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asio's io_service uses too many file descriptors
by pete＠mu.org 15 Aug '07

15 Aug '07

I posted this under a less suitable subject line a week ago, but I got no response. I hope the above live will trigger some help. I 've been doinking around with asio for a few weeks, and I've run into an issue I can't seem to wrap my head around. I've been playing with some code that originally was meant to pound a server with a large amount of packets for benchmarking purposes. It uses threads to launch hundreds of threads per second. When I replaced the old socket code with asio, and used a single io_service with run being called within each thread, I run out of file descriptors very quickly, and if I use a single io_service within each thread it's the same thing but the performance seems worse. Needless to say, this seems like a real limitation and I'm hoping I'm just being limited by my own misunderstanding, because I'm really enjoying the portability of asio. The docs that are there seem great, but there seems to be a lot more the library can do that I am missing out on, and I think the docs seem like they are not mentioning a lot of what asio an do. Can someone point me in the right direction for launching 1-to-N threads with a single send_to and a single receive_from within each thread that doesn't take the hit I'm seeing? It seems to me, that it's obvious that the io-service design is the difference, because I don't get the issue at all when I use plain old sockets, and the OS thread limit is then the only limitation. Any help would be greatly appreciated. FYI, I've done most of my experimenting on Linux and OSX. I can send some code samples if needed, but I think the problem should be apparent if anyone else has tried to use asio with large amounts of threads. Thanks, Pete

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boost serialization excessive warning messages
by Fei Liu 15 Aug '07

15 Aug '07

Hi Group, I am getting multiple warning messages like the following from boost serialization library: /usr/include/boost/archive/detail/iserializer.hpp:124: warning: unused parameter 'flags' I am pretty sure this is a common issue but I haven't found any clue through the web. Is there a way to turn off the warning through proper coding? I am using gcc on linux. Fei

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[iostreams] Different character type in a filtering stream [C1]
by frederic.mayot＠sgcib.com 15 Aug '07

15 Aug '07

Hi, I'd like to create a pipeline composed of filters that have different input and output character type. For example: file -> | Source | -> char -> | F1 | -> message -> | F2 | where F1 and F2 are input filters. F1 can be kind of a parser that would cut the stream into messages. The thing is that I could always rewrite a file_source but I think it's not a good design. What would you suggest? Thanks, ____________________________ Frederic MAYOT Société Générale - Equity IT 1221 Avenue of the Americas New York, NY 10020 +1 (212) 278-5558 +1 (917) 673-1339 ************************************************************************* This message and any attachments (the "message") are confidential and intended solely for the addressees. Any unauthorised use or dissemination is prohibited. E-mails are susceptible to alteration. Neither SOCIETE GENERALE nor any of its subsidiaries or affiliates shall be liable for the message if altered, changed or falsified. *************************************************************************

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Using cross-compiler to build the libraries
by Bruce Reid 15 Aug '07

15 Aug '07

I have been able to build (and link with) the libraries using the native gcc compiler on my linux-x86 platform, but have been unable to find a way to force the build process to use something like: /path/to/my/cross_compiler/for/linux-ppc/gcc Can someone please advise me in the proper way to build the libs with an absolute path to my cross compiler? Thanks very much for any help, Bruce CONFIDENTIALITY NOTICE: This email, together with any attachments, is intended only for use by Aristos Logic Corporation and the individual(s) to which it is addressed and may contain information that is privileged, confidential or exempt from disclosure. If you are not the intended recipient, you are hereby notified that any dissemination, distribution, or copying of this email, or any attachment, is strictly prohibited. If you have received this email in error, please notify Aristos Logic Corporation by sending an email to sysadm(a)aristoslogic.com and delete this email, along with any attachments, from your computer. Thank you.

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boost filesystem undefined reference...
by chun ping wang 15 Aug '07

15 Aug '07

./myfile/lib/libmy.a(my.o): In function `ZN4My6My_t4initERKNS0_10Settings_tE': C:/Boost/include/boost-1_34_1/boost/filesystem/path.hpp:302: undefined reference to `boost::filesystem::detail::status_api(std::string const&, unsigned int&)' ./myfile/lib/libmy.a(my.o): In function `_tcf_0': C:/CPW/cs_classes/./myfile/include/myerror.h:186: undefined reference to `boost::filesystem::detail::get_current_path_api(std::string&)' i build boost linking to a built boost filesystem file using mingw 3.4.5 including option. -l"boost_filesystem-mgw34-1_34_1" this is line 302 of path.hpp "const external_string_type external_file_string() const { return Traits::to_external( *this, file_string() ); }" "

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Searching through a vector of tuples...
by Graham Reitz 15 Aug '07

15 Aug '07

typedef boost::tuples::tuple<int,double> some_tuple; std::vector<some_tuple> vec_of_some_tuples; // ... stuff some data into the vector // ... search for a specific int in the vector of some_tuple What would be a good method, using an stl algorithm, to search through the vector above to match only the int portion of the tuple (ignoring the double)? Thanks, Graham

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boost.test and independent compilation/running of tests
by Alexander Schmolck 15 Aug '07

