February 2014 - Boost-users

Boost or Standard when there is the choice?
by Paolo Bolzoni 17 Feb '14

17 Feb '14

Dear list, I was wondering, what is the best pratice when you can select between a standard solution or a boost one? For example, std::tie or boost::tie? std::unordered_map or boost::unordered_map? Personally I tend to use std solutions, but does it make sense? Yours sincerely, Paolo Bolzoni

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[move] differences between results in C++03 and C++11 modes
by Adam Romanek 15 Feb '14

15 Feb '14

Hi! Some time ago I encountered a problem with assigning the return value of boost::move() to a non-const reference in C++11 mode, but not in C++03 mode. See [1] for a StackOverflow question that I created for this issue. It contains all the details so for brevity I won't repeat them here. Could anyone explain this issue? Is this a limitation of C++03 emulation or a defect in the implementation? Best regards, Adam Romanek [1] http://stackoverflow.com/questions/21138869/why-does-assigning-the-return-v…

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[boost.format] another compilation error with VC 2013
by Olaf Krzikalla 14 Feb '14

14 Feb '14

Hi boost, I've encountered another VC 2013 problem. alt_sstream doesn't compile, since its base class std::basic_streambuf has an explicitely nonthrowing dtor. I actually had to fix it at two places: - virtual ~basic_altstringbuf() + virtual ~basic_altstringbuf() BOOST_NOEXCEPT_OR_NOTHROW and + virtual ~basic_oaltstringstream() BOOST_NOEXCEPT_OR_NOTHROW + { } Please, can anyone explain the second place: why doesn't the compiler-generated dtor inherit the nothrow clause? Is it due to the other base class (base_from_member< shared_ptr<...> >)? The weird thing is that MS even advocates the usage of boost.format with MSVC 2013: http://msdn.microsoft.com/en-us/library/hh438469.aspx So I am not 100% sure, whether the problem is boost/MSVC-related or my configuration is wrong. Google is surprisingly quiet regarding the issue. Best Olaf

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Fwd: boost::unique_lock throw a exception
by shada 13 Feb '14

13 Feb '14

I use boost1.52 on windows2003sp2, boost::unique_lock throw a exception, please help me. stack is: *RaiseException_CxxThrowExceptionboost::throw_exception<boost::lock_error>[e:\library\boost_1_52\boost\throw_exception.hpp：67] boost::shared_mutex::timed_lock[e:\library\boost_1_52\boost\thread\win32\shared_mutex.hpp：430]boost::shared_mutex::lock[e:\library\boost_1_52\boost\thread\win32\shared_mutex.hpp：382]boost::unique_lock<boost::shared_mutex>::lock[e:\library\boost_1_52\boost\thread\locks.hpp：510]* ------------------------------------------------------------------------ *bool timed_lock(boost::system_time const& wait_until){ for(;;) { state_data old_state=state; for(;;) { state_data new_state=old_state; if(new_state.shared_count || new_state.exclusive) { ++new_state.exclusive_waiting; if(!new_state.exclusive_waiting) { boost::throw_exception(boost::lock_error()); } new_state.exclusive_waiting_blocked=true; } else { new_state.exclusive=true; }*

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Minimum perfect matching
by Paolo Bolzoni 13 Feb '14

13 Feb '14

Dear list, I am using boost graph and I need to solve a variant of the classic TSP. Boost providess a function (metric_tsp_approx) to get a Halmintonian cycle over a full connected metric weighted graph. However I need something slightly different. I need a path that visits all vertices starting and ending to two well known vertices (let be s and d). Seeking around, I found the suggestion of adding a node connected to s d and with the weight of the edge (s,d). The TSP solution of the new graph is the solution, just removing the new node. The problem is that now the graph is not complete anymore so the metric_tsp_approx's approach does not work anymore. Another possiblity is using a variant of Christofides algorithm, but one of the passages of that is the minimum weight perfect matching. I am a little confused by the documentation of the functions about Maximum Cardinality Matching(1), it is possible to use them to find the a maximum cardinality matching so that the total weight of all selected edges is minimal? Otherwise, is there an alternate approach to my problem? Yours faithfully, Paolo (1) http://www.boost.org/doc/libs/1_55_0/libs/graph/doc/maximum_matching.html

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Re: [Boost-users] intrusive data structures with custom pointer class
by Matei David 12 Feb '14

