March 2013 - Boost - lists.boost.org

GSoC 2013 - Boost registration?
by Paul A. Bristow 09 Apr '13

09 Apr '13

http://www.google-melange.com/gsoc/events/google/gsoc2013 March 18: 19:00 UTC Mentoring organizations can begin submitting applications to Google. March 29: 19:00 UTC Mentoring organization application deadline. Just checking that Boost has/is registering? Paul --- Paul A. Bristow, Prizet Farmhouse, Kendal LA8 8AB UK +44 1539 561830 07714330204 pbristow(a)hetp.u-net.com

3 3

future<>::then() Error returning future<void> (on trunk)
by Fernando Pelliccioni 07 Apr '13

07 Apr '13

Hi Vicente, hi all, I noticed that in the trunk there is a implementation of future<>::then(). Thank you very much for your efforts to implement it! The following example, compiles OK boost::future<int> f1 = boost::async([]() { return 123; }); f1.then([](boost::future<int> const& f) { return std::string(""); }); But this one fails to compile: boost::future<int> f1 = boost::async([]() { return 123; }); f1.then([](boost::future<int> const& f) { }); Here future<>::then() have to returns future<void> like ... boost::async([]() { }); Am I right? On the other hand, have you taken into account the following paper? http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3451.pdf Regards, Fernando Pelliccioni.

3 5

Review managers wanted for augmented data structures
by Vadim Stadnik 06 Apr '13

06 Apr '13

Hi all, At present, neither Boost library nor STL provides containers using augmented data structures. I suggest that the Boost community consider solving the challenging problem – how to extend STL by integrating advanced data structures. Is there an alternative of not integrating advanced data structures into STL? IMO, no, since it is equivalent to “STL must go”. C++ cannot ignore performance benefits provided by these data structures. On the other hand, advanced data structures can be implemented in many programming languages and this will make C++ less competitive. Augmented red-black trees could have been included in the very first version of STL. Why is it difficult and has not been done yet? The major obstacle for the integration is the C++ standard specification of computational complexities of single operations for containers and iterators. Augmented trees are non-standard due to different performance guarantees. At the same these data structures are beneficial for complex algorithms, since they offer a wider set of more efficient operations compared to standard containers. The typical performance improvement for one operation is O(log N) against O(N). For less efficient operations these trees normally provide running time O(log N) against O(1), which is good enough for many applications. The C++ STL will be under pressure as long as there are new data structures that offer better running time for user algorithms. Asymptotically, the main parameter that determines the running time of an algorithm is the total computational cost (to simplify the discussion we omit the effect of locality of reference). By definition, the total computational cost is the sum of costs of single operations multiplied by their frequencies. For a general purpose library, such as STL, it is impossible at the design stage to know frequencies of all container and iterator operations required in all possible user algorithms. A more reasonable and practical approach to STL would be to provide a wide set of interchangeable containers and data structures with different performance guarantees and allow programmers to make decisions about the most suitable containers for specific applications. Relatively small frequencies of inefficient operations do not have significant effect on the total computational cost of an algorithm. Thus, in principle, containers and iterators can provide even inefficient operation in order to support more unified interfaces and to improve the generality. The replacement of interchangeable containers offers the advantage of low development cost solutions to performance bottlenecks that arise due to enhancement requests and/or an increase in the number of elements processed by a user algorithm. Also, I’d like to note that the representation of sequences using augmented trees is a frequent point of confusion and probably the fact that was overlooked in the development of previous versions of STL. The general description of the method of augmenting data structures is given in the section 14.2 of this book T.H. Cormen, C.E. Leiserson, R.L. Rivest and C. Stein, Introduction to Algorithms, 2nd Edition, MIT Press and McGraw-Hill, 2001. The specific application of this method is provided for order statistic trees and interval trees. Unfortunately, there is no example of a sequence that stores unordered elements. Probably for this reason augmented red-black trees are often considered to be an improvement of search trees only. The efficient representation of sequences by the described red-black trees follows from the fact that augmenting by the counter of children nodes supports efficient mapping from non-negative integers into container elements. It works both for ordered and unordered containers with unique and multiple elements or keys. There are two libraries in the Boost review schedule: http://www.boost.org/community/review_schedule.html "STL Extensions" and "Countertree". None of them has as yet a review manager. The order of the reviews may not be significant. It is more important that at least one library pass the review. This would help integrating other advanced data structures. Are there Boost experts who could volunteer to take responsibility of review manager for any of these two libraries? Regards, Vadim Stadnik