15 Aug '07

Hi, I'm trying to figure out what the best way to use boost.test to achieve something close to TDD (test driven development) is; I should presumably also mention that I'm using qmake and not bjam as a build utility. I've managed to build and use boost.test fine (after figuring out that I needed to add -DBOOST_TEST_DYN_LINK), but what I haven't been able to achieve is to a) have several smaller test-cases/suites for TDD so that I can rapidly recompile and run a small subset of tests whilst I'm developing a specific class. b) have one big test-suite, integrating all the above, for regression testing to be run periodically (after the above subset of tests passed; on svn commit etc.) I haven't figured out how to set things up so that I can compile individual tests to .o files and then either simply build a complete regression suite executable from them or an executable from just one (or a few) of these tests; because I don't know how to use the autoregistration facilities without ending up with multiple main()s. My test files currently look something like this: //file foo_test.cpp #define BOOST_TEST_MODULE foo_test #include <boost/test/unit_test.hpp> #include "foo.h" // Test Suite BOOST_AUTO_TEST_SUITE(foo_test_suite); BOOST_AUTO_TEST_CASE(some_test_case) { // ... } BOOST_AUTO_TEST_SUITE_END(); What's the recommended way to go about this? thanks, 'as

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hash_multimap serialization issue
by Lorenzo Cavallaro 15 Aug '07

15 Aug '07

Dear Boost list, I'm trying to use the boost serialization class to serialize some objects. Unfortunately, I keep running into the same issue (compilation error) that I report here below for clarity $ g++-3.4 -fPIC -O2 -g -I. -c model.cpp -o model.o /usr/include/boost/serialization/access.hpp: In static member function +`static void boost::serialization::access::serialize(Archive&, T&, unsigned +int) [with Archive = boost::archive::text_oarchive, T = +__gnu_cxx::hash_multimap<addr_t, Events*, __gnu_cxx::hash<unsigned int>, +eqaddr, std::allocator<Events*> >]': /usr/include/boost/serialization/serialization.hpp:81: instantiated from `void +boost::serialization::serialize(Archive&, T&, unsigned int) [with Archive = +boost::archive::text_oarchive, T = __gnu_cxx::hash_multimap<addr_t, Events*, +__gnu_cxx::hash<unsigned int>, eqaddr, std::allocator<Events*> >]' /usr/include/boost/serialization/serialization.hpp:140: instantiated from +`void boost::serialization::serialize_adl(Archive&, T&, unsigned int) [with +Archive = boost::archive::text_oarchive, T = __gnu_cxx::hash_multimap<addr_t, +Events*, __gnu_cxx::hash<unsigned int>, eqaddr, std::allocator<Events*> >]' /usr/include/boost/archive/detail/oserializer.hpp:148: instantiated from `void +boost::archive::detail::oserializer<Archive, +T>::save_object_data(boost::archive::detail::basic_oarchive&, const void*) +const [with Archive = boost::archive::text_oarchive, T = +__gnu_cxx::hash_multimap<addr_t, Events*, __gnu_cxx::hash<unsigned int>, +eqaddr, std::allocator<Events*> >]' model.cpp:599: instantiated from here /usr/include/boost/serialization/access.hpp:109: error: 'class +__gnu_cxx::hash_multimap<addr_t, Events*, __gnu_cxx::hash<unsigned int>, +eqaddr, std::allocator<Events*> >' has no member named 'serialize' make: *** [model.o] Error 1 I've looked for this error on Internet and I found out that a discussion on the boost mailing list dated back on 2005 (http://lists.boost.org/boost-users/2005/08/13183.php) I tried making those changes but nothing happened and I still have the reported compilation error. For the sake of clarity, here's a snippet of the code I'm trying to compile #include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/serialization/base_object.hpp> #include <boost/serialization/utility.hpp> #include <boost/serialization/list.hpp> #include <boost/serialization/vector.hpp> #include <boost/serialization/hash_map.hpp> #include <ext/hash_map> using namespace std; using namespace __gnu_cxx; struct eqaddr { bool operator()(addr_t ret1, addr_t ret2) const { return ret1 == ret2; } }; typedef hash_multimap<addr_t, Events *, hash<addr_t>, eqaddr> model_t; class ModelMap { friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int file_version) { ar & map; } public: model_t map; ModelMap() { } ~ModelMap() { } }; I'm using libboost-serialization 1.33.1-10 (debian) Any idea on how to fix this? Am I doing something wrong? TIA, bye Lorenzo -- Lorenzo `Gigi Sullivan' Cavallaro <sullivan(a)security.dico.unimi.it> GPG key at http://security.dico.unimi.it/~sullivan/sullivan.asc Until I loved, life had no beauty; I did not know I lived until I had loved. (Theodor Korner) See the reality in your eyes, when the hate makes you blind. (A.H.X)

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How to import a dll to python
by desai3＠cooper.edu 14 Aug '07

14 Aug '07

Hi all: I am completely new to Python and Boost.python. (I have been using it for two days) I was trying out a tutorial example that is located in the boost_1_34_1\libs\example\tutorial folder of the standard Boost distribution. After running ./Bjam target-os=cygwin toolset = gcc it created hello.dll, hello.dll.a and hello.o files in boost_1_34_1\libs\python\example\tutorial\bin\gcc-3.4.4\debug. However, when I go to python and use "import python" it gives me following error ######################################## Traceback (most recent call last): File "<stdin>", line 1, in <module> ImportError: No module named hello ######################################## What am I doing wrong? I am completely new to this boost and python so simplified answers will help a lot. Thank you

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any_cast on polymoprhic types?
by Gross, Steve 14 Aug '07

14 Aug '07

Is there a way to use any_cast for polymorphic types? For instance, let's say I've got a Base class and a Derived class. I want to be able to any_cast a Derived * to a Base * successfully, like so: class Base { virtual ~Base() {} }; class Derived : public Base { virtual ~Derived() {} }; Derived d; boost::any a = &d; boost::any_cast<Base*>(a); // Will NOT throw an exception Thanks! --Steve

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