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thread abort exception
by Ninel Evol 07 Jul '07

07 Jul '07

Dear Boosters and C++ affectionados, one thing that C++ is missing amongst many others is the possibility to abort a thread in a clean fashion (so that the thread itself, i.e. the object will do the cleanup). The need for this arises virtually every time you use a background thread for doing the work (for example computations). Currently, you can have the thread check for an abort request every once in a while (bad), or you can just kill that sucker and do the cleanup in the main thread (not that nice either). A clean alternative would be if the main thread were able to "provoke" an exception in the worker thread. This "abort- request-exception" could than be caught by the worker thread. It could thereby do the entire cleanup itself (object-oriented). I added a little example below. The example is for Windows and VCPP (sorry for that). You can do the same in Linux by stopping the thread via pthread_kill(id,SIGSTOP) and then manipulating the EIP (see thread_info.h), but of course it's a bit messy due to the kernel includes, etc... Once you think about it, all you need in triggering exceptions in another thread is really an abort request. It could be either asynchronous or synchronized (mutex, with return value?). That's all you need - almost always though. The main thread handles the GUI and you almost always want the user to be able to abort operations. The smoothest way to implement this GUI-scheme is with worker threads, the downside being the lack of C++ support, currently. Different topic: ================ I read that some folks thought about the wxWidgets and the Boost (C-0x) team joining forces. I think that would be a marvelous idea! Currently the STL is quite useless. It basically serves for supporting book examples. For everything else you need either thread, network or GUI support (often all of them). As a result you have to use some library (wxWidgets, Qt). These of course all replace the STL completely - usually lacking some of those nice things the STL comes with (like exceptions). In other words: C-0x without GUI, thread and network support will just as well remain in the shadows of libraries providing that crucial functionality, sadly ignoring various accomplishments. Hold on, just cut my finger... Xo| Well, that's it anyway. Feel free to comment, as you like (as long as it doesn't relate to cutting fingers)! Blood waving, LC (myLC(a)gmx.net) Windows example (VCPP): ======================= #define WIN32_LEAN_AND_MEAN #include <tchar.h> #include <iostream> #include <windows.h> #include <signal.h> enum ThreadException { THREAD_ABORT_REQUEST }; DWORD threadID; unsigned long i; DWORD WINAPI ThreadFunction( LPVOID lpParam ) { try { for( ; i < 50; ++i) { std::cout << "Thead counting " << i << "..." << std::endl; Sleep( 1000 ); } std::cout << "Thead has finished counting." << std::endl; return 0; } catch( ThreadException e ) { if( e == THREAD_ABORT_REQUEST ) { std::cout << "Thread aborted." << std::endl; return 42; } else std::cerr << "Oops - unknown thread-exception" << std::endl; } catch( ... ) { std::cerr << "Unknown exception caught in thread!" << std::endl; } return 1; } __declspec( naked ) void throwAbort( void ) { throw THREAD_ABORT_REQUEST; } int _tmain( int argc, _TCHAR* argv[] ) { HANDLE threadHandle = CreateThread( 0, 0, ThreadFunction, 0, 0, &threadID ); if( !threadHandle ) { std::cerr << "Failed to create thread." << std::endl; return -1; } Sleep( 5000 ); if( SuspendThread( threadHandle ) == 0xFFFFFFFF ) { std::cerr << "Failed to suspend thread." << std::endl; return -2; } CONTEXT threadContext; threadContext.ContextFlags = CONTEXT_CONTROL; if( !GetThreadContext( threadHandle, &threadContext ) ) { std::cerr << "Failed to retrieve thread context." << std::endl; return -3; } threadContext.Eip = ( DWORD )throwAbort; if( !SetThreadContext( threadHandle, &threadContext ) ) { std::cerr << "Failed to set a new thread context." << std::endl; return -4; } if( ResumeThread( threadHandle ) == 0xFFFFFFFF ) { std::cerr << "Failed to resume thread." << std::endl; return -5; } Sleep( 3000 ); DWORD threadExitCode; if( !GetExitCodeThread( threadHandle, &threadExitCode ) ) { std::cerr << "Failed to get the thread's exit code." << std::endl; return -6; } std::cout << "The thread returned the exit code " << threadExitCode << "." << std::endl; return 0; } -- Ist Ihr Browser Vista-kompatibel? Jetzt die neuesten Browser-Versionen downloaden: http://www.gmx.net/de/go/browser

