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Regex failure
by Bob Kline 06 Feb '07

06 Feb '07

We have encountered a problem in the regex++ package, which reports having exhausted memory after examining a very short string with a regular expression of only modest complexity. I realize that the documentation for the package does not specify how much memory usage is too much, but since the same combination of regular expression and test string works without problems with a number of other programming toolsets (e.g., Python, Perl, C#) I'm guessing that the maintainers of the package would be interested in tracking down the problem (I would if it were my software). Here's a repro case which boils the problem down to the tiniest example: #include <boost/regex.hpp> int main() { boost::wregex e(L"^[^\\s]( ?([^\\s]+ ?)*[^\\s])?$"); boost::wcmatch m; boost::regex_match(L"codeine phosphate ", m, e); return 0; } I have confirmed that the behavior is present in the most recent version of the Boost code by retrieving and building the latest set of sources from CVS this morning. (I understand the usefulness of having the user perform this check, but making this a requirement, as the web instructions for submitting bug reports do, may be eliminating a substantial number of valuable reports; it took a number of attempts, with the connection to the CVS server hanging several times, before I could even get to the very lengthy build step.) The failure is not triggered if a version of regex_match is used which does not take the match_results argument, but then of course we don't get access to the match results. I'm pretty sure that the expression is boiled down to the least ambiguous form (without changing the semantics). In plain English, it's looking for strings that have no leading or trailing whitespace, and for which any internal whitespace runs are comprised solely of a single blank character. Doesn't seem like a very esoteric pattern. We have reproduced the behavior on Linux and on Windows. Hope this is useful. Feel free to contact me if you need any further information. Bob Kline

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Boost.Thread contained within a class?
by Joshua ChaitinPollak 06 Feb '07

06 Feb '07

Hello, I have a question about Boost.Thread. I am trying to create a class which upon instantiation creates a thread based upon itself, and then on destruction, stops the thread and cleans up after itself. A simple example is below. Is this possible, and if not, what alternatives do I have? The reason for this is to create a single external API (actually defined in a base class), and still have a background thread (hidden from the API) which can share that object's internal member variables. I'm looking to do something like this: class my_handler { public: boost::thread* background_thread; my_hander() : background_thread(NULL) { background_thread(*this); } ~my_hander() { if (background_thread != NULL) { running = false; background_thread.join(); } operator()() { while(running) { // do something } } }; -Thanks, Josh -- Joshua ChaitinPollak Software Engineer Kiva Systems

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When using singleton, I get "undefined symbol: _ZN9Singleton8just_oneE" error message
by Jin Sun 06 Feb '07

06 Feb '07

I am learning boost python. I have the following code: //test.cpp------------------------------------------------------------------ ----------------------------- #include <boost/python/module.hpp> #include <boost/python/class.hpp> #include <boost/python/def.hpp> #include <boost/python/reference_existing_object.hpp> #include <boost/python/return_value_policy.hpp> #include <utility> // classes to wrap class Singleton { public: static Singleton* get_it() {return &just_one;} private: Singleton() : x(0) {} public: int exchange(int n) // set x and return the old value { std::swap(n, x); return n; } private: int x; static Singleton just_one; }; // Wrapper code using namespace boost::python; BOOST_PYTHON_MODULE(singleton) { class_<Singleton, boost::noncopyable>("Singleton", no_init) .def("get_it", &Singleton::get_it, return_value_policy<reference_existing_object>()).staticmethod("get_it") .def("exchange", &Singleton::exchange) ; } //-------------------------------------------------------------------------- ------------------------------------------------ My Jamfile is as following: //-------------------------------------------------------------------------- ------------------------------------------------ # This is the top of our own project tree project-root ; # Include definitions needed for Python modules import python ; extension singleton # Declare a Python extension called hello : hello.cpp # source # requirements and dependencies for Boost.Python extensions <template>@boost/libs/python/build/extension ; //-------------------------------------------------------------------------- ---------------------------------------------- When I run it, I get the following error message: Python 2.5 (r25:51908, Jan 30 2007, 15:03:58) [GCC 4.0.2 20051125 (Red Hat 4.0.2-8)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> import singleton Traceback (most recent call last): File "<stdin>", line 1, in <module> ImportError: ./singleton.so: undefined symbol: _ZN9Singleton8just_oneE >>> Can anyone help me? Thanks!!! Jin Sun --------------------------------------------------------- Rekhi Hall 301 1400 Townsend Dr. Houghton MI, 49931 USA Phone: 906-370-2261 ---------------------------------------------------------

