July 2013 - Boost-users - lists.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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[Boost.Math special functions] Critical error in zeta.hpp, Boost 1.54.0
by Rainer Deyke 04 Jul '13

04 Jul '13

I'm getting compile errors when including "boost/math/special_functions/zeta.hpp" (which in turn is included indirectly by "boost/random.hpp"). This is in the recently released "boost_1_54_0.tar.bz2" under Linux Mint 16 for amd64, gcc 4.7.3. Minimal test case: #include "boost/math/special_functions/zeta.hpp" int main() {} Exact error message: In file included from source/eldwood/test/zeta.cpp:1:0: intermediate/usr_x86_64-pc-linux-gnu/include/boost/math/special_functions/zeta.hpp: In function ‘T boost::math::detail::zeta_imp(T, T, const Policy&, const Tag&)’: intermediate/usr_x86_64-pc-linux-gnu/include/boost/math/special_functions/zeta.hpp:877:24: error: ‘log_root_two_pi’ is not a member of ‘boost::math::constants’ intermediate/usr_x86_64-pc-linux-gnu/include/boost/math/special_functions/zeta.hpp:877:52: error: expected primary-expression before ‘,’ token intermediate/usr_x86_64-pc-linux-gnu/include/boost/math/special_functions/zeta.hpp:877:60: error: expected primary-expression before ‘>’ token intermediate/usr_x86_64-pc-linux-gnu/include/boost/math/special_functions/zeta.hpp:877:62: error: expected primary-expression before ‘)’ token The same error also manifests under clang. -- Rainer Deyke (rainerd(a)eldwood.com)

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Boost 1.54.0: bootstrap build fails for MinGW/MSYS
by Josue Andrade Gomes 04 Jul '13

04 Jul '13

Hi, Bjam build is failing for me on MinGW/MSYS. ================================================================================ Boost 1.54.0: $ cd boost_1_54_0/tools/build/v2/engine $ ./build.sh mingw ### ### Using 'mingw' toolset. ### rm -rf bootstrap mkdir bootstrap gcc -DNT -o bootstrap/jam0 command.c compile.c constants.c debug.c execcmd.c frames.c function.c glob.c hash.c hdrmacro.c headers.c jam.c jambase.c jamgram.c lists.c make.c make1.c object.c option.c output.c parse.c pathsys.c pathunix.c regexp.c rules.c scan.c search.c subst.c timestamp.c variable.c modules.c strings.c filesys.c builtins.c class.c cwd.c native.c md5.c w32_getreg.c modules/set.c modules/path.c modules/regex.c modules/property-set.c modules/sequence.c modules/order.c execnt.c filent.c ./bootstrap/jam0 -f build.jam --toolset=mingw --toolset-root= clean ...found 1 target... ...updating 1 target... ...updated 1 target... ./bootstrap/jam0 -f build.jam --toolset=mingw --toolset-root= don't know how to make modules/set.c don't know how to make modules/path.c don't know how to make modules/regex.c don't know how to make modules/property-set.c don't know how to make modules/sequence.c don't know how to make modules/order.c ...found 126 targets... ...updating 1 target... ...can't find 6 targets... ...can't make 2 targets... failed to write command file! ================================================================================ Boost 1.53.0: $ cd boost_1_53_0/tools/build/v2/engine $ ./build.sh mingw ### ### Using 'mingw' toolset. ### rm -rf bootstrap mkdir bootstrap gcc -DNT -o bootstrap/jam0 command.c compile.c constants.c debug.c function.c glob.c hash.c hdrmacro.c headers.c jam.c jambase.c jamgram.c lists.c make.c make1.c object.c option.c output.c parse.c pathunix.c regexp.c rules.c scan.c search.c subst.c timestamp.c variable.c modules.c strings.c filesys.c builtins.c pwd.c class.c native.c md5.c w32_getreg.c modules/set.c modules/path.c modules/regex.c modules/property-set.c modules/sequence.c modules/order.c execnt.c filent.c ./bootstrap/jam0 -f build.jam --toolset=mingw --toolset-root= clean ...found 1 target... ...updating 1 target... ...updated 1 target... ./bootstrap/jam0 -f build.jam --toolset=mingw --toolset-root= ...found 50 targets... ...updating 3 targets... [MKDIR] bin.ntx86 [COMPILE] bin.ntx86\b2.exe [COPY] bin.ntx86\bjam.exe ...updated 3 targets... Any idea? Thanks & regards josue -- Josue Andrade Gomes josuegomes.com

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async processing issues
by SRD 04 Jul '13