4 9

generate algorithm
by Fabian Bösch 02 Apr '13

02 Apr '13

Dear Boost community I am developing a library which extends the STL generate algorithm. It's aim is to improve performance for highly optimized (e.g. vectorized) generation mechanisms while it retains the same interface. This is especially useful when dealing with random number generation as there are several libraries (e.g. Intel MKL or AMD ACML) which provide means to generate a block of random values at once. However, the current STL generate algorithm is not able to cope with such "range generation". Is there any interest in a such a library for Boost? Cheers, Fabian Bösch

4 5

traits classes vs. metafunctions
by Stefan Strasser 01 Apr '13

01 Apr '13

Hi everyone, are there any guidelines for boost libraries on when to use traits classes and when to use a metafunction for each member of a would-be traits class? I've seen both in boost libraries. c++11 uses traits classes (iterator_traits, pointer traits, ...), but Abrahams and Gurtovoy [1] argue that traits classes ("traits blobs") should be avoided "at all costs" because they are an unnecessary concatenation of multiple metafunctions into one metafunction with multiple return values. in practice, this means that if a single 'traits class member' aka 'metafunction result' ought to differ from the defaults, the entire traits class has to be reimplemented by the user, not only the metafunction whose result ought to differ from the default. on the other hand, asking a user to implement 5 or more metafunctions is much more tedious than implementing a traits class. possibility 1) template<...> struct property1 : mpl::bool_<...>{}; template<...> struct property2 : mpl::bool_<...>{}; template<...> struct property3 : mpl::bool_<...>{}; 2) template<...> struct ..._traits{ typedef mpl::bool_<...> property1; typedef mpl::bool_<...> property2; typedef mpl::bool_<...> property3; }; you could provide both, but in which "direction"? does a traits class refer to metafunctions, or do metafunctions refer to a traits class? a) template<...> struct ..._traits{ typedef typename property1<...>::type property1; typedef typename property2<...>::type property2; typedef typename property3<...>::type property3; }; b) template<...> struct property1 : ..._traits<...>::property1{} template<...> struct property2 : ..._traits<...>::property2{} template<...> struct property3 : ..._traits<...>::property3{} which is accessed when "calling" the metafunction? it seems to me that metafunctions are better for the "caller" and traits classes are better for the implementor of the traits/metafunctions. in my case, the caller is a library and the implementor is the user, so you might choose a traits class over metafunctions. but what if a new member is added that wasn't there before (like "property4"). the implementor of an (old) traits class could not have known about the new member, so accessing the new member (by the library) will result in an error, while a new metafunction "property4" could simply return a default. should new properties of traits classes only be accessed after making sure they exist, using SFINAE? there isn't a precedent for this in c++11. only new traits classes were introduced, but no new members of already existing traits classes. should metafunctions always be preferred? why did c++11 choose traits classes over metafunctions, even though the concept of a metafunction was introduced in c++11 (<type_traits>). Thanks [1] Abrahams; Gurtovoy: C++ Template Metaprogramming, 2.2 Metafunctions

7 14

[mpi] Boost.MPI and MPI 3!
by Renato Forti 01 Apr '13

01 Apr '13

Hi All, Boost.MPI project will support MPI version 3 with that provide some support to fault tolerance! Have any work in this area? Thanks

2 2

Associative container using a vector
by Stefan Strasser 01 Apr '13

01 Apr '13

Hi everyone, I often find myself using a specific data structure and I'm wondering whether: - it has a wellknown name - there is a generic equivalent in a boost library - or there is interest to add one. The basic idea is that you have a bunch of values stored in one object of type A: struct A{ vector<Value> values; }; and then you have multiple objects of type B that each have to associate data with each value stored in A. you could use: struct B{ map<Value,Data> data; }; but since A::values already provides a contiguous index for the values you can just as well store the data in B in a vector with matching indexes, and make sure that the indexes used in A::values don't change: struct A{ vector<Value> values; vector<std::size_t> freelist; map<Value,std::size_t> index; void erase(...){ push index of unused value to freelist; } void push_back(Value){ reuse a freelist entry or values.push_back; } }; struct B{ vector<optional<Data> > data; }; keep in mind that there is one object A for many objects B. you can now access the associated data of many objects B by looking up the index once in object A, and by wasting some space in B::data for unused entries: b.data[a.index[value]] If Data is a pointer or any other type that knows an empty() state, you can also get rid of optional<> and generalize it as two template like: template<class Value> class index; template<class Mapped,class OptionalTraits=boost_optional_traits> class vector_map; Is there anything like that?

