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boost::variant - limit on the number of types
by Aaron Rocha 29 Sep '07

29 Sep '07

Hi there, I am using MSVC 8.0 and Boost 1.34.0 . I am trying to create a variant that can hold an object of one of 50 different classes but it has not worked. I keep getting a compile error indicating that the template contains too many arguments. I have played with preprocessor variables like BOOST_MPL_LIMIT_LIST_SIZE, BOOST_VARIANT_LIMIT_TYPES, and BOOST_MPL_CFG_NO_PREPROCESSED_HEADERS w/o success. I have also attempted to use boost::make_variant_over< > but it doesn't work past the type #20. Has anyone been able to do something similar? Thanks Be smarter than spam. See how smart SpamGuard is at giving junk email the boot with the All-new Yahoo! Mail at http://mrd.mail.yahoo.com/try_beta?.intl=ca

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[bind] MSVC 8.0 compiles _1 but not _2
by Mark Ruzon 29 Sep '07

29 Sep '07

Suppose you want to compute 3 - x for a vector of floats: using namespace std; vector<float> v; transform(v.begin(), v.end(), v.begin(), boost::bind(minus<float>(), _1, 3.0f)); This compiles fine on the MSVC 8.0 compiler. But I want to compute x - 3, and replacing _1 with _2 in the above expression yields a mess of errors, starting with: c:\program files\boost\boost_1_34_1\boost\bind.hpp(278) : error C2679: binary '[' : no operator found which takes a right-hand operand of type 'overloaded-function' (or there is no acceptable conversion) c:\program files\boost\boost_1_34_1\boost\bind.hpp(205): could be 'float boost::_bi::list1<A1>::operator [](boost::arg<I>) const' with [ A1=float &, I=1 ] Anybody have any thoughts on this one? Thanks, Mark

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Boost test manual can not be accessed
by Peng Yu 28 Sep '07

28 Sep '07

Hi, The following webpage can not be accessed. Can somebody fix it. http://www.boost.org/libs/test/doc/components/utf/getting_started/index.html Thanks Peng

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dynamic_pointer_cast doesn't work as expected
by Diego Bernini 28 Sep '07

28 Sep '07

Hi, see these lines: boost::shared_ptr<Executor> executor(&(createExecutor(subclass,name))); if(!executor) { throw LoadingClassException("createExecutor function of\""+subclass+"\" return null."); } //executor points to an object of class ExecDebugger that IS A Executor //(it's a plugin loaded at run time via Qt) boost::shared_ptr<Nameable> a=executor; boost::shared_ptr<Executor> sp; sp=boost::dynamic_pointer_cast<Executor>(a); --------------------------------------------------------------------------------------------------------------------- a is a Nameable, it points to a ExecDebugger object. ExecDebugger IS A Executor, Executor IS A Nameable...but sp is always ==0! Why?! Thanks, Diego Bernini

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Re: [Boost-users] fast_pool_allocator won't compile with VS 2005 SP1 using map
by Scott 28 Sep '07

28 Sep '07

I'm sorry, but I failed to mention I'm using boost 1.33.1 Scott

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fast_pool_allocator won't compile with VS 2005 SP1 using map
by Scott 28 Sep '07

28 Sep '07

I have a std::map that I'd like to use the fast_pool_allocator with. But when I declare it, I get errors with rebind. typedef std::pair<IndexVariant, Hints> IndexMapType; typedef boost::fast_pool_allocator<IndexMapType> IndexPoolAllocator; typedef std::map<IndexVariant, Hints, std::less< IndexVariant >, IndexPoolAllocator> ValueHints; 1>C:\Program Files\Microsoft Visual Studio 8\VC\include\map(28) : error C2903: 'rebind' : symbol is neither a class template nor a function template 1> C:\Program Files\Microsoft Visual Studio 8\VC\include\xtree(26) : see reference to class template instantiation 'std::_Tmap_traits<_Kty,_Ty,_Pr,_Alloc,_Mfl>' being compiled 1> with 1> [ 1> _Kty=nw::IndexVariant, 1> _Ty=nw::Hints, 1> _Pr=std::less<nw::IndexVariant>, 1> _Alloc=nw::IndexPoolAllocator, 1> _Mfl=false 1> ] However, if I substitute: typedef std::allocator<IndexMapType> IndexPoolAllocator; it all compiles fine. I'd appreciate any help with my problem! :) Thanks, Scott

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boost::result_of and gcc
by Martin Ecker 28 Sep '07

