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

boost::filesystem exception not caught on MacOS X
by Lothar May 21 Sep '08

21 Sep '08

Hi, I have a strange problem that an exception thrown by a boost::filesystem directory_iterator is not caugth on MacOS X. Please consider the following code: ("const string &dir" is a parameter) bool retVal = true; try { directory_iterator i(dir); directory_iterator end; while (i != end) { // do something ++i; } } catch (...) { retVal = false; } While this works perfectly on Windows and Linux (the exception is caught fine), on MacOS I get the following: terminate called after throwing an instance of 'boost::filesystem::basic_filesystem_error<boost::filesystem::basic_path<std::string, boost::filesystem::path_traits> >' what(): boost::filesystem::basic_directory_iterator constructor Abort trap The program runs fine (withouth the trap) if I comment out the upper lines. I use the boost 1.34.0 lib built as universal binary on MacOS 10.5, according to the instructions at http://svn.boost.org/trac/boost/wiki/CMakeConfigAndBuild I link to the static non-debug mt version of boost_filesystem. Exceptions within my program are caught fine, just this boost exception is not caught. The program is also compiled as non-debug. Any help would be very much appreciated. Regards, Lothar

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

08 Sep '08

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

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[statechart] history transitions make state-local-storage "un-cool"
by Mick Hollins 26 Jun '08

26 Jun '08

Apologies if this has been discussed before, but I couldn't find any mention of it: I am currently using the history facility of boost::fsm. I've discovered that when I re-enter a state, X, via a history transition I don't actually re-enter the same instance of X that I was in before, but instead enter a newly constructed instance of X. I just checked the UML spec regarding history transitions and it says that "Any necessary entry actions are performed", so given that boost::fsm uses constructors to represent entry actions I guess a new instance of X has to be constructed to ensure UML compliance. My actual concern is the effect this has on the "coolness" of state-local-storage (see http://boost-sandbox.sourceforge.net/libs/statechart/doc/faq.html#Whats_so_…) It seems to me that state-local-storage, which I agree is generally cool, is particularly un-cool (and bug-inducing) in the presence of history transitions. I'm not sure what a good alternative is, but just thought I'd raise the discussion. cheers, mick PS: does the history facility display the same semantics in boost::statechart? I plan to move to statechart real soon now ...

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regex lib for Windows Mobile
by Freeman Ng 07 May '08

07 May '08

I'm trying to get the regex library (Boost ver. 1.34.1) working under Visual Studio 7.0 and the Windows Mobile 6 SDK, and have run into the following problems: 1. Need to modify visualc.hpp to define BOOST_NO_STD_LOCALE and BOOST_NO_SWPRINTF. 2. WM6 runtime library doesn't have strxfrm() or wcsxfrm(). 3. regex lib makes direct calls to ansi versions of CreateFile(), LoadLibrary(), FindFirstFile(), and others (i.e. CreateFileA(), etc.) that don't exist on the WM platform. 4. w32_regex_traits.cpp has a pragma that links directly to a library that doesn't exist for WM. (user32.lib) #1 is normal and trivial, of course, but before I tackle #2 and #3 by either writing my own versions of the missing functions or modifying the regex source, and #4 by modifying the regex source (which I really hate to do, but I can't think of any other way around this one) I want to make sure I didn't miss anything. Is there some combination of #defines or project settings that should allow the library to build for VS 7 Windows Mobile? Am I about to do more work than I need to? Thanks. Freeman

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Re: [Boost-users] Applying Boost license to non boost projects
by Robert Marion 22 Apr '08

22 Apr '08

You may wish to consider applying the liberal BSD (http://www.opensource.org/licenses/bsd-license.php) or MIT (http://www.opensource.org/licenses/mit-license.php) licenses. These are both in widespread use for open source, and impose no restrictions, aside from attribution, on the user. Putting the license text at the top of all headers is not strictly necessary, but not a bad idea. Robert Marion http://www.palamida.com > I am interested in adopting the Boost Software license for an open source C++ > library (Castor: http://www.mpprogramming.com/2.html) > > [ snip ] > - Does this same guideline apply to non boost projects ? The need for stating > Boost.org there might confuse some users of non boost prj to think that the > library is supplied by Boost. > - Do all header files in my prj (which is a pure header library) need to > include this text at the top/somewhere in order to adopt the license. > > -Roshan

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Mac Xcode 3.0 Boost compile issue
by Daniel Lord 17 Apr '08

