October 2011 - Boost - lists.preview.boost.org

[parameter] type requirement compiler error
by lcaminiti 08 Nov '11

08 Nov '11

Hello all, The following parameter type requirement: (required (graph, *) ) (optional (root_vertex, (typename boost::graph_traits<graph_type>::vertex_descriptor), *boost::vertices(graph).first) ) Generates a GCC error: dfs.05.cpp:40: error: ‘graph_type’ was not declared in this scope Detailed code and error below. In fact, if I look at the code after pp, I can see that graph_type is define only after the type requirement is checked... why? What am I doing wrong? Thanks a lot! --Lorenzo #include <boost/graph/adjacency_list.hpp> #include <boost/graph/depth_first_search.hpp> #include <boost/range/irange.hpp> #include <boost/pending/indirect_cmp.hpp> #include <boost/parameter.hpp> #include <iostream> namespace graphs { BOOST_PARAMETER_NAME(graph) BOOST_PARAMETER_NAME(visitor) BOOST_PARAMETER_NAME(root_vertex) BOOST_PARAMETER_NAME(index_map) BOOST_PARAMETER_NAME(color_map) template< typename Size, typename IndexMap > boost::iterator_property_map<boost::default_color_type*, IndexMap, boost::default_color_type, boost::default_color_type&> default_color_map ( Size const& num_vertices, IndexMap const& index_map ) { std::vector<boost::default_color_type> colors(num_vertices); return &colors[0]; } BOOST_PARAMETER_FUNCTION( (void), depth_first_search, tag, (required (graph, *)) (optional (visitor, *, boost::dfs_visitor<>()) (root_vertex, (typename boost::graph_traits<graph_type>::vertex_descriptor), *boost::vertices(graph).first) (index_map, *, boost::get(boost::vertex_index, graph)) (in_out(color_map), *, default_color_map(boost::num_vertices(graph), index_map)) ) ) { std::cout << "here\n"; boost::depth_first_search(graph, boost::visitor(visitor). color_map(color_map).root_vertex(root_vertex). vertex_index_map(index_map)); } } // namespace graphs template< typename TimeMap > class dfs_time_visitor : public boost::default_dfs_visitor { typedef typename boost::property_traits< TimeMap >::value_type T; public: dfs_time_visitor(TimeMap dmap, TimeMap fmap, T& t) : dmap_(dmap), fmap_(fmap), time_(t) {} template< typename V, typename G > void discover_vertex ( V u, G const& g ) const { put(dmap_, u, time_++); } template< typename V, typename G > void finish_vertex ( V u, G const& g ) const { put(fmap_, u, time_++); } TimeMap dmap_; TimeMap fmap_; T& time_; }; using namespace boost; int main ( ) { typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS> G; typedef boost::graph_traits<G>::vertices_size_type size_type; enum {u, v, w, x, y, z, N}; char names[] = {'u', 'v', 'w', 'x', 'y', 'z'}; typedef std::pair<int, int> E; E edges[] = {E(u, v), E(u, x), E(x, v), E(y, x), E(v, y), E(w, y), E(w, z), E(z, z)}; G g(edges, edges + sizeof(edges) / sizeof(E), N); std::vector<size_type> dtime(boost::num_vertices(g)); std::vector<size_type> ftime(boost::num_vertices(g)); size_type t = 0; dfs_time_visitor<size_type*> vis(&dtime[0], &ftime[0], t); graphs::depth_first_search(g, vis); std::vector<size_type> dorder(N); boost::integer_range<size_type> r(0, N); std::copy(r.begin(), r.end(), dorder.begin()); std::sort(dorder.begin(), dorder.end(), boost::indirect_cmp<size_type*, std::less<size_type> >(&dtime[0])); std::cout << "order of discovery: "; for(int i = 0; i < N; ++i) std::cout << names[dorder[i]] << " "; std::cout << std::endl; std::vector<size_type> forder(N); std::copy(r.begin(), r.end(), forder.begin()); std::sort(forder.begin(), forder.end(), boost::indirect_cmp<size_type*, std::less<size_type> >(&ftime[0])); std::cout << "order of finish: "; for(int i = 0; i < N; ++i) std::cout << names[forder[i]] << " "; std::cout << std::endl; return 0; } $ g++ -Wall -I../../../../../boost-trunk.cygwin dfs.05.cpp dfs.05.cpp:40: error: ‘graph_type’ was not declared in this scope dfs.05.cpp:40: error: template argument 1 is invalid dfs.05.cpp:40: error: expected `::' before ‘,’ token dfs.05.cpp:40: error: expected identifier before ‘,’ token dfs.05.cpp:40: error: template argument 3 is invalid dfs.05.cpp:40: error: expected `::' before ‘{’ token dfs.05.cpp:40: error: expected class-name before ‘{’ token ../../../../../boost-trunk.cygwin/boost/parameter/preprocessor.hpp: In instantiation of ‘boost::parameter::aux::argument_pack<graphs::boost_param_params_40depth_first_search<int>, const boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, boost::no_property, boost::no_property, boost::no_property, boost::listS>, const dfs_time_visitor<main::size_type*>, boost::parameter::void_, boost::parameter::void_, boost::parameter::void_>’: dfs.05.cpp:88: instantiated from here ../../../../../boost-trunk.cygwin/boost/parameter/preprocessor.hpp:157: error: no type named ‘parameter_spec0’ in ‘struct graphs::boost_param_params_40depth_first_search<int>’ ../../../../../boost-trunk.cygwin/boost/parameter/preprocessor.hpp:158: error: no type named ‘parameter_spec0’ in ‘struct graphs::boost_param_params_40depth_first_search<int>’ ../../../../../boost-trunk.cygwin/boost/parameter/preprocessor.hpp: In instantiation of ‘boost::parameter::aux::argument_pack<graphs::boost_param_params_40depth_first_search<int>, const boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, boost::no_property, boost::no_property, boost::no_property, boost::listS>, boost::parameter::void_, boost::parameter::void_, boost::parameter::void_, boost::parameter::void_>’: dfs.05.cpp:88: instantiated from here ../../../../../boost-trunk.cygwin/boost/parameter/preprocessor.hpp:157: error: no type named ‘parameter_spec0’ in ‘struct graphs::boost_param_params_40depth_first_search<int>’ ../../../../../boost-trunk.cygwin/boost/parameter/preprocessor.hpp:158: error: no type named ‘parameter_spec0’ in ‘struct graphs::boost_param_params_40depth_first_search<int>’ dfs.05.cpp: In function ‘int main()’: dfs.05.cpp:88: error: no matching function for call to ‘depth_first_search(main()::G&, dfs_time_visitor<size_type*>&)’ -- View this message in context: http://boost.2283326.n4.nabble.com/boost-parameter-type-requirement-compile… Sent from the Boost - Dev mailing list archive at Nabble.com.

