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[Polygon] Multiple Holes
by Bagnall, Bryan D CIV SPAWARSYSCEN-PACIFIC, 56220 04 May '12

04 May '12

Hello, I'm trying to use Boost::polygon to do Boolean operations in my project. My project uses contours that I'm grabbing with OpenCV, processing with Boost::polygon, then writing out to an ESRI shapefile. OpenCV can give me a list of contours within contours within contours...etc, and shapefiles can be written out this way (see link for picture http://icode-mda.googlecode.com/svn/trunk/examples/09_KMLshp/shapefilesWithH oles/results/blobsWithHoles.png ) I haven't been able to jam all of the data in a single polygon_with_holes_data polygon. Is it true that boost::polygon::polygon_with_holes_data can only have an exterior contour and multiple holes, but no contours inside of the hole? In other words, could a single boost polygon support a continent with a lake, with an island, with a pond, with a small island... ? Is there another type that would support this? Maybe the Geometry library? My current work around is to have (1)the continent with a lake as one polygon, (2)the island with a pond as another,(3)the small island as another... Thanks, Bryan

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[Serialization] Issues with C++/CX in MSVC 11
by Brent Lewis 04 May '12

04 May '12

In porting a project from iOS to Windows 8, I'm continuing to use Boost 1.49 to save the state of the program. I'm having what seems to be problems with a compiler bug. I'm wondering if anyone has found a workaround? Thought it's probably not necessary, I'll explain exactly what I'm seeing in detail in case it's helpful. If one creates a new Visual Studio project from the C++ Metro style Direct3D application template, simply adding these lines to the main function works just fine: std::stringstream memStream(std::ios_base::binary | std::ios_base::in | std::ios_base::out); boost::archive::binary_oarchive oa(memStream); However, when I add the rest of the project files (even if I don't instantiate any of the classes - just adding the modules does it), the two same lines in the main function crash. I eliminated all the code from the modules that refer to serialization and archive classes, because I noticed that there was a lot of static initialization of singletons of templated archive classes. Even with minimal static initializers, still, the code fails to run. Closest thing I can tell is that the compiler is not correctly translating the this pointer when moving from a class's initializers into a superclasse's constructor when multiple inheritance is involved (and perhaps lots of templating is required too). To be specific, in one specific run of the application (note that I've removed the template parameters for brevity): Inside binary_oarchive_impl ctor, the this pointer is: 0x0091fcb8 moving into its superclass constructor, basic_binary_oprimitive, the this pointer is: 0x0091fcc1 That would suggest that the superclass is 9 bytes into the derived class, however: back inside the binary_oarchive_impl ctor, using the debugger: (boost::archive::basic_binary_oprimitive*)this : 0x0091fcc4 offsetof(basic_binary_oprimitive, m_sb) = 0 (offsets retrieved by inspecting/altering memory, since you can't get the offset of a reference type) offsetof(binary_oarchive_impl, m_sb) = 12 Which clearly indicates that the superclass is 12 bytes into the derived class. In the superclass, it initializes m_sb - which is a reference to the stream buffer the archive writes to. Stepping back out of the superclass constructor, back into the derived class constructor, m_sb points to the wrong memory, of course. Has anyone else experience this with C++/CX? Is there an existing bug report? We've got a Microsoft contact that's helping us iron out issues. Does anyone know a concise repro that'll help MS solve this problem faster? Thanks for any information.

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[Range] Weak concept assertions.
by Robert Jones 03 May '12

03 May '12

Here's a snippet from boost/range/algorithm_ext/push_back.hpp... namespace boost { namespace range { template< class Container, class Range > inline Container& push_back( Container& on, const Range& from ) { BOOST_RANGE_CONCEPT_ASSERT(( SinglePassRangeConcept<Container> )); BOOST_RANGE_CONCEPT_ASSERT(( SinglePassRangeConcept<const Range> )); BOOST_ASSERT( (void*)&on != (void*)&from && "cannot copy from a container to itself" ); on.insert( on.end(), boost::begin(from), boost::end(from) ); return on; } } // namespace range using range::push_back; } // namespace boost Shouldn't the first concept assert be asserting that 'Container' is in fact a container, not a range? Thx - Rob.