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[date_time] Set date/time/timezone?
by Pau Garcia i Quiles 06 Feb '07

06 Feb '07

Hello, Boost::Date_Time is great to get and manipulate time and date but, is it possible to *set* those values? What I would like to do is read a string/struct/container/whatever which contains a date, time and timezone and set those values as the system time, system date and system timezone (something like the SetSystemTime SetSystemTimeZoneInformation methods in Win32). Thank you. -- Pau Garcia i Quiles http://www.elpauer.org (Due to the amount of work, I usually need 10 days to answer)

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'boost::any::holder<ValueType>' : assignment operator could not be generated
by Magnus Therning 06 Feb '07

06 Feb '07

I've just installed the pre-built Boost libraries for Windows offered by boost-consulting.com. I started playing with program_options. I use the following options: options.add_options() ("help,h", "display this help message and exit") ("version,v", "output version information and exit") ("silly,s", po::value<int>(), "silly option") ; When compiling that code with Visual Studio 8.0 I get warnings about - 'boost::program_options::options_description' : assignment operator could not be generated - 'boost::any::holder<ValueType>' : assignment operator could not be generated The latter one seems to be the cause for a linking error: - unresolved external symbol "class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > boost::program_options::arg" g++ works just fine, no warnings, no link errors. Any suggestions on how to solve this? M

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Build difficulty on Darwin
by Rick Mann 06 Feb '07

06 Feb '07

Hi. I'm trying to build boost (to support a different project), and I'm having a certain amount of difficulty. I run: > $ bjam "-sTOOLS=darwin" stage and it goes off and churns for a bit, but a few things fail: > darwin-Link-DyLib-action bin/boost/libs/test/build/ > libboost_prg_exec_monitor.dylib/darwin/debug/shared-linkable-true/ > libboost_prg_exec_monitor-d-1_33_1.dylib > ld: Undefined symbols: > __Z8cpp_mainiPPc > /usr/bin/libtool: internal link edit command failed > > DYLD_LIBRARY_PATH=bin/boost/libs/test/build/ > libboost_prg_exec_monitor.dylib/darwin/debug/shared-linkable-true > export DYLD_LIBRARY_PATH > ld -dynamic -m -r -d -o "bin/boost/libs/test/build/ > libboost_prg_exec_monitor.dylib/darwin/debug/shared-linkable-true/ > libboost_prg_exec_monitor-d-1_33_1.lo" "bin/boost/libs/test/build/ > libboost_prg_exec_monitor.dylib/darwin/debug/shared-linkable-true/ > execution_monitor.o" "bin/boost/libs/test/build/ > libboost_prg_exec_monitor.dylib/darwin/debug/shared-linkable-true/ > cpp_main.o" \ > && \ > c++ -g -o "bin/boost/libs/test/build/ > libboost_prg_exec_monitor.dylib/darwin/debug/shared-linkable-true/ > libboost_prg_exec_monitor-d-1_33_1.dylib" "bin/boost/libs/test/ > build/libboost_prg_exec_monitor.dylib/darwin/debug/shared-linkable- > true/libboost_prg_exec_monitor-d-1_33_1.lo" \ > \ > -dynamiclib -install_name "libboost_prg_exec_monitor- > d-1_33_1.dylib" \ > && \ > rm -f "bin/boost/libs/test/build/ > libboost_prg_exec_monitor.dylib/darwin/debug/shared-linkable-true/ > libboost_prg_exec_monitor-d-1_33_1.lo" > > ...failed darwin-Link-DyLib-action bin/boost/libs/test/build/ > libboost_prg_exec_monitor.dylib/darwin/debug/shared-linkable-true/ > libboost_prg_exec_monitor-d-1_33_1.dylib... > ...skipped <@boost!lib>libboost_prg_exec_monitor-d-1_33_1.dylib for > lack of <@boost!libs!test!build/libboost_prg_exec_monitor.dylib/ > darwin/debug/shared-linkable-true>libboost_prg_exec_monitor- > d-1_33_1.dylib... > MkDir1 bin/boost/libs/test/build/libboost_prg_exec_monitor.dylib/ > darwin/release There are a few other failures (6 in all): libboost_prg_exec_monitor-d-1_33_1.dylib libboost_prg_exec_monitor-1_33_1.dylib libboost_test_exec_monitor-d-1_33_1.dylib libboost_test_exec_monitor-1_33_1.dylib libboost_unit_test_framework-d-1_33_1.dylib libboost_unit_test_framework-1_33_1.dylib In the end, I am unable to build a GNU tool that relies on boost regex, which is really all I want to do. Any help would be much appreciated. Thanks! (Current Mac OS X 10.4.8, current Xcode tools 2.4.1) -- Rick