04 Jul '13

Having a tough time learning ASIO. I'm trying to have one thread constantly listen for new file monitoring events (mthread) while another thread processes one task at a time (wthread). Somehow I'm still losing events that don't get placed on the task_queue and it would seem that once an event is lost, the file_handler callback for the dir_monitor stops working thereafter for good. So I'm having a few issues with my solution. If I comment out the sleep() method below, then for some reason the first two lines that have to do with the dir_monitor immediately after the while loop quickly eat through all available memory and the program will soon crash within a minute or two. Leaving the sleep in keeps things stable, or maybe it just eats away so slowly I don't notice it. Leaving sleep() in also has the problem of *I think* causing missed file events. The f_handler() function posts tasks that I create within the dir_monitor callback back to the main thread via the io_service.post(), but if its asleep, will it be able to place objects on the main processes task_queue? I think thats one point where I'm going wrong. If anyone sees where I'm going wrong, any help much appreciated. --- static queue<TaskObj *> task_queue; boost::asio::io_service io_service; void queue_task(TaskObj *task) { // pass task back to main thread. task_queue.push(task); } void f_handler(const boost::system::error_code &ec, const boost::asio::dir_monitor_event &ev) { TaskObj task = new TaskObj(...); // create task and place on queue by posting to main process io_service.post(boost::bind(queue_task, task)); } int main(...) { boost::asio::io_service work_service; boost::asio::dir_monitor dm(io_service); dm.async_monitor(f_handler); // dir_monitor thread boost::thread mthread = boost::thread(boost::bind(&boost::asio::io_service::run, boost::ref(io_service))); // setup work to prevent premature exit shared_ptr<boost::asio::io_service::work> work(new boost::asio::io_service::work(work_service)); // worker thread boost::thread wthread(boost::bind(&boost::asio::io_service::run, boost::ref(work_service))); wthread.detach(); while (true) { io_service.reset(); dm.async_monitor(f_handler); // losing all available memory from above two lines without the sleep() below // get first task off of queue and process in worker thread task = task_queue.front(); // functor executed in seperate thread work_service.post(boost::bind(&TaskObj::do_it, task)); sleep(3); }

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Confused with Depth-First-Search method, forward or cross edge found on a undirected graph ?
by lizy10b 03 Jul '13

