July 2013 - Boost-users - lists.preview.boost.org

Re: [Boost-users] boost::io_service run() never returns
by Marat Abrarov 07 Jul '13

07 Jul '13

Not sure if this can help, but there was a problem with serial port (asynchronous reading, maybe epoll-related) at Ubuntu. That problem wasn't related to Asio, it was an OS bug. Search asio-users mailing list for details. Regards, Marat Abrarov.

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Different behavior of boost::serialization of strings on text archive
by Andrea Ranieri 07 Jul '13

07 Jul '13

Hi all, I'm having some issue serializing a `std::string` with `boost::serialization` on a `text_oarchive`. AFAICT, I have two identical pieces of code that behaves differently in two different programs. This is the program that I believe is behaving correctly: #include <iostream> #include <string> #include <sstream> #include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> template <typename T> void serialize_deserialize(const T & src, T & dst) { std::string serialized_data_str; std::cout << "original data: " << src << std::endl; std::ostringstream archive_ostream; boost::archive::text_oarchive oarchive(archive_ostream); oarchive << src; serialized_data_str = archive_ostream.str(); std::cout << "serialized data: " << serialized_data_str << std::endl; std::istringstream archive_istream(serialized_data_str); boost::archive::text_iarchive iarchive(archive_istream); iarchive >> dst; } int main() { std::string archived_data_str = "abcd"; std::string restored_data_str; serialize_deserialize<std::string>(archived_data_str, restored_data_str); std::cout << "restored data: " << restored_data_str << std::endl; return 0; } And this is its output: original data: abcd serialized data: 22 serialization::archive 10 4 abcd restored data: abcd (You can compile it with: `g++ boost-serialization-string.cpp -o boost-serialization-string -lboost_serialization`) This one, on the other hand, is an excerpt of the program I'm writing (derived from [boost_asio/example/serialization/connection.hpp][1]) that serializes `std::string` data converting each character in its hex representation: /// Asynchronously write a data structure to the socket. template <typename T, typename Handler> void async_write(const T& t, Handler handler) { // Serialize the data first so we know how large it is. std::cout << "original data: " << t << std::endl; std::ostringstream archive_stream; boost::archive::text_oarchive archive(archive_stream); archive << t; outbound_data_ = archive_stream.str(); std::cout << "serialized data: " << outbound_data_ << std::endl; [...] And this is an excerpt of its output: original data: abcd serialized data: 22 serialization::archive 10 5 97 98 99 100 0 The version (`10`) is the same, right? So that should be the proof that I'm using the same serialization library in both programs. However, I really can't figure out what's going on here. I've been trying to solve this puzzle for almost an entire work day now, and I'm out of ideas. For anyone that may want to reproduce this result, it should be sufficient to download the [Boost serialization example][2], add the following line connection_.async_write("abcd", boost::bind(&client::handle_write, this, boost::asio::placeholders::error)); at line 50 of `client.cpp`, add the following member function in client.cpp /// Handle completion of a write operation. void handle_write(const boost::system::error_code& e) { // Nothing to do. The socket will be closed automatically when the last // reference to the connection object goes away. } add this `cout`: std::cout << "serialized data: " << outbound_data_ << std::endl; at `connection.hpp:59` and compile with: g++ -O0 -g3 client.cpp -o client -lboost_serialization -lboost_system g++ -O0 -g3 server.cpp -o server -lboost_serialization -lboost_system I'm using `g++ 4.8.1` under `Ubuntu 13.04 64bit` with `Boost 1.53` Any help would be greatly appreciated. Best regards Avio P.s. I'm posting this because the deserialization of the `std::string`s isn't working at all! :) [1]: http://www.boost.org/doc/libs/1_53_0/doc/html/boost_asio/example/serializat… [2]: http://www.boost.org/doc/libs/1_53_0/doc/html/boost_asio/examples.html#boos…