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[smart_ptr] scoped_array / shared_array (size_t) constructor
by Olaf van der Spek 07 Nov '11

07 Nov '11

Hi, Currently, one has to manually allocate the array and pass the ptr to the constructor of scoped_array / shared_array. boost::scoped_array<unsigned char> A(new unsigned char[100]); boost::shared_array<unsigned char> B(new unsigned char[100]); This requires one to repeat the type and shared_array requires two allocations (one extra for the control block). std::vector has a constructor from size_t and one can write: std::vector<unsigned char> V(100); This avoids the type duplication and it'd allow shared_array to do only a single allocation. A few choices have to be made: 1. Should "new T[sz]" or "new T[sz]()" be used? 2. What should happen when size = 0? Should it call new T[0] or should it just use NULL? https://svn.boost.org/trac/boost/ticket/4637 -- Olaf

10 46

Interest in bounded (Top-Bounded) Range adaptor.
by Fernando Pelliccioni 06 Nov '11

06 Nov '11

Is there interest in adding a Top-Bounded adaptor into Boost.Range ? Example: using namespace boost::adaptors; using namespace boost::assign; std::vector<int> input; input += 1,2,3,4,5,6,7,8,9; boost::copy( input | bounded(0), std::ostream_iterator<int>(std::cout, ",")); // prints nothing boost::copy( input | bounded(1), std::ostream_iterator<int>(std::cout, ",")); // prints 1, boost::copy( input | bounded(2), std::ostream_iterator<int>(std::cout, ",")); // prints 1,2, boost::copy( input | bounded(8), std::ostream_iterator<int>(std::cout, ",")); // prints 1,2,3,4,5,7,8, The above example is similar in behavior to ... boost::copy_n( input, 0, std::ostream_iterator<int>(std::cout, ",")); boost::copy_n( input, 1, std::ostream_iterator<int>(std::cout, ",")); boost::copy_n( input, 2, std::ostream_iterator<int>(std::cout, ",")); boost::copy_n( input, 8, std::ostream_iterator<int>(std::cout, ",")); The difference is that *copy_n* algorithm doesn't check for begin(range) != end(range) In the following line, an error occurs at runtime... boost::copy_n( input, 9, std::ostream_iterator<int>(std::cout, ",")); Unlike the following that runs ok... boost::copy( input | bounded(9), std::ostream_iterator<int>(std::cout, ",")); // prints 1,2,3,4,5,7,8,9, This behavior could be equated using *sliced(0, X)*, but sliced requires *RandomAccessRange*, unlike bounded that requires *SinglePassRange*. *bounded* code is based on *indexed* adaptor code, I think it is more efficient than *sliced* ( that uses *make_iterator_range* --> std::advance ). I don't know if this behavior can be achieved using other adapters, if so, please let me know. Is there interest in this for Boost? Regards, Fernando.