12 Feb '14

On Fri, 07 Feb 2014 16:00:31 -0500 boost-users-request(a)lists.boost.org wrote: > Message: 6 > Date: Fri, 07 Feb 2014 22:00:23 +0100 > From: Ion Gazta?aga <igaztanaga(a)gmail.com> > To: boost-users(a)lists.boost.org > Subject: Re: [Boost-users] intrusive data structures with custom > pointer class > Message-ID: <52F54967.9020704(a)gmail.com> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > El 06/02/2014 23:52, Matei David escribi?: > > Hi, > > > > > > I would like to use some boost::intrusive data structures (lists and > > trees) in a project I'm working on, but I ran into trouble trying to > > customize the existing classes to my needs. I decided to post my > > problem here, in case somebody knowledgeable of boost::intrusive > > *implementation details* can assist me. Thank you in advance. > > Hi Meti, > > You have a lot of questions, I hope I can answer most of them. > > > Background: > > > > In the project I'm working on, I need to manage a large number of > > objects in memory. The data is dynamic, so I need to be able to > > alloc&dealloc objects, in addition to keeping the objects in various > > lists&trees (for which I'm trying to use boost::intrusive). The RAM > > usage is large (think, >100GB), but the number of objects is smaller > > than 2^32. So one thing I'd like to do is to replace 8-byte raw > > pointers with 4-byte offsets into a deque. Doing this would solve > > the alloc/dealloc part. However, I now need to customize > > boost::intrusive containers to work with these 4-byte offsets > > instead of raw pointers. > > I guess the deque is a global object, right. What do you mean with > "offset" into a deque? It's the offset passed to "deque::operator[]"? Hi and thanks for the reply. Contrary to some of the things you said, I found a way to (partly?) implement my specific use case with boost::intrusive. However, I have some concerns: - I only tested a small part of the boost::intrusive functionality with my customizations, so my success might be superficial. Could you have a look and make an informed guess as to how stable this is? - I am concerned that further boost updates might inadvertently break my customizations, and I would hate to list =1.55 as a specific dependency (as opposed to >=1.55). I understand this can never be fully avoided, but I'm hoping you could decide to support my use case, either officially by including it in the code base and the docs, or at least non-officially by being aware of it. I found and fixed this along the way: https://svn.boost.org/trac/boost/ticket/9650 Let me restate my specific use-case: I have several types A, B,..., and I want each object a1 of type A to be kept in a tree (say) along with other A objects (not all A objects go in the same tree). Since there are so many A objects, I care about their memory usage. Specifically, I want to replace 8-byte pointers (A*) by 4-byte handles (which I call Ptr<A>). An A-handle is really an uint32_t offset into the array of type A objects. A B-handle is also an offset, but into another array, holding B objects. Thus: - The transformation handle-to-object_address is O(1). - The transformation object_address-to-handle is prohibitive. - I can only use A-handles for A objects stored in a unique A-object array. If I construct an A object elsewhere, I can refer to it with a raw pointer, but not with an A-handle. - Objects of type B are stored in a different array than objects of type A. This means, in particular, that handles are not freely re-interpretable as real/smart pointers are with casts. So, dereferencing the A handle 42 gives me the A object number 42 from the A object array; but dereferencing the same handle reinterpreted as a B handle gives me the object number 42 from the B object array. NOTE: These pointer casts are my primary source of concern. I will come back to this below. My goal is to make boost::implicit structures work with these handles instead of raw/smart pointers. Intuition tells me there isn't a serious reason why they shouldn't, and that this type of scenario is general enough to be of interest to others, and therefore to boost maintainers. My (partial) success is here: https://github.com/mateidavid/sga/raw/matei-dev/src/Dev/factory.hpp https://github.com/mateidavid/sga/raw/matei-dev/src/Dev/test-i_list-orig.cpp https://github.com/mateidavid/sga/raw/matei-dev/src/Dev/test-i_tree-orig.cpp The code is a work in progress. You'll need a few more included files. I'm compiling with, e.g.: $ [g++|clang++] [-DNONSTATIC_VALUE_TRAITS] -I <path_to_1_55> -g -O0 -std=c++0x -pedantic -Wall -Wextra -o test-i_list-orig test-i_list-orig.cpp common.cpp globals.cpp For lists with nonstatic traits, you need the bug fix mentioned earlier. > > - Given a type T, I rolled out pointer-replacement class Ptr<T> > > which holds a 4-byte int, and upon operator*, it produces a Ref<T> > > object. > > - A reference-replacement Ref<T> class similarly holds a 4-byte int, > > it implements operator& which produces the associated Ptr<T> > > object, and it also provides an operator T& () conversion which > > dereferences the object from the deque. > > - With these, I tried a custom traits struct looking like this: > > value_type = node := T > > node_ptr = pointer := Ptr<T> > > reference := Ref<T> > > Boost.Intrusive models (or tries to model) a pointer type that can be > modeled with std::pointer_traits (more precisely > boost::intrusive::pointer_traits). In that model the reference type > must be a type that implements the dot operator. Sadly in C++ there > is no way to implement a class that overloads this operator. That's > why your pseudo-reference type will not work. I thought about this. There are 2 different perspectives. From the point of view of the boost::intrusive data structures (e.g., list), I think these structures should never ever dereference any object they store. So, e.g. inside list.hpp, if we have somewhere an object val of type "reference" (such as in insert()), the code should never use "o.<field> = 42". Instead, whatever fields the data structure needs to access (like r/w access to parent pointers), they should access them through the traits class methods (e.g. traits::set_field(o,42)). However, this already seems to be the case today. From the POV of the traits classes, indeed, these need to dereference values. First of all, there is a problem with the function signatures. In http://www.boost.org/doc/libs/1_55_0/doc/html/intrusive/value_traits.html the signature of to_node_ptr should be changed from: static node_ptr to_node_ptr (value_type &value) to: static node_ptr to_node_ptr (pointer_traits<pointer>::reference value) This just involves changing the docs; you can change the signature (as I did in my customization) and it compiles just fine. Also, even with the right signature, the function should never do: { return value.get_node_ptr(); } but instead: { return (&value)->get_node_ptr(); } because both reference::operator& and pointer::operator-> are overloadable. However, the concern about traits classes is not as serious as the one about the data structures because users are given the option to write their own traits classes anyhow. So overall, I think the problem with the dot operator isn't serious enough to make this use case unattainable. > > A. The traits classes seem to be there to support 2 existing > > customization types, namely the situation where "node" is a base > > class of "value" (implementing "base hooks") and the situation > > where "node" is a member of "value" (implementing "member hooks"). > > My situation represents a 3rd customization type. > > You can use function_hook, the hook does not need to be a member or > base class. The hack I used seems to work for now. In the future, I think it would be nice to have the option to explicitly specify the header node (so the container would just use a pointer) in the interest of clearly separating any type of node/value allocation from the containers. But I wouldn't say that's a priority. > > B. Even though the traits classes allow one to specify pointer > > types, it's possible (?) that under the hood the classes were > > designed to support only raw pointers and smart pointers, not the > > indirect offset-like pointers I need. > > See previous answer about supported reference types. > > > Given A&B, it seems to me that in my customization I would need 2 > > different hacks. In the interest of code stability, I started > > wondering whether it is feasible to adapt existing boost::intrusive > > data to my needs (my first instinct) as opposed to simply rolling > > out my own rbtree. > > I don't know the impact of supporting smart reference types. It might > be impossible, I haven't tried it. > > > 0. Obviously: Have you seen a similar situation being dealt with > > before? Maybe there's an existing solution out there. My reluctance > > to rolling out my own intrusive rbtrees is due to the fact I'd have > > to test them, as opposed to using a known implementation. > > > > 1. Are boost::intrusive data structures supposed to support custom > > pointer classes (neither real pointers nor smart pointers)? For > > instance, in 1.46 I found this code in > > boost/intrusive/detail/tree_algorithms.hpp > > Yes, boost::interprocess::offset_ptr (but a raw reference can be > converted to a smart pointer easily). > > > static node_ptr uncast(const_node_ptr ptr) > > { > > return node_ptr(const_cast<node*>( > > ::boost::intrusive::detail::boost_intrusive_get_pointer(ptr))); > > } > > However, intrusive lists worked just fine in 1.46, which suggests > > this was simply a bug. > > This was fixed in recent Boost releases using pointer_traits to > implement this function. You can customize pointer_traits to > implement your own version. > > > 2. Can you point me to an example of defining and using custom > > pointer class with boost::intrusive? To enable compilation (of > > lists only) in 1.46, I had to customize std::iterator_traits (that > > part I understood), but then also boost::pointer_to_other and > > boost::intrusive::detail::smart_ptr_type. Even though the code > > compiled, I don't know what those are doing exactly, so I'm weary of > > them. > > See the example in libs/intrusive/example/doc_offset_ptr.cpp and > boost/interprocess/offset_ptr.hpp. See the most recent boost version > for fixed bugs. A dumb smart pointer is used in boost intrusive > tests, and it's found in libs/intrusive/test/smart_ptr.hpp, but it's > a bit oudated. Anyway I think pointer requirements for > Boost.Intrusive might no be correctly specified and it might require > some fixes. Recent versions uses pointer_traits, and I recommend you > this approach. > > > 3. In 1.55, I have a few more pages of errors, I think mainly due to > > these pointer customization issues I don't fully understand. > > Something seems to have changed from 1.46 to 1.55. Is there a > > reference about what changed? Or is there a portable way of rolling > > out such a custom pointer class? > > pointer_traits was specified and all code was ported to use this > customization point. The reference type is assumed to be a raw > reference (as there is no way to overload operator dot to implement a > working smart reference). > > The only why to use Boost.Intrusive would be to implement a smart > pointer (of any pointee type) that can be fastly obtained from raw > reference. If this is your case, Boost.Intrusive might already have > all that you need. If you need a "smart reference", then > Boost.Intrusive is not prepared for this and I don't know how many > effort would require adding support for this (even if this approach > is feasible). > > The problem with "node" objects embedded in the container could be > solved with an option that allows external allocation of these nodes. > > Best, > > Ion Empirically, since I got the containers (at least partially) working with non-standard references, they must be already prepared to handle those. Theoretically, as I described above, the containers themselves should never have to dereference specific fields anyhow, and therefore should be immune to reference type changes. The more serious concern, ***and the reason I wrote all this***, is with pointer casts. Unlike raw or smart pointers, these handles are type-specific. So casting them to something else and then dereferencing that object should be done with care. Take bstree, for instance. Its base class (bstbase3) inherits from node & Value_Traits. The way you obtain access to the Value_Traits struct (used with stateful traits) is through a pointer which you later want to dereference: typedef typename pointer_traits<node_ptr>::template rebind_pointer<const real_value_traits>::type const_real_value_traits_ptr; const_real_value_traits_ptr real_value_traits_ptr() const { return pointer_traits<const_real_value_traits_ptr>::pointer_to( this->get_real_value_traits()); } With handles, the only way I see for this to work is to eventually transform handles into real pointers. So, Ptr<T>::rebind<U>::type should be U* except for U in {T, const T} and possibly {void, const void}. I initially tried to wrap voids as well, but I get errors. (Try adding -DWRAP_VOID when compiling test-i_list-orig.cpp) The problem are these casts: - In iiterator_members: const_void_pointer := pointer_traits<NodePtr>::rebind_pointer<const void> - In iiterator: void_pointer := pointer_traits<node_ptr>::rebind_pointer<void> - In list_iterator: const_real_value_traits_ptr := pointer_traits<void_pointer>::rebind_pointer<const real_value_traits> - iiterator_members ctor takes as 2nd argument a const_void_pointer - list_iterator ctor calls iiterator_members ctor, passing as 2nd arg a const_real_value_traits_ptr When I wrap voids: const_void_pointer := Ptr<const void> void_pointer := Ptr<const void> const_real_value_traits_ptr := value_traits* which means the container code is trying to cast: Ptr<T> -> value_traits* -> Ptr<const void> -> value_traits* -> deref, and the 2nd cast fails. However, things seemed to work ok if I don't wrap voids. So the main concern with my use case is that: ***intrusive containers should not cast node_ptr objects into other types of pointers (not even void*), and then attempt to cast them back***. They can cast other pointers (such as value_traits*) to void* and back, but not node_ptr-s. Please have this use case in mind when further developing boost::intrusive. The files I linked above can serve as a basic test case. I can help writing up this use case in slightly more detail if you think that would be useful for others. Thanks, Matei

