August 2010 - Boost-users - lists.preview.boost.org

[DateTime] from time_t to ptime and back - or not
by Christoph Duelli 23 Aug '10

23 Aug '10

[I am using Boost 1.43.0 on linux, gcc 4.4.1] I am having trouble with date_time's ptime. I am passing it a time_t, and store that in a ptime object. When I retrieve the time_t, I am getting a different value than the one I passed to it originally. (the difference seems to be 2 hours - in all probability due to UTC vs local time issues). Code: time_t now = time(NULL); boost::posix_time::ptime pt = boost::posix_time::from_time_t(now); struct tm tm = to_tm(pt); time_t should_be_now = mktime(&tm); BOOST_CHECK_EQUAL(now, should_be_now); fails for me: now is by 7200 seconds (i.e. 2 hours) ahead of. Is this a bug in date_time or am I just failing to use it properly? Thank you, and best regards Christoph

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[bind]Help! Can we modify parameters before pass them into bind (see the context below for details)
by jungleman 23 Aug '10

23 Aug '10

Hi, I have some problems on function template bind. the original usage of bind is : bind(func, _1, _2), and I wonder whether I can modify the parameters before pass them into bind, for example, functype function = bind(func, *_1, *_2). So that, when I use function(a, b), it will do like this: func(*a, *b). May it work, or some way else to do this? I just wanna do this in one line code. thanks in advance. -- Stay hungry, stay foolish !

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Boost.Intrusive issues on IBM compiler
by Jeremiah Willcock 22 Aug '10

22 Aug '10

It appears that almost all of the Boost.Intrusive tests (at <URL:http://tinyurl.com/2bzhglh>, for example) fail on IBM's compiler. I get similar results, like the following from the test suite, from my own code: An expression of type "overloaded function: U::to_node_ptr" cannot be converted to type "boost::intrusive::list_node<void *> *(boost::intrusive::detail::base_hook_traits<boost::intrusive::testvalue<hooks<void *>,0>,boost::intrusive::list_node_traits<void *>,1,boost::intrusive::default_tag,1>::*)(testvalue<hooks<void *>,0> &)" Is there an easy workaround for this issue? Is there a plan to fix it? This has also been reported a couple of months ago as bug 4412 (<URL:https://svn.boost.org/trac/boost/ticket/4412>). Thank you. -- Jeremiah Willcock

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axpy_prod Weirdness
by Jane Shevtsov 22 Aug '10

22 Aug '10

I have a little program that implements an ecological network analysis algorithm. (It looks at the importance of indirect energy or matter flows between species.) 01 //dea.cpp -- The fundamental DEA algorithm 02 03 #include <boost/numeric/ublas/matrix.hpp> 04 #include <boost/numeric/ublas/operation.hpp> 05 #include <boost/numeric/ublas/io.hpp> //for test 06 #include "storage_adaptors.hpp" //for test 07 08 using boost::numeric::ublas::matrix; 09 10 void dea(const matrix<double>[], int, int, matrix<double>[]); 11 matrix<double> indflow(const matrix<double> & Ndea, const matrix<double> & Gdea); 12 13 int main() { 14 using boost::numeric::ublas::make_matrix_from_pointer; 15 matrix<double> Garr[4]; 16 matrix<double> Narr[2]; 17 double G1[3][3] = {0, 0, 0, 0.33333, 0, 0, 0.66667, 1, 0}; 18 double G2[3][3] = {0, 0, 0, 0.6, 0, 0, 0.4, 1, 0}; 19 double G3[3][3] = {0, 0, 0, 0.55, 0, 0, 0.45, 1, 0}; 20 double G4[3][3] = {0, 0, 0, 0.5, 0, 0, 0.5, 1, 0}; 21 Garr[0] = make_matrix_from_pointer(G1); 22 Garr[1] = make_matrix_from_pointer(G2); 23 Garr[2] = make_matrix_from_pointer(G3); 24 Garr[3] = make_matrix_from_pointer(G4); 25 dea(Garr, 2, 4, Narr); 26 std::cout << Narr[0] << std::endl; 27 matrix<double> ratio = indflow(Narr[0], Garr[0]); 28 std::cout << ratio << std::endl; 29 return 0; 30 } 31 32 //The fundamental DEA algorithm 33 //Takes array of G matrices, window size, array length and empty array for N_DEA matrices as input 34 void dea(const matrix<double> Garr[], int win, int arrLen, matrix<double> Narr[]) { 35 using namespace boost::numeric::ublas; 36 int matSize = Garr[0].size1(); 37 for (int i = 0; i < arrLen - win; i++) { 38 matrix<double> Gprod = identity_matrix<double>(matSize); 39 Narr[i] = identity_matrix<double>(matSize); 40 //the core loop 41 for (int j = 0; j < win; j++) { 42 Gprod = prod(Gprod, Garr[i+j]); 43 Narr[i] += Gprod; 44 } 45 } 46 } 47 48 //computes indirect flow fraction 49 matrix<double> indflow(const matrix<double> & Ndea, const matrix<double> & Gdea) { 50 using namespace boost::numeric::ublas; 51 int matSize = Ndea.size1(); 52 matrix<double> iflow = Ndea - Gdea - identity_matrix<double>(matSize); //Ind = N-G-I 53 matrix<double> frac = zero_matrix<double>(matSize, matSize); //inialize indirect flow fraction matrix 54 //perform division for nonzero, off-diagonal elements 55 for (int i=0; i<matSize; i++) { 56 for (int j=0; j<matSize; j++) { 57 if (i != j && Ndea(i,j) != 0) //avoid division by zero 58 frac(i, j) = iflow(i, j) / Ndea(i, j); 59 } 60 } 61 return frac; 62 } The correct output is below. [3,3]((1,0,0),(0.33333,1,0),(1.26667,1,1)) [3,3]((0,0,0),(0,0,0),(0.473683,0,0)) The code given above works, but to speed it up, I tried replacing the first line of the core loop in dea() with axpy_prod(Gprod, Garr[i+j], Gprod, true);. This gives the following wrong output: [3,3]((1,0,0),(0,1,0),(0,0,1)) [3,3]((0,0,0),(0,0,0),(0,0,0)) And if I use axpy_prod(Gprod, Garr[i+j], Gprod, false);, I get: [3,3]((3,0,0),(1.26666,3,0),(2.33334,3,3)) [3,3]((0,0,0),(0.736843,0,0),(0.714285,0.666667,0)) What gives? When should I avoid using axpy_prod? -- ------------- Jane Shevtsov Ecology Ph.D. candidate, University of Georgia co-founder, <www.worldbeyondborders.org> Check out my blog, <http://perceivingwholes.blogspot.com>Perceiving Wholes "The whole person must have both the humility to nurture the Earth and the pride to go to Mars." --Wyn Wachhorst, The Dream of Spaceflight

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[bind]Help! Can we modify parameters before pass them into bind (see the context below for details)
by jungleman 22 Aug '10

22 Aug '10

Hi, I have some problems on function template bind. when I uses stl algorithm adjacent_find(inputIterator begin, inputIterator) -- Stay hungry, stay foolish !

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[asio] Feature request for serializable types.
by Germán Diago 22 Aug '10

22 Aug '10

Hello. I'm using boost.asio and trying to serialize a boost.variant, which is serializable because each of the fields I used in the variant have a serialize method required by boost.serialization library. I want to send my variant as binary data. This is not easy although I have a serialize method because this does not work: async_write(mysocket, boost::asio::buffer(myserializablevariant), when_done); I think all serializable types should be automatically usable as boost::asio::buffer, like std::vector, in this call. I think this shouldn't be too hard to implement, but I don't know how to serialize my data in binary format in a straight-forward way. Any ideas? Thanks in advance.

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thread-safe initialization for singleton
by Kraus Philipp 22 Aug '10

22 Aug '10

Hi, I have written a class with static methods and properties. Now the class must be used in a multithreaded environment, so I get some race conditions error. I use boost::thread for implementating the threads. I have found boost_once but I don't know how to use it, so my class properties are initialized once. Thanks Phil

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multiple serialized objects to same file
by Oscar Pernas 21 Aug '10

21 Aug '10

Hi! I know that this question is asked before but I cant see any answer about it. Is posible with boost serialization to write different objects to the same file? if is possible, is possible to access to each object with an iterator or with position like binary files? thanks -- Óscar Pernas Plaza.

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[BGL] segFault
by John Robertson 21 Aug '10

21 Aug '10

I'm trying to obtain an iterator of edges with a different ordering than that given in egdes(g). The following compiles but segfaults at std::sort( VE.begin(), VE.end(), ordering< Graph, edd >() ); (runs ok if the above line is commented out) //////////////////////////////////////////////////////////////////////////////////////////////////////////////// typedef Traits::edge_descriptor edd; // Create ordering template < typename Graph, typename edd > struct ordering { Graph & g; bool operator ()(const edd & a, const edd & b) { return g[a].eName < g[b].eName; } }; template < typename Graph > int initialize_container( Graph & g ) { typename graph_traits<Graph>::edge_iterator edge_iter, edges_end; // create vector of edge descriptors. std::vector< Traits::edge_descriptor > VE(num_edges(g)+1); int i = 1; // (Sometimes I like to start at 1.) //insert edge descriptors into vector of edge descriptors. for (tie(edge_iter, edges_end) = edges(g); edge_iter != edges_end; ++edge_iter) { cout << " *edge_iter = " << *edge_iter << endl; VE[i++] = *edge_iter; } // segfaults here //sort vector of edge descriptors. std::sort( VE.begin(), VE.end(), ordering< Graph, edd >() ); //print sorted edge descriptors. for( int i = 1; i < num_edges(g)+1; ++i ) cout << " -Edge " << i << " = " << VE[i] << endl; } Thanks

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[BGL] Updating the source vertex of an edge in-place
by Daniel Trebbien 21 Aug '10

21 Aug '10

I need to be able to update the source vertex of an edge in-place. The only option that I see is to remove the edge with `remove_edge` and then add a new edge with `add_edge`. The problem, however, is that I think this will mess up a property map of an edge property if it cannot expand to map a new value for the newly-added edge. Thus, I would like to update the edge in-place. How do I do this?