03 Jul '13

Hi there I have a problem with the DFS method (Boost 1.53). I found when invoking the DFS method on a undirected graph, the "forward_or_cross_edge" was called more than one times. But as the document says "In an undirected graph this method is never called". http://www.boost.org/doc/libs/1_53_0/libs/graph/doc/DFSVisitor.html I performed the test based on the file_dependencies.cpp example (examples/file_dependencies.cpp; http://www.boost.org/doc/libs/1_53_0/libs/graph/doc/file_dependency_example…) 1) Change the graph type from "bidirectionalS" to "undirected". 2)Implement all the 8 DFS vistor "event methods" (Initialize Vertex, Start Vertex, Discover Vertex, Examine Edge, Tree Edge, Back Edge, Forward or Cross Edge, Finish Vertex) in the cycle_detector struct to print the vertex names, edge sources and targets. 3)comment out some code at the begining of the example cpp files as the topological_sort method raise exception upon the undirected graph. The results: the forward_or_cross_edge method was called five times. initialize_vertex: dax.h initialize_vertex: yow.h initialize_vertex: boz.h initialize_vertex: zow.h initialize_vertex: foo.cpp initialize_vertex: foo.o initialize_vertex: bar.cpp initialize_vertex: bar.o initialize_vertex: libfoobar.a initialize_vertex: zig.cpp initialize_vertex: zig.o initialize_vertex: zag.cpp initialize_vertex: zag.o initialize_vertex: libzigzag.a initialize_vertex: killerapp start_vertex: dax.h discover_vertex: dax.h examine_edge: dax.h --> foo.cpp tree_edge: dax.h --> foo.cpp discover_vertex: foo.cpp examine_edge: foo.cpp --> dax.h back_edge: foo.cpp --> dax.h examine_edge: foo.cpp --> zow.h tree_edge: foo.cpp --> zow.h discover_vertex: zow.h examine_edge: zow.h --> foo.cpp back_edge: zow.h --> foo.cpp finish_vertex: zow.h examine_edge: foo.cpp --> foo.o tree_edge: foo.cpp --> foo.o discover_vertex: foo.o examine_edge: foo.o --> foo.cpp back_edge: foo.o --> foo.cpp examine_edge: foo.o --> libfoobar.a tree_edge: foo.o --> libfoobar.a discover_vertex: libfoobar.a examine_edge: libfoobar.a --> foo.o back_edge: libfoobar.a --> foo.o examine_edge: libfoobar.a --> bar.o tree_edge: libfoobar.a --> bar.o discover_vertex: bar.o examine_edge: bar.o --> bar.cpp tree_edge: bar.o --> bar.cpp discover_vertex: bar.cpp examine_edge: bar.cpp --> dax.h back_edge: bar.cpp --> dax.h examine_edge: bar.cpp --> yow.h tree_edge: bar.cpp --> yow.h discover_vertex: yow.h examine_edge: yow.h --> dax.h back_edge: yow.h --> dax.h examine_edge: yow.h --> bar.cpp back_edge: yow.h --> bar.cpp examine_edge: yow.h --> zag.cpp tree_edge: yow.h --> zag.cpp discover_vertex: zag.cpp examine_edge: zag.cpp --> yow.h back_edge: zag.cpp --> yow.h examine_edge: zag.cpp --> boz.h tree_edge: zag.cpp --> boz.h discover_vertex: boz.h examine_edge: boz.h --> bar.cpp back_edge: boz.h --> bar.cpp examine_edge: boz.h --> zig.cpp tree_edge: boz.h --> zig.cpp discover_vertex: zig.cpp examine_edge: zig.cpp --> boz.h back_edge: zig.cpp --> boz.h examine_edge: zig.cpp --> zig.o tree_edge: zig.cpp --> zig.o discover_vertex: zig.o examine_edge: zig.o --> zig.cpp back_edge: zig.o --> zig.cpp examine_edge: zig.o --> libzigzag.a tree_edge: zig.o --> libzigzag.a discover_vertex: libzigzag.a examine_edge: libzigzag.a --> libfoobar.a back_edge: libzigzag.a --> libfoobar.a examine_edge: libzigzag.a --> zig.o back_edge: libzigzag.a --> zig.o examine_edge: libzigzag.a --> zag.o tree_edge: libzigzag.a --> zag.o discover_vertex: zag.o examine_edge: zag.o --> zag.cpp back_edge: zag.o --> zag.cpp examine_edge: zag.o --> libzigzag.a back_edge: zag.o --> libzigzag.a finish_vertex: zag.o examine_edge: libzigzag.a --> killerapp tree_edge: libzigzag.a --> killerapp discover_vertex: killerapp examine_edge: killerapp --> libzigzag.a back_edge: killerapp --> libzigzag.a finish_vertex: killerapp finish_vertex: libzigzag.a finish_vertex: zig.o finish_vertex: zig.cpp examine_edge: boz.h --> zag.cpp back_edge: boz.h --> zag.cpp finish_vertex: boz.h examine_edge: zag.cpp --> zag.o forward_or_cross_edge: zag.cpp --> zag.o !!!!!! finish_vertex: zag.cpp finish_vertex: yow.h examine_edge: bar.cpp --> boz.h forward_or_cross_edge: bar.cpp --> boz.h !!!!!! examine_edge: bar.cpp --> bar.o back_edge: bar.cpp --> bar.o finish_vertex: bar.cpp examine_edge: bar.o --> libfoobar.a back_edge: bar.o --> libfoobar.a finish_vertex: bar.o examine_edge: libfoobar.a --> libzigzag.a forward_or_cross_edge: libfoobar.a --> libzigzag.a !!!!!! finish_vertex: libfoobar.a finish_vertex: foo.o finish_vertex: foo.cpp examine_edge: dax.h --> bar.cpp forward_or_cross_edge: dax.h --> bar.cpp !!!!!! examine_edge: dax.h --> yow.h forward_or_cross_edge: dax.h --> yow.h !!!!!! finish_vertex: dax.h What is the problem? Thanks. Zhiyu 2013-06-24 lizy10b

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Applied GUI on chat server/client examples of boost.asio
by Journeyer J. Joh 03 Jul '13

03 Jul '13

Hi list, This is not a question nor an answer. And not an advertisement. I made an ultra simple GUI on boost.asio example code below. http://www.boost.org/doc/libs/1_53_0/doc/html/boost_asio/examples.html My code is on github. https://github.com/Journeyer/wxboost It is implemented from wxwidgets example code for wxTextCtrl under samples/text I don't have any purpose on this post. If anyone cloned my source code and compile and runs he/she would be able to talk with me and with anyone who did the same experiment. My chat server is running until it breaks. I am doing this just for fun ^^; FYI: build environment is Ubuntu/GCC/gtk/wxwidgets/boost Windows7/MinGW/wxwidgets/boost Best regards Journeyer ---------------------------------------- Journeyer J. Joh o o s a p r o g r a m m e r a t g m a i l d o t c o m ----------------------------------------

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[build] Build with multiple processes under MSVC10
by Igor R 03 Jul '13

03 Jul '13

Hello, Is the subj possible? Adding "cxxflags=/MP" to b2 line doesn't seem to work. Thanks.