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[boost.tr1] compilation errors with VC 2013
by Olaf Krzikalla 12 Feb '14

12 Feb '14

Hi, I have encountered plenty of compilation errors with VC 2013 caused by including <boost/tr1/memory.hpp> or <boost/tr1/functional.hpp>. The errors happen with all versions tried (1.40, 1.53 and 1.55). Is boost.tr1 deprecated for newer compilers? Best Olaf

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Compilation problem with has_binary_operator.hpp on Mac OSX
by Tim Burgess 12 Feb '14

12 Feb '14

Hi, I'm building a framework project using Xcode 4.6 configured to use the Apple GCC 4.2 compiler (my project also uses wxWidgets, so this compiler is required). Using Boost 1.55.0 I get: cd /Users/tim/Developer/RBSpeech setenv LANG en_US.US-ASCII /Applications/Xcode.app/Contents/Developer/usr/bin/llvm-gcc-4.2 -x objective-c++ -arch x86_64 -fmessage-length=0 -pipe -Wno-trigraphs -fpascal-strings -O0 -Wreturn-type -Wunused-variable -Wuninitialized -Wshorten-64-to-32 -DDEBUG=1 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Develop er/SDKs/MacOSX10.8.sdk -fasm-blocks -mmacosx-version-min=10.6 -gdwarf-2 -fvisibility-inlines-hidden -iquote /Users/tim/Library/Developer/Xcode/DerivedData/RBSpeech-gglcnsigefizlfbidkwh bsxvlwng/Build/Intermediates/RBSpeech.build/Debug/RBSpeech.build/RBSpeech-ge nerated-files.hmap -I/Users/tim/Library/Developer/Xcode/DerivedData/RBSpeech-gglcnsigefizlfbidk whbsxvlwng/Build/Intermediates/RBSpeech.build/Debug/RBSpeech.build/RBSpeech- own-target-headers.hmap -I/Users/tim/Library/Developer/Xcode/DerivedData/RBSpeech-gglcnsigefizlfbidk whbsxvlwng/Build/Intermediates/RBSpeech.build/Debug/RBSpeech.build/RBSpeech- all-target-headers.hmap -iquote /Users/tim/Library/Developer/Xcode/DerivedData/RBSpeech-gglcnsigefizlfbidkwh bsxvlwng/Build/Intermediates/RBSpeech.build/Debug/RBSpeech.build/RBSpeech-pr oject-headers.hmap -I/Users/tim/Library/Developer/Xcode/DerivedData/RBSpeech-gglcnsigefizlfbidk whbsxvlwng/Build/Products/Debug/include -I/users/tim/developer/libraries/wxwidgets/include -I/users/tim/developer/libraries/cryptopp -I/users/tim/developer/libraries/boost_1_55_0 -I/users/tim/developer/sources/surfacereader -I/Users/tim/Library/Developer/Xcode/DerivedData/RBSpeech-gglcnsigefizlfbidk whbsxvlwng/Build/Intermediates/RBSpeech.build/Debug/RBSpeech.build/DerivedSo urces/x86_64 -I/Users/tim/Library/Developer/Xcode/DerivedData/RBSpeech-gglcnsigefizlfbidk whbsxvlwng/Build/Intermediates/RBSpeech.build/Debug/RBSpeech.build/DerivedSo urces -F/Users/tim/Library/Developer/Xcode/DerivedData/RBSpeech-gglcnsigefizlfbidk whbsxvlwng/Build/Products/Debug -I/Users/tim/developer/libraries/wxwidgets/build-debug/lib/wx/include/osx_co coa-unicode-static-2.9 -I/Users/tim/developer/libraries/wxwidgets/include -D_FILE_OFFSET_BITS=64 -D__WXMAC__ -D__WXOSX__ -D__WXOSX_COCOA__ -include /Users/tim/Library/Developer/Xcode/DerivedData/RBSpeech-gglcnsigefizlfbidkwh bsxvlwng/Build/Intermediates/PrecompiledHeaders/RBSpeech-Prefix-filshqejewqv wmcnuphmjzrmapcf/RBSpeech-Prefix.pch -c /Users/tim/Developer/RBSpeech/../Sources/SurfaceReader/RBSpeech.mm -o /Users/tim/Library/Developer/Xcode/DerivedData/RBSpeech-gglcnsigefizlfbidkwh bsxvlwng/Build/Intermediates/RBSpeech.build/Debug/RBSpeech.build/Objects-nor mal/x86_64/RBSpeech.o cc1objplus: warning: -Wuninitialized is not supported without -O In file included from /users/tim/developer/libraries/boost_1_55_0/boost/type_traits/has_left_shift .hpp:43, from /users/tim/developer/libraries/boost_1_55_0/boost/lexical_cast.hpp:165, from /Users/tim/Developer/RBSpeech/../Sources/SurfaceReader/RBStringFuncs.hpp:11, from /Users/tim/Developer/RBSpeech/../Sources/SurfaceReader/RBSpeech.h:27, from /Users/tim/Developer/RBSpeech/../Sources/SurfaceReader/RBSpeech.mm:4: /users/tim/developer/libraries/boost_1_55_0/boost/type_traits/detail/has_bin ary_operator.hpp:155: error: expected unqualified-id before 'do' The project uses OSX10.8 as its base SDK, but has OSX10.6 as its deployment target to provide backward compatibility and I made sure that my Boost libraries specified the 10.6 SDK as a minimum. Can anybody advise, please? Best wishes. Tim Burgess