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[asio] documentation example, bind semantics
by John M. Dlugosz 03 May '12

03 May '12

In boost_asio/tutorial/tutdaytime3.html, the code shown is: void handle_accept(tcp_connection::pointer new_connection, const boost::system::error_code& error) { and is called via a function object: boost::bind(&tcp_server::handle_accept, this, new_connection, boost::asio::placeholders::error) I get after my coworkers I'm mentoring in the area of C++ skills to pass smart pointers by const-ref not by value, since the atomic inc/dec is very costly. I believe that a boost::function (and now std::function) will hold the object by value even if the function being bound declares it as reference, and the INVOKE phase will bind the parameter to the stored copy in the function object. So handle_accept can and should be declared as using a const tcp_connection::pointer& as well, right? Is there any reason not to? —John

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[Boost.Integer] On Win32, boost::uint_t<65>::fast has 64 bits?
by Scott Meyers 03 May '12

03 May '12

The type yielded by boost::uint_t<N>::fast seems pretty clear: "The easiest-to-manipulate, built-in, unsigned integral type with at least N bits." But when I run the following program, which prints the number of bits in the type returned by boost::uint_t<65>::fast (i.e., a type with at least 65 bits), I get 64. #include <iostream> #include <climits> #include <boost/integer.hpp> int main() { std::cout << "boost::uint_t<65>::fast has " << CHAR_BIT * sizeof(boost::uint_t<65>::fast) << " bits\n"; } I get the same results with VC10, VC11 beta, and gcc 4.7 on Win32 with Boost 1.49. I must be doing something wrong, right? But what? Thanks, Scott

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Fusion warning cleanup
by Belcourt, Kenneth 03 May '12

03 May '12

Hi, Could these (and other) auto generated headers be emitted so they don't trigger these sorts of warnings? We get these warnings with multiple compilers. Thanks. -- Noel Belcourt CC-1 crayc++: WARNING File = /scratch1/kbelco/boost/boost/status/../boost/fusion/tuple/detail/preprocessed/tuple_fwd.hpp, Line = 21 The source file does not end with a new-line character. #endif ^ CC-1 crayc++: WARNING File = /scratch1/kbelco/boost/boost/status/../boost/fusion/tuple/detail/preprocessed/make_tuple.hpp, Line = 21 The source file does not end with a new-line character. #endif ^ CC-1 crayc++: WARNING File = /scratch1/kbelco/boost/boost/status/../boost/fusion/tuple/detail/preprocessed/tuple_tie.hpp, Line = 21 The source file does not end with a new-line character. #endif ^

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[Range] Predicate type checking.
by Robert Jones 02 May '12

02 May '12

I'm pretty sure I'm have a 'Doh!' moment here, but why does this compile? Surely the last line of main is gibberish; the value type of m is pair, not S, so int_from_S is not a valid function? #include <boost/range.hpp> #include <boost/range/adaptor/transformed.hpp> #include <map> struct S { S( ) { } int i; }; int int_from_S( S s ) { return s.i; } int main( ) { std::map<unsigned, S> m; m[0]=S(); m | boost::adaptors::transformed(int_from_S); } Thx, - Rob.

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config. how to check if std::shared_ptr & std::scoped_ptr availability?
by niXman 02 May '12

02 May '12

Hello! I need to check if std::shred_ptr & std::scoped_ptr availability. I read boost.config and found: http://www.boost.org/doc/libs/1_49_0/libs/config/doc/html/boost_config/boos… But in this list don't exist macro that I need. Ideas? Thanks. -- Regards, niXman

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multiarray sub_array
by Petros 01 May '12

01 May '12

Hi, I want to be able to create an array view on a subset of a multi_array(MA)’s dimensions. So, say I have a MA of dimension M and I want to choose N (N <M) dimensions of it which I put on a boost::array. Say, I want to keep the entire range for each dimension. Is there a way to do this in a general fashion, i.e. w/out the use of the subscript operator on the indices object ? The documentation mentions something like : typedef boost::multi_array< double, 3 > Grid3D; typedef Grid3D::size_type size_type; typedef Grid3D::index index; typedef Grid3D::index_range index_range; typedef Grid3D::array_view<2>::type Slice2D; index_range r1; //( 0, iMax); index_range r3; //( 0, kMax); Grid3D::index_gen indices; Slice2D sliceJ2 = grid[indices [r1] [2] [r3] ]; but this is not sufficient for a generic construction. And also, what is the difference between array_view and subarray ? Thank you very much in advance, Petros

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fatal error C1001 with VS2010, boost 1.49, and shared_ptr.hpp
by Phillip Hellewell 01 May '12

01 May '12

I'm upgrading to boost 1.49 and getting this fatal error while compiling a source file that uses shared_ptr: 1>C:\mycomps\base\target\dependency\include\boost/smart_ptr/shared_ptr.hpp(362): fatal error C1001: An internal error has occurred in the compiler. 1> (compiler file 'msc1.cpp', line 1420) 1> To work around this problem, try simplifying or changing the program near the locations listed above. 1> Please choose the Technical Support command on the Visual C++ 1> Help menu, or open the Technical Support help file for more information Line 362 of shared_ptr.hpp is: shared_ptr( shared_ptr<Y> && r, typename boost::detail::sp_enable_if_convertible<Y,T>::type = boost::detail::sp_empty() ) Looks like the compiler is crashing with an access violation; any suggestions other than wait for a patch from Microsoft? I don't want to have to disable features like BOOST_HAS_RVALUE_REFS or BOOST_SP_NO_SP_CONVERTIBLE, but that may be my only choice :( Thanks, Phillip

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