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[type_traits] an is_iterator, not is_pointer, trait
by Belcourt, K. Noel 03 Nov '11

03 Nov '11

Hi, I'm looking to use a trait in enable_if that can distinguish between a raw pointer and any other valid iterator type, essentially the difference between iterator traits and the raw pointer specialization. template <class Iterator> struct iterator_traits; template <class T> struct iterator_traits<T*>; I was hoping to find a boost::is_iterator type trait which would return false_type for is_iterator<int*> (any raw pointer) and true type for any other valid iterator. This would allow me to group iterators via is_pointer and is_iterator. I was just wondering if this already exists somewhere? Thanks. -- Noel Belcourt

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Re: [Boost-users] [Gil] TIFF file with mixed 8/16 bit channel depths
by Christian Henning 03 Nov '11

03 Nov '11

Corinna, this has to wait until tomorrow. Hope that's ok with you. But I can see from the source code that the input image should be cymk16161688_image_t and not just cymk8_image_t. Christian

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[Boost.Endian] Review Results
by joel falcou 03 Nov '11

03 Nov '11

Hi everyone, after some delay, here is the result of the review of Beman Dawes' Boost.Endian library. First, I want to thanks all participants of the review that lead to very deep and interesting discussions on the matter. 5 votes were cast : 2 unconditionally in favor, 3 conditionally in favor after changes made and there is a mini-review. The verdict is that Boost.Endian is **CONDITIONNALY ACCEPTED** Here is what needs to be done to get the library ready for a mini-review: * Common use case scenarios should be developed. * Example programs should be developed for the common use case scenarios. * Documentation should illuminate the differences between endian integer/float type and endian conversion approaches to the common use case scenarios, and provide guidelines for choosing the most appropriate approach in user's applications. * Conversion functions supplying results via return should be provided. * Platform specific performance enhancements such as use of compiler intrinsics or relaxed alignment requirements should be supported. * Endian integer (and floating) types should be implemented via the conversion functions. If that can't be done efficiently, consideration should be given to expanding the conversion function signatures to resolve the inefficiencies. * Benchmarks that measure performance should be provided. It should be possible to compare platform specific performance enhancements against portable base implementations, and to compare endian integer approaches against endian conversion approaches for the common use case scenarios. * Float (32-bits) and double (64-bits) should be supported. IEEE 754 is the primary use case. * Support for user defined types (UDTs) is desirable, and should be provided where there would be no conflict with the other concerns. * There is some concern that endian integer/float arithmetic operations might used inadvertently or inappropriately. The impact of adding an endian_buffer class without arithmetic operations should be investigated. * Stream insertion and extraction of the endian integer/float types should be documented and included in the test coverage. * Binary I/O support that was investigated during development of the Endian library should be put up for mini-review for inclusion in the Boost I/O library. From this point, I will let Beman prepare Endian for the mini-review and I already volunteer to manage the mini-review so informations are not scattered around. Regards

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[fusion] Adapted struct I/O
by Mateusz Łoskot 03 Nov '11

03 Nov '11

Hi, I'm still taking early steps with Boost.Fusion. I'm trying to adapt a bunch of struct and template struct for easy I/O operations. I don't understand one thing from the docs. Here we go; 1) Given the example [1] of template struct adoption: namespace demo { template<typename Name, typename Age> struct employee { Name name; Age age; }; } // Any instantiated demo::employee is now a Fusion sequence BOOST_FUSION_ADAPT_TPL_STRUCT( (Name)(Age), (demo::employee) (Name)(Age), (Name, name) (Age, age)) [1] http://www.boost.org/doc/libs/1_47_0/libs/fusion/doc/html/fusion/adapted/ad… 2) The included comment says "demo::employee is now a Fusion sequence". 3) Jumping to I/O and out docs, reading that [2] "The I/O operators: << and >> work generically on all Fusion sequences. " [2] http://www.boost.org/doc/libs/1_47_0/libs/fusion/doc/html/fusion/sequence/o… 4) Means, I should be able to stream Fusion-adopted demo::employee #include <iostream> #include <string> #include <boost/fusion/adapted/struct/adapt_struct.hpp> #include <boost/fusion/include/adapt_struct.hpp> #include <boost/fusion/sequence/io.hpp> #include <boost/fusion/include/io.hpp> // code from above example goes here int main() { demo::employee<std::string, int> e; std::cout << e << std::endl; } 5) Given what I have learned above, I expect the cout << e to work: $ g++ -I/home/mloskot/dev/boost/_svn/trunk boost_fusion.cpp boost_fusion.cpp: In function ‘int main()’: boost_fusion.cpp:28:18: error: no match for ‘operator<<’ in ‘std::cout << e’ ... I assume complete error is not necessary as my question is of general nature. Is my expectation valid? Best regards, -- Mateusz Loskot, http://mateusz.loskot.net Charter Member of OSGeo, http://osgeo.org Member of ACCU, http://accu.org

