July 2005 - Boost-users - lists.boost.org

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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BGL: INTERNAL COMPILER ERROR in VC7.1
by Yariv Tal 10 Jun '07

10 Jun '07

This one was already posted by Nicholas Burlett awhile back (see http://lists.boost.org/MailArchives/boost-users/msg06534.php) but I have some new info that may help. The problem: ========= When compiling code that uses the boost.graph library the VC7.1 compiler shouts: c:\boost_1_32_0\boost\mpl\aux_\preprocessed\plain\apply_wrap.hpp(48) : fatal error C1001: INTERNAL COMPILER ERROR As Nicholas already noted, this seems to be due to some compiler problem with the boost.graph out_edge_iterators since it is caused by the following lines in my code: (FilteredGraphGenerator::FilteredGraph is a typedef of a boost::filtered_graph) typedef boost::graph_traits<FilteredGraphGenerator::FilteredGraph> ::out_edge_iterator oedge_iterator; oedge_iterator edgesItr, edgesEnd; boost::tie(edgesItr, edgesEnd) = boost::out_edges(itr->first, m_g.m_filteredGraph); while (edgesItr != edgesEnd) { // do anything! } In fact, it seems to be related to the operator!= between iterators (if the while loop is commented out it compiles). How ever, the error persists even after changing the operator!= to operator== : while (edgesItr == edgesEnd) { // do anything! } ========================================================================== Some findings: =========== * We used to use boost_1_30_0 and the code used to compile PERFECTLY. The problem only appeared after migrating to boost_1_32_0. * Calling directly to the "equal" function in iterator_core_access instead of the operator== works. typedef boost::graph_traits<FilteredGraphGenerator::FilteredGraph> ::out_edge_iterator oedge_iterator; oedge_iterator edgesItr, edgesEnd; boost::tie(edgesItr, edgesEnd) = boost::out_edges(itr->first,m_g.m_filteredGraph); while (boost::iterator_core_access::equal(edgesItr, edgesEnd, boost::mpl::true_())) { // do somthing } * The error message location is at the mpl::apply_wrap2 function. Any relation to the mpl::apply2 function used for declaring the operator== in the BOOST_ITERATOR_FACADE_INTEROP_HEAD macro? Have these functions changed since v1.30.0?

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[BGL] how to actually search with DFS/BFS?
by martin f krafft 22 Nov '06

22 Nov '06

This may seem like a silly question, but how does one actually search with DFS or BFS? Say I want to find the first node for which a predicate returns true in a BFS traversal starting at node N... The function signatures don't have a parameter for "criteria" or "predicate", so I guess it's up for a Visitor to implement such a check. What is not clear to me is how the visitor functions can break out of the search once a condition is true. Thanks, -- martin; (greetings from the heart of the sun.) \____ echo mailto: !#^."<*>"|tr "<*> mailto:" net@madduck invalid/expired pgp subkeys? use subkeys.pgp.net as keyserver! spamtraps: madduck.bogus(a)madduck.net "information superhighway" is just an anagram for "i'm on a huge wispy rhino fart".

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Building boost for 64-bit on AIX
by Patrik Jonsson 17 Aug '06

17 Aug '06

Hi, I'm trying to build boost (1.32.0) on an IBM SP2 under AIX5, using the 64-bit ABI. This is troublesome. I do: bjam "-sTOOLS=gcc" "-sGXX=g++ -maix64 -pthread" --prefix=$HOME --libdir=$HOME/lib64-gcc --includedir=$HOME/include-gcc install But it doesn't work. I get loads of errors like: gcc-Link-action bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/libboost_date_time-gcc-d-1_32.so ld: 0711-738 ERROR: Input file bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/greg_month.o: XCOFF32 object files are not allowed in 64-bit mode. collect2: ld returned 8 exit status set -e LIBPATH=bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true:$LIBPATH export LIBPATH "g++" -maix64 -pthread -g -fPIC -shared -o "bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/libboost_date_time-gcc-d-1_32.so" "bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/greg_month.o" "bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/greg_weekday.o" "bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/date_generators.o" ...failed gcc-Link-action bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/libboost_date_time-gcc-d-1_32.so... ...skipped <@boost!lib64-gcc>libboost_date_time-gcc-d-1_32.so for lack of <@boost!libs!date_time!build/libboost_date_time.so/gcc/debug/shared-linkable-true>libboost_date_time-gcc-d-1_32.so... It seems it's using -maix64 ok when trying to build the library, but not when compiling... Can anyone tell me what the proper way of building boost under these conditions are? Thanks, /Patrik Jonsson

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case insensitive less_than string comparison
by Matthias Kaeppler 07 Mar '06

07 Mar '06

Hi, I am aware that string_algo has an if_iequal functor. Is there also an equivalent for a less-than comparison? I have to compare strings ignoring the case but taking locales into account. Right now I'm calling boost::algorithm::to_lower on two copies of the original strings. I'm not so sure if this is very efficient when I'm comparing thousands of strings. Here's the functor as it is now: struct FileLessNameA : std::binary_function<const File&,const File&,bool> { bool operator() (const File& lhs, const File& rhs) const { std::string path1( lhs.get_name().c_str() ); std::string path2( rhs.get_name().c_str() ); boost::algorithm::to_lower( path1 ); boost::algorithm::to_lower( path2 ); return path1 < path2; } }; Any suggestions for improvements appreciated :) Regards, Matthias -- Matthias Kaeppler