3 4

[config] BOOST_NOEXCEPT on MSVC
by Michael Marcin 01 Apr '13

01 Apr '13

Why isn't BOOST_NOEXCEPT defined to be throw() for msvc? Microsoft Visual Studio 11.0\VC\include\yvals.h defines: #define _NOEXCEPT throw () and the rest of the standard library implementation uses it ex. void swap(thread& _Other) _NOEXCEPT { // swap with _Other _STD swap(_Thr, _Other._Thr); } http://msdn.microsoft.com/en-us/library/wfa0edys.aspx states: throw() The function does not throw an exception. However, if an exception is thrown out of a function marked throw(), the Visual C++ compiler will not call unexpected (see unexpected (CRT) and unexpected (<exception>) for more information). If a function is marked with throw(), the Visual C++ compiler will assume that the function does not throw C++ exceptions and generate code accordingly. Due to code optimizations that might be performed by the C++ compiler (based on the assumption that the function does not throw any C++ exceptions) if a function does throw an exception, the program may not execute correctly. It seems a better choice here than expanding BOOST_NOEXCEPT to nothing.

2 1

[fusion] What do we do with nil ?
by Joel de Guzman 31 Mar '13

31 Mar '13

Hello, This is a constantly nagging issue. There are a couple of places where nil is a PP define especially on the Mac: - objc.h #ifndef nil #define nil __DARWIN_NULL #endif and - MacTypes.h #ifndef nil #define nil NULL #endif So people complain because fusion uses nil as: namespace boost { namespace fusion { struct nil; }} So, nil is a reserved word in Objective-C. But this is C++! And that define is SUCH A BAD PRACTICE in C++! Some folks, like Paul Mensonides maintains a strong stance against this: I would just use #define nil nil as a sanity check and call it done. If the symbol is already defined, compilation error (or at least warning on overly permissive compilers). The symbol will be need to be undefined in between the inclusion of the two libraries. Workarounds like nil_ and (min)(...) just perpetuate the problem. Fix the root problem rather than treating the symptom indefinitely. Otherwise, where is the line drawn? Even if you can't provide a transparent fix (such as defining nil as a constant and min/max as functions), the backwards compatibility argument fails in the long run. The amount of effort required to make the necessary changes to existing code will eventually be outweighed by the effort to implement workarounds put into new code (as well as educate everyone that they are necessary)--especially in cases like these which can mostly be emulated in a way that causes most existing code to work. As I said over and over again, I'm listening and I would want to "fix" this issue if someone comes up with a reasonable (tested) patch that: 1) Detects the platform 2) Renames fusion::nil to something else (only for the affected platform) Yet, no-one wants to do this. Instead we get nasty remarks such as those found here: https://svn.boost.org/trac/boost/ticket/5010#comment:16 What do we do? I'm seeking for a resolution. Regards, -- Joel de Guzman http://www.boostpro.com http://boost-spirit.com

4 5

Re: [boost] Review managers wanted for augmented data structures
by Jonathan Wakely 31 Mar '13

31 Mar '13

8:08 PM, "Vadim Stadnik" wrote: > > Is there an alternative of not integrating advanced data structures into > STL? Why do they need to be put "into STL"? Why can't they exist in addition to it, or alongside it? > Augmented trees are non-standard due to different performance guarantees. They're non-standard because they're not in the standard. > A more reasonable and practical approach to STL would be to provide a wide > set of interchangeable containers and data structures with different > performance guarantees and allow programmers to make decisions about the > most suitable containers for specific applications. That's exactly what the STL is. The STL is about iterators and algorithms and concepts, not a fixed set of predefined containers. You've claimed the STL makes your containers "illegal" which is an odd claim that I can't agree with. Extending the STL with alternative containers is not just acceptable, I'm pretty sure it was intended by Stepanov et al. If your containers don't meet the complexity requirements of an Associative Container as defined in the standard that's fine, just don't claim it is an Associative Container and there shouldn't be a problem, surely. I don't understand why you think there are objections to non-standard containers. The containers in the standard are not suitable for all situations and are not the only choices, if there's a more suitable non-standard container then using it makes sense. This doesn't put the STL "under pressure", it proves its value, because existing algorithms work with both standard and non-standard containers if they model the required concepts.