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[propertytree] more beginners questions
by Dietmar Hummel 21 Aug '10

21 Aug '10

Hi! I have some more questions regarding property tree (for parsing xml) and maybe someone could help me. Lets assume we have the following xml file to read: <a> <b> <c><d>1</d></c> <c><d>2</d></c> <c><d>3</d></c> <x></x> </b> </a> Now, my idea was to parse all the c-nodes by calling a specific function for each of them. Something like this... void parseDNode( const boost::property_tree::ptree& v ) { //... } void parseCNode( const boost::property_tree::ptree::value_type& v ) { parseDNode( v.second.get_child( "d" ) ); } void load( const std::string& filename ) { boost::property_tree::ptree pt; boost::property_tree::read_xml(filename, pt); BOOST_FOREACH( boost::property_tree::ptree::value_type &v, pt.get_child( "a.b.c" ) ) { parseCNode( v ); } } ---- Now I have several questions for this: 1. The code doesn't work as expected, it just handles the first one of the c nodes 2. The function parseCNode() also doesn't work. I assumed that v is a reference to the c node where I have to claim the d-node by get_child. But it seems v is already pointing to d? 3. I don't understand why BOOST_FOREACH is working with value_type here. As far as I see, get_child returns a self_type which should be a ptree? See also the different parameter lists for parseCNode and parseDNode... Thanks in advance.... Regards Dietmar

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MPICH2 + Boost.MPI Collective Problems
by Stephan Hackstedt 21 Aug '10

21 Aug '10

Hi there, i have a big problem by running MPI programs which use the Boost.MPI library. When i'm trying to run programs on *more *than one node, collective operations like communicator::barrier<http://boost.org/doc/libs/1_44_0/doc/html/boost/mpi/communicator.html#id918…>or broadcast,<http://boost.org/doc/libs/1_44_0/doc/html/boost/mpi/broadcast.html>or even the environment<http://boost.org/doc/libs/1_44_0/doc/html/boost/mpi/environment.html>destructor (cause of FINALIZE, which is colletive) causing the programm to crash. I got errors like this : *[1]terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::mpi::exception> >' [1] what(): MPI_Barrier: Other MPI error, error stack: [1]PMPI_Barrier(362).................: MPI_Barrier(MPI_COMM_WORLD) failed [1]MPIR_Barrier_impl(255)............: [1]MPIR_Barrier_intra(79)............: [1]MPIC_Sendrecv(186)................: [1]MPIC_Wait(534)....................: [1]MPIDI_CH3I_Progress(184)..........: [1]MPID_nem_mpich2_blocking_recv(895): [1]MPID_nem_tcp_connpoll(1746).......: Communication error with rank 0: * I also tested this with the simple broadcast example from the Boost.MPI tutorial - same errors.. But when using the original MPI equivalent without the Boost.MPI library, such as MPI_Barrier<http://www.mpi-forum.org/docs/mpi-11-html/node66.html#Node66>, the programm runs well. I am using MPICH2 on Ubuntu 10.04 platforms. Someone had problems like this or know a fix for that? Regards, stephan

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Using unordered_set or unordered_map to hold small array(s) of ints
by B Hart 21 Aug '10

21 Aug '10

Can someone please provide an example of how to best use unordered_map/set to store/lookup many small arrays of integers. e.g. unsigned int I[5] = {1000,3344455,12455222,8832232}; I'm guessing that there is no facility for using raw C++ arrays, and that one must wrap them in a struct. Thanks in advance.

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Beginner question: Why boost::signal creates another instance of the slot object ?
by Mauricio Gomes 20 Aug '10

20 Aug '10

Hi, I am running the program below (Vista with boost 1.43, mingw/gcc 4.5.1). I would expect slot.x to be 5 but it is zero. Why boost::signal creates another instance of the slot object ? What am I missing here ? Thank you in advance for your attention, Mau. ---------------------------------------------------------------- #include <iostream> #include <boost/signal.hpp> struct S { int x; S (): x(0) {} void operator () (int i) { std::cout << "&slot1 = " << this << std::endl; x = i; std::cout << "slot1.x = " << this->x << std::endl; } }; int main () { S slot; boost::signal<void (int)> sig; std::cout << "&slot2 = " << &slot << std::endl; sig.connect (slot); sig (5); std::cout << "slot2.x = " << slot.x << std::endl; return 0; } -------------------------------------------------------------------- Output: &slot2 = 0x22fee4 &slot1 = 0x341448 slot1.x = 5 slot2.x = 0

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How to best use unordered_set or unordered_map to hold small array(s) of ints
by B Hart 20 Aug '10

20 Aug '10

I posted this last night, but not sure it went through to the list as I don't see it in my sent items and I never got any responses. Sorry if it is duplicate. I'm hoping someone could offer an example or advice on how to best use unordered_set or unordered_map to hold many small arrays of unsigned integers. I would like to use the built in hash function rather than have to create one. Also, since I have many of these small arrays, keeping the memory footprint small and the hash time at a minimum are important concerns. A typical int array would hold 5 unsigned ints. Maybe someone could offer example code or suggestions. The samples I see are always the trivial case of just entering a single number or string as key or value. Thanks.

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[property tree] silly beginners question
by Dietmar Hummel 20 Aug '10

20 Aug '10

Hi all! I am trying to read an xml file with property tree (first try). Because I have dots int the tag names I must use the extended version of the get functions. So here is the slightly modified example code, which sadly does'nt compile on vc2008. Probably its a totally silly error on my side... // Loads debug_settings structure from the specified XML file void load(const std::string &filename) { // Create an empty property tree object using boost::property_tree::ptree; ptree pt; // Load the XML file into the property tree. If reading fails // (cannot open file, parse error), an exception is thrown. read_xml(filename, pt); // Get the filename and store it in the m_file variable. // Note that we construct the path to the value by separating // the individual keys with dots. If dots appear in the keys, // a path type with a different separator can be used. // If the debug.filename key is not found, an exception is thrown. std::string m_file = pt.get< std::string >( '/', "debug/filename" ); // Get the debug level and store it in the m_level variable. // This is another version of the get method: if the value is // not found, the default value (specified by the second // parameter) is returned instead. The type of the value // extracted is determined by the type of the second parameter, // so we can simply write get(...) instead of get<int>(...). int m_level = pt.get( '/', "debug/level", 0); // Iterate over the debug.modules section and store all found // modules in the m_modules set. The get_child() function // returns a reference to the child at the specified path; if // there is no such child, it throws. Property tree iterators // are models of BidirectionalIterator. std::vector< std::string > m_modules; BOOST_FOREACH( ptree::value_type &v, pt.get_child( '/', "debug/modules" ) ) { m_modules.push_back( v.second.data() ); } } vc says: 1>c:\projekte\proptreetest\proptreetest\proptreetest.cpp(23) : error C2664: 'std::basic_string<_Elem,_Traits,_Ax> boost::property_tree::basic_ptree<Key,Data>::get<std::string>(const boost::property_tree::string_path<String,Translator> &,const Type &) const': Konvertierung des Parameters 1 von 'char' in 'const boost::property_tree::string_path<String,Translator> &' nicht möglich 1> with 1> [ 1> _Elem=char, 1> _Traits=std::char_traits<char>, 1> _Ax=std::allocator<char>, 1> Key=std::string, 1> Data=std::string, 1> String=std::string, 1> Translator=boost::property_tree::id_translator<std::string>, 1> Type=std::string 1> ] 1> and 1> [ 1> String=std::string, 1> Translator=boost::property_tree::id_translator<std::string> 1> ] So, it looks to me like the compiler does'nt know about the extended get functions... Regards Dietmar

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[Log] How to use?
by Olivier Tournaire 20 Aug '10