5 12

[lockfree] review
by Gordon Woodhull 05 Nov '11

05 Nov '11

Hi Tim, Hopefully I'll have at least a partial review. I only know enough about the subject to be a little dangerous. (One course in concurrent data structures, one successfully implemented lockfree hash table - except for the memory reclamation. Unspecified barriers and ABA problems. :p ) Considering the difficulty of the subject, you seem to have carefully chosen a small set of algorithms where at least there is consensus that the sources you are using have solved the problem correctly. I apologize if this has already been covered, but I don't see anything in the documentation about which platforms and compilers this has been tested on. These algorithms are extremely susceptible to compiler and processor optimizations. Anyway, I thought I would try to run the tests, and maybe try changing the testing methodology a little, but I got a few compiler errors, below. Defining uint fixed most of these, but bench_1.cpp also appears to be out of date? Of course I also have my lack of understanding of boost build library linking to contend with. Hope to try again later. Cheers, Gordon ~/lib/boost_lockfree/libs/lockfree/test ~/src/boost-trunk grodo-mcwoohu:test gordon$ bjam ...found 141 targets... ...updating 21 targets... darwin.compile.c++ ../../../bin.v2/libs/lockfree/test/bench_1.test/darwin-4.5.3/debug/threading-multi/bench_1.o g++: unrecognized option '-no-cpp-precomp' bench_1.cpp: In function 'void test_fifo_pop()': bench_1.cpp:67:23: error: no matching function for call to 'boost::lockfree::fifo<long int>::dequeue(long int*)' ../../../boost/lockfree/fifo.hpp:214:10: note: candidate is: bool boost::lockfree::detail::fifo<T, freelist_t, Alloc>::dequeue(T&) [with T = long int, freelist_t = boost::lockfree::caching_freelist_t, Alloc = std::allocator<long int>] bench_1.cpp: In function 'void test_fifo_pop_unsafe()': bench_1.cpp:77:30: error: no matching function for call to 'boost::lockfree::fifo<long int>::dequeue_unsafe(long int*)' ../../../boost/lockfree/fifo.hpp:255:10: note: candidate is: bool boost::lockfree::detail::fifo<T, freelist_t, Alloc>::dequeue_unsafe(T&) [with T = long int, freelist_t = boost::lockfree::caching_freelist_t, Alloc = std::allocator<long int>] bench_1.cpp: In function 'void test_stack_pop()': bench_1.cpp:87:19: error: no matching function for call to 'boost::lockfree::stack<long int>::pop(long int*)' ../../../boost/lockfree/stack.hpp:179:10: note: candidate is: bool boost::lockfree::stack<T, freelist_t, Alloc>::pop(T&) [with T = long int, freelist_t = boost::lockfree::caching_freelist_t, Alloc = std::allocator<long int>] bench_1.cpp: In function 'void test_stack_pop_unsafe()': bench_1.cpp:97:26: error: no matching function for call to 'boost::lockfree::stack<long int>::pop_unsafe(long int*)' ../../../boost/lockfree/stack.hpp:207:10: note: candidate is: bool boost::lockfree::stack<T, freelist_t, Alloc>::pop_unsafe(T&) [with T = long int, freelist_t = boost::lockfree::caching_freelist_t, Alloc = std::allocator<long int>] "g++" -ftemplate-depth-128 -O0 -fno-inline -Wall -g -dynamic -no-cpp-precomp -gdwarf-2 -fexceptions -fPIC -I"../../.." -c -o "../../../bin.v2/libs/lockfree/test/bench_1.test/darwin-4.5.3/debug/threading-multi/bench_1.o" "bench_1.cpp" ...failed darwin.compile.c++ ../../../bin.v2/libs/lockfree/test/bench_1.test/darwin-4.5.3/debug/threading-multi/bench_1.o... ...skipped <p../../../bin.v2/libs/lockfree/test/bench_1.test/darwin-4.5.3/debug/threading-multi>bench_1 for lack of <p../../../bin.v2/libs/lockfree/test/bench_1.test/darwin-4.5.3/debug/threading-multi>bench_1.o... ...skipped <p../../../bin.v2/libs/lockfree/test/bench_1.test/darwin-4.5.3/debug/threading-multi>bench_1.run for lack of <p../../../bin.v2/libs/lockfree/test/bench_1.test/darwin-4.5.3/debug/threading-multi>bench_1... darwin.compile.c++ ../../../bin.v2/libs/lockfree/test/fifo_test.test/darwin-4.5.3/debug/threading-multi/fifo_test.o g++: unrecognized option '-no-cpp-precomp' fifo_test.cpp:103:18: error: 'uint' does not name a type fifo_test.cpp: In member function 'void fifo_tester<freelist_t>::add()': fifo_test.cpp:116:14: error: 'uint' was not declared in this scope fifo_test.cpp:116:19: error: expected ';' before 'i' fifo_test.cpp:116:26: error: 'i' was not declared in this scope fifo_test.cpp:116:31: error: 'nodes_per_thread' was not declared in this scope fifo_test.cpp: In member function 'void fifo_tester<freelist_t>::run()': fifo_test.cpp:187:1: error: 'nodes_per_thread' was not declared in this scope "g++" -ftemplate-depth-128 -O0 -fno-inline -Wall -g -dynamic -no-cpp-precomp -gdwarf-2 -fexceptions -fPIC -I"../../.." -c -o "../../../bin.v2/libs/lockfree/test/fifo_test.test/darwin-4.5.3/debug/threading-multi/fifo_test.o" "fifo_test.cpp" ...failed darwin.compile.c++ ../../../bin.v2/libs/lockfree/test/fifo_test.test/darwin-4.5.3/debug/threading-multi/fifo_test.o... ...skipped <p../../../bin.v2/libs/lockfree/test/fifo_test.test/darwin-4.5.3/debug/threading-multi>fifo_test for lack of <p../../../bin.v2/libs/lockfree/test/fifo_test.test/darwin-4.5.3/debug/threading-multi>fifo_test.o... ...skipped <p../../../bin.v2/libs/lockfree/test/fifo_test.test/darwin-4.5.3/debug/threading-multi>fifo_test.run for lack of <p../../../bin.v2/libs/lockfree/test/fifo_test.test/darwin-4.5.3/debug/threading-multi>fifo_test... darwin.link ../../../bin.v2/libs/lockfree/test/freelist_test.test/darwin-4.5.3/debug/threading-multi/freelist_test ld: library not found for -lboost_thread collect2: ld returned 1 exit status "g++" -o "../../../bin.v2/libs/lockfree/test/freelist_test.test/darwin-4.5.3/debug/threading-multi/freelist_test" "../../../bin.v2/libs/lockfree/test/freelist_test.test/darwin-4.5.3/debug/threading-multi/freelist_test.o" -lboost_thread -lboost_unit_test_framework -g ...failed darwin.link ../../../bin.v2/libs/lockfree/test/freelist_test.test/darwin-4.5.3/debug/threading-multi/freelist_test... ...skipped <p../../../bin.v2/libs/lockfree/test/freelist_test.test/darwin-4.5.3/debug/threading-multi>freelist_test.run for lack of <p../../../bin.v2/libs/lockfree/test/freelist_test.test/darwin-4.5.3/debug/threading-multi>freelist_test... darwin.compile.c++ ../../../bin.v2/libs/lockfree/test/ringbuffer_test.test/darwin-4.5.3/debug/threading-multi/ringbuffer_test.o g++: unrecognized option '-no-cpp-precomp' ringbuffer_test.cpp:209:14: error: 'uint' does not name a type ringbuffer_test.cpp: In member function 'void ringbuffer_tester::add()': ringbuffer_test.cpp:225:14: error: 'uint' was not declared in this scope ringbuffer_test.cpp:225:19: error: expected ';' before 'i' ringbuffer_test.cpp:225:26: error: 'i' was not declared in this scope ringbuffer_test.cpp:225:31: error: 'nodes_per_thread' was not declared in this scope ringbuffer_test.cpp: In member function 'void ringbuffer_tester::run()': ringbuffer_test.cpp:284:1: error: 'nodes_per_thread' was not declared in this scope ringbuffer_test.cpp: In member function 'void ringbuffer_tester_buffering::add()': ringbuffer_test.cpp:315:14: error: 'uint' was not declared in this scope ringbuffer_test.cpp:315:19: error: expected ';' before 'i' ringbuffer_test.cpp:315:26: error: 'i' was not declared in this scope ringbuffer_test.cpp:315:31: error: 'nodes_per_thread' was not declared in this scope ringbuffer_test.cpp: In member function 'void ringbuffer_tester_buffering::run()': ringbuffer_test.cpp:386:1: error: 'nodes_per_thread' was not declared in this scope

8 63

Re: [boost] [lockfree] review
by Boehm, Hans 05 Nov '11

05 Nov '11

[Dave Abrahams pointed me at this thread.] Alexander Terekhov <terekhov <at> web.de> writes: > > Dave Abrahams wrote: > > > > on Thu Aug 25 2011, Alexander Terekhov <terekhov-AT-web.de> wrote: > > > > > Ilya Sokolov wrote: > > >> > > >> > > >> AFAIK, in the example above another thread can't observe reordering > > >> without introducing UB. > > > > > > I meant "observed" as in "check the sequence of writes in the generated > > > code". > > > > Do we care about what the generated code looks like? IIUC what counts > > is the sequence of memory states that another another thread can see. > > > > > But int can be simply changed to relaxed atomic<int> so that another > > > thread can observe reordering without UB. > > > > Sure. > > I meant that for the example upthread, with an int instead of relaxed > atomic<int>, another thread's code triggering UB does not prevent us > from observing reordered writes in the writing thread's code (in > generated code), by looking at it. > > Changing int to relaxed atomic<int> simply removes UB but does not > change the relevant code in the writing thread. > > regards, > alexander. > I agree with Alexander and most of the recent postings. If I write mx.lock(); x = 1; mx.unlock(); my.lock(); y = 1; my.unlock(); There is nothing to prevent the stores to x and y from becoming visible out of order at the hardware level. Enforcing ordering here would add needless and substantial cost. But a data-race-free program cannot observe such reordering. (One reference for that is Sarita Adve's and my PLDI 08 paper. Unofficial TR version at http://www.hpl.hp.com/techreports/2008/HPL-2008- 56.html. I believe Mark Batty et al have a much more complete and formal proof.) If we change x and y to be atomic variables, and the stores to be memory_order_relaxed, then an observer can tell the difference. I.e. if x and y are initially zero, and another thread does r1 = y; r2 = x; (or the acquire versions), it can see r1 = 1 and r2 = 0, since there are no synchronizes-with relationships between threads, and thus nothing to enforce ordering. If you use memory_order_relaxed, or even the acquire/release forms, things do get MUCH more complicated. The equivalent rules for other languages are an interesting story. I believe Posix implentors assume the above rules. I have a PPoPP 2007 paper that explains why that's not exactly what Posix actually states. OpenMP 3.0 has stricter rules which are also not consistently obeyed, and are somewhat fixed in OpenMP 3.1. (See my MSPC 11 paper for some details.) Java has arguably the same rules as C++ in this respect. In my mind, the main way in which sequential consistency differs from the cheaper acquire/release semantics that Alexander wants is that a) Dekker's algorithm (which by itself isn't that practically interesting), plus a number of real lock-free algorithms (which do matter) don't work. b) In my mind, acquire/release is a far more difficult model to explain to non- experts than the model for C++ with only sequentially consistent atomics. You can no longer reason about interleaving thread actions, either for purposes of determining the existence of a data-race, nor when defining what data-race- free programs mean. This was extensively discussed in C++ meetings starting in about 2005. The current solution with default-sequentially-consistent atomics, but explicit support for weaker ordering, was the resulting committee compromise. Hans