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How to wrap a static function, which returns a reference to a static object.
by Jin Sun 06 Feb '07

06 Feb '07

I am learning Boost Python. One question is bothering me. I have some code like the following. class A { Public: static B* getB() { return _B;} private: A(); staitc B* _B; } How to wrap function getB()? thanks!!! Jin Sun --------------------------------------------------------- Rekhi Hall 301 1400 Townsend Dr. Houghton MI, 49931 USA Phone: 906-370-2261 ---------------------------------------------------------

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problem with unit test framework
by Vincent Torri 05 Feb '07

05 Feb '07

Hey, I'm trying to use the unit test framework of Boost, but my program seg fault. My code is based on that example: http://boost.org/libs/test/example/unit_test_example3.cpp Here is the code : http://rafb.net/p/5UDMk864.html Here is the backtrace : http://rafb.net/p/GT86KB44.html does someone see the problem ? thank you Vincent Torri

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seed for hash
by Rares Vernica 05 Feb '07

05 Feb '07

Hi, Does the hash function uses a seed? If a call: boost::hash<std::string> string_hash; std::size_t h = string_hash("Hash me"); and then after a year I call again: string_hash("Hash me"); Does it return the same value? Thanks a lot, Ray

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[boost::serialization] Howto store derived classes through pointer to base - with templates and own archive?
by Marc Wäckerlin 05 Feb '07

05 Feb '07

Hi I have the following problem: My class structure is somehow like that: class A; // is pure virtual template <int NUM, typename ENUM> class B: public A; [...] I use my BinaryWrite archive class, as specified in thread: "[boost::serialization] Binary Stream with noAdditional Info: Here's the solution! [Howto derieve ownserialization archive?]" Now, when I try to stream a std::vector < boost::shared_ptr < A > > then I see in the function-trace log, that my writer has been called for the parent type A, but not for the derived types (B, C, ...). After this, I read again the "Except for one special case" part in the Archive Class Reference manual. After this, I added the following code in front of my archive type: ==================================================================== namespace image { class BinaryWriter; class BinaryReader; } #define BOOST_ARCHIVE_CUSTOM_OARCHIVE_TYPES ::image::BinaryWriter #define BOOST_ARCHIVE_CUSTOM_IARCHIVE_TYPES ::image::BinaryReader #include <boost/archive/detail/iserializer.hpp> #include <boost/archive/detail/oserializer.hpp> #include <boost/archive/detail/common_iarchive.hpp> #include <boost/archive/detail/common_oarchive.hpp> #include <boost/serialization/export.hpp> ==================================================================== But it still does not step into the correct child. After some more reading, I guess, that I'd have to use BOOST_CLASS_EXPORT(B), but that does not compile, because B is a template class. What's wrong, what's missing, what do I have to do? Thank you Regards Marc

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