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[property_tree] Compilation Problem when #including <boost/property_tree/json_parser.hpp>
by Adi Shavit 12 Feb '14

12 Feb '14

Hi, On VS2010, the following code does not compile if I restore the commented out #include: *// #include <boost/property_tree/json_parser.hpp>* struct X { enum Labels { ERROR, ONE, TWO, THREE }; // problem => ^^^^^ }; void f() { X::Labels r = X::ERROR; // problem => ^^^^^ } The VS2010 errors are: t.cpp(5): error C2059: syntax error : 'constant' t.cpp(5): error C2143: syntax error : missing ';' before '}' t.cpp(5): error C2238: unexpected token(s) preceding ';' t.cpp(7): error C2059: syntax error : '}' t.cpp(7): error C2143: syntax error : missing ';' before '}' t.cpp(7): error C2059: syntax error : '}' t.cpp(11): error C2589: 'constant' : illegal token on right side of '::' t.cpp(11): error C2059: syntax error : '::' It seems that somewhere inside the #include hierarchy the symbol ERROR is #defined to cause this code to fail. Renaming ERROR to something else avoids this problem. I think I tracked it into ' boost/spirit/home/classic/iterator/impl/file_iterator.ipp' but I'm not sure where exactly it is coming from. Adi

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compilation error while using intel c++ XE 14.0
by Bo Chen 12 Feb '14

12 Feb '14

Hi, While I compile the code(see attached) based on the boost 1.54/1.55 using intel compiler c++ XE 14.0, I got following error. Could you help please? Thanks. Chen Bo 1>------ Build started: Project: intelTest, Configuration: Debug Win32 ------ 1>Build started 07/02/2014 18:09:33. 1>ClCompile: 1> ***** ClCompile (Win32 - Intel C++) 1> intelTest.cpp 1> Warning #672: the command line options do not match those used when precompiled header file "Debug\intelTest.pchi" was created 1> 1>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xutility(2215): error : no instance of overloaded function "std::_Copy_impl" matches the argument list 1> argument types are: (boost::detail::multi_array::array_iterator<int, const int *, boost::mpl::size_t<3U>, boost::detail::multi_array::const_sub_array<int, 2U, const int *>, boost::random_access_traversal_tag>, boost::detail::multi_array::array_iterator<int, const int *, boost::mpl::size_t<3U>, boost::detail::multi_array::const_sub_array<int, 2U, const int *>, boost::random_access_traversal_tag>, boost::detail::multi_array::array_iterator<int, int *, boost::mpl::size_t<3U>, 1> boost::detail::multi_array::sub_array<int, 2U>, boost::random_access_traversal_tag>, boost::detail::iterator_category_with_traversal<std::input_iterator_tag, boost::random_access_traversal_tag>, boost::detail::iterator_category_with_traversal<std::input_iterator_tag, boost::random_access_traversal_tag>) 1> return (_Copy_impl(_First, _Last, 1> ^ 1> detected during: 1> instantiation of "_OutIt std::_Copy_impl(_InIt, _InIt, _OutIt, std::tr1::false_type) [with _InIt=boost::detail::multi_array::array_iterator<int, const int *, boost::mpl::size_t<3U>, boost::detail::multi_array::const_sub_array<int, 2U, const int *>, boost::random_access_traversal_tag>, _OutIt=boost::detail::multi_array::array_iterator<int, int *, boost::mpl::size_t<3U>, boost::detail::multi_array::sub_array<int, 2U>, boost::random_access_traversal_tag>]" at line 2227 1> instantiation of "_OutIt std::copy(_InIt, _InIt, _OutIt) [with _InIt=boost::detail::multi_array::array_iterator<int, const int *, boost::mpl::size_t<3U>, boost::detail::multi_array::const_sub_array<int, 2U, const int *>, boost::random_access_traversal_tag>, _OutIt=boost::detail::multi_array::array_iterator<int, int *, boost::mpl::size_t<3U>, boost::detail::multi_array::sub_array<int, 2U>, boost::random_access_traversal_tag>]" at line 322 of 1> "C:\Users\chbeb9\Downloads\boost_1_55_0\boost/multi_array/view.hpp" 1> instantiation of "boost::detail::multi_array::multi_array_view<T, NumDims> &boost::detail::multi_array::multi_array_view<T, NumDims>::operator=(const boost::detail::multi_array::multi_array_view<T, NumDims> &) [with T=int, NumDims=3U]" at line 447 of "C:\Users\chbeb9\Downloads\boost_1_55_0\boost/multi_array.hpp" 1> instantiation of "boost::multi_array<T, NumDims, Allocator> &boost::multi_array<T, NumDims, Allocator>::resize(const boost::detail::multi_array::extent_gen<NumDims> &) [with T=int, NumDims=3U, Allocator=std::allocator<int>]" at line 32 of "intelTest.cpp" 1> 1> compilation aborted for intelTest.cpp (code 2)

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Boost::preprocess __VAR_ARGS__ compile fail
by garthh 12 Feb '14

