September 2008 - Boost-users - lists.preview.boost.org

[variant] variant member function apply_visitor( visitor ) thread-safe?
by Hicham Mouline 08 Sep '08

08 Sep '08

Hello, Is the apply_visitor() method per se thread-safe, meaning, if i have variant object, and i visit it from different threads at same time, and if i assume the visitor i write is thread-safe, my question is about the machinery of apply_visitor() itself, is it thread-safe? regards,

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asio::serial_port how to know how many bytes are available for read
by Jean-Sebastien Stoezel 08 Sep '08

08 Sep '08

Hi, Is there a way to know how many bytes are available for read from a serial port, using asio::serial_port::read_some? The sockets have bytes_readable or something similar... Any equivalent for the serial ports? Thanks! Jean

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Borland c++ 5.8.2 and Boost 1.3.6 - Thread problem???
by Stephen Kierzewski 08 Sep '08

08 Sep '08

Hello, Has anyone successfully compiled the Boost libraries with the Borland / Codegear Turbo C++ Pro, compiler version 5.8.2? I was able to build the libraries but I got a lot of errors and a simple Hello World program using boost::thread will not work. Any help on switches or tweaks I can do to get Boost to work would be appreciated. Here is the program I am compiling and the error I get when running it. I am linking to the debug version of the multi-threaded DLL (boost_thread-bcb-mt-d-1_36.dll) The sample program compiles fine but when I run it I get an assertion error and the program terminates. Any feedback is welcome. Thank you, Stephen ________________________________ Assertion failed: p_ != 0, file .\boost/intrusive_ptr.hpp, line 149 Abnormal program termination ________________________________ #include <boost/thread/thread.hpp> #include <iostream> using namespace std; void hello_world() { cout << "Hello world, I'm a thread!" << endl; } int main(int argc, char* argv[]) { // start a new thread that calls the "hello_world" function boost::thread my_thread(&hello_world); // wait for the thread to finish my_thread.join(); return 0; }

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Boost Graph Library and Boehm Garbage Collector
by FBSL 08 Sep '08

08 Sep '08

Hello I am having trouble to garbage-collect adjacency_list<>. I have instanciated it with correctly garbage-collected vectors and lists (I have copied vecS and listS definitions, and added Boehm GC's default allocator so that they are garbage-collected). In my application I need to dynamically allocate many graphs, but it does not work, there is a (big) memory leak. Unfortunately, there is no template argument in adjacency_list<> to specify Boehm GC's allocator. Does anyone have a hint ? Snippet code "main.cpp" follows, compiled with Boost Graph Library 1.32, Boehm GC 6.4 and G++ 3.3.5, with command line : $ g++ -o main main.cpp -lgc -lgccpp -- #include <boost/graph/adjacency_list.hpp> #include <gc/gc_allocator.h> #include <gc/gc_cpp.h> #include <iostream> #include <vector> #include <list> using namespace std; using namespace boost; namespace boost { struct collected_vecS {}; struct collected_listS {}; template <class ValueType> struct container_gen<collected_vecS, ValueType> { typedef vector<ValueType,gc_allocator<ValueType> > type; }; template <class ValueType> struct container_gen<collected_listS, ValueType> { typedef list<ValueType,gc_allocator<ValueType> > type; }; template <> struct parallel_edge_traits<collected_vecS> { typedef allow_parallel_edge_tag type; }; template <> struct parallel_edge_traits<collected_listS> { typedef allow_parallel_edge_tag type; }; namespace detail { template <> struct is_random_access<collected_vecS> { enum { value = true }; typedef true_type type; }; } } typedef adjacency_list<collected_vecS, collected_vecS, directedS, no_property, no_property, no_property, collected_listS> graph; int main() { // leaks... while(true){ graph * g=new (UseGC) graph; for(unsigned int i=0; i<100; ++i){ add_vertex(*g); } for(unsigned int i=0; i<100; ++i){ for(unsigned int j=0; j<100; ++j){ add_edge(i,j,*g); } } } }

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throw exception in boost
by gj_uestc 08 Sep '08

08 Sep '08

Hi, all When I use boost_1_36 in intel compiler, I got such error "runtime support for RTTI is disabled".It seems like RTTI is used in exception.hpp. Is there a way to let me choose not use the exception.hpp? I remembered in boose_1_35 you have to defined Macro "BOOST_NO_EXCEPTIONS" then "exception.hpp" would be included, otherwise this file is not necessary. Thanks Juan

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Catching boost::thread_interrupted
by rbock＠eudoxos.de 08 Sep '08

08 Sep '08

Hi, currently I am making my first steps using Boost.Thread (1.36.0). The interrupt feature looks very cool, so I tried to use it, but somehow failed to catch boost::thread_interrupted. The code is attached to this mail. I was expecting to see something like Thread 0x60b050 got interrupted Thread 0x60b3e0 got interrupted Instead I got Thread 0x60b050 caught something else Thread 0x60b3e0 caught something else Can somebody please enlighten me? Thanks and regards, Roland

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Boost.MPL.Vector -> Boost.Tuple
by Олег Царев 08 Sep '08

08 Sep '08

typedef boost::mpl::vector< A, B, C > Sequence; typedef typename Question< Sequence >::type Result; BOOST_MPL_ASSERT( boost::mpl::is_same< Result, boost::tuple< A, B, C > >); How write Question? I don't want to write specialisation for every dimension of tuple manually. Implementation should be compatible with the last stable Boost release (1.36) Thank you

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What is the logic behind the library naming conventions?
by cowwoc 07 Sep '08

07 Sep '08

Hi, I am investigating possible library naming convention and I would appreciate getting your feedback on why Boost uses the naming convention it does. The discussion thread can be found here: http://discuss.joelonsoftware.com/default.asp?design.4.676033.4 I am sure the Boost team put a lot of thought into this so I would appreciate your insight on this discussion. Thank you, Gili -- View this message in context: http://www.nabble.com/What-is-the-logic-behind-the-library-naming-conventio… Sent from the Boost - Users mailing list archive at Nabble.com.

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Mutidimensional subscriptor operator
by Agustín K-ballo Bergé 07 Sep '08

07 Sep '08

Is there anything at boost that will help me build classes that support multidimensional subscriptor operator? I'm thinking in some CRTP-based solution in which I implement a subscriptor operator taking a tuple (or any other sequence of types type), that would create all the intermediate proxy types needed. Agustín K-ballo Bergé.-

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[dataflow][review] Dataflow.Signals and threading - new docs and examples
by Stjepan Rajko 07 Sep '08

07 Sep '08

Hello, I have added a section on threading to the Dataflow.Signals tutorial: http://tinyurl.com/69subd (my hosting provider appears to be having some intermittent problems today - I apologize to any reviewers impacted by this) This new section summarizes information related to threading, and presents a new example component that uses the Threadpool library by Oliver Kowalke to provide support for asynchronous signals. Here is an excerpt regarding the Threadpool component: The purpose of the component is to make a signal call asynchronous. Instead of the consumer component processing the signal immediately, the signal call will be added to a thread pool and processed later. async_component is a class template, templated on the threadpool type, and the type of the underlying component that will process the asynchronous signal. The three examples provided are: * mixing synchronous and asynchronous signals * assigning priorities to tasks / signals * using asynchronous signals for cyclic networks Thanks to everyone that has participated in the discussion regarding this library so far. I hope this documentation update will provide some additional information on how the library can be used / extended. Stjepan

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