6 19

Determining interest in Delegates submission
by Jared McKee 05 Nov '11

05 Nov '11

I would like to determine interest in a possible library submission. I have written some code which converts a member function and object pointer combination to a free function for use in C style callbacks. It has some limitations which I will describe shortly. The basic idea is to be able to convert: R (B::*)(T0,T1,…) and B* to R (*)(T0,T1,…) Here's an example usage: class foo { int x; int test(int v) {return x + v;} }; foo* a = new foo; a->x = 3; int (*f)(int) = delegate(a, &foo::inc); cout << f(4) << endl; // outputs "7" When I first attempted this I used a technique where I allocated some executable memory in the heap and dynamically created a free function to call the member function for the instance. It was fun attempting that but, as you can imagine, as soon as I used the optimizer flags on my compiler I would get segment faults :) My second approach was to use templates and the Boost Preprocessor library to create appropriate static arrays of pointers to free functions matching the required signatures and then hand those pointers out each time the delegate() function is called. The two downsides to this are: you can only call delegate() for a certain function signature a limited number of times, and it adds a lot of potentially unused code to your executable. Here's the code (I've stripped out error checking for the sake of illustration): #include <boost/preprocessor.hpp> #ifndef _delegate_h_ #define _delegate_h_ #define MAX_DELEGATES 256 #define DELEGATE_PARAMS 0 #include "delegate_template.hpp" #undef DELEGATE_PARAMS #define DELEGATE_PARAMS 1 #include "delegate_template.hpp" #undef DELEGATE_PARAMS // … #endif // delegate_template.hpp #define DELEGATE_STORE BOOST_PP_CAT(DELEGATE_STORE,**DELEGATE_PARAMS) template <class B, class R BOOST_PP_ENUM_TRAILING_PARAMS(**DELEGATE_PARAMS, class T) > struct DELEGATE_STORE { typedef B* objectPointer; typedef R (B::*memberFunction)( BOOST_PP_ENUM_PARAMS(DELEGATE_**PARAMS, T) ); typedef R (*freeFunction)( BOOST_PP_ENUM_PARAMS(DELEGATE_**PARAMS, T) ); static int delegateCount; static int delegateMax; static objectPointer delegateObjectPointer[MAX_**DELEGATES]; static memberFunction delegateMemberFunction[MAX_**DELEGATES]; template <int i> static R func( BOOST_PP_ENUM_BINARY_PARAMS(**DELEGATE_PARAMS, T, v) ) { return (delegateObjectPointer[i]->***delegateMemberFunction[i])( BOOST_PP_ENUM_PARAMS(DELEGATE_**PARAMS, v) ); } static const freeFunction delegateFreeFunction[MAX_**DELEGATES]; static freeFunction getDelegate(objectPointer o, memberFunction m) { int delegateIndex = delegateCount++; delegateObjectPointer[**delegateIndex] = o; delegateMemberFunction[**delegateIndex] = m; return delegateFreeFunction[**delegateIndex]; } }; template <class B, class R BOOST_PP_ENUM_TRAILING_PARAMS(**DELEGATE_PARAMS, class T) > int DELEGATE_STORE<B,R BOOST_PP_ENUM_TRAILING_PARAMS(**DELEGATE_PARAMS, T) >::delegateCount = 0; template <class B, class R BOOST_PP_ENUM_TRAILING_PARAMS(**DELEGATE_PARAMS, class T) > int DELEGATE_STORE<B,R BOOST_PP_ENUM_TRAILING_PARAMS(**DELEGATE_PARAMS, T) >::delegateMax = MAX_DELEGATES; template <class B, class R BOOST_PP_ENUM_TRAILING_PARAMS(**DELEGATE_PARAMS, class T) > typename DELEGATE_STORE<B,R BOOST_PP_ENUM_TRAILING_PARAMS(**DELEGATE_PARAMS, T) >::memberFunction DELEGATE_STORE<B,R BOOST_PP_ENUM_TRAILING_PARAMS(**DELEGATE_PARAMS, T) > ::delegateMemberFunction[MAX_**DELEGATES] = {0}; > template <class B, class R BOOST_PP_ENUM_TRAILING_PARAMS(**DELEGATE_PARAMS, class T) > typename DELEGATE_STORE<B,R BOOST_PP_ENUM_TRAILING_PARAMS(**DELEGATE_PARAMS, T) >::objectPointer DELEGATE_STORE<B,R BOOST_PP_ENUM_TRAILING_PARAMS(**DELEGATE_PARAMS, T) > ::delegateObjectPointer[MAX_**DELEGATES] = {0}; > #define FUNC_POINTER(z, n, params) &DELEGATE_STORE<B,R BOOST_PP_ENUM_TRAILING_PARAMS(**DELEGATE_PARAMS, T) >::template func< n >, template <class B, class R BOOST_PP_ENUM_TRAILING_PARAMS(**DELEGATE_PARAMS, class T) > const typename DELEGATE_STORE<B,R BOOST_PP_ENUM_TRAILING_PARAMS(**DELEGATE_PARAMS, T) >::freeFunction DELEGATE_STORE<B,R BOOST_PP_ENUM_TRAILING_PARAMS(**DELEGATE_PARAMS, T) > ::delegateFreeFunction[MAX_**DELEGATES] = { > BOOST_PP_REPEAT(MAX_DELEGATES, FUNC_POINTER,) }; template <class B, class R BOOST_PP_ENUM_TRAILING_PARAMS(**DELEGATE_PARAMS, class T) > R (*delegate( B* b, R (B::*f)( BOOST_PP_ENUM_PARAMS(DELEGATE_**PARAMS, T) ) ))( BOOST_PP_ENUM_PARAMS(DELEGATE_**PARAMS, T) ) { return DELEGATE_STORE<B,R BOOST_PP_ENUM_TRAILING_PARAMS(**DELEGATE_PARAMS, T) >::getDelegate(b, f); } // end Thankyou very much if you managed to read all the way to here! By the way, this is my first active participation in any open source project :) Jared

3 5

[interprocess] message_queue hangs when another process dies
by Sergei Politov 03 Nov '11