17 Apr '08

This is a specific error with Xcode 3.0 on Leopard not a generic Boost question: Something is screwy with the paths between Boost and Xcode: Xcode 3.0 needs to find the Boost includes, so I added my directory containing the top of the Boost tree (the boost_1_34_1 directory) to the User header Search paths in the build configuration for the target. No problem, everything appears to be found. However, adding that search path screws up something else: An error pops up in c++locale.h highlighting the line: const int __ret = std::snprintf(__out, __size, __fmt, __prec, __v); and claiming: "error: 'snprintf' is not a member of 'std'." What the freak? It compiles fine from the command line with g++ and using -I<same path to boost as above>. So it is some wierd interaction with Boost and Xcode paths but it make no sense to me. It's almost as if Boost is redefining something. But what? This does not occur if I don't add the Boost search paths but of course then the Boost definitions are not found. The program is a simple one from O'Reilly's C+++ Cookbook show below: #include <boost/filesystem/operations.hpp> #include <boost/filesystem/fstream.hpp> #include <iostream> using namespace boost::filesystem; int main(int argc, char** argv) { if (argc < 2) { std::cerr << "Usage: " << argv[0] << " [dir name]\n"; return(EXIT_FAILURE); } path fullPath = // Create the full, absolute path name system_complete(path(argv[1], native)); if (!exists(fullPath)) { std::cerr << "Error: the directory " << fullPath.string( ) << " does not exist.\n"; return(EXIT_FAILURE); } if (!is_directory(fullPath)) { std::cout << fullPath.string( ) << " is not a directory!\n"; return(EXIT_SUCCESS); } directory_iterator end; for (directory_iterator it(fullPath); it != end; ++it) { // Iterate through each // element in the dir, std::cout << it->leaf( ); // almost as you would if (is_directory(*it)) // an STL container std::cout << " (dir)"; std::cout << '\n'; } return(EXIT_SUCCESS); }

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Eclipse integration of bjam
by Ruediger Berlich 01 Apr '08

01 Apr '08

Dear all, I am using Eclipse/CDT under Linux as my standard IDE. So far I'm building my projects using Eclipse's own build mechanisms. Is anybody using bjam as a build mechanism in Eclipse/CDT and should I expect problems when making a switch to bjam ? Thanks and Best Regards, Ruediger

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boost serialization & module boundaries
by Christian Widmer 19 Mar '08

19 Mar '08

Hi, I'm trying to use boost to serialize a machine learning library that I'm working with. It all worked out very conveniently, but it seems now, that I have hit a dead end. I've been looking on the net but couldn't find any information that worked for me, so here we go: The problem is, that the library consists of several modules, which are dynamically linked. For instance the class KernelMachine has a field kernel of type Kernel, which is contained in a separate module (in the sense of a shared object). The following code compiles, but when I try to serialize a CKernelMachine object I get an "unregistered_class" error. (CKernel does serialize fine, when called directly) class CKernelMachine : public CClassifier { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & boost::serialization::base_object<CClassifier>(*this); ar.register_type(static_cast<CGaussianKernel *>(NULL)); ar & kernel; std::cout << "done CKernelMachine" << std::endl; } protected: CKernel* kernel; }; I found some threads that pointed me towards BOOST_CLASS_EXPORT, but I'm not exactly sure how to use it. So my question is - is it in principle even possible to serialize across module (shared-object) boundaries. If so, how should I go about? Any pointers would be greatly appreciated. - Chris

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[serialization] Cannot increase version of stored objects
by Robert Bielik 15 Mar '08

15 Mar '08

I need to update the version certain objects in my structure, but I cannot get the version number incremented. Scenario: I have a class MyClass which have several entries of InternalClass objects (which is the one I want a new version of): class MyClass { ... template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & BOOST_SERIALIZATION("MyInternals", m_vector_of_internal_class_objects); } std::vector<InternalClass> m_vector_of_internal_class_objects; class InternalClass { template<class Archive> void save(Archive & ar, const unsigned int version) const { ar & BOOST_SERIALIZATION("data", m_data); } template<class Archive> void load(Archive & ar, const unsigned int version) { if (version == 0) { old_data_t tmp; ar & BOOST_SERIALIZATION("data", tmp); m_data = convertToNewData(tmp); } else { BOOST_CHECK(version == 1); ar & BOOST_SERIALIZATION("data", m_data); } } BOOST_SERIALIZATION_SPLIT_MEMBER() new_data_t m_data; } } Then in the body (.cpp) I define: BOOST_CLASS_VERSION(MyClass::InternalClass, boost::serialization::object_class_info) BOOST_CLASS_VERSION(MyClass::InternalClass, 1) But when saving to the XML archive file, I still get version="0" for the InternalClass objects (?) /R

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[python] "Interpreter not initialized"
by Robert Dailey 13 Mar '08

13 Mar '08

Hi, When I execute the following code: BEGIN CODE -------------------------------------------------- #define BOOST_PYTHON_DEF( func ) boost::python::def( #func, func ) using namespace boost::python; static char const* PrintHelloWorld() { return "Hello World!"; } BOOST_PYTHON_MODULE(Script) { BOOST_PYTHON_DEF( PrintHelloWorld ); } void BeginPythonTest() { try { Py_Initialize(); initScript(); Py_Finalize(); } catch( error_already_set const& /*err*/ ) { PyErr_Print(); } catch( std::invalid_argument const& /*err*/ ) { PyErr_Print(); } } -------------------------------------------------- END CODE I receive the following error message: *Fatal Python error: Interpreter not initialized (version mismatch?)* This occurs when I step over the call to initScript() (in the code snippet above). I have no idea why this is happening. I'm currently linking against boost 1.34.1. I built all the libraries for boost myself using bjam. I built the multithreaded debug and release shared libraries. I'm using the SDK from Python 2.5.1. I also built the debug and release shared libraries for Python myself. My operating system is Microsoft Windows XP Professional. All help is appreciated. Thanks in advance!

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