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boost::io_service run() never returns
by shunguang 06 Jul '13

06 Jul '13

I have the following simplified code to read data from a RS232 port. For some (from beginning) runs, io.run() returns immediately and m_handler() is called which is expected. but sometimes (a fresh run from beginning), io.run() goes into a inside forever loop(stacked inside forever) even for the first time called inside the while loop. And this happens randomly. What's is/are the potential problem(s) at here? Thanks. -shunguang #define BUF_SIZE 512 char data[BUF_SIZE]; void my_handler(const boost::system::error_code& err, std::size_t bytes_transferred) { printf("%d\n", bytes_transferred); if (!err){ process_data(); } } void test_serial_port( int argc, char* argv[] ) { // hard coded parameters const char *PORT = "COM1"; serial_port_base::baud_rate BAUD(9600); serial_port_base::character_size CSIZE( 8 ); serial_port_base::flow_control FLOW( serial_port_base::flow_control::software ); serial_port_base::parity PARITY( serial_port_base::parity::none ); serial_port_base::stop_bits STOP( serial_port_base::stop_bits::one ); io_service io; serial_port port( io, PORT ); // go through and set all the options as we need them // all of them are listed, but the default values work for most cases port.set_option( BAUD ); port.set_option( CSIZE ); port.set_option( FLOW ); port.set_option( PARITY ); port.set_option( STOP ); while( !kbhit() ) { io.reset(); port.async_read_some( boost::asio::buffer(data, BUF_SIZE), boost::bind(&my_handler, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred ) ); io.run(); Sleep(300); } } -- View this message in context: http://boost.2283326.n4.nabble.com/boost-io-service-run-never-returns-tp464… Sent from the Boost - Users mailing list archive at Nabble.com.

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[filesystem] current_path
by Ovanes Markarian 06 Jul '13

06 Jul '13

Hello *, I need to create a relative symlink. To do so I currently use current_path function: auto current_path = fs::current_path(); BOOST_SCOPE_EXIT(&current_path) { fs::current_path(current_path); }BOOST_SCOPE_EXIT_END fs::current_path(some_base_path_here); fs::create_symlink ( fs::path("..")/some_subdirectory/image_name.filename() , original_name.filename() ) ; Is there any better way to create a relative symlink? What happens if I call current_path(whatever) in a multi-threaded environment? Is it thread-safe or should I synchronize the access to it? Many thanks, Ovanes

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[multi_index] emplace support
by Brian Wood 06 Jul '13

06 Jul '13

I'm wondering about emplace support in multi_index. Any news on that is of interest. -- Brian Ebenezer Enterprises - In G-d we trust. http://webEbenezer.net

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Re: [Boost-users] Do correct instructions for MinGW install exist?
by lizy10b 06 Jul '13

06 Jul '13

Hi Kirk Joppy, I have got most of the 1.53 libraries built with MinGW, though some of them do not work correctly till now. I would like to share with you the following steps I did. 1. Add the bin folder of MinGW to your windows environment variable "PATH". 2. Open a the new commandline window, and type "bootstrap.bat mingw" in the boost souce root dir to build the b2.exe and bjam.exe. 3. Type "b2 toolset=gcc --prefix=G:\boost_1_53_0\my-build' to build the libraries. Hope it works. cheers. Zhiyu Li 2013-07-02 lizy10b 发件人： Kirk Joppy 发送时间： 2013-07-02 12:12:50 收件人： boost 抄送：主题： [Boost-users] Do correct instructions for MinGW install exist? Dear Boost users, I have recently been trying to install boost 1.53 for use with MinGW. I followed the instructions here http://www.boost.org/doc/libs/1_53_0/more/getting_started/windows.html#prep… to the letter with resulting failure. I then noticed that when running b2 install --prefix=G:\boost_1_53_0\my-build from G:\boost_1_53_0\tools\build\v2 as per the instructions, the first few lines of output read warning: No toolsets are configured warning: Configuring default toolset "msvc" warning: If the defrault is wrong, your build may not work correctly warning: Use the "toolset=xxxxx" option to override our guess warning: For more configuration options, please consult <webpage> I have consulted the recommended web page and I think I have gotten a working install. However, given that the instructions as written are incorrect I would like to ask 1. Is there a correct, definitive source of instructions for installing boost (with MinGW)? 2. Should the documentation be corrected? I think this error is important given that the section I was working from is specifically indicated to pertain to non-MSVC builds. 3. I have found several conflicting sources of information regarding how to build boost for use with static linking. StackOverflow, for example, has several posts about this, none of which agree with each other. Is there are definitive, correct source of this information? If not I suppose I will post to this mailing list asking about it. Thank you for your consideration. Regards, kjoppy _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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[MSM] Problem with passing event as a reference to base event class
by samriti katoch 05 Jul '13