03 Nov '11

Hi, I have found the following problem with message_queue on win32 (MSVC 2008 + Windows Vista). Suppose we have 2 processes, one sends messages to queue, another reads them. When reading process dies (for instance using End process) during message_queue.receive the another process hangs in send. As I found during investigation, it tries to lock interprocess mutex, but it is already locked by dead process. So this message queue instance becomes unusable. I attached the example. Steps to reproduce: 1) Start "mq.exe s" (i.e. with argument s) It outs: sender: $PID 2) Start mq.exe without arguments. It outs: receiver: $PID 0 1 2 3 4 This time sender outs: send done: 3) At this point the message queue is empty and receiver waits for messages. End it with Task Manager. 4) Enter some number in sender console and press Enter. 5) The sender hangs in message_queue.send Best Regards, Sergei

6 13

Boost.Algorithm design question
by Marshall Clow 03 Nov '11

03 Nov '11

So, what do people prefer (and why?): template<typename InputIterator, typename V> bool none_of_equal ( InputIterator first, InputIterator last, V const &val ) { for ( ; first != last; ++first ) if ( val == *first ) return false; return true; } or template<typename InputIterator, > bool none_of_equal ( InputIterator first, InputIterator last, iterator_traits<InputIterator>::value_type const &val ) { for ( ; first != last; ++first ) if ( val == *first ) return false; return true; } In the first case, I think there's (possible) conversion from V to iterator_traits<InputIterator>::value_type each time through the loop. In the second case, there is not. Of course, the (mythical?) smart compiler would do the conversion once and save the result for reuse. -- Marshall Marshall Clow Idio Software <mailto:mclow.lists@gmail.com> A.D. 1517: Martin Luther nails his 95 Theses to the church door and is promptly moderated down to (-1, Flamebait). -- Yu Suzuki

17 79

[1.48.0 Beta 1][fusion] MacTypes.h conflict with nil
by Jeff Flinn 03 Nov '11

03 Nov '11

reposted from "[1.48.0] Beta 1 is now available from SourceForge" thread for better visibilty. Mac 10.6 Xcode 3.2.6 gcc 4.2: In compiling our application, upgrading from boost_1_44_0 I get conflicts with MacTypes.h define of nil when compiling cons_fwd.hpp from fusion. Any thoughts? Jeff

3 3

Interest in boost.deepcopy
by Allan Johns 02 Nov '11

02 Nov '11

Just gauging initial interest in a boost.deepcopy library, analogous to deepcopy in python. Each type would register deepcopy behaviour with the library (there are similarities to boost.serialize). Boost.deepcopy would supply out-of-the-box registration for pod types, pointer types, arrays, stl containers and common boost containers. Example: template<typename T> void deepcopy(deepcopycontext& ctxt, const T& obj) { ...; } Why not use boost::serialize and serialize into memory then out again I hear you say? That's a great approach, but only when every object requires the same deepcopy behaviour (also, it's not too optimal). The problem is, I need specific behaviour in some types. Specifically, I need copy-on-write behaviour for a Buffer class that I'm using. For example: void deepcopy(deepcopycontext& ctxt, const Buf& b) { if(!ctxt.contains(&b)) { Buf b2(b); // doesn't copy the buf data, just holds a shared ptr internally. Data is only cloned when b/b2 is written to ctxt.insert(&b, b2); } } I attempted to model this a while ago using boost.serialize, but it turned out pretty clunky, I started needing a few decorator classes for special cases, etc. Apologies for the oversimplified examples above, just wanting to get interest in the jist of it. Please let me know if this overlaps with existing boost functionality also (I'm not aware of anything atm). Feedback appreciated. Thx, Allan

9 18

[multi_array] Ticket#4874 "multi_array compile errors using Visual C++ 2010 in debug mode"
by Stephan T. Lavavej 02 Nov '11

02 Nov '11

Hi Boost devs, VC10 users are occasionally encountering https://svn.boost.org/trac/boost/ticket/4874 and reporting it to MS. For example, see http://connect.microsoft.com/VisualStudio/feedback/details/687655/compilati… where I've explained what's going on (I wrote this analysis back in Feb 2010 and I believe it's still correct): The problem is that multi_array iterators report themselves as input iterators, which can't be written to (e.g. as the destination of a copy()). Under IDL=0, copy() doesn't actually care how its destination iterator is marked with an iterator category tag, it just tries to write to the destination iterator, and that works. Under IDL > 0, copy() wants to know whether its source and destination iterators are both random-access, in which case it can perform a range check and unwrap the destination iterator for increased performance. It does this by overloading foo(input_iterator_tag, output_iterator_tag) and foo(random_access_iterator_tag, random_access_iterator_tag) and calling foo(category(source), category(destination)). If both source and destination are random-access, both overloads are viable (i.e. callable) and the second overload is preferred, so it's actually called. Otherwise, source is required to be at least an input iterator (maybe stronger) and destination is required to be at least an output iterator (maybe stronger) so the first overload must be viable and the second overload will be non-viable, so the first overload wins by default. However, if the destination is not marked as an output iterator or stronger, then the first overload is non-viable as well as the second, so overload resolution fails and boom. Thanks, Stephan T. Lavavej Visual C++ Libraries Developer

2 1

[atomic] comments
by Tim Blechmann 01 Nov '11

01 Nov '11

hi helge and others, ... has been rather quiet about the boost.atomic review, so i want to raise a view issues: shared memory support: the fallback implementation relies on the spinlock pool that also used by the smart pointers. however this pool is per-process, so the fallback implementation won't work in shared memory. can this be changed/fixed? atomic::is_lock_free(): is_lock_free is set to either `true' or `false'. however in some cases, there are alignment constraints (iirc, 64bit atomics on ia32/x86_64 require a 64bit alignment). afaict there are not precautions to take care of this, are there? compile-time vs run-time dispatching: some instructions are not available on every CPU of a specific architecture. e.g. cmpxchg8b or cmpxchg16b are not available on all ia32/x86_64 cpus. i would appreciate if these instructions would not be used before performing a CPUID check, whether these instructions are really available (at least in a legacy mode) cmpxchg16b: currently cmpxchg16b doesn't seem to be supported. this instruction is required for some lock-free data structures (e.g. there is a dequeue algorithm, that requires a pair of tagged pointers). maybe this can be a starting point to discuss boost.atomic ... cheers, tim

6 38

[config] clang.hpp is not up-to-date
by Michel Morin 01 Nov '11

01 Nov '11

boost/config/compiler/clang.hpp is not up-to-date. For example, BOOST_NO_AUTO_DECLARATIONS is *always* defined (even if clang supports this feature). Is it worth fixing this on the release branch? P.S. I can make a patch, but before doing that I'd like to confirm whether __has_feature(cxx_auto_type) means that multi-declarator auto is supported or not. The following page says nothing about multi-declarator auto. http://clang.llvm.org/docs/LanguageExtensions.html Doug? Regards, Michel

3 4

Silly Boost.Locale default narrow string encoding in Windows
by Alf P. Steinbach 01 Nov '11