12 Feb '14

This simple piece of code doesn't compile for me in boost 1.54 on MacOSX: #include <boost/preprocessor.hpp> #define debugprintf(...) \ printf(BOOST_PP_SEQ_ELEM(0, BOOST_PP_VARIADIC_TO_SEQ(__VA_ARGS__))) main () { debugprintf("test"); } I've spent ages on it without success. Any suggestions would be greatly appreciated! Compile output: error: too few arguments provided to function-like macro invocation debugprintf("boost test"); ^ main.cpp:15:17: note: expanded from macro 'debugprintf' fprintf(stderr, BOOST_PP_SEQ_ELEM(0, BOOST_PP_VARIADIC_TO_SEQ(__VA_ARGS__))); \ ^ /usr/local/Boost/1.54/include/boost/preprocessor/seq/elem.hpp:22:39: note: expanded from macro 'BOOST_PP_SEQ_ELEM' # define BOOST_PP_SEQ_ELEM(i, seq) BOOST_PP_SEQ_ELEM_I(i, seq) ^ /usr/local/Boost/1.54/include/boost/preprocessor/seq/elem.hpp:41:45: note: expanded from macro 'BOOST_PP_SEQ_ELEM_I' # define BOOST_PP_SEQ_ELEM_I(i, seq) BOOST_PP_SEQ_ELEM_II(BOOST_PP_SEQ_ELEM_ ## i seq) ^ /usr/local/Boost/1.54/include/boost/preprocessor/seq/elem.hpp:43:62: note: expanded from macro 'BOOST_PP_SEQ_ELEM_II' # define BOOST_PP_SEQ_ELEM_II(im) BOOST_PP_SEQ_ELEM_III(im) ^ main.cpp:21:2: error: use of undeclared identifier 'BOOST_PP_SEQ_ELEM_III' debugprintf("boost test"); -- View this message in context: http://boost.2283326.n4.nabble.com/Boost-preprocess-VAR-ARGS-compile-fail-t… Sent from the Boost - Users mailing list archive at Nabble.com.

2 1

unable to use find() function in boost::associative property maps.
by Aniket Pugaonkar 12 Feb '14

12 Feb '14

Hi, The current boost::associative_property_map interface in boost::property_map does not provide a *find()* function interface from where we can find a key type from associative map. Although the associative property map concept was mainly developed for using boost::get and boost::put function efficiently on unique associative containers (such as std::map), it still does not have any interface for using find() function for searching whether an element exists in a map, My problem is explained below: I have a map, and I define a associative property map on it. as follows: std::map< int, int > *mymap*; boost::associative_property_map< std::map< int, int > > *my_asso_map* ( mymap ); I have a template function, named " exists_in " which checks whether a particular key_value, is present in the map or not. The function is as follows: *template* <typename map_t, typename key_t> bool *exists_in*(map_t map, key_t key) { return map.*find*(key) != map.end(); } ======================================== If I call this template function on mymap, it gives me no error: if( !exists_in ( mymap, key ) ----> no error Now, if I call template function on my_asso_map, it throws an error : if( !exists_in( my_asso_map, key ) ---->> error error: âclass boost::associative_property_map<std::map<int, int > >â has no member named âendâ error: âclass boost::associative_property_map<std::map<int, int > >â has no member named âfindâ I understand, my_asso_map just stores the address of mymap and provides get and put efficiently. But there are instances, where I have to *search* a key in my map. ( for example, if else loop as provided above ). I want to hide *mymap *and just expose *my_asso_map* to the user and everywhere I want to pass my_asso_map.. I am able to do this except for the *find*() function, because of which I had to keep passing my original *mymap *to the function/ functor and then use exists_in template function. Is there any way to implement a find() utility for associative property maps ? If find() interface can be added in library, that would be simply great ! Thanks, -- Thanks and regards, Aniket Pugaonkar

1 0

Inconsistent 1.55 downloads
by Rob Conde 11 Feb '14

11 Feb '14

The contents of boost_1_55_0.zip and boost_1_55.tar.bz2 are not consistent from: http://sourceforge.net/projects/boost/files/boost/1.55.0/ The tar.bz2 version compiles on linux, but the zip version does not. It complains about unknown modules when running b2. Rob Conde

2 2

How to compile boost with non-standard clang installations.
by Bill White 11 Feb '14

11 Feb '14

I am trying to build boost using clang. I know there are many sources of advice for doing this, but I can't seem to find a description of my exact system, and my attempts to adapt them have not been notably successful. Here are my configuration constraints: 1.) Clang is not the system compiler. It is compiled in installed in separately, with prefix $a/clang. So, $a/clang/bin/clang++ is the C++ compiler, and so forth. I am using the tip of the llvm/clang tree. 2.) I want to use libc++, which is installed in $a/clang/lib/libc++.so. I also want to use the libc++ abi, which is installed in $a/clang/lib/libcxxabi.so. 3.) The libc++ standard library include files are installed in $a/include/c++/v1. For most programs I compile with the options -nostdinc++ -isystem $a/clang/include/c++/v1 -std=c++11 and link with -stdlib=libc++ -L$a/clang/lib -lcxxabi This seems to work pretty well for most circumstances. However, I can't figure out how to translate this to boost 1.55.0. I tried: ./bootstrap.sh --with-toolset=clang --prefix=$a/clang ./b2 toolset=clang \ cxxflags="-std=c++11 -nostdinc++ -isystem $a/clang/include/c++/v1 -stdlib=libc++" \ linkflags="-stdlib=c++ -L$a/clang/lib" \ --prefix=$a/clang -j10 define=BOOST_SYSTEM_NO_DEPRECATED stage release However, the compilations failed. They all seemed to fail compiling type_traits. A typical failure is: clang-linux.compile.c++.without-pth bin.v2/libs/regex/build/clang-linux-3.0/release/threading-multi/icu.o In file included from libs/regex/build/../src/icu.cpp:20: In file included from ./boost/regex/config.hpp:43: In file included from ./boost/config.hpp:40: In file included from ./boost/config/select_stdlib_config.hpp:37: In file included from ./boost/config/no_tr1/utility.hpp:21: In file included from /local/billw/arch/glnxa64/clang/include/c++/v1/utility:157: In file included from /local/billw/arch/glnxa64/clang/include/c++/v1/__tuple:16: /local/billw/arch/glnxa64/clang/include/c++/v1/type_traits:3308:31: error: expected expression static const bool value = decltype(__test<_Tp>(nullptr))::value; ^ 1 error generated. "clang++" -c -x c++ -std=c++11 -nostdinc++ -isystem /local/billw/arch/glnxa64/clang/include/c++/v1 -O3 -finline-functions -Wno-inline -Wall -pedantic -pthread -fPIC -std=c++11 -nostdinc++ -isystem /local/billw/arch/glnxa64/clang/include/c++/v1 -DBOOST_ALL_NO_LIB=1 -DBOOST_REGEX_DYN_LINK=1 -DBOOST_SYSTEM_NO_DEPRECATED -DNDEBUG -I"." -o "bin.v2/libs/regex/build/clang-linux-3.0/release/threading-multi/icu.o" "libs/regex/build/../src/icu.cpp" ...failed clang-linux.compile.c++.without-pth bin.v2/libs/regex/build/clang-linux-3.0/release/threading-multi/icu.o... (Here $a is /local/billw/arch/glnxa64.) I apologize for the length of this, but I didn't know what to leave out. Thanks in advance.