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date_time io bug in 1.33?
by Serge Skorokhodov 05 Sep '05

05 Sep '05

Hi, The following code looks pretty suspicious to me: extern const wchar_t* pts; // pts = L"2004071" std::wistringstream wiss(pts); wtime_input_facet* wtif = new wtime_input_facet; wtif->set_iso_format(); wiss.imbue(std::locale(std::locale::classic(), wtif)); ptime pt; wiss >> pt; std::string dbgs = to_iso_string(pt); // dbgs == "20040711T000000" Seems to be a bug? TIA -- Serge

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Thread cancellation
by Chris Coleman 01 Sep '05

01 Sep '05

Hi, I know at present that the Boost Threads implementation does not provide a terminate() / cancel() function, but the documentation suggests that work is in progress to implement this feature once a safe and portable way is found. I was just wondering whether this will appear soon in future releases, or if it is likely to be some time? At present I can kill a thread internally by simply throwing an exception and not catching it. But externally I cannot. I have a thread pool server I built some time ago using the pthread API and I'm porting it to use Boost Threads. The server has add() and remove() thread methods. Within the remove function under the pthread implementation I could call pthread_cancel(thrID) and that would be that, Obviously I cant call thread.cancel() as I'd like here and was wondering if there were any simple ways to signify that a particular thread should terminate? Cheers Chris This message has been checked for viruses but the contents of an attachment may still contain software viruses, which could damage your computer system: you are advised to perform your own checks. Email communications with the University of Nottingham may be monitored as permitted by UK legislation.

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strange filesystem dll behaviour
by Paul 28 Aug '05

28 Aug '05

Hi, I'm having killer problems with the filesystem library. I'm compiling it with bjam "-sTOOLS=mingw", which seems to work just fine. All the tests pass etc. Then I wrote this simple program: #include <boost/filesystem/path.hpp> #include <iostream> using namespace std; using namespace boost::filesystem; int main() { try { path p("c:",native); } catch (exception & e) { cerr << "Error: " << e.what() << endl; return 1; } cerr << "Ok" << endl; return 0; } and compiled it with the Makefile: test: test.cpp Makefile g++ -g -I../boost/boost-compiled -I. -Wall -c test.cpp g++ -g -Wl,-enable-stdcall-fixup -Wl,-subsystem,console -Wall -o test.exe test.o libboost_filesystem-mgw-d-1_32.lib g++ -g -Wl,-enable-stdcall-fixup -Wl,-subsystem,console -Wall -o test-dll.exe test.o -L. -lboost_filesystem-mgw-d-1_3 (adjust for your paths, I copied the dlls and libs into the local dir Just To Be Sure). The output of running the two programs is as follows: paul@xyz ~/test $ ./test Ok paul@xyz ~/test $ ./test-dll.exe Error: boost::filesystem::path: invalid name "c:" in path: "c:" Why does it behave differently depending on the linkage? If I must use a .lib, what if it needs to be used in multiple .dlls of mine? Help? Thanks Paul

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tribool question
by Serge Skorokhodov 11 Aug '05

11 Aug '05

Hi, I'm using boost::logic::tribool for expressing logical flags that may be nulls by their nature (patient not asked, he/she doesn't know etc.). Default initialization to 'false' seems to be quite unnatural in this context and initialization to 'undetermined' seems to be prefered. Is any significant reason for boost::logic::tribool default constructor initializing the value to 'false'? TIA -- Serge

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[serialization] serializing dynamic arrays
by Ivan Rachev 08 Aug '05

08 Aug '05

Does anyone have an idea how to serialize dynamic arrays of objects? An example follows at the end. Its weakness shows up when an outside pointer points to an element in the array. The problem is that the type being serialized is T but not T*. Thanks, Ivan #include <fstream> #include <boost/archive/text_iarchive.hpp> #include <boost/serialization/access.hpp> #include <boost/serialization/split_member.hpp> class A { friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) {} }; //IVAN Element always points to the beginning of an array of // 'Size' elements. The array is NOT null-terminated. If // size == 0, Elements may hold an undefined value. User // is responsible for initializing, new-ing and delete-ing. // Assumption: if there is an outside pointer to an object // inside this array, after loading the array // that pointer will hold a different object. template <typename T> struct DynamicArray { int Size; T* Element; friend class boost::serialization::access; template<class Archive> void save(Archive & ar, const unsigned int version) const { ar & Size; for (int i = 0; i < Size; ++i) ar & Element[i]; } template<class Archive> void load(Archive & ar, const unsigned int version) { ar & Size; //TODO: assert(Size >=0); if (Size > 0) { Element = new T[Size]; for (int i = 0; i < Size; ++i) ar & Element[i]; } } BOOST_SERIALIZATION_SPLIT_MEMBER() }; int main() { DynamicArray<A> ArrayOfAs; A* secondElement; std::ifstream ifs("test.txt"); boost::archive::text_iarchive ia(ifs); ia & ArrayOfAs; ia & secondElement; // this guy will point to a copy of the // 2nd element but NOT the 2nd element itself delete [] ArrayOfAs.Element; }

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