20 Aug '10

Hi all, i am currently trying to use Boost.Log in my application. After fighting the two last days, I still do not understand how to correctly use the lib. I would like the result to be the same as the one provided by the example advanced_use.cpp. So, I wrote a simple class to make some tests. As I want to use the logging library in a shared library (an application plugin), I made a simple test: compile the class which uses Log in a shared library and link an executable against this library. I also have created an executable which directly compiles the class (so does not link against the shared library). Basically, I have a test_boost_log class. The constructor is a copy/paste of the code from the example advanced_use.cpp: #include "test_boost_log.hpp" #include <cassert> #include <iostream> #include <fstream> #include <boost/shared_ptr.hpp> #include <boost/log/common.hpp> #include <boost/log/filters.hpp> #include <boost/log/formatters.hpp> #include <boost/log/attributes.hpp> #include <boost/log/sinks.hpp> #include <boost/log/utility/empty_deleter.hpp> #include <boost/log/utility/scoped_attribute.hpp> namespace logging = boost::log; namespace fmt = boost::log::formatters; namespace flt = boost::log::filters; namespace sinks = boost::log::sinks; namespace attrs = boost::log::attributes; namespace src = boost::log::sources; namespace keywords = boost::log::keywords; using boost::shared_ptr; // Here we define our application severity levels. enum severity_level { normal, notification, warning, error, critical }; // The formatting logic for the severity level template< typename CharT, typename TraitsT > inline std::basic_ostream< CharT, TraitsT >& operator<< ( std::basic_ostream< CharT, TraitsT >& strm, severity_level lvl) { static const char* const str[] = { "normal", "notification", "warning", "error", "critical" }; if (static_cast< std::size_t >(lvl) < (sizeof(str) / sizeof(*str))) strm << str[lvl]; else strm << static_cast< int >(lvl); return strm; } int foo(src::logger& lg) { BOOST_LOG_FUNCTION(); BOOST_LOG(lg) << "foo is being called"; return 10; } test_boost_log::test_boost_log() { // For now we only create a text output sink: typedef sinks::synchronous_sink< sinks::text_ostream_backend > text_sink; shared_ptr< text_sink > pSink(new text_sink); { text_sink::locked_backend_ptr pBackend = pSink->locked_backend(); shared_ptr< std::ostream > pStream(&std::clog, logging::empty_deleter()); pBackend->add_stream(pStream); shared_ptr< std::ofstream > pStream2(new std::ofstream("sample.log")); assert(pStream2->is_open()); pBackend->add_stream(pStream2); } logging::core::get()->add_sink(pSink); src::logger lg; BOOST_LOG(lg) << "Hello, World!"; pSink->locked_backend()->set_formatter(fmt::stream << fmt::attr("LineID") // First an attribute "LineID" is written to the log << " [" << fmt::date_time< boost::posix_time::ptime >("TimeStamp", "%d.%m.%Y %H:%M:%S.%f") << "] [" << fmt::attr< severity_level >("Severity", std::nothrow) << "] [" << fmt::time_duration< boost::posix_time::time_duration >("Uptime") << "] [" // then this delimiter separates it from the rest of the line << fmt::if_(flt::has_attr("Tag")) [ fmt::stream << fmt::attr< std::string >("Tag") << "] [" // yet another delimiter ] << fmt::named_scope("Scope", keywords::iteration = fmt::reverse) << "] " << fmt::message()); // here goes the log record text shared_ptr< logging::attribute > pCounter(new attrs::counter< unsigned int >(1)); // Since we intend to count all logging records ever made by the application, // this attribute should clearly be global. logging::core::get()->add_global_attribute("LineID", pCounter); // And similarly add a time stamp shared_ptr< logging::attribute > pTimeStamp(new attrs::local_clock()); logging::core::get()->add_global_attribute("TimeStamp", pTimeStamp); // And an up time stopwatch BOOST_LOG_SCOPED_THREAD_ATTR("Uptime", attrs::timer); // Let's also track the execution scope from which the records are made boost::shared_ptr< logging::attribute > pNamedScope(new attrs::named_scope()); logging::core::get()->add_thread_attribute("Scope", pNamedScope); // We can mark the current execution scope now - it's the 'main' function BOOST_LOG_FUNCTION(); // Let's try out the counter attribute and formatting BOOST_LOG(lg) << "Some log line with a counter"; BOOST_LOG(lg) << "Another log line with the counter"; { BOOST_LOG_NAMED_SCOPE("Tagging scope"); // Now these lines will be highlighted with the tag BOOST_LOG(lg) << "Some tagged log line"; BOOST_LOG(lg) << "Another tagged log line"; } // And this line is not highlighted anymore BOOST_LOG(lg) << "Now the tag is removed"; pSink->set_filter( flt::attr< severity_level >("Severity", std::nothrow) >= warning // Write all records with "warning" severity or higher || flt::attr< std::string >("Tag", std::nothrow).begins_with("IMPORTANT")); // ...or specifically tagged src::severity_logger< severity_level > slg; // These two lines test filtering based on severity BOOST_LOG_SEV(slg, normal) << "A normal severity message, will not pass to the output"; BOOST_LOG_SEV(slg, error) << "An error severity message, will pass to the output"; { // Next we try if the second condition of the filter works // We mark following lines with a tag BOOST_LOG_SCOPED_THREAD_TAG("Tag", std::string, "IMPORTANT MESSAGES"); BOOST_LOG(slg) << "Some really urgent line"; } pSink->reset_filter(); // And moreover, it is possible to nest logging records. For example, this will // be processed in the order of evaluation: BOOST_LOG(lg) << "The result of foo is " << foo(lg); } I have added another method to test the logger state: void test_boost_log::a_test_method_to_see_if_the_logger_is_still_working() { src::severity_logger< severity_level > slg; BOOST_LOG_SEV(slg, error) << "An error severity message, will pass to the output"; } My main: #include "test_boost_log.hpp" int main(int argc, char** argv) { test_boost_log tbl; tbl.a_test_method_to_see_if_the_logger_is_still_working(); return 0; } Here is the output of the program: Hello, World! 1 [17.08.2010 21:22:43.083302] [] [00:00:00.000076] [test_boost_log::test_boost_log()] Some log line with a counter 2 [17.08.2010 21:22:43.083445] [] [00:00:00.000217] [test_boost_log::test_boost_log()] Another log line with the counter 3 [17.08.2010 21:22:43.083484] [] [00:00:00.000256] [Tagged line] [Tagging scope<-test_boost_log::test_boost_log()] Some tagged log line 4 [17.08.2010 21:22:43.083517] [] [00:00:00.000289] [Tagged line] [Tagging scope<-test_boost_log::test_boost_log()] Another tagged log line 5 [17.08.2010 21:22:43.083556] [] [00:00:00.000328] [test_boost_log::test_boost_log()] Now the tag is removed 6 [17.08.2010 21:22:43.083598] [error] [00:00:00.000370] [test_boost_log::test_boost_log()] An error severity message, will pass to the output 7 [17.08.2010 21:22:43.083633] [normal] [00:00:00.000405] [IMPORTANT MESSAGES] [test_boost_log::test_boost_log()] Some really urgent line 9 [17.08.2010 21:22:43.083673] [] [00:00:00.000444] [int foo(boost::log_mt_posix::sources::logger&)<-test_boost_log::test_boost_log()] foo is being called 8 [17.08.2010 21:22:43.083668] [] [00:00:00.000440] [test_boost_log::test_boost_log()] The result of foo is 10 *terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::log_mt_posix::missing_value> >'* * what(): Requested attribute value not found* So, the logger throws, sample.log is created, but empty. The library and the executable are compiled with -DBOOST_LOG_USE_CHAR and -DBOOST_LOG_DYN_LINK If someone could help... Best regards, Olivier PS: boost_1.42, log_1.0 (from sourceforge), g++4.3.4, 64bits ubuntu

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A question about "prim_minimum_spanning_tree.hpp"
by 王伟 20 Aug '10

20 Aug '10

Hi, I'm studying MST algorithms in GPU recently.I need BGL implementation as coparison,But I have a problem in using prim_minimum_spanning_tree.hpp.The problem is:when I use large input(e.g. >1M),there's a "segmnetation error" problem.But when the input(e.g. 1K) is small,the result is noproblem. I haven't found know the reason yet.My complier is gcc 4.1.2,OS is RHEL5. Help would be appreciated. Thanks in advance. Wang wei The complete code is in the attachment.

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Some trouble using mutexes
by Ernest Galbrun 20 Aug '10

20 Aug '10

Dear boost users, I would be really grateful if someone could give me a hint about what I am doing wrong with the mutex and thread class (I am using boost 1.43, on windows XP running visual c++ 2010, the library has been built using the bjam utility). I have a main thread that creates an object of class robot : class Robot { private: boost::mutex tcpLock; boost::thread continuousThread; ... } Robot k3; this thread launches a thread that makes continuous calls to a member function of the robot. Since this function uses network ressources, I want it to be safe so i use a lock The function called is the only function in my program that uses this lock : int Robot::sendMsg(string msg, int n, vector<string>* answer) { tcpLock.lock(); (do stuff with the tcp io service) tcpLock.unlock(); return 0; } Of course, I also call this function from the main thread. And I have disruptive behavior, which I don't understand. When debugging, I see that the 'active_count' of the tcpLock object stays negative or ==0, which seem absolutely wrong to me, but I don't understand how it could ever be anything other than 0 or 1. Any clue, advice, web link, or soft injures are welcome ! -- Ernest Galbrun

2 1

ptree info format - block commenting
by Hite, Christopher 20 Aug '10

20 Aug '10

http://www.boost.org/doc/libs/1_41_0/doc/html/boost_propertytree/parsers .html#boost_propertytree.parsers.info_parser I'm using the ptree info format. How about C-style commenting out of a block of config stuff like? /* Stuff I { don't need } */ Chris

1 0

[Interprocess] "You cannot bind an lvalue to an rvalue reference" in 1.44 using VC10
by Phil Ratzloff 20 Aug '10

20 Aug '10

When I attempt to compile a project using boost::interprocess I get compile errors when I include managed_mapped_file.hpp when using VC10. I can create a simple project that is just the following code: #include <boost\interprocess\managed_mapped_file.hpp> int main(int argc, char* argv[]) { return 0; } When compiling, I get the following errors: Empty.cpp c:\lib\boost_1_44_0\boost\interprocess\detail\move.hpp(342): error C2440: 'return' : cannot convert from 'boost::interprocess::mapped_region' to 'boost::interprocess::mapped_region &&' You cannot bind an lvalue to an rvalue reference c:\lib\boost_1_44_0\boost\interprocess\mapped_region.hpp(159) : see reference to function template instantiation 'boost::interprocess::mapped_region &&boost::interprocess::move<boost::interprocess::mapped_region&>(T)' being compiled with [ T=boost::interprocess::mapped_region & ] c:\lib\boost_1_44_0\boost\interprocess\detail\move.hpp(342): error C2440: 'return' : cannot convert from 'boost::interprocess::detail::file_wrapper' to 'boost::interprocess::detail::file_wrapper &&' You cannot bind an lvalue to an rvalue reference c:\lib\boost_1_44_0\boost\interprocess\detail\file_wrapper.hpp(63) : see reference to function template instantiation 'boost::interprocess::detail::file_wrapper &&boost::interprocess::move<boost::interprocess::detail::file_wrapper&>(T)' being compiled with [ T=boost::interprocess::detail::file_wrapper & ] c:\lib\boost_1_44_0\boost\interprocess\detail\move.hpp(342): error C2440: 'return' : cannot convert from 'boost::interprocess::file_mapping' to 'boost::interprocess::file_mapping &&' You cannot bind an lvalue to an rvalue reference c:\lib\boost_1_44_0\boost\interprocess\file_mapping.hpp(62) : see reference to function template instantiation 'boost::interprocess::file_mapping &&boost::interprocess::move<boost::interprocess::file_mapping&>(T)' being compiled with [ T=boost::interprocess::file_mapping & ] When I look at move.hpp(342) I find the following code: #if defined(BOOST_MOVE_DOXYGEN_INVOKED) ...unused code... #else template <class T> inline typename remove_reference<T>::type&& move(T&& t) { return t; } #endif It is complaining about the "return t;" statement. I have just moved up from boost 1.43, where I have been working without problems with VC10. Is there something I should be doing to prevent this, or is it a bug?