5 12

[gil] undocumented/unintended concept requirements in color_convert
by Michael Marcin 31 Mar '13

31 Mar '13

I was trying to add other color spaces support and noticed that the rgb to cmyk converter contains: typedef typename channel_type<P2>::type T2; T2 x = channel_traits<T2>::max_value()-get_color(dst,black_t()); if (x>0.0001f) { float x1 = channel_traits<T2>::max_value()/float(x); T2 should model: http://www.boost.org/doc/libs/1_53_0/libs/gil/doc/html/g_i_l_0264.html but this code additionally requires T2 to be greater-than comparable to float and convertible to float.

3 4

[exception] uncaught_exception_count, scope(failure), scope(success)
by Evgeny Panasyuk 31 Mar '13

31 Mar '13

Hello All, There is implementation of uncaught_exception_count - https://github.com/panaseleus/stack_unwinding/blob/master/boost/exception/u… . uncaught_exception_count is a function similar to std::uncaught_exception from standard library, but instead of boolean result it returns unsigned int showing current count of uncaught exceptions. uncaught_exception_count allow us to implement scope(failure) and scope(success) features from D language in C++. ( previous discussion is at http://boost.2283326.n4.nabble.com/scope-exit-D-style-scope-failure-and-sco… ) Implementation of uncaught_exception_count is tested on {Clang 3.2, GCC 3.4.6, GCC 4.1.2, GCC 4.4.6, GCC 4.4.7, MSVC2005SP1, MSVC2008SP1, MSVC2010SP1, MSVC2012} x {x32, x64}. There are also live stress tests - detection of 500 simultaneous uncaught exceptions: GCC 4.6.3: http://liveworkspace.org/code/2qmSso%240 GCC 4.7.2: http://liveworkspace.org/code/dY0VD%240 Clang 3.2: http://liveworkspace.org/code/49MaPk%240 I think that uncaught_exception_count (and uncaught_exception_count_latch primitive) can be added into Boost.Exception library, at least into "detail" section. After that scope(failure) and scope(success) features can be implemented in Boost.ScopeExit library. Note, approximately 14 of 16 Boost.ScopeExit examples in manual are in fact emulations of scope(failure)/scope(success). So, looks like in first place Boost.ScopeExit was introduced to simplify emulation of scope(failure) and scope(success) features. What do you think? Thank you. Best Regards, Evgeny Panasyuk

5 11

Experimenting with modular Boost
by Jonathan Wakely 30 Mar '13

30 Mar '13

The instructions at https://svn.boost.org/trac/boost/wiki/TryModBoost seem to be bogus, apparently because the cloned repo contains no .gitmodules file so the 'git submodule update --init' command does nothing, and I then get an error for the last step: $ cmake -P forward_headers.cmake CMake Error: Error processing file:forward_headers.cmake I'm "only" using Git 1.7.12 but I don't think that's the problem. The older instructions at https://svn.boost.org/trac/boost/wiki/CMakeModularizationStatus refer to a non-existent http://github.com/boost-lib/boost URL, so they don't work either. I've looked at several other wiki pages, but they're also inconsistent or don't help. Is there any accurate documentation for modular Boost? How does someone try modular boost?

2 1

[Filesystem] v3 path separator changes
by Alexander Lamaison 30 Mar '13

30 Mar '13

I'm finally getting round to moving to Filesystem v3 and now my code is breaking all over the place. The cause is the output of string() on Windows which has changed behaviour. I'm manipulating Unix paths for use over SFTP, but doing so on Windows. For instance I might want to append "c" to the Unix path "/a/b". path p("/a/b"); p /= "c"; cout << p.string(); In version 2 this would output "/a/b/c" but now it produces "/a/b\c". Why the breaking change? I'm trying to understand the rationale behind many of the v3 changes which [1] and [2] don't even begin to cover. [1] http://www.boost.org/doc/libs/1_53_0/libs/filesystem/doc/v3.html [2] http://www.boost.org/doc/libs/1_53_0/libs/filesystem/doc/deprecated.html Alex -- Swish - Easy SFTP for Windows Explorer (http://www.swish-sftp.org)

8 33

[switch generator] status
by Jeff Flinn 29 Mar '13

29 Mar '13

Does anyone know the current status of Steven's switch generator library, I see it was reviewed/accepted in 2008, but I don't see it in trunk or any release. Thanks, Jeff