28 Sep '07

Hello, I'm running into a problem when using boost::result_of with gcc 3.4.2 and 4.2.1 (with MingW). The following program compiles fine with Visual C++ 8.0, but not with gcc: ------------------------------- #include <boost/utility/result_of.hpp> struct test_function1 { template <typename SignatureT> struct result; template <typename T> struct result<test_function1 (T)> { typedef T type; }; template <typename T> T operator () (T t) const { return t; } }; template <typename ArgT> struct test_function2 { template <typename SignatureT> struct result; template <typename T> struct result<test_function2 (T)> { typedef T type; }; template <typename T> T operator () (T t) const { return t; } }; int main(int argc, char *argv[]) { typedef boost::result_of< test_function1(int)>::type result_type; typedef boost::result_of< test_function2<float>(int)>::type result_type; return 0; } ------------------------------- The error message I get is for the second typedef using test_function2: E:/Projects/Third Party/boost/boost/utility/result_of.hpp: In instantiation of `boost::detail::result_of_nested_result<test_function2<float>, test_function2<float> ()(int)>': E:/Projects/Third Party/boost/boost/utility/result_of.hpp:75: instantiated from `boost::detail::result_of_impl<test_function2<float>, test_function2<float> ()(int), false>' E:/Projects/Third Party/boost/boost/utility/detail/result_of_iterate.hpp:24: instantiated from `boost::result_of<test_function2<float> ()(int)>' main.cpp:43: instantiated from here E:/Projects/Third Party/boost/boost/utility/result_of.hpp:68: error: invalid use of undefined type `struct test_function2<float>::result<test_function2<float> ()(int)>' I get the same error if I simply wrap test_function1 in another template class as nested struct and then use it instead of test_function2. Am I attempting to do something fundamentally wrong here, or is it a bug in gcc? Thanks, Martin

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1.33.1 read_graphviz possible parser issue
by Brian Stadler 28 Sep '07

28 Sep '07

Hi all, I'm reading in thousands of files in the graphviz language into a program using read_graphviz(), library version 1.33.1. I noticed a problem with some of my results and discovered that read_graphviz doesn't appear to be interpreting the files correctly. The structure of the graphs is preserved (no edges gone astray). However, the labeling of the nodes is changed. I confirmed this by reading in a file and immediately writing it back out using write_graphviz(). Below is the code used to read in the files. It's very simple as I have nothing special being reprsented. Could someone else check this and confirm this is a problem. I've checked the bugs list and 1.34.x release notes and found nothing addressing the particular issue. thanks all. My read_graphviz code: bool file; ifstream in(openfile.c_str(), ios::in); dynamic_properties dp; dp.property("node_id", get(&ed_node::vertex_name, ug)); <--simple adjacency list with bundled properties being used file = read_graphviz(in, ug, dp, "node_id"); Source graphviz file: strict graph { 0 -- 3; 0 -- 4; 1 -- 3; 1 -- 4; 2 -- 3; 2 -- 4; 3 -- 4; } Output graphviz file: graph G { 0; 1; 2; 3; 4; 0--1 ; 0--2 ; 3--1 ; 3--2 ; 4--1 ; 4--2 ; 1--2 ; }

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[gil] questions about usage
by Chris Weed 28 Sep '07

28 Sep '07

Hi, I have had great success using gil, and I have some questions and feedback. I didn't see a way to create an image of floating point values. I use my own typedef as follows, but I would think this should be in gil: typedef boost::gil::pixel<float,gray_layout_t> value32f_pixel_t; It is quite common to use square filters in image processing, and I think it would be useful to overload subimage_view with a fixed offset from all 4 sides. template <typename View> inline View subimage_view(const View& src, int border) { return View(src.width()-border*2,src.height()-border*2,src.xy_at(border,border)); } I also had a need for an "image" constructor that would take a size and allocator, but not initialize the values: image(const point_t& dimensions, std::size_t alignment, const Alloc alloc_in = Alloc()) : _memory(0), _align(alignment), _alloc(alloc_in) { allocate_and_default_construct(dimensions); } The biggest change I would suggest is adding the ability to take a view of a view, a const_view of a const_view, and a const_view of a view. This would make writing functions much easier. Thanks, Chris

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custom allocators for shared_ptr
by Cory Nelson 28 Sep '07

28 Sep '07

It would be useful if shared_ptr and family provided a way to give a custom allocator. For instance, to replace the quick allocator with a lock-free one. -- Cory Nelson

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