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[interprocess] Best practice question on shared resources.
by Moritz 01 Nov '09

01 Nov '09

Hi there, I am writing a "server" that is capable of communicating data to many "clients". Because I am implementing different communication modes (async, sync), I need special methods to lock and unlock a managed shared memory segment. My question is how to store the mutex, semaphore and managed_shared_memory segment information that are required in the lock and unlock methods. I see different approaches to implement this on client side. 1. Open the resources in the constructor of the client. Save pointers to the resources as members. So it is possible to access the resources in every method of the client class without opening them every time. The problem is that I do not recognize if the resources were closed because they only throw on opening (using linux). 2. Open the resources in the functions. That means I have to create the resource objects every time the function is called. So I have a chance to recognize if the resources have been removed. But I think this will create some useless overhead. Has anybody implemented something similar to this. How would you handle the shared resources? Thanks in advance Moritz Illustration: 1. class client { client() { _mtx = new boost::interprocess::named_mutex(...); } void lock() { _mtx.lock() } boost::interprocess::named_mutex * _mtx; }; versus 2. class client { void lock() { boost::interprocess::named_mutex mutex(...); mutex.lock() } };

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Re: [Boost-users] building some boost libs for Windows ce
by Tom Aylesworth 01 Nov '09

01 Nov '09

> I want to build two libs, statechart and signals, for Windows CE using > MSVC 8.0. I have found suprisingly little info on how to accomplish this, > and I wonder if anyone has done this before and have any configuration > files I could refer to, to save some time (I really don't know much about > bjam)? We're not using statechart or signals, but we are using several of the other Boost libraries under Windows Mobile 5 with MSVC 9. Best info I found was here: http://cowo.supersized.org/archives/27-Compiling-BOOST-1.35.0-with-STLPort-… I had to make another change to use MSVC 9 but you shouldn't need to for 8. We're also using wcelibcex to provide C library routines that aren't provided by Microsoft. You may not need them for the statechart and signals libraries, but here's a link just in case: http://wcelibcex.sourceforge.net/ Thomas Aylesworth Senior Software Engineer RealityMobile http://www.realitymobile.com/

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date_time O/S conversion routine limitation
by Zachary Turner 01 Nov '09

01 Nov '09

Hello list, Apologies for the cross-post, this originally went to the boost-users list a day or so ago but it got no responses, and then I also realized it was actually more appropriate here. Suppose I have a cross-platform agent that communicates with a server. Agent from platform X sends a message to the server which contains a date/time. Server sends a message to another agent running platform Y with the same date/time. In practice X/Y are always either windows/linux or linux/windows. The server always tells the agent which platform's native format the time is represented in, so there should be no problem. Ideally I'd like to write the following code: ptime time; if (msg.is_from_windows()) { time = from_ftime<ptime>(msg.time()); } else { time = from_time_t(msg.time()); } But this doesn't work because from_ftime<> is not defined on linux. If from_ftime<> is already templated on the FILETIME type, is there any reason it needs to be #ifdef'd out on non-windows platforms? I mean, a FILETIME is really just a uint64, can't the templated function also just operate on a boost::uint64_t? Zach

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Bind to first available port
by Mathew Benson 31 Oct '09

31 Oct '09

I know how to do this with Windows sockets, but how do I bind a UDP listen socket to the first available port? I want to send a packet from client to the server to subscribe to data and tell the server what port to send the subscribed data to. I don't care what port the client listens to. If I hard code it, I can only run a single client on a PC. I want to bind to the first available one so I can run as many clients on the same PC as I want.

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Redirecting test output to an XML file
by Stephen Torri 31 Oct '09

31 Oct '09

I have the following code that I am using to regression test part of my library. The project uses automake and autoconf to build the Makefiles then runs the tests via 'make check'. I would like to see all the test result output written as XML files in the directory where the test files reside. That way I can use a script to gather them up and craft a web page off of them. My question: How to redirect Boost Test output to an XML file? I see I can use --log_format=XML to make an XML file but not quite sure how to incorporate that into automake and autoconf. Stephen ---------------------------------------- #include "Elf_arc_utils.h" #define BOOST_TEST_DYN_LINK #define BOOST_TEST_MODULE Suites #include <boost/test/unit_test.hpp> #include <string> BOOST_AUTO_TEST_SUITE(getType) BOOST_AUTO_TEST_CASE(getTypeMin) { using namespace libreverse::elf_module; BOOST_TEST_CHECKPOINT("getType minimum case"); std::string result = arc::ElfArcUtils::getType(arc::E_ARC_MACH_ARC5); BOOST_CHECK_EQUAL ( result, "R_ARC_NONE"); } BOOST_AUTO_TEST_CASE(getTypeMax) { using namespace libreverse::elf_module; std::string result = arc::ElfArcUtils::getType(arc::E_ARC_MACH_ARC8); BOOST_CHECK_EQUAL ( result, "R_ARC_B22_PCREL"); } BOOST_AUTO_TEST_CASE(expectedUnknown) { using namespace libreverse::elf_module; std::string result = arc::ElfArcUtils::getType(4); BOOST_CHECK_EQUAL ( result, "unknown"); } BOOST_AUTO_TEST_CASE(negativeValue) { using namespace libreverse::elf_module; std::string result = arc::ElfArcUtils::getType(-1); BOOST_CHECK_EQUAL ( result, "unknown"); } BOOST_AUTO_TEST_SUITE_END()