2 1

[config] gcc implemented N3276 decltype
by Michel Morin 29 Mar '13

29 Mar '13

gcc 4.8.1 and 4.9.0 will support N3276 decltype. ( http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52748 ) May I commit an attached patch? Regards, Michel

3 4

Helping With Boost?
by Thales 29 Mar '13

29 Mar '13

Hello! I'm a C++ programmer (Windows 7 platform, Visual Studio) and I'm interested in helping with this project. I've downloaded the latest from the repository and have built the Win32 libraries. Is there anything I can try my hand at to get started? :-) Thanks for any feedback, ...John

4 5

GSoC: Getting ready for the application
by Boris Schaeling 27 Mar '13

27 Mar '13

Can those who planned to add a proposal but didn't do yet update https://svn.boost.org/trac/boost/wiki/SoC2013 as soon as possible? And can those who added a proposal check it one last time? Andrew reminded me that Boost wasn't accepted last year because we had a superficial list of ideas without realistic goals and expectations. We should be able to increase our chances if we document actual requirements and possibly design approaches. According to Google they look extensively at every org's ideas page. So this is really important. Thanks, Boris

5 4

Serialise on Mac OSX 10.8, XCode and GCC
by Tim Burgess 27 Mar '13

27 Mar '13

Hi, I have an XCode c++ project that uses the static serialisation library (as well as FileSystem, IOStream and System). The project started out on XCode 3.6 on Mac OSX 10.6, where it successfully built and ran using Boost 1_49_0, built against Apple's 10.6 SDK. However, I needed to use the XCode debugger to track down some run-time issues and found I couldn't access the debugger on this version of XCode (I'm blind and have to use the VoiceOver utility to gain access to my Mac). Having taken advice, I upgraded to Mac OSX 10.8, SDK 10.8 and XCode 4.6, which solves my debugging issue. Unfortunately, my project no longer links correctly. The linker complains that it can't find symbols for my architecture (x86_64) - the messages are in the the form: "boost::archive::basic_xml_iarchive<boost::archive::xml_wiarchive>::load_sta rt(char const*)", referenced from: "boost::archive::basic_xml_iarchive<boost::archive::xml_wiarchive>::load_ove rride(boost::archive::version_type&, int)", referenced from: "boost::archive::basic_xml_iarchive<boost::archive::xml_wiarchive>::load_ove rride(boost::archive::class_id_type&, int)", referenced from: (I've truncated the output here for brevity). I get no linker errors for any of the other Boost binaries - it's only the serialisation library that creates a problem. The project is configured to compile with the llvmgcc42 compiler, as it also uses the wxWidgets libraries, which don't support compilation using clang. Boost versions tried: 1_50_0, 1_52_0 and 1_53_0. Boost build options tried: 1 - Default (no options specified) - this worked on Mac OSX 10.6, Snow Leopard. 2 - As follows: macosx-version=10.3 macosx-version-min=10.6 architecture=combined threading=multi link=static address-model=32_64 3 - As follows: architecture=combined address-model=32_64 I'm a novice using Boost and the Mac, so would appreciate any suggestions as to how I can resolve this issue. Best wishes. Tim Burgess Raised Bar Ltd. Tel: +44 (0)1827 719822 Web: http://www.raisedbar.net We can supply Roland and Avid products with specialist pre and post-sales support for visually-impaired users - just drop us a line for a quote. Don't forget to sign our on-line petition to lobby for improved access to music education and music technology at: http://www.raisedbar.net/petition.htm

6 18

Re: [boost] [Boost-commit] svn:boost r83608 - trunk/status
by Steven Watanabe 27 Mar '13

27 Mar '13

AMDG On 03/27/2013 12:13 PM, chhenning(a)gmail.com wrote: > > Modified: trunk/status/Jamfile.v2 > ============================================================================== > --- trunk/status/Jamfile.v2 (original) > +++ trunk/status/Jamfile.v2 2013-03-27 15:13:44 EDT (Wed, 27 Mar 2013) > @@ -86,6 +86,7 @@ > fusion/test # test-suite fusion > geometry/test # test-suite geometry > gil/test # test-suite gil > + gil/io/test # test-suite gil::io This just broke the regression tests: ERROR: rule "jpeg.init" unknown in module "toolset". /run/media/steven/regression/tools_bb/build/project.jam:995: in using ../libs/gil/io/test/Jamfile.v2:12: in modules.load In Christ, Steven Watanabe

