA." This is already considered on the guidelines insome way. "Preserve the test from the preceding versions [author] The test from the preceding versions should not be changed when the author modifies its library. These not changed tests are a probe of compatibility with the preceding version. When these test must be changed they indicate a breaking user code issue. So instead of changing them add new ones stating explicitly on which version they were included. Old tests that should fail can be moved to the compile_fail or run_fail tests on the Jamfile. " The Daniel proposal implies some changes in the writing rights of the authors. I prefer to let this point out of these guidelines. Of course I think that this is a good idea. There is another guideline that could be used by the Boost comunity to check the author has not changed the old test cases. "Inspect announced modifications [author, user, RM] The use of the diff file will help to inspect that the modifications introduced have been correctly included on the documentation and a good test coverage has been done. This will result in a non official mini-review of the library. " I will add to check that the old testcases have not been changed. > Finally, please consider the idea of "core" and "new" release cycles, where the > components in "core" have much more stringent requirements on how and when they > are allowed to change. IMO this is out of the scope of the guidelines. Note that at the end it is up to the author to make the modification he/she consider pertinent. Could you send what you have in mind in the form of guidelines? > Finally, do you think it may have been better to start this thread on > boost.devel? I belived that i did it on both. I'm answering to both each time. Should I start a new thread including the guidelines contents? Vicente

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[geometry] area, length, centroid, behavior
by Barend Gehrels 13 Mar '09

13 Mar '09

I would like to hear the opinion of potential geometry users on the list about the following. For the three geometries, point, linestring (= sequence of points), polygon: What should the generic "area" algorithm return for point and linestring? - 0 (zero) - compiler error (so this function is not defined for them at all) - exception Personally I would feel for 0 (zero) because you can then request the "area" in a generic collection, regardless of what is inside. What should the generic "length" algorithm return for polygon? - 0 (zero) - its perimeter - compiler error - exception What should the generic "centroid" algorithm return for point and linestring? - the point / the average its points - compiler error - exception and for an invalid polygon (e.g. no points at all, or not closed)? - exception - return "false" (if centroid is passed as a reference parameter) - ? (we've not always the compiler error option here because points are usually stored in a runtime collection) Thanks, Barend

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