01 Nov '11

When I engage the compiler-in-my-mind to the example given at http://cppcms.sourceforge.net/boost_locale/html/ namely <code> #include <boost/locale.hpp> #include <boost/filesystem/path.hpp> #include <boost/filesystem/fstream.hpp> int main() { // Create and install global locale std::locale::global(boost::locale::generator().generate("")); // Make boost.filesystem use it boost::filesystem::path::imbue(std::locale()); // Now Works perfectly fine with UTF-8! boost::filesystem::ofstream hello("שלום.txt"); } </code> then it fails to work when the literal string is replaced with a `main` argument. A conversion is then necessary and must be added. It breaks the principle of least surprise. It breaks the principle of not paying for what you don't (want to) use. I understand, from discussions elsewhere, that the author(s) have chosen a narrow string encoding that requires inefficient & awkward conversions in all directions, for political/religious reasons. Maybe my understanding of that is faulty, that it's no longer politics & religion but outright war (and maybe that war is even over, with even Luke Skywalker dead or deadly wounded). However, I still ask: why FORCE INEFFICIENCY & AWKWARDNESS on Boost users -- why not just do it right, using the platforms' native encodings. Cheers, - Alf

9 43

[unordered] 1.48 beta1 fails to compile with MSVC 2010 SP 1, error C2027: use of undefined type 'boost::type'
by Johan Lindvall 01 Nov '11

01 Nov '11

After trying out beta 1, I am seeing some failures with unordered containers, see attached file. Microsoft (R) C/C++ Optimizing Compiler Version 16.00.40219.01 for x64 The code compiles without problems under 1.47.0. Unfortunately, I cannot yet publish the source code that triggers this problem. Any hints where to start investigating this? -- /Johan.

2 5

Re: [boost] [Tokenizer] Compile error with lots of missing binary operator statments
by Collin Day 31 Oct '11

31 Oct '11

Previously, I had posted what I thought was a bug. I did not think to do this originally, but I just tried a simple Hello World program that included boost/tokenizer.hpp. It compiled fine. I then looked at where the sample code was pulling headers from, and it appears that the download included old boost headers it was including instead of 1.47.0. I completley missed this. I apologize - and take back the error - there is none :) Thanks!

1 0

[Tokenizer] Compile error with lots of missing binary operator statments
by Collin Day 31 Oct '11

31 Oct '11

Hi all, make[1]: Entering directory `/home/collin/projects/Cpp/plugins/PluginFramework/projects/plugin_framework' mkdir -p build/Debug/GNU-Linux-x86 g++ -c -g -DPF_PLATFORM_LINUX -DAPR_DECLARE_STATIC -DAPU_DECLARE_STATIC -I../../include/ -I../../include/darwin86 -I.. -o build/Debug/GNU-Linux-x86/Path.o Path.cpp In file included from ../../include/boost/mpl/apply.hpp:23:0, from ../../include/boost/iterator/iterator_facade.hpp:34, from ../../include/boost/iterator/iterator_adaptor.hpp:15, from ../../include/boost/token_iterator.hpp:21, from ../../include/boost/tokenizer.hpp:20, from Path.cpp:4: ../../include/boost/mpl/apply_wrap.hpp:81:31: error: missing binary operator before token "(" ../../include/boost/mpl/apply_wrap.hpp:173:31: error: missing binary operator before token "(" In file included from ../../include/boost/mpl/bind.hpp:27:0, from ../../include/boost/mpl/lambda.hpp:18, from ../../include/boost/mpl/apply.hpp:25, from ../../include/boost/iterator/iterator_facade.hpp:34, from ../../include/boost/iterator/iterator_adaptor.hpp:15, from ../../include/boost/token_iterator.hpp:21, from ../../include/boost/tokenizer.hpp:20, from Path.cpp:4: ../../include/boost/mpl/apply_wrap.hpp:81:31: error: missing binary operator before token "(" ../../include/boost/mpl/apply_wrap.hpp:173:31: error: missing binary operator before token "(" In file included from ../../include/boost/mpl/lambda.hpp:18:0, from ../../include/boost/mpl/apply.hpp:25, from ../../include/boost/iterator/iterator_facade.hpp:34, from ../../include/boost/iterator/iterator_adaptor.hpp:15, from ../../include/boost/token_iterator.hpp:21, from ../../include/boost/tokenizer.hpp:20, from Path.cpp:4: ../../include/boost/mpl/bind.hpp:364:31: error: missing binary operator before token "(" ../../include/boost/mpl/bind.hpp:531:31: error: missing binary operator before token "(" In file included from ../../include/boost/mpl/lambda.hpp:22:0, from ../../include/boost/mpl/apply.hpp:25, from ../../include/boost/iterator/iterator_facade.hpp:34, from ../../include/boost/iterator/iterator_adaptor.hpp:15, from ../../include/boost/token_iterator.hpp:21, from ../../include/boost/tokenizer.hpp:20, from Path.cpp:4: ../../include/boost/mpl/aux_/full_lambda.hpp:230:31: error: missing binary operator before token "(" In file included from ../../include/boost/iterator/iterator_facade.hpp:34:0, from ../../include/boost/iterator/iterator_adaptor.hpp:15, from ../../include/boost/token_iterator.hpp:21, from ../../include/boost/tokenizer.hpp:20, from Path.cpp:4: ../../include/boost/mpl/apply.hpp:138:31: error: missing binary operator before token "(" make[1]: *** [build/Debug/GNU-Linux-x86/Path.o] Error 1 make[1]: Leaving directory `/home/collin/projects/Cpp/plugins/PluginFramework/projects/plugin_framework' make: *** [.build-impl] Error 2 I looked on the web, and everything that looks remotley like this said it was a problem with GCC > 4.4, but was fixed in boost 1.37. I have tried with both gcc 4.4.6 and 4.5.3. I don't think I am missing anything since it is just an include file, but I could be wrong. any help would be appreciated. I tried the boost users mailing list with no luck after a couple of days. This is a more detailed example - it looks as though the same problem repeats for many files. Would it be appropriate to file a bug if I can't find any answers here? Thanks!

1 1

[math][distributions] superfluous checking of parameters?
by Thijs (M.A.) van den Berg 31 Oct '11

31 Oct '11

The boost math distributions check validity of distribution the same parameters multiple times. E.g. in normal.hpp, class normal_distribution, the constructor, normal_distribution(RealType mean = 0, RealType sd = 1) : m_mean(mean), m_sd(sd) { // Default is a 'standard' normal distribution N01. static const char* function = "boost::math::normal_distribution<%1%>::normal_distribution"; RealType result; detail::check_scale(function, sd, &result, Policy()); detail::check_location(function, mean, &result, Policy()); } however, those are *again* checked in e.g. the pdf() non member function inline RealType pdf(const normal_distribution<RealType, Policy>& dist, const RealType& x) { ... if(false == detail::check_scale(function, sd, &result, Policy())) { return result; } ... } Why is that? It's done in a consistent way across all distributions. Can we remove the check inside the non member functions that are already checked in the constructor?