1 0

[log] calling init_from_stream() or init_from_settings() more than once (reinitialize at runtime)
by Oskar Nordquist 19 Aug '10

19 Aug '10

Hello, I've just started experimenting with the unofficial Boost.Log by Andrey Semashev. I would like to know the defined behaviour of calling init_from_stream() and init_from_settings() more than once, i.e. is it possible to re-initialize with new settings at run time? Basically I would like to do this: boost::log::settings setts; setts["Sink:File"]["Filter"] = "%Severity% > 4"; setts["Sink:File"]["Destination"] = "TextFile"; setts["Sink:File"]["FileName"] = "MyApp_%3N.log"; setts["Sink:File"]["AutoFlush"] = true; setts["Sink:File"]["RotationSize"] = 10 * 1024 * 1024; // 10 MiB boost::log::init_from_settings(setts); // ... later on change severity filter to >= 0 setts["Sink:File"]["Filter"] = "%Severity% >= 0"; boost::log::init_from_settings(setts); This does not work. It seems I am able to add new sinks without problem, but modifying existing sinks is not possible. I think that being able to reinitialize at runtime is an absolutely vital feature. Being able to change a settings file and then just reinit to turn on logging! Please tell me this is already supported and I am doing something wrong, or at least that this will be supported in the future :) Regards, Oskar

1 0

[mpl] Reconstructing an mpl::list from mpl::l_item's.
by AJG 19 Aug '10

19 Aug '10

Hi there, Using mpl::remove, et al. I can eliminate types from an mpl::list. However, it appears that the result is not an actual mpl::list, but some sort of indexed, cons-like structure composed of mpl::l_item types. Is there a way to recreate an mpl::list proper using these l_item's? E.g. typedef mpl::list<foo, bar, qux> L; typedef mpl::remove<L, bar>::type R; typedef mpl::???<R>::type => mpl::list<foo, qux>; Thanks!

2 1

filesystem lambda and for_each
by Jean-Christophe Roux 19 Aug '10

19 Aug '10

hello, Despite some research, I am struggling to combine boost filesystem, boost lambda and STL for_each. 32 std::string str = ""; 33 std::string path = "/tmp"; 34 boost::filesystem::directory_iterator it(path); 35 while(it != boost::filesystem::directory_iterator()) 36 { 37 str += it->path().filename() + "<br>"; 38 ++it; 39 } works fine but 40 std::for_each(boost::filesystem::directory_iterator(path), boost::filesystem::directory_iterator(), 41 str += *boost::lambda::_1.path().parent_path() ); does not compile with the error message that : error: ‘const struct boost::lambda::lambda_functor<boost::lambda::placeholder<1> >’ has no member named ‘path’ I don't understand why and I don't really see how I could have this work. Also, I am wondering why with _1 instead of boost::lambda::_1 I am getting: error: reference to ‘_1’ is ambiguous /usr/local/include/boost/lambda/core.hpp:69: thanks!

2 1

Throwing an exception in a packaged_task: is there a clear example?
by Mark Wilson 19 Aug '10

19 Aug '10

Hello, I am throwing an exception from a packaged_task, and then trying to catch it with f.get() (where f is a unique_future); it doesn't work, the program just terminates with: terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::unknown_exception>' what(): std::exception Is there a simple example somewhere, or could someone provide one, that makes clear how this mechanism is supposed to work? The Threads documentation does not show how to do this... Here is my simple program, based on the example in the docs: #include <boost/thread.hpp> #include <boost/thread/future.hpp> #include <boost/exception/all.hpp> struct MyException { MyException() { } }; int calculate_the_answer_to_life_the_universe_and_everything() { throw MyException(); return 42; } int main() { boost::packaged_task<int> task(calculate_the_answer_to_life_the_universe_and_everything); boost::unique_future<int> f(task.get_future()); boost::thread t(boost::move(task)); try { f.get(); } catch(MyException& ex) { std::cout << "EXCEPTION!" << std::endl; } } Thanks, Mark Wilson

2 2

[serialization] tuples and portable_binary_archive
by Richard Ulrich 19 Aug '10

19 Aug '10

I used boost serialize with some smaller projects, which always worked nicely. But now I want to use it on a bigger one. And I wonder why some things seem to be missing. - tuple: There is code on the Internet in various places for bridging boost::serialize with boost::tuple. But why isn't there an official version in either boost::serialize or boost::tuple? - portable_binary_archive: There are also some implementations around, one even in the examples of boost::serialization. But why is it not in the official library itself? Sure I could use the code I found, but it would feel better if it was part of the library. That's especially true for serialization where I want to be 99.99999999% sure, the data can always be read back in. Rgds Richard

2 1

[serialization] Different behaviors between archive and its polymorphic variant
by Maxime van Noppen 19 Aug '10

19 Aug '10

Hi, I'm trying to make a custom archive class that works either with the template flavor or via the polymorphic_archive. It compiles but produces a different behavior and I can't find why. Basically I did a trivial oarchive class that overloads (via save_override) how are treated NVP. When used with the template version it works, whereas with the polymorphic version it doesn't. The code is attached. There is a preprocessor switch to choose the template or polymorphic version (-DPOLY). $ g++ poly.cc -lboost_serialization && ./a.out <name=u><name=id_>42</name=id_> </name=u> $ g++ -DPOLY poly.cc -lboost_serialization && ./a.out 42 This is with Boost 1.43 and g++ 4.5.0. I looked at various archive implementations but couldn't find any code that I could relate to this problem. Thanks, -- Maxime

3 9

A problem in using "prim_minimum_spanning_tree.hpp"
by 王伟 19 Aug '10

19 Aug '10

Hi, I'm studying MST algorithms in GPU recently.I need BGL implementation as coparison,But I have a problem in using prim_minimum_spanning_tree.hpp.The problem is:when I use large input(e.g. >1M),the result is wrong,all the parent of vertices is "no parent".But when the input(e.g. 1K) is small,the result is noproblem. I haven't found know the reason yet.My complier is gcc 4.1.2,OS is RHEL5. Help would be appreciated. Thanks in advance. Wang wei The complete code is: #include <iostream> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/prim_minimum_spanning_tree.hpp> #include <fstream> #include <string.h> using namespace std; int main() { using namespace boost; typedef adjacency_list < vecS, vecS, undirectedS, property<vertex_distance_t, long>, property < edge_weight_t, int > > Graph; typedef std::pair < long, long >E; //read graph data from file long num_nodes,num_edges,u,v; int w; ifstream infile; infile.open("convertResult.txt"); if(!infile) { cerr<<"error:unable to open file."<<endl; return -1; } infile>>num_nodes>>num_edges; E edges[num_edges]; int weights[num_edges]; for(long i=0;i<num_edges;i++) { infile>>u>>v>>w; edges[i] = make_pair(u,v); weights[i] = w; } //construct input parameters Graph g(edges, edges + sizeof(edges) / sizeof(E), weights, num_nodes); property_map<Graph, edge_weight_t>::type weightmap = get(edge_weight, g); std::vector < graph_traits < Graph >::vertex_descriptor > p(num_vertices(g)); //call the BGL PRIM prim_minimum_spanning_tree(g, &p[0]); //output the result ofstream outfile; outfile.open("primResult.txt"); for (std::size_t i = 0; i != p.size(); ++i) if (p[i] != i) outfile<< "parent[" << i << "] = " << p[i] << std::endl; else outfile<< "parent[" << i << "] = no parent" << std::endl; return EXIT_SUCCESS; }

1 0

[Serialization] serializing derived class through base class pointer
by Dante Stroe 19 Aug '10

19 Aug '10

Hi, I have a problem with serializing a derived classes through a pointer to a base class. I tried registering with the syntax from the documentation: |ar.template register_type<derived_one>(); | , which works well in case the derived class has a default constructor (just like the example). I just don't know what the syntax is for the case where the derived class does not have a default constructor (if I use the same syntax to register the derived class then I get a compilation error about the fact that there is no. I can provide an example in case this is not clear enough. Or, is it an absolute requirement for all derived classes to have a default constructor? Thank you and best regards, Dante

1 0

[Filesystem] is_directory( ) for a non-existent path.
by Robert Jones 19 Aug '10

19 Aug '10

This is probably something of a shot in the dark, but somewhere between 1.33.1 and 1.37 the behaviour of is_directory() for a non-existent directory changed from failing (or throwing) in 1.33.1 to simply returning false (1.37). Can anyone enlighten me when this was. Trac references would be lovely. Thx - Rob.