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[1.34.1, program_options] fix example/Jamfile.v2
by Vladimir Prus 07 Jul '07

07 Jul '07

It turns out that program_option's example/Jamfile.v2 got stale, and does not work in 1.34.0, at all. The attached patch fixes that, OK for 1.34.1? - Volodya

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[Report] 1 regressions on RC_1_34_0 (2007-07-07)
by Douglas Gregor 07 Jul '07

07 Jul '07

Boost Regression test failures Report time: 2007-07-06T18:00:26Z This report lists all regression test failures on release platforms. Detailed report: http://engineering.meta-comm.com/boost-regression/CVS-RC_1_34_0/developer/i… 1 failures in 1 libraries serialization (1) |serialization| test_list_xml_warchive_dll: msvc-8.0

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Re: [boost] [fusion][ping] how to initialize a container of non-const references to objects, from a container of objects
by dan marsden 07 Jul '07

07 Jul '07

Stjepan Rajko wrote: >Found a case where it doesn't compile - adapting your example to how ... >However, if I change this to: > > typedef fusion::vector<> vec; > vec v; > fusion::transform_view<vec, make_ref> t(v, make_ref()); > fusion::vector<> vec_of_references(t); // does not compile > >The problem is that since vec_of_references is a vector of size 0 then >it can't initialize from the transform_view because vector0 has no >constructors defined (so only copy constructible). > >For sake of consistency, would it be possible to add a templated >constructor to vector0 that could take a fusion sequence and do >nothing with it? I'm using this from a templated class and it would >be helpful if I didn't have to specially treat the size 0 case. Vector, list and deque (experimental) all have converting ctors for the zero length case now. >Or, perhaps there is another simple solution I'm missing... :-) No, I think your solution is simple and the right one, it definitely improves the uniformity of container behaviour in Fusion. Thanks for pointing this one out Cheers Dan ___________________________________________________________ Yahoo! Answers - Got a question? Someone out there knows the answer. Try it now. http://uk.answers.yahoo.com/

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[fusion] Illegal partial specialization error.
by Michael Marcin 06 Jul '07

06 Jul '07

If I include <boost/fusion/support/tag_of.hpp> my compiler (derived from Metrowerks 9.4) gives me several errors claiming illegal partial specializations. It looks like it's partially specializing forward declarations of the tag_of structure. I don't know if that's allowed (from the error I assume probably not) but it certainly seems to be pointless to me. Are these perhaps supposed to be more than declarations? Thanks, Michael Marcin

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Interest in a static-sized version of cvalarray
by Michael Tegtmeyer 06 Jul '07

06 Jul '07

Some time ago I posted a message to this list about interest in a static-sized version of cvalarray. I'll include the original message for reference. I received some emails stating that there was interest. The implementation has been in the sandbox for some time now. I'd like to guage interest again to determine if it is worth working to add to boost. The implementation has not been boostified because it is in active use here where I work (autotool land) so if there is interest, some additional work needs to be done to absorb the boost framework. The implementation is complete without any known bugs. There is only one header but you can go though the normal ./configure, make, make install to put it somewhere. Tests can be run using 'make check' and documentation is in the doc directory. Of additional interest since my previous post: the implementation will now automaticallty unroll all numeric ops at compile time (subject to the compiler) up to a predefined array size. My original post: Hello, I am trying to guage interest in a fixed sized version of valarray. I frequently found myself using small(-ish) compile-time known sized numeric arrays that don't justify the overhead of operator new in std::valarray but needed the math interface that valarray provided. I wrote a static-sized version of valarray for this purpose. It is modeled after std::valarray and implements about 90% of valarray's interface (obviously resizing is not included, neither is gslice due to the result not being known at compile time). Examples of it's use are: float _v[10] = {...}; size_t _i[5] = {...}; cvalarray<float,10> v1(_v); cvalarray<float,5> v2 = v1[cslice<0,5,2>()]; v1[cslice<0,3,3>()] = 0.0f; cvalarray<size_t,5> ind(_i); cvalarray<float,5> cvalB = v1[ind]; v2 *= (v2 + v1) / 2.0; //all of the usual math ops I have a complete implementation that models std::valarray in every possible way (with compile-time known limitations) including expression-template support for the numeric ops. My testing indicates a decent performance increase over gcc4's valarray for small number of elements <1000. If anyone has any interest, I'll put together some docs and throw it in the sandbox. Mike Tegtmeyer