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Cross-platform date/time problems
by Zachary Turner 30 Oct '09

30 Oct '09

Suppose I have a cross-platform agent that communicates with a server. Agent from platform X sends a message to the server which contains a date/time. Server sends a message to another agent running platform Y with the same date/time. In practice X/Y are always either windows/linux or linux/windows. The server always tells the agent which platform's native format the time is represented in, so there should be no problem. Ideally I'd like to write the following code: ptime time; if (msg.is_from_windows()) { time = from_ftime<ptime>(msg.time()); } else { time = from_time_t(msg.time()); } But this doesn't work because from_ftime<> is not defined on linux. If from_ftime<> is already templated on the FILETIME type, is there any reason it needs to be #ifdef'd out on non-windows platforms? Or does someone maybe have another solution to being able to support the use-case I've mentioned above? Zach

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[MPI] GCC 4.4.1 Compilation errors
by joel 30 Oct '09

30 Oct '09

I upgraded to gcc 4.4 and got the following error when compiling Boost MPI ./boost/mpi/detail/mpi_datatype_oarchive.hpp: In member function ‘void boost::mpi::detail::mpi_datatype_oarchive::save_enum(const T&, mpl_::true_)’: ./boost/mpi/detail/mpi_datatype_oarchive.hpp:64: error: expected primary-expression before ‘enum’ ./boost/mpi/detail/mpi_datatype_oarchive.hpp:64: error: expected ‘;’ before ‘enum’ Is it a known bug ? -- ___________________________________________ Joel Falcou - Assistant Professor PARALL Team - LRI - Universite Paris Sud XI Tel : (+33)1 69 15 66 35

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[program_options] Custom validate for asio endpoints
by Ryan McConnehey 30 Oct '09

30 Oct '09

I'm trying to validate an ip address and port that is being passed in through the command line arguments. I could retrieve the string and do the validation outside program options. I thought it would be better to use the custom validate function shown in the documentation. I'm trying to retrieve the information as a boost::asio::ip::udp::endpoint. Even after creating the validate function the compiler is complaining that there is no user defined function or stream operator. I've include some code to show what I'm doing. Any help would be great. Ryan class CommandLine { static void validate(boost::any & v, std::vector<std::string> const& values) { using namespace boost::program_options; // Make sure no previous assignment to 'v' was made. validators::check_first_occurrence(v); // Extract the first string from 'values'. If there is more than // one string, it's an error, and exception will be thrown. std::string const& s = validators::get_single_string(values); // Do regex match and convert the interesting part to int. if (validIPandPort(s)) { v = boost::any(createEndpoint(s)); } else { throw validation_error("invalid value"); } } static ApplicationArguments process(const int argc, char * argv[]) { ApplicationArguments returnApplicationArguments; //Create an options menu with all parameters allowed, to be passed in through the command line arguments. boost::program_options::options_description menu("Usage: program.exe -a ip:port,ip:port -r ip:port,ip:port\nOptions:"); menu.add_options() ("ip1,a" , boost::program_options::value<boost::asio::ip::udp::endpoint>() , "description") ("ip2,r" , boost::program_options::value<boost::asio::ip::udp::endpoint>() , "description") ; //Process the command line arguments and place them in a map. boost::program_options::variables_map vm; boost::program_options::store(boost::program_options::parse_command_line(argc, argv, menu), vm); boost::program_options::notify(vm); return returnApplicationArguments; } }; static void validate(boost::any & v, std::vector<std::string> const& values, boost::asio::ip::udp::endpoint * target_type, int) { CommandLine::validate(v, values); }

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Change return type automatically
by Surya Kiran Gullapalli 30 Oct '09

30 Oct '09

Hello, I've a class with multiple boost signals like this class A { private: boost::signal<void()> m_voidSignal ; boost::signal<void (const string&)> m_stringSignal ; public: boost::signal<void()>& voidSignal() { return m_voidSignal ; } boost::signal<void (const string&)>& stringSignal { return m_stringSignal ; } } ; when i'm connecting signals to slots, I do some thing like this. A a; a.voidSignal().connect (...) ; This works fine. But I've many signals with different signatures. what I want to achieve is a single interface where I want to map every signal to enums and access signal from the enums like this. class A { public: typedef enum { VoidSignal, StringSignal ... } ; SignalIds ; // return type should be deducted automatically from the enum ReturnType& getSignal (SignalId) ; ... } ; So that I can do some thing like this A a; a.getSignal (A::VoidSignal).connect (...) ; a.getSignal (A::StringSignal).connect (...) ; Basically with a single interface, I want to change the return type automatically. Can I achieve something like this with any of the boost libraries (mpl, fusion etc) ? Any pointers on this would be of great help. Thanks, Surya

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building some boost libs for Windows ce
by Frank Black 30 Oct '09

30 Oct '09

Hi, I want to build two libs, statechart and signals, for Windows CE using MSVC 8.0. I have found suprisingly little info on how to accomplish this, and I wonder if anyone has done this before and have any configuration files I could refer to, to save some time (I really don't know much about bjam)? Thanks!

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