1 0

[1.43.0] Release notice
by Beman Dawes 19 Aug '10

19 Aug '10

Release 1.43.0 of the Boost C++ Libraries is now available. These open-source libraries work well with the C++ Standard Library, and are usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use. This release contains two new libraries (functional/factory, functional/forward), a major range library upgrade, plus numerous enhancements and bug fixes for other libraries. For details, including download links, see http://www.boost.org/users/news/version_1_43_0 The release can also be downloaded directly from SourceForge. See http://sourceforge.net/projects/boost/files/ To install this release on your system, see http://www.boost.org/doc/libs/1_43_0/more/getting_started/index.html Thanks to all who contributed, --The Boost release team

4 5

[BGL] adjacency_list.hpp requires to link with serialization lib in 1.44?
by Oliver Koenig 19 Aug '10

19 Aug '10

Hello, when trying to update Boost from 1.43 to 1.44 in our code we noticed that in 1.44 we need to link to the serialization lib as soon as boost/graph/adjacency_list.hpp is included. Is this correct behavior or is this a bug? To reproduce this it is sufficient to build the following test program hello_adjacency_list.cpp (tested with MSVC-9.0): #include <iostream> #include <boost/graph/adjacency_list.hpp> int main(){ std::cout << "hello adjacency_list\n"; return 0; } With the boost build rule "exe hello_adjacency_list : hello_adjacency_list.cpp ;" compilation fails with: compile-c-c++ ..\..\..\bin\even_utils\test\graph\msvc-9.0\release\address-model-64\threading-multi\hello_adjacency_list.obj hello_adjacency_list.cpp msvc.link ..\..\..\bin\even_utils\test\graph\msvc-9.0\release\address-model-64\threading-multi\hello_adjacency_list.exe LINK : fatal error LNK1104: cannot open file 'libboost_serialization-vc90-mt-1_44.lib' Using the build rule "exe hello_adjacency_list : hello_adjacency_list.cpp /boost//serialization : <link>shared<define>BOOST_SERIALIZATION_DYN_LINK ;" everything works fine. Sincerely ok -- -------------------------------------------- Oliver Koenig Dr.sc.techn. ETH Email: koenig(a)even-ag.ch EVEN - Evolutionary Engineering AG Technoparkstrasse 1 CH-8005 Zurich Tel : +41 (0)44 500 93 60 Fax : +41 (0)44 500 93 61 Mail : info(a)even-ag.ch WWW : www.even-ag.ch -------------------------------------------- -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.

5 6

how to detect TCP communication problems on time with synchronous operations
by Gözde Bahar KOŞ 19 Aug '10

19 Aug '10

Hello, I'm using synchronous TCP communication via asio sockets. I have following problems: First problem; When I unplug ethernet cable, "eth0: Link is Down" is written in the console, but socket.write_some command does not detect link down failure. Second problem; During socket.connect command, if I plug ethernet cable, connect command does not detect this till "Connection timed out" error occurs. If I run socket.connect again, it detects the connection. How can I detect these plug/unplug events as soon as the event occurs? Best Regards, Gözde Koş ###################################################################### Dikkat: Bu elektronik posta mesaji kisisel ve ozeldir. Eger size gonderilmediyse lutfen gondericiyi bilgilendirip mesaji siliniz. Firmamiza gelen ve giden mesajlar virus taramasindan gecirilmekte, guvenlik nedeni ile kontrol edilerek saklanmaktadir. Mesajdaki gorusler ve bakis acisi gondericiye ait olup Aselsan A.S. resmi gorusu olmak zorunda degildir. ###################################################################### Attention: This e-mail message is privileged and confidential. If you are not the intended recipient please delete the message and notify the sender. E-mails to and from the company are monitored for operational reasons and in accordance with lawful business practices. Any views or opinions presented are solely those of the author and do not necessarily represent the views of the company. ######################################################################

2 1

Re: [Boost-users] Placeholders and iterator arithmetic in MPL
by Rob Platt 18 Aug '10

18 Aug '10

Steven Watanabe wrote: > After I included all the right headers, it compiled for me. > The only problem is that you're dereferencing past the > end of the sequence. Indeed, thank you! One of my previous attempts was written to avoid the past-the-end, or so I thought... But [slaps forehead] I somehow was thinking that reverse_iter_fold would give reverse_iterators, like those found in the STL. Whereas, next<> and prior<> always operate forwards. So, I had them mixed up. This little example does the job neatly: template<class T> struct works : reverse_iter_fold< T, vector_c<long>, push_front<_1, if_<empty<_1>, long_<0>, deref< next<_2> > > > > {}; It substitutes a long_<0> for the first step of the reverse_iter_fold, when next<> would be past the end. It could be adapted to iter_fold when using prior<>. Dave Abrahams wrote: > stylistically, may I suggest > > struct fails : reverse_iter_fold< .... > {}; You're right to correct me -- I should know that since I have the (your) book! Thank you both for your help, Rob

1 0

Dynamic Properties and Removing Edges/Vertex
by ef 18 Aug '10

18 Aug '10

Hello, I am pretty new and inexperienced so forgive me if any of this is incorrect, any corrections would be appreciated. I am currently using Dot/Graphviz libaries of boost to create a graph. However my graph is huge, to the point where memory will run out. I have devised an algorithm to remove edges/and vertex that are unused when I am done with them. When an vertex/edge is added using read_graphviz function the following happens: the vertex/edge is added to some data structures, as well as the function add_vertex and add_edge are called. I think memory management is pretty straight forward for those situation. The issues that I think will be of some concern is that in order to map names and properties of these vertex, data is added via dynamic properties. >From what I have seen there is no way of removing information from these dynamic properties. (So even if I remove the vertex/edges there is still some residue left in the dp). My question is this correct? Are there functions to remove a certain vertex/edge dynamic property or is this done using the function remove_vertex/edge. From the source code I have seen there is no such thing. Do I need to edit the dynamic property class and make a special delete function, or am I incorrect in my thinking? Any Advice is appreciated, Thanks! EF

2 1

Placeholders and iterator arithmetic in MPL
by Rob Platt 18 Aug '10

18 Aug '10

Hello folks. I'm trying to use the iter_fold and reverse_iter_fold algorithms in MPL, since I want to operate on sub-ranges of an input sequence. Now if I do just the trivial case of dereferencing the current element, then all is well: struct works { typedef typename reverse_iter_fold< T, vector_c<long>, push_front<_1, deref< _2 > > >::type type; }; I can successfully instantiate this with, for example, vector_c<int,1,2,3,4>. But when I do iterator arithmetic (e.g. prior, next or begin) I run into trouble: struct fails { typedef typename reverse_iter_fold< T, vector_c<long>, push_front<_1, deref< next<_2> > > >::type type; }; -- error messages about arg 3 - I suspect that prior is being applied to the placeholder arg type itself, not to the iterator. I'm wondering if I should be using lambda/apply, but I've tried that without success. What's a would-be template metaprogrammer to do? Regards Rob

3 2

[1.44] PDF build of documentation is now available
by John Maddock 18 Aug '10

18 Aug '10

The PDF build of the documentation for Boost-1.44 is now available for download from https://sourceforge.net/projects/boost/files/ The direct links are: https://sourceforge.net/projects/boost/files/boost-docs/1.44.0/boost_1_44_p… https://sourceforge.net/projects/boost/files/boost-docs/1.44.0/boost_1_44_p… https://sourceforge.net/projects/boost/files/boost-docs/1.44.0/boost_1_44_p… https://sourceforge.net/projects/boost/files/boost-docs/1.44.0/boost_1_44_p… As usual please note that this only includes the subset of Boost documentation that is authored in quickbook/boostbook/docbook and so has an automatic conversion to PDF format. Enjoy! Regards, John.

1 0

boost asio sequential?
by Lloyd 18 Aug '10

18 Aug '10

hi, I have a simple boost asio server (copied from asio sample), multiple clients can connect to the server, but the operation performed only in a sequential manner. that is only after completing the first reqest, the second one is performed. Is this the defined behavior? Thanks, Lloyd ______________________________________ Scanned and protected by Email scanner

3 4

thread problem - incorrect checksum for freed object - object was probably modified after being freed
by Kraus Philipp 17 Aug '10

17 Aug '10

Hi, I create some boost::threads: std::vector< worker<T,D> > l_worker; boost::thread_group l_threadgroup; for(std::size_t i=0; i < p_threads; ++i) { l_worker.push_back( worker<T,D>(p_iteration, p_stepsize, m_fulltable, m_derivation, m_optimize, m_static, p_batch) ); l_threadgroup.create_thread( boost::bind( &worker<T,D>::optimize, l_worker[i] ) ); } l_threadgroup.join_all(); In the constructor of my worker-object makes a copy of the parameters ( p_iteration = std::size_t, p_stepsize = T (double), p_batch = std::vector and the others are std::map): ... ) : m_iteration( p_iteration ), m_stepsize( p_stepsize ), m_symbols(), m_derivation(), m_initvalues(), m_staticvalues(), m_batch() { std::copy( p_derivation.begin(), p_derivation.end(), std::inserter(m_derivation, m_derivation.begin())); std::copy( p_initvalues.begin(), p_initvalues.end(), std::inserter(m_initvalues, m_initvalues.begin())); std::copy( p_syms.begin(), p_syms.end(), std::inserter(m_symbols, m_symbols.begin())); } in the optimize-method I use this code: GiNaC::exmap l_dynamic; // exmap is == std::map for(typename std::map<std::string, std::pair<T,T> >::iterator it = m_initvalues.begin(); it != m_initvalues.end(); ++it) l_dynamic[ m_symbols[it->first] ] = it->second.first; If I create only one thread, everything works fine. On more thread I'll get main(4398,0xa07ad720) malloc: *** error for object 0xd2b880: incorrect checksum for freed object - object was probably modified after being freed. *** set a breakpoint in malloc_error_break to debug My idea is to create p_threads number of my worker objects and add some data with the constructor parameters. Than I call the join_all method so every object can work with their own data and after join_all is finished I receive the data from every object. Can someone please explain to me what I did wrong. Thanks Phil

1 0

Problem with nested bind
by przemyslaw.sliwa＠uk.bnpparibas.com 17 Aug '10

17 Aug '10

Hello, I am trying to make a simple nested bind in boost. I have the fillowing structure: struct eventInterval { double start, finish, weight; }; and a typedef typedef boost::shared_ptr<eventInterval> eventIntervalPtr; and then I am trying to copy (actually push back to a vector) all elements which have weight > 0.0. I cannot sompile this bit of code: std::vector<eventIntervalPtr> posIntervals, negIntervals, intervals(eventPtr->decomposeIntervals(anchorDate, today)); std::transform(intervals.begin(), intervals.end(), std::back_inserter(posIntervals), boost::bind(std::greater<double>(), boost::bind(&eventInterval::weight, _1), 0.0)); Could someone help me with this issue? Thanks ___________________________________________________________ This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and delete this e-mail. Any unauthorised copying, disclosure or distribution of the material in this e-mail is prohibited. Please refer to http://www.bnpparibas.co.uk/en/information/legal_information.asp?Code=ECAS-… for additional disclosures.