1 1

[property_tree] hex integer translator
by Steve Hartmann 11 Feb '14

11 Feb '14

I am using property_tree to parse some xml files provided by outside sources. Within those xml files, sometimes integers are represented as decimal, others are represented as hex. Below is an example line where a property named Index uses a hex representation. <Index>#x7000</Index> So I tried to read this as an integer, with the following source line, but that throws an exception since it does not now how to translate the hex format from the xml file. deviceList.second.get<int>("Index") So my question is: is there a translator already included in the property_tree <that I just cannot find>, or do I need to write my own translator to deal with hex integers. Thanks, Steven

1 0

[container.string] why isn't memcpy used in the internals?
by Adam Romanek 11 Feb '14

11 Feb '14

Hi! Recently I've been trying to improve the performance of a code that makes heavy use of std::string (lots of constructions and destructions). My first thought was to use boost::container::string as it does not use reference-counting and uses small-string optimization, so it should be a perfect replacement for std::string when it comes to performance. Right... But the problem is that switching to boost::container::string only made things worse in the general case. I wrote "in the general case" because when strings to be held are small and SSO may be applied then boost::container::string outperforms std::string considerably. However, in the general case constructing boost::container::string from a C string is significantly slower than constructing std::string. My investigation showed that std::string uses memcpy to copy the C string into its buffer while boost::container::string does not. The memcpy comes from std::char_traits::copy so maybe boost::container::string could use it too? I guess the rest of operations from std::char_traits (find, move, assign etc.) could be utilized too as std::char_traits has been carefully crafted with performance in mind. Should I create a ticket for this issue? Best regards, Adam Romanek

2 4

How to use graph properties
by Paolo Bolzoni 11 Feb '14

11 Feb '14

Dear list, I need to keep track of two special vertices in my graph, So I thought to attach two vertex_descriptor as graph properties so have easy access any moment. Properties work fine for edges or vertices, but I cannot make them work for the graph. In the bottom is the C++ code. The graph has the two properties, now how I cat get and put them? This code does not work and the error messages are impossible to read for me. Otherwise that is the way to keep graph-wise properties? The code compiles removing the two puts, so I assume the error is there. Yours sincerely, Paolo #include <boost/graph/adjacency_list.hpp> namespace boost { enum graph_source_t { graph_source = 100 }; BOOST_INSTALL_PROPERTY (graph, source); enum graph_destination_t { graph_destination = 101 }; BOOST_INSTALL_PROPERTY (graph, destination); } typedef size_t graph_vertex; typedef boost::adjacency_list < boost::vecS, boost::vecS, boost::undirectedS, boost::no_property, boost::no_property, boost::property < boost::graph_source_t, graph_vertex, boost::property < boost::graph_destination_t, graph_vertex, boost::no_property>>> graph_t; static_assert(std::is_same<graph_vertex, boost::graph_traits<graph_t>::vertex_descriptor>::value, "Check out the vertex descriptor type!"); int main() { using namespace boost; graph_t g; add_edge(0, 1, g); put(graph_destination, g, 0); put(graph_source, g, 1); }