3 7

[proto] Recent (rvalue support) changes in proto causes a whole bunch of regressions in Spirit
by Joel de Guzman 31 Oct '11

31 Oct '11

Hi, This code: #include <boost/spirit/include/qi.hpp> int main() { namespace qi = boost::spirit::qi; qi::rule<char const*> r; r %= (+qi::char_); return 0; } no longer works as expected. r %= (+qi::char_) becomes a no-op. Before it calls either: template <typename Expr> friend rule& operator%=(rule& r, Expr const& expr); // non-const version needed to suppress proto's %= kicking in template <typename Expr> friend rule& operator%=(rule& r, Expr& expr); Both defined in the rule class. Correct me if I'm wrong, but it seems the changes in proto forces us to support rvalue refs, but we are not ready for that yet and it's too late in the release cycle. Thoughts? Regards, -- Joel de Guzman http://www.boostpro.com http://boost-spirit.com

4 4

[c++1] BOOST_NOEXCEPT macros?
by Beman Dawes 31 Oct '11

31 Oct '11

Since Boost already has BOOST_NO_NOEXCEPT and at least one compiler (GCC) supports C++11 noexcept, I'd like to start using it in Boost code. So how about a <boost/detail/noexcept.hpp> header with the usual boilerplate and this: #ifndef BOOST_NO_NOEXCEPT # define BOOST_NOEXCEPT # define BOOST_NOEXCEPT_IF(Predicate) #else # define BOOST_NOEXCEPT no_except # define BOOST_NOEXCEPT_IF(Predicate) no_except(Predicate) #endif As was pointed out in a previous thread, there isn't any reliable C++03 alternative for either of these two, so nothing is attempted, and that's OK in C++03 code. We could also define BOOST_NOEXCEPT_OPERATOR(Predicate), and have it fall back to true in C++03 code. I'm not expert enough to know if that is reliable or even useful, so am not proposing it. Comments? --Beman

12 37

[interprocess] native Windows cond_var + mutex
by Dan Brown 31 Oct '11

31 Oct '11

Hi, Attached is a patch to implement interprocess_condition and interprocess_mutex natively on Windows. Following are some detailed notes. I hope this isn't too awkward of a time for a submission like this - I realize there's a lot of 1.48 activity going on. One more note about the patch - IIRC, some patch utils won't create directories. This patch is intended to be applied to boost/interprocess and relies on a new directory boost/interprocess/sync/win32. Background I started out by looking at http://www.cs.wustl.edu/~schmidt/win32-cv-1.html. This appears to be from the late '90s and is the basis for ACE's cond_var implementation. The solution in section 3.4 is arguably the most correct implementation. However, this solution relies on the atomicity of SignalObjectAndWait(). SOAW() may have been atomic for unicore systems common at the time but from what I've read is not atomic for multicore (it prevents context switches on a single core but ignores concurrent threads on other cores), and win32 documentation backs this up. While the paper argues that this leads to unfairness, I don't think the solution is correct without this atomicity. Wait/signal/wait problem One problem that I came across is what I'll call the wait/signal/wait problem. Setting the state, thread 1 is waiting on a condition and thread 2 has just completed cond_signal. Without an atomic SOAW(), thread 1 may release the external mutex without obtaining the associated semaphore. Another thread, thread 3, may obtain the external lock and find the cond_var signaled and behave correspondingly. This I believe is incorrect - a waiter which obtains the external mutex after the signaler has exited signal()should not find cond_var signaled. This situation is unlikely but it makes assumptions about the scheduler that I am not comfortable with. If there's a flaw in my reasoning hopefully someone will point that out. This solution This solution is structurally somewhat similarly to the paper's solution. One point to note is that notify_one()/signal() blocks on an event in the same manner as notify_all()/broadcast(). There may be a solution which does not block the signaler while wake-processing is occurring, but I saw additional complexity on that path and decided to forgo it for the time being. I hope the solution is correct but have only testing to validate. I haven't used any formal methods to back it up. Maybe I'll construct a Petri net sometime. That's always .. fun. I throw this solution on the mercy of the court. External mutex I have yet to see production examples of cond_var use where signalers do not hold the external mutex while they signal, but this use case is allowed by POSIX. My original solution (if it is in fact a solution) relies on some particular external mutex being held by all waiters and signalers for some particular condition variable. I recently added two mutexes to solve that situation but I have only minimal testing experience with that recent addition. Use of these new locks is demarcated with WIN32_POSIX_SEMANTICS. Interprocess vs. Intraprocess I'm not sure if there is support for process-specific synchronization objects in boost.interprocess, but if support is present or was added at some future time this could help optimize things for win32. At the moment win32 interprocess mutexes rely on assigning random names to mutexes (only named mutexes can cross platform boundaries in win32), and all mutex operations have to look up the mutex by this name. Interprocess seems to have been designed primarily with pthreads in mind, and things get a little awkward on Windows in this regard. Similarly, it would be nice to be able to use the native condition variables that win32 added for Vista+, but these can't be used across processes according to the documentation, and so can't be used AFAICT for inteprocess_condition. Correspondingly, an intraprocess_mutex would be able to forgo the win32 mutex name lookups. Miscellaneous Not all interprocess tests currently pass. There are some additional variations of mutex like the upgradable/sharable, etc., that I haven't looked at in detail. I'm hoping that this patch goes far enough that it'll have some momentum. I'm happy to either complete this work in the future or help whoever undertakes the task, but I may not be able to justify much of my time to the task in the short term to my employer. I realized a little too late that I didn't keep formatting entirely consistent with the existing code. Apologies. Hopefully it's only the opening block curlies. Thanks. Dan

3 13

[C++ Now! 2012] Call for Submissions
by Brian Wood 30 Oct '11

30 Oct '11

Hartmut Kaiser: > The C++ Now! Conference is dedicated to discussion and education > about C++, an open and free language and standard. It costs a lot to buy a copy of the standard now! Hope conference goes well and maybe I can attend someday. -- Brian Wood Ebenezer Enterprises http://webEbenezer.net

1 0

[BGL] How to provide a vertex_index property for my graph
by ShNaYkHs ShNaYkHs 30 Oct '11

30 Oct '11

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.