05 Jul '13

Hi, I have noticed a strange problem with event processing with msm. My events derive publicly from a base events struct like this: struct BaseEvent { virtual ~BaseEvent() {} }; struct ConcreteEvent : public BaseEvent {}; I my FSM i have a transition defined for ConcreteEvent, When I do this : void foo(const BuddyEvent& event) { fsm->process_event(event); // event is of type ConcreteEvent } The fsm fires a no_transition , and I see a message saying no transition for ConcreteEvent in state X (state X has a valid transition for ConcreteEvent) However this succeeds: void foo(const BuddyEvent& event) { fsm->process_event(ConcreteEvent(0); } I am using boost-1.49 and the boost msm library that comes bundled with this. So my question is, why is msm not able to generate a valid transition for a concrete event passed as a reference to its base tyoe. Thanks!

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Any special differences between unix and windows source code packages?
by lizy10b 05 Jul '13

05 Jul '13

Hi there, I would like to know are there any differences (other than compression types) between the unix platform source code package (.tar.bz2, tar.gz) and windows platform ones (.7z, .zip) ? PlatformFile unixboost_1_54_0.tar.bz2 boost_1_54_0.tar.gz windowsboost_1_54_0.7z boost_1_54_0.zip Thanks. Zhiyu Li 2013-07-02 lizy10b

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mapped_file::close()
by Millman, Mark 04 Jul '13

04 Jul '13

In Windows using VisualStudio 10 I've created a mapped_file as char * OpenRW(std::string filePath ) { <<fragment >> mfp = new boost::iostreams::mapped_file_params(filePath); mfp->mode = boost::iostreams::mapped_file::readwrite; mfp->new_file_size = size; mfp->offset = 0; mf = new boost::iostreams::mapped_file(*mfp); return mf->data(); } I later close the file void Close() { <<fragment>> mf->close(); delete mfp; delete mf; } And then want to reopen it { char* fileName = filePath.c_str(); int test = _open(fileName,_O_BINARY|_O_RDWR); } but test is returned -1 -- note that I am able to open the file _O_RDONLY. If I close the application and restart it, then I can read the file _O_RDWR (i.e. test is returned with a valid handle) Is this a bug or am I doing something wrong? Thanks Mark

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undefined reference to Thread ( Newbie )
by Sahil Sachdeva 04 Jul '13

04 Jul '13

Hello all, I am trying to compile and use the Boost 1.54 libraries and have run into a dead end. I compiled and installed the libraries like mentioned in the documentation: ./bootstrap.sh./b2 install I even tried a complete reinstall using: ./bootstrap.sh./b2 threading=multi install I have linked using -lboost_thread and -L<path to boost>/bin.v2/libs. boost_system is also linked in the same manner. i am still getting the following linker errors: undefined reference to boost::thread::start_thread_noexcept() undefined reference to boost::thread::join_noexcept() I am using gcc 4.6.3 on Ubuntu 12.04 in eclipse. Does anyone know how i can fix this? Best, Sahil

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