2 2

Re: [Boost-users] Boost-users Digest, Vol 3709, Issue 1
by Deepa S 11 Feb '14

11 Feb '14

Hi Gennadiy, Yes I would like to know how I need to write my own main in this case? Also I was wondering if there is any workaround that was found other than re-writing the main? Thanks, Deepa Here is what I am trying to do, may not be the best way, but trying to re-run the test suite ts1 - 3 consecutive times to test for repeatability: bool init_unit_test_suite(int argc, char **argv) { test_suite* ts1 = BOOST_TEST_SUITE( "SKUResourcesTestSuite" ); ts1->add( BOOST_TEST_CASE(&TestCase1) ); ts1->add( BOOST_TEST_CASE(&TestCase2) ); framework::master_test_suite().add( ts1 ); for(int i = 0;i < 3;i++) { framework::master_test_suite().add( ts1 ); } return true; } Deepa S <mslvada <at> yahoo.com> writes: > Wanted to check if there was any resolution to the error indicated > in this post: > http://lists.boost.org/boost-users/2010/06/59564.php > > I am running into a similar issue and would like to know how to resolve it. What exactly is the issue? Do you want to write your own main? Gennadiy On Monday, February 10, 2014 10:30 PM, "boost-users-request(a)lists.boost.org" <boost-users-request(a)lists.boost.org> wrote: Send Boost-users mailing list submissions to boost-users(a)lists.boost.org To subscribe or unsubscribe via the World Wide Web, visit http://lists.boost.org/mailman/listinfo.cgi/boost-users or, via email, send a message with subject or body 'help' to boost-users-request(a)lists.boost.org You can reach the person managing the list at boost-users-owner(a)lists.boost.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Boost-users digest..." Today's Topics: 1. Re: Regarding post: Using Boost.Test in Iteration (Gennadiy Rozental) 2. [container.string] why isn't memcpy used in the internals? (Adam Romanek) 3. Re: [container.string] why isn't memcpy used in the internals? (Ion Gazta?aga) 4. [property_tree] Compilation Problem when #including <boost/property_tree/json_parser.hpp> (Adi Shavit) 5. Re: [property_tree] Compilation Problem when #including <boost/property_tree/json_parser.hpp> (Edward Diener) ---------------------------------------------------------------------- Message: 1 Date: Mon, 10 Feb 2014 07:16:06 +0000 (UTC) From: Gennadiy Rozental <rogeeff(a)gmail.com> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] Regarding post: Using Boost.Test in Iteration Message-ID: <loom.20140210T081523-687(a)post.gmane.org> Content-Type: text/plain; charset=us-ascii Deepa S <mslvada <at> yahoo.com> writes: > Wanted to check if there was any resolution to the error indicated > in this post: > http://lists.boost.org/boost-users/2010/06/59564.php > > I am running into a similar issue and would like to know how to resolve it. What exactly is the issue? Do you want to write your own main? Gennadiy ------------------------------ Message: 2 Date: Mon, 10 Feb 2014 09:18:20 +0100 From: Adam Romanek <romanek.adam(a)gmail.com> To: "boost-users(a)lists.boost.org" <boost-users(a)lists.boost.org> Subject: [Boost-users] [container.string] why isn't memcpy used in the internals? Message-ID: <52F88B4C.40707(a)gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Hi! Recently I've been trying to improve the performance of a code that makes heavy use of std::string (lots of constructions and destructions). My first thought was to use boost::container::string as it does not use reference-counting and uses small-string optimization, so it should be a perfect replacement for std::string when it comes to performance. Right... But the problem is that switching to boost::container::string only made things worse in the general case. I wrote "in the general case" because when strings to be held are small and SSO may be applied then boost::container::string outperforms std::string considerably. However, in the general case constructing boost::container::string from a C string is significantly slower than constructing std::string. My investigation showed that std::string uses memcpy to copy the C string into its buffer while boost::container::string does not. The memcpy comes from std::char_traits::copy so maybe boost::container::string could use it too? I guess the rest of operations from std::char_traits (find, move, assign etc.) could be utilized too as std::char_traits has been carefully crafted with performance in mind. Should I create a ticket for this issue? Best regards, Adam Romanek ------------------------------ Message: 3 Date: Mon, 10 Feb 2014 09:54:36 +0100 From: Ion Gazta?aga <igaztanaga(a)gmail.com> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] [container.string] why isn't memcpy used in the internals? Message-ID: <52F893CC.8020703(a)gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed El 10/02/2014 9:18, Adam Romanek escribi?: > Hi! > > Recently I've been trying to improve the performance of a code that > makes heavy use of std::string (lots of constructions and destructions). > My first thought was to use boost::container::string as it does not use > reference-counting and uses small-string optimization, so it should be a > perfect replacement for std::string when it comes to performance. > > Right... But the problem is that switching to boost::container::string > only made things worse in the general case. I wrote "in the general > case" because when strings to be held are small and SSO may be applied > then boost::container::string outperforms std::string considerably. > However, in the general case constructing boost::container::string from > a C string is significantly slower than constructing std::string. > > My investigation showed that std::string uses memcpy to copy the C > string into its buffer while boost::container::string does not. The > memcpy comes from std::char_traits::copy so maybe > boost::container::string could use it too? I guess the rest of > operations from std::char_traits (find, move, assign etc.) could be > utilized too as std::char_traits has been carefully crafted with > performance in mind. > > Should I create a ticket for this issue? Yes, please. I'm slowly trying to benchmark and improve Boost.Container performance, I haven't started optimizing basic_string so your ticket could be a good start point. In a quick inspection I see that the constructor is dispatched to basic_string::assign(It, It) and that assignment is not optimized at all. I should definitely write a assignment function that dispatches to std::char_traits::copy, as it could be used to optimize several member functions. Best, Ion ------------------------------ Message: 4 Date: Mon, 10 Feb 2014 12:29:39 +0200 From: Adi Shavit <adishavit(a)gmail.com> To: boost-users(a)lists.boost.org Subject: [Boost-users] [property_tree] Compilation Problem when #including <boost/property_tree/json_parser.hpp> Message-ID: <CAEWUs4h_ExtG5fG9L=x2p0hss_f=r_eVyrwoPaTN-RYyJPcH0g(a)mail.gmail.com> Content-Type: text/plain; charset="iso-8859-1" Hi, On VS2010, the following code does not compile if I restore the commented out #include: *// #include <boost/property_tree/json_parser.hpp>* struct X { enum Labels { ERROR, ONE, TWO, THREE }; // problem => ^^^^^ }; void f() { X::Labels r = X::ERROR; // problem => ^^^^^ } The VS2010 errors are: t.cpp(5): error C2059: syntax error : 'constant' t.cpp(5): error C2143: syntax error : missing ';' before '}' t.cpp(5): error C2238: unexpected token(s) preceding ';' t.cpp(7): error C2059: syntax error : '}' t.cpp(7): error C2143: syntax error : missing ';' before '}' t.cpp(7): error C2059: syntax error : '}' t.cpp(11): error C2589: 'constant' : illegal token on right side of '::' t.cpp(11): error C2059: syntax error : '::' It seems that somewhere inside the #include hierarchy the symbol ERROR is #defined to cause this code to fail. Renaming ERROR to something else avoids this problem. I think I tracked it into ' boost/spirit/home/classic/iterator/impl/file_iterator.ipp' but I'm not sure where exactly it is coming from. Adi

2 1

[MPL] implementing a "trait"?
by John M. Dlugosz 11 Feb '14

11 Feb '14

I want to mark certain types as being of a category of my invention (e.g. is_pretty), for purposes of using enable_if in the same manner is standard type traits such as is_arithmetic etc. The trait will be false by default, and I'd declare something to nominate types that should be seen to have that trait. I want it to follow inheritance; if B has been declared to be in my category, and C is derived from B, then C will also be in that category without needing to do anything more (though some way to turn it _off_ would be available). Can someone advise me on an easy way to structure this? Thanks, —John

6 10

retrieve data using associative property maps with boost::bimaps - failed
by Aniket Pugaonkar 10 Feb '14