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Re: [boost] [IBD] Help request, A Woman's Point of View
by james.jones＠firstinvestors.com 06 Jul '07

06 Jul '07

From: "Jake Voytko" <jakevoytko(a)gmail.com> > OK, I think it's time we try to remain professional and back off a little. > Matias clearly didn't mean any harm by what he said, and he had good intent. > Joaqu?n raises valid points in his email, and I think these need to be > addressed, and negative discussions aren't going to advance the topic any. I absolutely agree that no harm was intended. However, I don't think it's the job of Boost to try to right some perceived wrong in the general programming community - beyond the wrong of not having great open-source C++ libraries, of course! It's clearly the case that there are way more men than women programmers. Whether this is a major problem or not is debatable, and I don't think it's a debate that belongs on the boost-devel list. But even if it *is* a problem, it's not one we need or should try to solve. We already have a whole set of problems - ones involving C++ programming - that we need to solve and that this community was set up to solve. The problem with "affirmative action" in open source projects is exactly the same as in regular hiring, i.e. the token minority brought in will be suspected of being not as good technically as the rest of the group. This is not because that minority can't be just as good or better, but because affirmative action itself is based around the idea of giving extra - undeserved - bonuses to these minorities. The paradoxical result may be that really deserving minority candidates may stay away if they have enough dignity. "I don't want your lousy handouts," they'll think. Anyway, just as I don't think boost-devel is the place to debate whether an unbalanced sex ratio is a problem in programming, I also don't think it's the place to debate the pros and cons of affirmative action. So I will drop this now that I've had my say. Please let's not let Boost get distracted by this issue. - James Jones Administrative Data Mgmt. Webmaster 375 Raritan Center Pkwy, Suite A Data Architect Edison, NJ 08837

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Boost is a finalist in the SourceForge.net Community Choice Awards
by David Abrahams 06 Jul '07

06 Jul '07

According to http://sourceforge.net/awards/cca we're nominated in this category: Best Technical Design: The project most likely to inspire awe with its technical perfection If you think Boost deserves this award, go to http://sourceforge.net/awards/cca and vote for us. I'm not sure what we'd win, but it's always nice to be recognized. Cheers! -- Dave Abrahams Boost Consulting http://www.boost-consulting.com The Astoria Seminar ==> http://www.astoriaseminar.com

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Re: [boost] [IBD] Help request, A Woman's Point of View
by james.jones＠firstinvestors.com 06 Jul '07

06 Jul '07

From: "Stjepan Rajko" <stipe(a)asu.edu> > Anyway, I'd really like to applaud Matias for actively trying to > address the gender imbalance, since if it wasn't for the female > dancers that were encouraging of my participation in dance, I wouldn't > be a dancer now (and I suspect not nearly as happy a person). I think > that until you start to fix the gender imbalance, you don't even > realize what kind of useful feedback, opinions, and participation you > might be missing out on. You may find that women find it creepy for 50 guys to be, in effect, calling out, "Hey, join us! Come on, we're nice people! And we'll listen to you - here, you can sit next to me!" Don't force it. - James Jones Administrative Data Mgmt. Webmaster 375 Raritan Center Pkwy, Suite A Data Architect Edison, NJ 08837

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Fw: [Boost C++ Libraries] #911: [bind] inline placeholder macro
by Peter Dimov 06 Jul '07

06 Jul '07

Boost C++ Libraries wrote: > #911: [bind] inline placeholder macro > -----------------------------------------+---------------------------------- > Reporter: daniel_walker(a)users.sf.net | Owner: nobody > Type: Patches | Status: assigned > Milestone: | Component: None I'd like to set the Component of this ticket to 'bind', but Trac doesn't let me. How does one go about adding a new Component?

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