2 1

Program Options of Filesystem Path's - confused!
by John Dlugosz 17 Aug '10

17 Aug '10

OK, If I take a po:wvalue<std::wstring>()->notifier(&datadir_set) the string gets passed to datadir_set, and within that function it implicitly converts the string to a fs::wpath instance to call set_me. It works as expected. void set_me (const fs::wpath& p); void datadir_set (const std::wstring& s) { wcout << L"** set data dir to " << s << L".\n"; set_me (s); } However, if I declare the program option as po::wvalue<fs::wpath>()->notifier(&set_me) then when it runs I get "invalid option value". It apparently can't convert the argv token into a wpath? But it's not a compile-time error so it thinks it knows how to, but gets an error actually doing it? I have no trouble passing long string literals to the constructor, e.g. fs::wpath f1 (L"C:\\here\\there.txt"); The program option takes "." on the command line just fine, so it's the specific value of the string it doesn't like! I tried with Unix-style slashes, with no difference. A little experimenting tells me that it doesn't like having spaces in the string! Note that the quotes are understood by the run-time library that calls main, so the whole string (without surrounding quotes) is present in one element of argv. It works just fine when taking the argument as a string. This seems like a bug, somewhere. --John TradeStation Group, Inc. is a publicly-traded holding company (NASDAQ GS: TRAD) of three operating subsidiaries, TradeStation Securities, Inc. (Member NYSE, FINRA, SIPC and NFA), TradeStation Technologies, Inc., a trading software and subscription company, and TradeStation Europe Limited, a United Kingdom, FSA-authorized introducing brokerage firm. None of these companies provides trading or investment advice, recommendations or endorsements of any kind. The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from any computer.

3 7

[1.44.0] Release 1.44.0 is now available
by Beman Dawes 17 Aug '10

17 Aug '10

Release 1.44.0 of the Boost C++ Libraries is now available. These open-source libraries work well with the C++ Standard Library, and are usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use. This release contains two new libraies (Meta State Machine & Polygon) and numerous enhancements and bug fixes for existing libraries. For details, including download links, see http://www.boost.org/users/download/version_1_44_0 The release can also be downloaded directly from SourceForge. See http://sourceforge.net/projects/boost/files/ To install this release on your system, see http://www.boost.org/doc/libs/release/more/getting_started/index.html Thanks, --The Boost release team Beman Dawes Daniel James Eric Niebler Rene Rivera Vladimir Prus

1 0

Trac needs more milestones?
by Paul A. Bristow 17 Aug '10

17 Aug '10

I note that a milestone for the next version 1.45? isn't available yet for Trac tickets. Would it be useful to create a few 'spares' 1.45, 1.46, 1.47 ... to avoid this problem each release? I think there is a case for more than one release ahead - sometime one knows that testing time is going to mean it will miss the next release, so setting a milestone further ahead makes perfect sense. (Rare 1.n.1 cases can be added too if they prove necessary). (And/or does adding new milestones need to go the (endless?) list of release managers tasks?) Thanks. Paul --- Paul A. Bristow Prizet Farmhouse Kendal, UK LA8 8AB +44 1539 561830, mobile +44 7714330204 pbristow(a)hetp.u-net.com

3 2

Program options: Set function for an option?
by Ingo Maindorfer 17 Aug '10

17 Aug '10

Hi! Let's assume we have this: (stolen from tutorial): // Declare the supported options. po::options_description desc("Allowed options"); desc.add_options() ("compression", po::value<int>(), "set compression level") ; po::variables_map vm; po::store(po::parse_command_line(ac, av, desc), vm); po::notify(vm); ... if (vm.count("compression")) { cout << "Compression level was set to " << vm["compression"].as<int>() << ".\n"; } else { cout << "Compression level was not set.\n"; } Is there a way to set a new int to "compression" programmatically like this: vm["compression"].set( 42 ) ? Best regards, Ingo

1 0

[Log] Some questions on severity_logger usage
by Olivier Tournaire 17 Aug '10

17 Aug '10

Hi all, I am trying to use Boost.Log for my application. The log code is in shared library (a plugin). Here is how I set up my .so logging, according to the documentation: // ville_numerique_logging.hpp #include <boost/log/common.hpp> #include <boost/log/core.hpp> #include <boost/log/trivial.hpp> #include <boost/log/filters.hpp> #include <boost/log/formatters.hpp> #include <boost/log/utility/init/to_file.hpp> enum severity_level { normal, notification, warning, error, critical }; BOOST_LOG_DECLARE_GLOBAL_LOGGER_INIT(my_logger, boost::log::sources::severity_logger< >) { boost::log::init_log_to_file ( boost::log::keywords::file_name = "/home/olivier/ville_numerique.log", boost::log::formatters::attr< unsigned int >("LineID"), boost::log::keywords::format = "[%TimeStamp%]: %_%" // log record format ); // boost::log::core::get()->set_filter // ( // boost::log::filters::attr< boost::log::trivial::severity_level >("Severity") >= boost::log::trivial::info // ); return boost::log::sources::severity_logger< >(); } In some of my method, I then try lo log: src::severity_logger< >& lg = my_logger::get(); BOOST_LOG_SEV(lg, normal) << "A regular message"; BOOST_LOG_SEV(lg, warning) << "Something bad is going on but I can handle it"; BOOST_LOG_SEV(lg, critical) << "Everything crumbles, shoot me now!"; But, nothing happens. The file is not created. If I uncomment the set_filter lines, it throws an exception: "Requested attribute value not found" Could you please help? I am fighting with this for a too long time now. Regards, Olivier ----------------------------------------------------- Olivier Tournaire MATIS - Institut Géographique National 73, Ave de Paris 94165 St Mandé cedex, France tel: (+33) 1 43 98 84 29 fax: (+33) 1 43 98 85 81

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TypeError: No registered converter was able to extract a C++ pointer to type char from this Python object of type str
by Brian Ray 17 Aug '10