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[Gil] TIFF file with mixed 8/16 bit channel depths
by Corinna Kinchin 03 Nov '11

03 Nov '11

Hello, I'm using boost::gil::read_image(in, img, tiff_tag()); as part of a process to extract raw image data from a TIFF file, and it works beautifully for cmyka TIFF files containing either 5 x 8-bit channels, or 5 x 16-bit channels. But it seems using this technique mangles image data contained in a (photoshop generated) TIFF file which contains CMYK channels with both 8 and 16 bit depths (mixed). Here is an extract from the ImageMagick 'identify -verbose' output on such a file: Depth: 8/16-bit Channel depth: cyan: 16-bit magenta: 16-bit yellow: 16-bit black: 8-bit alpha: 8-bit It seems that read_image treats the TIFF file as if it contains 5 x 8-bit channels (the TIFFTAG_BITSPERSAMPLE property and hence the _bits_per_sample info value for the TIFF file is set to 8), so the CMY channel image data isn't read in correctly ... at least that's my best guess. Does anyone out there know whether boost::gil can be made to support 8/16bit TIFF files - eg if there's an extension (or hack ;) which could do the trick? Or any other options (eg other libraries) which could be worth investigation? Many thanks for reading this far, and if you have any remotely relevent ideas it would be great to hear them ... All the best, Corinna ... Corinna Kinchin email: ckinchin(a)datazone.com Datazone Ltd. Tel: +353 64 66 28964 Palm Gate, Greenane, Fax: +353 64 66 28965 Killarney, Co. Kerry, Ireland URL: http://www.miramo.com Datazone - makers of `Miramo', the automated publishing tool

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MSVC++ 2010 and BOOST_STATIC_ASSERT
by Sunil Thomas 03 Nov '11

03 Nov '11

Hi all! I've noticed that MSVC++ 2010 has implemented static_assert (compile time checks); and probably as a result, the code that used to build fine in MSVC++ 2008 is now generating the following error. code: BOOST_STATIC_ASSERT(N==1) *error C2338: (N==1)* ** Appreciate if anyone who has resolved this error can share their experiences.. Thanks, --Thomas. **

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Boost.Pool: Writing a base class for per-class pool allocation
by Freddie Witherden 03 Nov '11

03 Nov '11

Hi all, I am currently trying to write a base class which overloads new and delete so that they allocate from a boost pool: template<typename T> class pool_object { public: static void* operator new(size_t) { return pool_.malloc(); } static void operator delete(void *p) { pool_.free(p); } private: static boost::pool<> pool_; }; template<typename T> boost::pool<> pool_object<T>::pool_(sizeof(T)); The idea is that one can write: class foo : public pool_object<foo> { ... }; The problem with this is that boost::pool is not thread-safe. The thread-safe variant is a singleton pool. However, this is parametrized by a size: boost::singleton_pool<sizeof(T)> -- which is a problem as T is incomplete. Are there any solutions other than sticking my own mutex into the class? Regards, Freddie.

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[RapidXML] Cannot open XML files unless in main
by Alec Taylor 03 Nov '11

03 Nov '11

Good afternoon, Unfortunately only my 10 lines [main only]: http://ideone.com/WOmcphowever works, whilst my 20 lines [OO with functions] doesn't: http://ideone.com/R7mir How can I get this to work? I am aware that boost property tree wraps RapidXML... so maybe you can help me out here? Thanks for all suggestions, Alec Taylor

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boost.mpi serialization... error?
by Jacques C. Richard 02 Nov '11