1 0

[C++ Now! 2012] Call for Submissions
by Hartmut Kaiser 30 Oct '11

30 Oct '11

INAUGURAL C++ NOW! CONFERENCE 2012 Aspen CO, USA, May 14-18, 2012, www.cppnow.org CALL FOR SUBMISSIONS We invite you to submit session proposals to the Inaugural C++ Now! Conference: C++Now! 2012 (Aspen CO, USA, May 14 - 18, 2012). Based on the successful traditions of 5 years of BoostCon, which was the main face-to-face event for all things C++ and Boost (www.boost.org) C++Now! 2012 will present leading speakers from the whole C++ community. The conference name is changing to C++ Now! to reflect the current value of the language, the focus on its new state (from the new Standard), and the need to continually look to the future so the language remains useful to the C++ community. The focus of this conference will be the new C++11 language Standard and as usual Boost: what's new in C++, its Standard library, and in the Boost libraries, how to write and maintain them, how to evangelize or to deploy Boost within your organization. The new C++ Standard, but also the infrastructure and process of Boost, its vision and mission - no matter what you are interested in, it all comes together in the C++Now! sessions. Meet the colleagues, and feel the inspiration to support your work with C++ and Boost for the next year. The C++ Now! Conference is dedicated to discussion and education about C++, an open and free language and standard. Our Conference will focus on discussion and education about open source software usage and developments in the C++ developer and user community. To reflect the breadth of the C++ and Boost communities, the conference includes sessions aimed at three constituencies: C++ and Boost end-users, hard-core Boost library and tool developers, and researchers pushing the boundaries of computation. The program fosters interaction and engagement within and across those groups, with an emphasis on hands-on, participatory sessions. As a multi-paradigm language, C++ is a melting pot where the most compelling ideas from other programming communities are blended in powerful ways. Historically, some of the most popular sessions at C++Now! have highlighted these concepts, from DSLs to functional programming to transactional memory and more. Bring your C#, Python, Ruby or Haskell influences to bear in an environment that will broaden their exposure. IMPORTANT DATES New proposal submissions due: January 10th, 2012. Proposals decisions sent (tentative program available): February 17th, 2012. Fully scheduled program available: February 25th, 2012. Session materials due: April 15th, 2012. BEST PRESENTATION AWARDS We know how much effort it takes to prepare talks for our conference. For this reason we will award the best presentations in the following categories: Best Presentation, Best Short Presentation, Best Tutorial, and Best Workshop. The awards will be given based on the audience's voting. Each award will include the author's name listed on the cover of the C++Now! website for that year and a plaque containing all the C++Now! conference information. SESSION TOPICS Topics of interest include, but are not restricted to, the following: * C++11 and how it changes life for users and library writers * General tutorial sessions on C++11, the C++11 Standardslibrary, and one or more Boost libraries * In-depth sessions on using specific Boost libraries * Case studies on using Boost * Experts panels * Advanced sessions on implementation techniques used within Boost libraries * Development workshops to extend or enhance existing Boost libraries * Workshops on design process * Infrastructure workshops such as Build tools, Website, Testing * Concepts and Generic Programming * Hardware and infrastructure presentations focused on how libraries can make better use of the technology * Software development tools and their application to C++ and or Boost * Other topics likely to be of great interest to Boost users and developers Interactive and collaborative sessions are encouraged, as this is the style of learning and participation that has proven most successful at such events. Sessions can be tutorial based, with an emphasis on interaction and participant involvement, or workshop based, whether hands-on programming or paper-based, discussion-driven collaborative work. SESSION FORMATS Presentations Presentations focus on a practitioner's ideas and experience with anything relevant to C++11, Boost and users. Panels Panels feature three or four people presenting their ideas and experiences relating to C++11 and Boost's relevant, controversial, emerging, or unresolved issues. Panels may be conducted in several ways, such as comparative, analytic, or historic. Tutorials Tutorials are sessions at which instructors teach conference participants specific skills relevant to C++11 and Boost. Workshops Workshops provide an active arena for advancements in Boost-relevant topics. Workshops provide the opportunity for experienced practitioners to develop new ideas about a topic of common interest and experience. Author's Corner These were introduced at BoostCon 2008, and were a great Presentations success They are short (30 minute) sessions, focusing on tips on usage and design. In addition, we're looking to uncover the hidden design gems in Boost libraries. Tool Vendors We actively encourage tool vendors and ISP's to submit Presentations proposals for a special Tool Vendors Session Track aimed at products related to Boost and C++ (compilers, libraries, tools, etc.). Other formats may also be of interest. Don't hold back a proposal just because it doesn't fit into a pigeonhole. SUBMITTING A PROPOSAL Standard Sessions are 60 minutes. You may submit a proposal for fractions or multiples of 90-minutes. Fractional proposals will be grouped into 60 minute sessions covering related topics. Longer sessions, such as tutorials and classes, will be assigned 90 minute, three hour (i.e. half day), or six hour (i.e. full day) time slots. Please include: * The working title. * Type of session: presentation, panel, tutorial, workshop, authors corner, vendor track, other. * A paragraph or two describing the topic covered, suitable for the conference web site. * Proposed length: 10-20 minute short talks, 45 minutes, 90 minutes, half day, full day. * Alternate lengths, if you are willing to make adjustments: 10- 20 minute short-talks, 45 minutes, 90 minutes, half-day, full day. * Audience: users, developers, both. * Level: basic, intermediate, advanced. * A biography, suitable for the conference web site. * Your contact information (will not be made public). SUBMISSION DETAILS All submissions should be made through the EasyChair conference management system: http://www.easychair.org/conferences/?conf=cppnow2012. If you have not already registered at EasyChair, you will need to do so in order to submit your proposal. All submissions will go through a peer review process. Authors are invited (but are not required) to submit PDF versions of full papers of up to 10 pages in ACM conference proceedings format (see http://www.acm.org/sigs/publications/proceedings-templates) The full papers are not required unless you want them published in the proceedings. All accepted proposals will be made available in the Association for Computing Machinery (ACM) Digital Library (approval pending). Best papers, after further reviews, will be considered to be book chapters or journal articles in a renowned journal. The session materials go on the C++Now! website and will be available to attendees. For general information on the C++Now! 2012 paper submission or the scope of technical papers solicited, please refer to the conference website at www.cppnow.org. For any other questions about the submission process or paper format, please contact the Program Committee at cppnow2012(a)easychair.com. If you have any technical problems with EasyChair, please contact EasyChair for help. Note: Presenters must agree to grant a non-exclusive perpetual license to publish submitted materials, either electronically or in print, in any media related to C++ Now!. Hartmut Kaiser, email: hartmut.kaiser(a)gmail.com (Program Committee Chair) Dave Abrahams, email: dave(a)boostpro.com (Conference Chair) On behalf of the conference organizers

1 0

Re: [boost] Silly Boost.Locale default narrow string encoding in Windows
by Daniel James 29 Oct '11

29 Oct '11

On Saturday, 29 October 2011, Peter Dimov wrote: > > > The "dir" command has no problem displaying arbitrary file names directly > to the console (presumably via WriteConsoleW), but once it has to write to > a file, it needs to convert to narrow and no code page other than 65001 can > express the above file name. > This is not that relevant to the wider issue, but wide streams will work for console output if you first do this: if (_isatty(_fileno(stdout))) _setmode(_fileno(stdout), _O_U16TEXT); if (_isatty(_fileno(stderr))) _setmode(_fileno(stderr), _O_U16TEXT); i.e. set the output mode to UTF-16 when writing to the console. This only works for recent versions of Visual C++. Obviously doesn't fix piped output.

3 2