17 Aug '10

Hello: I think I am experience a build problem here but not really sure; nonetheless, below is a simple example that illustrates my problem. Any idea what I might be doing wrong. I am using boost_1_43_0 built with gcc 4.2.1 on i686 running darwin. I am linking to the standard 2.5 python that comes with the distro. Please note that the PyRun_SimpleString("import sys"); does not error at all. The error comes from when the call to import(). I am not sure if this is a clue or not but gdb seems not to know what line it is on. I am guessing it is just confused because of all the inlines. I suspect this is a linking issues of some sort. However I did check that they are all linking to the correct location. Why does it convert the const char * to a str in the first place. Seems to be thrashing around a bit. -- Brian /// contents of boost_python_issue.cpp #include <boost/python.hpp> using namespace boost::python; int main(int argc, char **argv) { Py_Initialize(); try { PyRun_SimpleString("import sys"); // This raises exception object sys = import("sys"); } catch (boost::python::error_already_set) { PyErr_Print(); } Py_Finalize(); } // Compiled with 'g++ -I. -I/usr/include -I/usr/local/include -I../../includes/python2_5_1 -g -L/usr/local/lib boost_python_issue.cpp -lboost_system -lboost_python -lm -lpython2.5 -o boost_python_issue' Output from gdb: (gdb) break main Breakpoint 1 at 0x100001319: file boost_python_issue.cpp, line 9. (gdb) r Starting program: /Project/zephyr/src/Composer/boost_python_issue Reading symbols for shared libraries .++++++++..... done Breakpoint 1, main (argc=1, argv=0x7fff5fbff6d8) at boost_python_issue.cpp:9 9 Py_Initialize(); (gdb) s 11 PyRun_SimpleString("import sys"); (gdb) 13 object sys = import("sys"); (gdb) boost::python::str::str (this=0x7fff5fbff690, s=0x10000169d "sys") at str.hpp:150 150 str(const char* s) : base(s) {} // new str (gdb) boost::python::detail::str_base::str_base (this=0x7fff5fbff690, s=0x10000169d "sys") at libs/python/src/str.cpp:39 39 )) (gdb) object [inlined] () at /Users/bray/sources/boost_1_43_0/boost/python/object_core.hpp:534 Line number 534 out of range; errors.hpp has 55 lines. (gdb) expect_non_null<PyObject> [inlined] () at /Users/bray/sources/boost_1_43_0/boost/python/errors.hpp:43 44 if (x == 0) (gdb) object [inlined] () at /Users/bray/sources/boost_1_43_0/boost/python/object_core.hpp:513 534 : object_base(expect_non_null((PyObject*)p)) (gdb) object_base [inlined] () at /Users/bray/sources/boost_1_43_0/boost/python/object_core.hpp:513 513 : m_ptr(p) (gdb) boost::python::detail::str_base::str_base (this=0x7fff5fbff690, s=<value temporarily unavailable, due to optimizations>) at libs/python/src/str.cpp:40 40 {} (gdb) 0x000000010000154d in boost::python::str::str (this=0x7fff5fbff690, s=0x10000169d "sys") at str.hpp:150 150 str(const char* s) : base(s) {} // new str (gdb) boost::python::import (name=@0x7fff5fbff690) at libs/python/src/import.cpp:19 19 char *n = python::extract<char *>(name); (gdb) extract [inlined] () at /Users/bray/sources/boost_1_43_0/boost/python/extract.hpp:156 156 # else (gdb) boost::python::api::object_base::ptr () at /Users/bray/sources/boost_1_43_0/boost/python/object_core.hpp:542 543 return m_ptr; (gdb) extract [inlined] () at /Users/bray/sources/boost_1_43_0/boost/python/extract.hpp:216 156 : base(o.ptr()) (gdb) extract_pointer [inlined] () at /Users/bray/sources/boost_1_43_0/boost/python/extract.hpp:216 219 ) (gdb) boost::python::converter::get_lvalue_from_python (source=0x1005cb1e0, converters=@0x100409500) at libs/python/src/converter/from_python.cpp:128 128 void* x = objects::find_instance_impl(source, converters.target_type); (gdb) boost::python::objects::find_instance_impl (inst=0x1005cb1e0, type={<boost::totally_ordered<boost::python::type_info,boost::python::type_info,boost::detail::empty_base<boost::python::type_info>,boost::detail::false_t>> = {<boost::totally_ordered1<boost::python::type_info,boost::detail::empty_base<boost::python::type_info> >> = {<boost::less_than_comparable1<boost::python::type_info,boost::equality_comparable1<boost::python::type_info, boost::detail::empty_base<boost::python::type_info> > >> = {<boost::equality_comparable1<boost::python::type_info,boost::detail::empty_base<boost::python::type_info> >> = {<boost::detail::empty_base<boost::python::type_info>> = {<No data fields>}, <No data fields>}, <No data fields>}, <No data fields>}, <No data fields>}, m_base_type = 0x7fff885a066c "c"}, null_shared_ptr_only=false) at libs/python/src/object/class.cpp:485 485 if (Py_TYPE(Py_TYPE(inst)) != &class_metatype_object) (gdb) 490 for (instance_holder* match = self->objects; match != 0; match = match->next()) (gdb) 497 } (gdb) boost::python::converter::get_lvalue_from_python (source=0x1005cb1e0, converters=@0x100409500) at libs/python/src/converter/from_python.cpp:129 129 if (x) (gdb) 132 lvalue_from_python_chain const* chain = converters.lvalue_chain; (gdb) 133 for (;chain != 0; chain = chain->next) (gdb) 135 void* r = chain->convert(source); (gdb) boost::python::converter::(anonymous namespace)::convert_to_cstring (obj=0x1005cb1e0) at libs/python/src/converter/builtin_converters.cpp:46 46 return PyString_Check(obj) ? PyString_AsString(obj) : 0; (gdb) 47 } (gdb) boost::python::converter::get_lvalue_from_python (source=0x1005cb1e0, converters=<value temporarily unavailable, due to optimizations>) at libs/python/src/converter/from_python.cpp:136 136 if (r != 0) (gdb) 132 lvalue_from_python_chain const* chain = converters.lvalue_chain; (gdb) 133 for (;chain != 0; chain = chain->next) (gdb) 140 } (gdb) 0x00000001001a1128 in extract_pointer [inlined] () at /Users/bray/sources/boost_1_43_0/boost/python/extract.hpp:219 219 ) (gdb) boost::python::import (name=<value temporarily unavailable, due to optimizations>) at libs/python/src/import.cpp:19 19 char *n = python::extract<char *>(name); (gdb) boost::python::extract<char*>::operator char* () at /Users/bray/sources/boost_1_43_0/boost/python/extract.hpp:138 138 return (*this)(); (gdb) boost::python::converter::extract_pointer<char*>::operator() () at extract.hpp:231 232 if (m_result == 0 && m_source != Py_None) (gdb) boost::python::converter::extract_pointer<char*>::operator() () at extract.hpp:233 233 (throw_no_pointer_from_python)(m_source, registered_pointee<Ptr>::converters); (gdb) boost::python::converter::throw_no_pointer_from_python (source=0x1005cb1e0, converters=@0x100409500) at libs/python/src/converter/from_python.cpp:256 256 (throw_no_lvalue_from_python)(source, converters, "pointer"); (gdb) 257 } (gdb) boost::python::converter::throw_no_pointer_from_python (source=0x1005cb1e0, converters=@0x100409500) at libs/python/src/converter/from_python.cpp:256 256 (throw_no_lvalue_from_python)(source, converters, "pointer"); (gdb) boost::python::converter::(anonymous namespace)::throw_no_lvalue_from_python (source=0x1005cb1e0, converters=@0x100409500, ref_type=0x1001a8e55 "pointer") at libs/python/src/converter/from_python.cpp:201 201 void throw_no_lvalue_from_python(PyObject* source, registration const& converters, char const* ref_type) (gdb) 215 )); (gdb) boost::python::type_info::name () at /Users/bray/sources/boost_1_43_0/boost/python/type_id.hpp:156 156 { (gdb) boost::python::detail::gcc_demangle (mangled=0x7fff885a066c "c") at libs/python/src/converter/type_id.cpp:116 116 static mangling_map demangler; (gdb) 121 , compare_first_cstring()); (gdb) std::vector<std::pair<char const*, char const*>, std::allocator<std::pair<char const*, char const*> > >::end () at /usr/include/c++/4.2.1/bits/stl_vector.h:349 349 inline bool (gdb) __normal_iterator [inlined] () at /usr/include/c++/4.2.1/bits/stl_iterator.h:654 817 { return __lhs.base() - __rhs.base(); } (gdb) std::vector<std::pair<char const*, char const*>, std::allocator<std::pair<char const*, char const*> > >::end () at /usr/include/c++/4.2.1/bits/stl_vector.h:331 331 { return iterator(this->_M_impl._M_start); } (gdb) boost::python::detail::gcc_demangle (mangled=0x7fff885a066c "c") at libs/python/src/converter/type_id.cpp:121 121 , compare_first_cstring()); (gdb) lower_bound<__gnu_cxx::__normal_iterator<std::pair<const char*, const char*>*, std::vector<std::pair<const char*, const char*>, std::allocator<std::pair<const char*, const char*> > > >, std::pair<const char*, const char*>, boost::python::<unnamed>::compare_first_cstring> [inlined] () at /usr/include/c++/4.2.1/bits/stl_algo.h:98 98 return __last - __first; (gdb) operator-<std::pair<const char*, const char*>*, std::vector<std::pair<const char*, const char*>, std::allocator<std::pair<const char*, const char*> > > > [inlined] () at /usr/include/c++/4.2.1/bits/stl_iterator_base_funcs.h:119 119 std::__iterator_category(__first)); (gdb) __distance<__gnu_cxx::__normal_iterator<std::pair<const char*, const char*>*, std::vector<std::pair<const char*, const char*>, std::allocator<std::pair<const char*, const char*> > > > > [inlined] () at /usr/include/c++/4.2.1/bits/stl_iterator_base_funcs.h:2948 Line number 2948 out of range; stl_iterator_base_funcs.h has 182 lines. (gdb) distance<__gnu_cxx::__normal_iterator<std::pair<const char*, const char*>*, std::vector<std::pair<const char*, const char*>, std::allocator<std::pair<const char*, const char*> > > > > [inlined] () at /usr/include/c++/4.2.1/bits/stl_iterator.h:116 156 __i += __n; (gdb) lower_bound<__gnu_cxx::__normal_iterator<std::pair<const char*, const char*>*, std::vector<std::pair<const char*, const char*>, std::allocator<std::pair<const char*, const char*> > > >, std::pair<const char*, const char*>, boost::python::<unnamed>::compare_first_cstring> [inlined] () at /usr/include/c++/4.2.1/bits/stl_algo.h:2952 2952 while (__len > 0) (gdb) boost::python::detail::gcc_demangle (mangled=0x7fff885a066c "c") at libs/python/src/converter/type_id.cpp:121 121 , compare_first_cstring()); (gdb) 123 if (p == demangler.end() || strcmp(p->first, mangled)) (gdb) 128 ); (gdb) 132 if (status == -1) (gdb) 143 : keeper.p; (gdb) 152 if (cxxabi_cxa_demangle_is_broken() (gdb) cxxabi_cxa_demangle_is_broken [inlined] () at /Users/bray/sources/boost_1_43_0/libs/python/src/converter/type_id.cpp:94 97 if (!was_tested) { (gdb) 99 free_mem keeper(cxxabi::__cxa_demangle("b", 0, 0, &status)); (gdb) 100 was_tested = true; (gdb) 101 if (status == -2 || strcmp(keeper.p, "bool") != 0) { (gdb) 103 } (gdb) ~free_mem [inlined] () at /Users/bray/sources/boost_1_43_0/libs/python/src/converter/type_id.cpp:86 87 std::free(p); (gdb) boost::python::detail::gcc_demangle (mangled=0x7fff885a066c "c") at libs/python/src/converter/type_id.cpp:152 152 if (cxxabi_cxa_demangle_is_broken() (gdb) 183 p = demangler.insert(p, std::make_pair(mangled, demangled)); (gdb) 331 { return iterator(this->_M_impl._M_start); } (gdb) 183 p = demangler.insert(p, std::make_pair(mangled, demangled)); (gdb) std::vector<std::pair<char const*, char const*>, std::allocator<std::pair<char const*, char const*> > >::insert () at /usr/include/c++/4.2.1/bits/vector.tcc:93 95 if (this->_M_impl._M_finish != this->_M_impl._M_end_of_storage (gdb) 102 _M_insert_aux(__position, __x); (gdb) std::vector<std::pair<char const*, char const*>, std::allocator<std::pair<char const*, char const*> > >::_M_insert_aux (this=0x1001bfd40, __position={_M_current = 0x0}, __x=@0x7fff5fbff5a0) at vector.tcc:245 245 _M_insert_aux(iterator __position, const _Tp& __x) (gdb) 247 if (this->_M_impl._M_finish != this->_M_impl._M_end_of_storage) (gdb) 260 const size_type __old_size = size(); (gdb) std::vector<std::pair<char const*, char const*>, std::allocator<std::pair<char const*, char const*> > >::size () at /usr/include/c++/4.2.1/bits/stl_vector.h:400 400 { return size_type(this->_M_impl._M_finish - this->_M_impl._M_start); } (gdb) std::vector<std::pair<char const*, char const*>, std::allocator<std::pair<char const*, char const*> > >::_M_insert_aux (this=0x1001bfd40, __position={_M_current = 0x0}, __x=@0x7fff5fbff5a0) at vector.tcc:261 261 if (__old_size == this->max_size()) (gdb) 267 size_type __len = __old_size != 0 ? 2 * __old_size : 1; (gdb) 88 if (__builtin_expect(__n > this->max_size(), false)) (gdb) 91 return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp))); (gdb) 275 __new_finish = (gdb) __uninitialized_copy_a<std::pair<const char*, const char*>*, std::pair<const char*, const char*>*, std::pair<const char*, const char*> > [inlined] () at /usr/include/c++/4.2.1/bits/stl_uninitialized.h:114 114 _Is_POD()); (gdb) __uninitialized_copy_aux<std::pair<const char*, const char*>*, std::pair<const char*, const char*>*> [inlined] () at stl_uninitialized.h:254 254 { return std::uninitialized_copy(__first, __last, __result); } (gdb) uninitialized_copy<std::pair<const char*, const char*>*, std::pair<const char*, const char*>*> [inlined] () at stl_uninitialized.h:254 254 { return std::uninitialized_copy(__first, __last, __result); } (gdb) __gnu_cxx::new_allocator<std::pair<char const*, char const*> >::construct () at /usr/include/c++/4.2.1/ext/new_allocator.h:107 107 { ::new(__p) _Tp(__val); } (gdb) std::vector<std::pair<char const*, char const*>, std::allocator<std::pair<char const*, char const*> > >::_M_insert_aux (this=0x1001bfd40, __position={_M_current = 0x0}, __x=@0x7fff5fbff5a0) at vector.tcc:280 280 ++__new_finish; (gdb) 281 __new_finish = (gdb) __uninitialized_copy_a<std::pair<const char*, const char*>*, std::pair<const char*, const char*>*, std::pair<const char*, const char*> > [inlined] () at /usr/include/c++/4.2.1/bits/stl_uninitialized.h:114 114 _Is_POD()); (gdb) __uninitialized_copy_aux<std::pair<const char*, const char*>*, std::pair<const char*, const char*>*> [inlined] () at stl_uninitialized.h:254 254 { return std::uninitialized_copy(__first, __last, __result); } (gdb) uninitialized_copy<std::pair<const char*, const char*>*, std::pair<const char*, const char*>*> [inlined] () at stl_uninitialized.h:254 254 { return std::uninitialized_copy(__first, __last, __result); } (gdb) std::vector<std::pair<char const*, char const*>, std::allocator<std::pair<char const*, char const*> > >::_M_insert_aux (this=0x1001bfd40, __position={_M_current = 0x0}, __x=<value temporarily unavailable, due to optimizations>) at vector.tcc:293 293 std::_Destroy(this->_M_impl._M_start, this->_M_impl._M_finish, (gdb) 295 _M_deallocate(this->_M_impl._M_start, (gdb) std::_Vector_base<std::pair<char const*, char const*>, std::allocator<std::pair<char const*, char const*> > >::_M_deallocate () at /usr/include/c++/4.2.1/bits/stl_vector.h:135 136 if (__p) (gdb) std::vector<std::pair<char const*, char const*>, std::allocator<std::pair<char const*, char const*> > >::_M_insert_aux (this=0x1001bfd40, __position={_M_current = 0x0}, __x=<value temporarily unavailable, due to optimizations>) at vector.tcc:298 298 this->_M_impl._M_start = __new_start; (gdb) 299 this->_M_impl._M_finish = __new_finish; (gdb) 300 this->_M_impl._M_end_of_storage = __new_start + __len; (gdb) boost::python::detail::gcc_demangle (mangled=0x7fff885a066c "c") at vector.tcc:103 103 return iterator(this->_M_impl._M_start + __n); (gdb) boost::python::detail::gcc_demangle (mangled=0x7fff885a066c "c") at libs/python/src/converter/type_id.cpp:183 183 p = demangler.insert(p, std::make_pair(mangled, demangled)); (gdb) 185 } (gdb) ~free_mem [inlined] () at /Users/bray/sources/boost_1_43_0/libs/python/src/converter/type_id.cpp:86 87 std::free(p); (gdb) boost::python::detail::gcc_demangle (mangled=0x7fff885a066c "c") at libs/python/src/converter/type_id.cpp:189 189 } (gdb) boost::python::converter::(anonymous namespace)::throw_no_lvalue_from_python (source=<value temporarily unavailable, due to optimizations>, converters=<value temporarily unavailable, due to optimizations>, ref_type=0x1001a8e55 "pointer") at libs/python/src/converter/from_python.cpp:215 215 )); (gdb) handle<PyObject> [inlined] () at /Users/bray/sources/boost_1_43_0/boost/python/handle.hpp:75 75 : m_p( (gdb) boost::python::detail::manage_ptr<_object> (p=0x1005ad6b8) at handle.hpp:55 55 inline T* manage_ptr(T* p, ...) (gdb) 57 return expect_non_null(p); (gdb) expect_non_null<PyObject> [inlined] () at /Users/bray/sources/boost_1_43_0/boost/python/errors.hpp:43 44 if (x == 0) (gdb) 0x000000010018a81d in boost::python::converter::(anonymous namespace)::throw_no_lvalue_from_python (source=<value temporarily unavailable, due to optimizations>, converters=<value temporarily unavailable, due to optimizations>, ref_type=0x1001a8e55 "pointer") at libs/python/src/converter/from_python.cpp:215 215 )); (gdb) boost::python::converter::(anonymous namespace)::throw_no_lvalue_from_python (source=<value temporarily unavailable, due to optimizations>, converters=<value temporarily unavailable, due to optimizations>, ref_type=0x1001a8e55 "pointer") at libs/python/src/converter/from_python.cpp:217 217 PyErr_SetObject(PyExc_TypeError, msg.get()); (gdb) 219 throw_error_already_set(); (gdb) boost::python::throw_error_already_set () at libs/python/src/errors.cpp:61 61 throw error_already_set(); (gdb) error_already_set [inlined] () at /Users/bray/sources/boost_1_43_0/boost/python/errors.hpp:19 19 virtual ~error_already_set(); (gdb) boost::python::throw_error_already_set () at libs/python/src/errors.cpp:61 61 throw error_already_set(); (gdb) TypeError: No registered converter was able to extract a C++ pointer to type char from this Python object of type str Program exited normally.

