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Re: [boost] [SVN Configuration] Request an additional MIME type to support Scalable Vector Graphics (SVG)
by Jeroen N. Witmond 19 Jan '09

19 Jan '09

Peter Foley wrote on 2007-08-23 11:52:25 GMT: > Should I simply update my local configuration file to include the line: > > *.svg = svn:eol-style=native; svn:mime-type=image/svg+xml > > Any advice would be greatly appreciated. With this autoprop set, `svn add` gets into trouble (at least for me) adding a file with extension .svg. I had to change the svn:mime-type to text/svg+xml to get it to work. Regards, Jeroen.

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utility class: lazy data type
by Zachary Turner 19 Jan '09

19 Jan '09

I wrote this class to support lazy evaluation and caching of values. It seems like it would be useful for inclusion as a miscellaneous class in boost. It seems like this pattern occurs pretty often in practice, it's even the fundamental implementation method for singletons, and at least I often have tons of boost::optionals in my code, with get accessors on the classes that check if there's a value, if not call a fetch function, and then return the value. It's cleaner to just call get every single time and not worry about it. I don't consider myself a guru, so suggestions on how to make it better are, of course, appreciated. template<class T> class lazy { public: explicit lazy(function<T ()> fetch) : _fetch(fetch) { } T get() { if (!_cached) _cached = _fetch(); return _cached.get(); } private: optional<T> _cached; function<T ()> _fetch; }; Perhaps such a class is too trivial to be included, but here it is nonetheless.

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[interthreads] Library under development v0.3
by vicente.botet 19 Jan '09

19 Jan '09

Hi, I have add the fork_after function to Boost.InterThreads. The prototype allows to execute asynchronously N functions and execute asynchronously a function that depends on the completion of N functions. bith::shared_launcher ae; BOOST_AUTO(actT, bith::fork_all(ae, fct1, fct2)); BOOST_AUTO(act, bith::fork_after(ae, fct3, actT)); act.wait(); bith::shared_launcher is an asynchronous executor (AE) that executes asynchronously a function on a new thread. bith::fork_all request the AE to execute asynchronously each function. It returns a fusion tuple of the asynchronous completion token (ACT) associated the the ae. bith::fork_after request the AE to execute a function asynchronously once each one of ACTs in the dependency tuple parameter are ready. It is similar to the async_with_dependencies proposed Peter Dimov. I have used for that Boost.Future (Anthony proposal). I've added also some act traits, as value type, is movable, has_future_if, has_thread_if. The library is available at Boost Sandbox: https://svn.boost.org/svn/boost/sandbox/interthreads and Boost Vault: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=intert… Includes every thing on the Sandbox + Html documentation + Boost.Futures + Boost.ThreadPool adaptations I'd appreciate it if people could take a look, test it on their compiler and give me some feedback. Best regrads, Vicente _____________________ Vicente Juan Botet Escribá

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BoostCon'09 Registration Now Open
by David Abrahams 18 Jan '09

18 Jan '09

Greetings, Boosters and former BoostCon attendees The third annual Boost conference (BoostCon), featuring a keynote address by Andrei Alexandrescu, will take place May 3-8 2009 in Aspen, Colorado. The conference is now open for registration! Please go to http://www.boostcon.com/registration and reserve your place at the year's premier C++ event today. -- Dave Abrahams BoostPro Computing http://www.boostpro.com

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Boost Library Authors: BoostCon submission deadline approaching
by Hartmut Kaiser 18 Jan '09

18 Jan '09

Hi all, at last year's BoostCon, one of the highlights was the authors corner track. These were 20-30 minute sessions held by Boost library authors talking about their libraries. Most of the attendees of those sessions found them to be very interesting and useful. At this year's BoostCon we would like to have a similar track again. Unfortunately by now we don't have any related submissions. So I thought I explicitly encourage boost authors who are planning to be in Austin this year to consider giving a 30 minute introductory talk about their libraries. This is not a huge effort in terms of preparation, but adds a lot to the conference. You can find the details about BoostCon and the submission process here: http://www.boostcon.com/program/call-for-sessions. Please spread the word! Regards Hartmut Program Chair

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[uitility/result_of] CodeGear support of result_of
by joaquin＠tid.es 18 Jan '09

18 Jan '09

Hi, Seemingly, CodeGear does not support boost::result_of http://tinyurl.com/8onbjj I propose that this is officially recognized so that including <boost/utility/result_of.hpp> results in BOOST_NO_RESULT_OF being defined rather than the current compile error. This will benefit those result_of-dependent libraries honoring BOOST_NO_RESULT_OF (vg. Boost.Parameter). Joaquín M López Muñoz Telefónica, Investigación y Desarrollo||* *

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[any] Will it be in C++0x?
by Andrey Semashev 17 Jan '09

17 Jan '09

Suddenly, it occurred to me that STL does not provide an instrument for dynamic typed variables (or variants). I didn't see such a tool in TR1 either. So, are there any plans to include such a tool in C++0x? Boost.Any seems to me a very simple, yet very useful example of utility of that kind. It would be great if STL provided a similar instrument out of box.

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[smart_ptr] make_shared performance
by Frank Mori Hess 17 Jan '09

17 Jan '09

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I've been doing a little benchmarking (trivial benchmark program attached) of boost::make_shared performance. With svn trunk, I don't see much improvement from using make_shared, in fact for large objects it is much slower. I would guess this is due to the increased overhead of copying sp_ms_deleter for large types. I wonder if anyone has any ideas for improving the situation? -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFJcP7d5vihyNWuA4URApVPAJ9EfS6MtkNHTUgb/gOTD/nRngPiUQCeL6K0 MtkmtRAmzKlN1m0eXO9t5k0= =LpQ1 -----END PGP SIGNATURE-----

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[interprocess] Arithmetic error
by Henrik Sundberg 17 Jan '09

17 Jan '09

Disclaimer: I have no minimal reproducing program. The problem occurs at line 458 in mapped_region.hpp: 456 //We calculate the difference between demanded and valid offset 457 std::size_t page_size = this->get_page_size(); 458 m_extra_offset = (offset - (offset / page_size) * page_size); I've found out that page_size gets the value 0. It only seems to happen in my single core computer. It works for other Kubuntu 8.10 systems. The code is needed during so-load. The library is used from two other libraries that are loaded by the program (like a diamond library load). I've been discussing the problem in this forum: http://www.safirsdk.com/forum/phpBB3/viewtopic.php?f=4&t=61 The code is open (available from the site of the forum). It is a whole framework though, not just a small program. I don't know if this is a compiler bug, a Boost bug or a bug in the program. I think that the page size is supposed to be cached, but that this somehow doesn't happen in this setup. I get the error every time. Preloading the library avoids the problem. I.e. starting like this works: LD_PRELOAD=libdots_kernel.so dobexplorer /$

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Mixing protocol
by Joel Falcou 17 Jan '09

17 Jan '09

So far BOOST proposes various prtocols for meta-function : - the result_of protocol - the apply<> protocol of MPL - the ::type protocol of traits Can those protocols be mixed somehow without any side-effects when used with the various aforementionned protocol ? -- ___________________________________________ Joel Falcou - Assistant Professor PARALL Team - LRI - Universite Paris Sud XI Tel : (+33)1 69 15 66 35

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