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single thread in loop
by SRD 03 Jul '13

03 Jul '13

I'm using boost 1.53 on windows 7. I have a main loop which runs some checks and when events are received, results in callbacks that add tasks onto a queue. I then pull a task off the queue, wish to start a thread (and only one thread) to handle the task, and continue to loop checking for certain events. And each time I go through the loop, I want to check to see if the current thread has completed before pulling off another task to process. My problem is that I'm not sure how to write the thread in to do this and not join because I have to keep looping to check for certain events. void my_callback(...); MyTask *task; while (true) { event_checks(); switch(state) { case STATE1: if (!queue.empty()) task = queue.front(); // ... break; case STATE2: // check if thread is still running, otherwise, start new thread boost::thread(&MyTask::do_it, task); // ... break; // ... } I tried things similar to the below but couldn't get that quite right. boost::thread t; while (true) { // ... if (t.timed_join(0) == false) { t = boost::thread(&MyTask::do_it, task); } // ... Any help much appreciated.

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Thread pools and Boost Asio
by Rodrigo Madera 02 Jul '13

02 Jul '13

Hey there. I use Boost Asio for async code everywhere in C++, even where there is absolutely no IO whatsoever. Just (ab)using Asio "for the async of it." Searching the net for the current status of async frameworks for C++, I see that there is an unofficial (please correct me if I'm wrong) threadpool library. Will it become official? If not, does the Boost community offer something simpler than Asio for this? I just feel that I'm abusing Asio, where something simpler would suffice. And threadpool might be it. Would be nice to see if other people are async'ing out there. Best regards, Rodrigo Madera

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[asio] Getting started with strand
by Michael Powell 02 Jul '13

02 Jul '13

Hello, I want to get started using asio strand if at all possible. Getting started, however, I am struggling with a couple of errors/issues. For starters: * Cannot find std::enable_shared_from_this, std::move: they do not exist in our environment. * From there a ton of what look like steady-timer-related errors. Many of the errors are linker errors I think. Symbols cannot be resolved, such like this. I am pretty sure I am linking with the correct Boost libraries (statically, multi-threaded). Possibly need to rebuild Boost with different compiler settings? Also, possibly we do not have the correct compile-time switches enabled. Possibly also not linking with the correct libraries. We are cross-compiling into ArchLinux for ARM using Sourcery CodeBench, basically a GCC 4.7.2 based environment. That or are we stuck with the old-style approach to scheduling asio io_service callbacks? Would much prefer strands if we can somehow manage it. Thank you... Regards, Michael Powell

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boost 1.54 and intel compiler ?
by avib369 . 02 Jul '13

02 Jul '13

I have noticed that the Intel Compiler is no longer mentioned ? Has this compiler been dropped ? Ta, Avi

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Serializing containers of movable but noncopyable types
by Daniel Mitchell 02 Jul '13

02 Jul '13

While attempting to serialize a std::vector<T>, where T is a movable but noncopyable type, I was getting blown up by the call to s.push_back() on line 65 of collections_load_imp.hpp (Boost 1.53.0). In my local copy of that header I changed s.push_back(t.reference()) to s.push_back(std::move(t.reference())). Is this a safe change? Is there a better way to handle this case?

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[enable_shared_from_this] Disappeared
by Michael Powell 02 Jul '13

02 Jul '13

Hello, Where did it go from 1.53? We have not upgraded our compiler environment at all, so we are still depending on boost::enable_shared_from_this, however, this seems to have been dropped for std::enable_shared_from_this, which we do not have. Sounds like a bug report? Regards, Michael Powell

2 1

Random generators for Monte Carlo simulations
by Frédéric Bron 02 Jul '13

02 Jul '13

Hi, A collegue of mine performs Monte Carlo simulations. I made him switch with success to boost::random a few years ago. He recently found the following reference: http://www.agner.org/random and http://www.agner.org/random/ran-instructions.pdf The author proposes generators that are not implemented in boost called "Mother of All", "SFMT" and a special one that is a combination of two different generators (SFMT and Mother of All). Has anybody already done that using boost::random? Regards, Frédéric

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Re: [Boost-users] [boost] Boost 1.54.0 released!
by John Maddock 02 Jul '13

02 Jul '13

The PDF build of the boost documentation (for those libraries that support it) is now at https://sourceforge.net/projects/boost/files/boost-docs/1.54.0/. Please let me know if there are any SNAFU's. Regards, John.

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[zlib] Which version to use
by Michael Powell 02 Jul '13

02 Jul '13

Hello, Some of the build depends on zlib being readily available. For 1.53, I was building against zlib 1.2.7. Is that sufficient for 1.54? There is a zlib 1.2.8 available; worth upgrading to? Yes, no, possibly so? Thank you... Regards, Michael Powell

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