10 Feb '14

Hi, I am facing compilation error in the following code. I do understand why the error is, but I could not find a good solution. Here is my code and question explained in detail *What I want to do:* I want to store a key- value pair where both key and its respective values is unique. But After I create a map, I want to use the VALUE and get the corresponding key. Essentially the best way is a bimap. So I do the following using associative property maps. *What I did:* 1. define a bimap (my_bimap ) 2. define associative property map for left view of bimap ( right_asso_bimap ) 3. define associative property map for right view of bimap ( left_asso_bimap ) 4. fill the bimap using *left* view associative property map. i.e. *use boost::put( left_asso_bimap, key, value )* 5. Now using *right* view associative property map, retrieve key for given value i.e. use *boost::get( right_asso_bimap, value )* My main motive is to use GET and PUT helper functions for insertion and retrieval from a bimap. Use PUT to insert in LEFT BIMAP. and Use GET to retrieve from RIGHT BIMAP. I know the error is because of non-const-ness of the iterators because of which I cannot de-reference using iterators. But what would be the alternative to this ? This link here explains how to define parameters for bimap in order for iterators to be mutable. http://www.boost.org/doc/libs/1_55_0/libs/bimap/doc/html/boost_bimap/the_tu… *But I get the error below: * In file included from main.cpp:2:0: /usr/local/include/boost/property_map/property_map.hpp: In instantiation of 'boost::associative_property_map<UniquePairAssociativeContainer>::value_type& boost::associative_property_map<UniquePairAssociativeContainer>::operator[](const key_type&) const [with UniquePairAssociativeContainer = boost::bimaps::views::list_map_view<boost::bimaps::relation::member_at::right, boost::bimaps::detail::bimap_core<int, boost::bimaps::list_of<long unsigned int>, mpl_::na, mpl_::na, mpl_::na> > boost::associative_property_map<UniquePairAssociativeContainer>::reference = const int&; boost::associative_property_map<UniquePairAssociativeContainer>::value_type = const int; boost::associative_property_map<UniquePairAssociativeContainer>::key_type = long unsigned int]': /usr/local/include/boost/property_map/property_map.hpp:357:54: required from 'Reference boost::get(const boost::put_get_helper<Reference, PropertyMap>&, const K&) [with PropertyMap = boost::associative_property_map<boost::bimaps::views::list_map_view<boost::bimaps::relation::member_at::right, boost::bimaps::detail::bimap_core<int, boost::bimaps::list_of<long unsigned int>, mpl_::na, mpl_::na, mpl_::na> > > Reference = const int&; K = int]' main.cpp:41:35: required from here /usr/local/include/boost/property_map/property_map.hpp:502:20: error: no match for 'operator[]' (operand types are 'boost::associative_property_map<boost::bimaps::views::list_map_view<boost::bimaps::relation::member_at::right, boost::bimaps::detail::bimap_core<int, boost::bimaps::list_of<long unsigned int>, mpl_::na, mpl_::na, mpl_::na> > >::C {aka boost::bimaps::views::list_map_view<boost::bimaps::relation::member_at::right, boost::bimaps::detail::bimap_core<int, boost::bimaps::list_of<long unsigned int>, *mpl_::na, mpl_::na, mpl_::na> >}' and 'const key_type {aka const long unsigned int}')* *return (*m_c)[k];* ^ Here my code. You can also see the code here on this website link:* http://coliru.stacked-crooked.com/a/59cbf2c564bf22b2 <http://coliru.stacked-crooked.com/a/59cbf2c564bf22b2>* #include <boost/bimap.hpp> #include <boost/property_map/property_map.hpp> #include <boost/bimap/property_map/set_support.hpp>#include <boost/bimap/list_of.hpp>#include <iostream> using namespace boost; int main() {typedef int vertex_descriptor_t;namespace bm = boost::bimaps;typedef bm::bimap< vertex_descriptor_t, bm::list_of<size_t> > vd_idx_bimap_t;typedef boost::associative_property_map<vd_idx_bimap_t::left_map> Lasso_vd_idx_bimap_t;typedef boost::associative_property_map<vd_idx_bimap_t::right_map> Rasso_vd_idx_bimap_t; // define bimap and assoc prop map for itvd_idx_bimap_t my_bimap;Lasso_vd_idx_bimap_t Lmy_asso_bimap(my_bimap.left );Rasso_vd_idx_bimap_t Rmy_asso_bimap(my_bimap.right); typedef typename vd_idx_bimap_t::value_type value_type; my_bimap.insert( value_type( 1, 100 ) ); my_bimap.insert( value_type( 2, 200 ) ); int z = 1; std::cout << "value = " << get ( my_bimap.left, z ) << std::endl; // prints correctly value = 100 // use left asso bimap for inserting to bimap boost::put( Lmy_asso_bimap, 3, 300 ); // correct // print bimap using *left view*for(auto t = my_bimap.left.begin(); t != my_bimap.left.end(); ++t) std::cout << t->first << " " << t->second << "\n"; int y = 2;*z **= boost::get( Lmy_asso_bimap, y ); // CORRECT OUTPUT for left view * std::cout << "value = " << z << std::endl; // Use right asso bimap to get key based on supplied value y = 100;*z = boost::get( Rmy_asso_bimap, y );* *// -->> ERROR HERE for right view* std::cout << "value = " << z << std::endl; // print map again. (*right view*)for(auto t = my_bimap.right.begin(); t != my_bimap.right.end(); ++t) std::cout << t->first << " " << t->second << "\n"; } Please let me know whether this is a potential bug, or the code semantics is incorrect. Or the current library cannot support this. ? Regards, Aniket Pugaonkar -- Thanks and regards, Aniket Pugaonkar

1 0

interprocess library deadlocked
by Hernán Leoni 10 Feb '14

10 Feb '14

Hi everyone, I'm using boost interprocess, and in some cases I get the interprocess library deadlocked, now I'm using internal timed locks, so, I get timeout exception Fortunately it is not that frequent, but it is an issue I need to resolve before going live, When this happens the shared memory cannot be used at all, so it needs to be removed and a new one must be created. I'm not sure yet why these internal mutexes are getting locked and never unlocked, it may be happening with some process being killed unexpectedly. I was wanting to see if anybody has already figured out which approach is better for this case. Thanks a lot, Hernan

1 0

Regarding post: Using Boost.Test in Iteration
by Deepa S 10 Feb '14

10 Feb '14

Hi Gennadiy/Gaurav, Wanted to check if there was any resolution to the error indicated in this post: http://lists.boost.org/boost-users/2010/06/59564.php I am running into a similar issue and would like to know how to resolve it. Thanks, Deepa

2 1

Attn: We need GSoC 2014 mentors for Boost!
by Niall Douglas 09 Feb '14

09 Feb '14

Dear Boost community, We are now just five days away from the closing date for Google Summer of Code 2014 registration. Last year's GSoC was a huge success, with Google funding work on Boost to the tune of $35,000 and paying over $8,000 in costs for three representatives of Boost to attend the GSoC mentor's summit at Google HQ. As part of filling in our application for 2014, we must supply to Google a list of potential GSoC mentors and potential GSoC projects for summer 2014. We do NOT want a repeat of 2012 when our application was rejected due to an insufficiently long list of prospective mentors and projects! At the time of writing, we have just *eight* prospective mentors, and we need more to be sure of being approved by Google! Therefore, if you think yourself able to mentor a student doing some work on Boost this summer, *please* consider adding a description of the proposed work item and your name to the list at https://svn.boost.org/trac/boost/wiki/SoC2014. If you want to know more about mentoring a Google Summer of Code funded student work before you nominate yourself, please feel free to ask on the main Boost developers mailing list boost(a)lists.boost.org. Thank you in advance for your time. Niall Douglas (Boost Google Summer of Code admin) Boris Schäling (Boost Google Summer of Code backup admin)

2 4

Boost.Asio ssl session reuse
by Krzysztof Trzepla 09 Feb '14

09 Feb '14

Hello, Is there a way to cache ssl session using Boost.Asio library, so that it can be later on reused with an abbreviated handshake? If so, I will appreciate any example. -- Regards, Krzysztof Trzepla

1 0

[Boost.Python] Wrapping a heterogeneous container
by Mario Lang 08 Feb '14

08 Feb '14

Hi. I have finally figured out how to (mostly) wrap a container of boost::variant<> in boost::python: http://blind.guru/boost_python-and-boost_variant.html The only problem left is the fact that I have to disable the use of reference semantics (proxies) in vector_indexing_suite. If I pass false for the NoProxy template parameter of vector_indexing_suite<>, I can no longer dereference container elements: >>> import bpv >>> bpv.make_vector()[0] Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: No Python class registered for C++ class boost::variant<a, b, boost::detail::variant::void_, ...> However, I have a converter registered with to_python_converter<> that handles extracting the proper Python object from a variant. This works if NoProxy is true. However, if NoProxy is true, container elements do not have reference semantics, so in-place modifications will be lost. To me, it also looks like the TypeError raise above is sort of bogus, since I actually used to_python_converter to register conversion for this particular type. So I guess there are different types of registries involved, but the message does not indicate which registry is did refer to. Does anyone know if I can enable reference semantics for a heterogeneous container wrapped with indexing_suite? -- CYa, ⡍⠁⠗⠊⠕

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