02 Nov '11

I am trying boost::mpi on a big code & getting the following error message from mac mpiC++ (same from an intel super-computer). Can anyone pick out something quickly from that to help please or do you need to see more? I'd like to figure out what I did to not do it! :) Thanks! Jacques Process=1's mpe_decomp1d MiniGridSize= 3 3 3 Pause @ "main: 879: Domain decomposition" if 1 process: <Enter> or <Return> continues; ^C aborts: init_internal_neighbors_wf: Process 1 of 2 exchanging (if necessary) w/+/-1! Sender=1, Receiver=0 [jacques-richards-mac-mini:00474] *** Process received signal *** [jacques-richards-mac-mini:00474] Signal: Segmentation fault (11) [jacques-richards-mac-mini:00474] Signal code: Address not mapped (1) [jacques-richards-mac-mini:00474] Failing at address: 0x200000001 [jacques-richards-mac-mini:00474] [ 0] 2 libSystem.B.dylib 0x00007fff86fa51ba _sigtramp + 26 [jacques-richards-mac-mini:00474] [ 1] 3 ??? 0x0000000000000000 0x0 + 0 [jacques-richards-mac-mini:00474] [ 2] 4 Mg 0x000000010010ff0e _ZN5boost3mpi6detail24ignore_skeleton_oarchiveINS1_16content_oarchiveEE13save_overrideIP12lattice_typeEEvRKT_i + 40 [jacques-richards-mac-mini:00474] [ 3] 5 Mg 0x000000010010ff3a _ZN5boost7archive6detail18interface_oarchiveINS_3mpi6detail16content_oarchiveEElsIKP12lattice_typeEERS5_RT_ + 42 [jacques-richards-mac-mini:00474] [ 4] 6 Mg 0x000000010010ff6e _ZNK5boost13serialization3nvpIKP12lattice_typeE4saveINS_3mpi6detail16content_oarchiveEEEvRT_j + 40 [jacques-richards-mac-mini:00474] [ 5] 7 Mg 0x000000010010ff93 _ZN5boost13serialization6access1 ... .. .

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Re: [Boost-users] [BGL] How to provide a vertex_index property for my graph
by gongyiling 02 Nov '11

02 Nov '11

"ShNaYkHs ShNaYkHs" 写入消息 news:CA+GAXM2Kt7KjUamMuXUeo2_SL-GTWg0k2UjerJTNQi7sizUipQ@mail.gmail.com... > Hello, > Since my graph use setS as a VertexList, I have to either provide a > vertex_index property map for my graph to be able to use some functions > requiring a vertex_index (e.g. write_graphviz). My graph is defined as: > typedef adjacency_list<setS, setS, undirectedS, NodeData, EdgeData> Graph; > Where NodeData and EdgeData are structures. Can you please give me a very > simple example of how to provide a vertex_index property map for my graph > ? > I mean, since an adjacency_list that uses listS or setS as the vertex > container does not automatically provide this vertex_id property, how can > I > add it to the code bellow ? > I tried to use an associative_property_map to include index for vertices, > but it doesn't work (errors): > #include <boost/graph/iteration_macros. > hpp> > #include <boost/graph/adjacency_list.hpp> > using namespace std; > using namespace boost; > struct NodeData > { > int label; > float influance; > /* etc ... */ > }; > struct EdgeData > { > int age; > /* etc ... */ > }; > typedef map<vecS, size_t> IndexMap; > IndexMap mapIndex; > associative_property_map<IndexMap> propmapIndex(mapIndex); > typedef adjacency_list<setS, setS, undirectedS, NodeData, EdgeData> Graph; > typedef Graph::vertex_descriptor NodeID; > typedef Graph::edge_descriptor EdgeID; > int main() > { > Graph g; > NodeID n0 = add_vertex(g); g[n0].label = -1; > NodeID n1 = add_vertex(g); g[n1].label = -1; > EdgeID edge; bool ok; > tie(edge, ok) = boost::add_edge(n0, n1, g); > if (ok) g[edge].age = 10; > int i=0; > BGL_FORALL_VERTICES(v, g, Graph) > { > put(propmapIndex, v, i++); > } > return 0; > } > Thanks for answer. -------------------------------------------------------------------------------- you can using vertex bundle property as you vertex index, here is the code I modified according to above: #include <boost/graph/iteration_macros.hpp> #include <boost/graph/adjacency_list.hpp> using namespace std; using namespace boost; struct NodeData { int label; float influance; int index; //add by gyl /* etc ... */ }; struct EdgeData { int age; /* etc ... */ }; typedef adjacency_list<setS, setS, undirectedS, NodeData, EdgeData> Graph; typedef Graph::vertex_descriptor NodeID; typedef Graph::edge_descriptor EdgeID; int main() { Graph g; NodeID n0 = add_vertex(g); g[n0].label = -1; g[n0].index = 0; //add by gyl, init index 0. NodeID n1 = add_vertex(g); g[n1].label = -1; g[n1].index = 1; //add by gyl, init index 1. EdgeID edge; bool ok; tie(edge, ok) = boost::add_edge(n0, n1, g); if (ok) g[edge].age = 10; int i=0; BGL_FORALL_VERTICES(v, g, Graph) { put(boost::get(&NodeData::index, g)/*by gyl get bundle property map*/, v, i++); } return 0; } at last, I think you should post this to boost.user maillist instead here. _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost

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