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Program Options - help display
by John Dlugosz 16 Aug '10

16 Aug '10

cout << opt; displays a formatted report using some built-in width. How can I make it appreciate the actual width of the command window instead? The formatting leaves much to be desired if default values are included. The description is forced into a very narrow column. --John TradeStation Group, Inc. is a publicly-traded holding company (NASDAQ GS: TRAD) of three operating subsidiaries, TradeStation Securities, Inc. (Member NYSE, FINRA, SIPC and NFA), TradeStation Technologies, Inc., a trading software and subscription company, and TradeStation Europe Limited, a United Kingdom, FSA-authorized introducing brokerage firm. None of these companies provides trading or investment advice, recommendations or endorsements of any kind. The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from any computer.

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Function or Bind question
by John Dlugosz 16 Aug '10

16 Aug '10

The command-line-argument library has a callback function 'notifier' used like this: po::wvalue<std::wstring>()->notifier(&foo) If I write void foo (const std::wstring& s) { C::bar(s); } it works fine. wstring and void are the template arguments to the function object. Now if I write notifier(&C::bar) instead, I get a huge spiel of compiler errors. Yet, from the body of foo you can see that s can be implicitly converted to the type of bar's argument (const boost::filesystem::wpath&) and the return type is also void. I thought that generalized functions objects pretty much worked that if you can write the call in normal code, it makes the correct wrapper to do that. What am I missing? --John TradeStation Group, Inc. is a publicly-traded holding company (NASDAQ GS: TRAD) of three operating subsidiaries, TradeStation Securities, Inc. (Member NYSE, FINRA, SIPC and NFA), TradeStation Technologies, Inc., a trading software and subscription company, and TradeStation Europe Limited, a United Kingdom, FSA-authorized introducing brokerage firm. None of these companies provides trading or investment advice, recommendations or endorsements of any kind. The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from any computer.

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32- and 64-bit builds on same machine
by Johan Råde 16 Aug '10

16 Aug '10

Hi, What is the most convenient way to build Boost if I need both 32- and 64-bit builds on the same Windows machine? I could of course install two separate copies of the entire Boost source tree, and build one from the 32-bit Visual studio command prompt, and the other from the 64-bit Visual Studio command prompt. But that seems a bit wasteful. I tried building from the same source tree twice, once using the 32-bit command prompt and once using the 64-bit command prompt, but that did not work. (Nothing happened during the second build.) Thank you, Johan Råde

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Problem with simple type extraction
by Christian Henning 16 Aug '10

16 Aug '10

Hi there, I cannot understand why the code below gives me a static assertion. As far as I know I use a very common technique to to extract a type from templated class using specialization over this class. #include <boost/assert.hpp> #include <boost/type_traits/is_same.hpp> #include <boost/gil/gil_all.hpp> namespace boost { namespace gil { template< typename T > struct bit_field_type{ typedef T type; }; template< typename BitField, typename ChannelBitSizes, typename Layout, bool IsMutable > struct bit_field_type< bit_aligned_pixel_reference< BitField , ChannelBitSizes , Layout , IsMutable > > { typedef BitField type; }; } // namespace gil } // namespace boost int main(int argc, char* argv[]) { typedef boost::gil::bit_aligned_image1_type< 1, boost::gil::gray_layout_t >::type gray1_image_t; typedef gray1_image_t::view_t::reference ref; typedef boost::gil::bit_field_type< ref >::type bit_field_t; BOOST_STATIC_ASSERT(( boost::is_same< bit_field_t, unsigned char >::value )); return 0; } The type for gray1_image_t::view_t::reference is the following: boost::gil::bit_aligned_pixel_reference< unsigned char, boost::mpl::vector1_c< unsigned int, 1 > , boost::gil::layout< boost::mpl::vector1< boost::gil::gray_color_t >, boost::mpl::range_c< int, 0, 1> > , 1 > Can somebody tell what wrong. I have been staring at this for too long. I'm using MS Visual Studio 9 and 10. Thanks in advance, Christian

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