2 1

Adding gil extensions to boost_release
by Christian Henning 27 Mar '13

27 Mar '13

Hi all, quick question: Is the release branch open? Thanks, Christian

4 8

[gil] YCbCr color space added
by Christian Henning 27 Mar '13

27 Mar '13

Hi all, there has been some interest in adding the ycbcr color space to gil. For that I just added the color space with color conversions and a new image type for subsampled images. Thanks for Juan Puertos for the color conversion routines! I believe, so far, the ycbcr is very rudimentary and there is a lot of more work to do but it's a beginning. Please let me know what you think. Sources: http://svn.boost.org/svn/boost/trunk/boost/gil/extension/toolbox/color_spac… http://svn.boost.org/svn/boost/trunk/boost/gil/extension/toolbox/image_type… Regards, Christian

1 0

Re: [boost] [multi-array] compiler errors with visual studio 2012 (nfarnsworth@web.de)
by Dan Searles 27 Mar '13

27 Mar '13

>Date: Sat, 23 Mar 2013 14:12:24 +0100 (CET) >From: nfarnsworth(a)web.de >To: boost(a)lists.boost.org >Subject: [boost] [multi-array] compiler errors with visual studio 2012 >Message-ID: > <trinity-07de36eb-bb16-4dc9-b97b-68516d068e24-1364044344811@3capp-webde-bs37> > >Content-Type: text/plain; charset="UTF-8" > > > Hello, > have this c++ example which compiles with Visual Studio 2010 but with Visual > Studio 2012 I got this compiler errors: > 1>------ Build started: Project: MultiArrayDemo, Configuration: Debug Win32 > ------ > 1> MultiArrayDemo.cpp > 1>d:\sandbox\multiarraydemo\multiarraydemo\multiarraydemo.cpp(11):error > C2059: syntax error : '<' > 1> d:\sandbox\multiarraydemo\multiarraydemo\multiarraydemo.cpp(25) > : see reference to class template instantiation 'Data<T>' being compiled > 1>d:\sandbox\multiarraydemo\multiarraydemo\multiarraydemo.cpp(11):error > C2238: unexpected token(s) preceding ';' > ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== > The example uses the boost 1.53 version. Here is the example code: > #include "stdafx.h" > #include <boost/multi_array.hpp> > const int rows = 3; > const int cols = 5; > template<class T> struct Data > { > typedef boost::multi_array<T,2> data_type; > typedef typename data_type::array_view<1>::type view_type; //here is the > first error > typedef typename data_type::index_range range; > Data() > :A(boost::extents[rows][cols]) > { > double tmp[] = > {1.0,2.0,3.0,4.0,5.0,6.0,7.0,8.0,9.0,10.0,11.0,12.0,13.0,14.0,15.0}; > A.assign(tmp,tmp+ (rows * cols)); > } > data_type A; > }; > int _tmain(int argc, _TCHAR* argv[]) > { > > Data<double>* data = new Data<double>(); > Data<double>::view_type myView = > data->A[boost::indices[0][Data<double>::range()]]; > delete data; > return 0; > } > Does anybody know how to solve this problem? > Best regards and thank you in advance > Niklas According to Microsoft, the code is non-conformant. Visual Studio 2010 allowed the code to be compiled, but 2012 tightened the requirement. See: http://msdn.microsoft.com/en-us/library/bb531344.aspx (Second point, "Use the template keyword...", but note that they highlighted the wrong keyword). The simple fix is to add the keyword 'template': typedef typename data_type::template array_view<1>::type view_type; //here is the first error Dan Searles

1 0

[fusion] sequence io manipulators
by Jeff Flinn 27 Mar '13

27 Mar '13

When streaming unrelated fusion sets to unrelated ostringstreams from different threads, I get an invalid iterator error. This appears to be due to using a boost::fusion::detail::stream_data::attach's local static arena instance. static void attach(Stream& stream, T const& data) { static arena ar; // our arena ar.data.push_back(new T(data)); stream.pword(get_xalloc_index<Tag>()) = ar.data.back(); } I assume there are issues with using the unguarded stream_data::data std::vector<T*> from multiple threads. This implementation looks problematic in that the arena data does not get cleaned up until program exit as well. Jeff

5 7

[atomic] Could you merge to trunk?
by Vicente J. Botet Escriba 26 Mar '13

26 Mar '13

Hi, there are some modification on trunk that need to be merged to release branch because there are some incompatibilities. Could this be done soon? Thanks, Vicente

3 2