January 2014 - Boost-users - lists.preview.boost.org

boost multiprecision & STL map
by tridiak＠ihug.co.nz 19 Jan '14

19 Jan '14

I have a boost/C++ error which I am having a difficult time figuring out. Compiler error : Call to member function '__construct_node' is ambiguous Where StellarID()==0) {return errInvalidID;} if (stellarObjects.find(obj->StellarID())!= stellarObjects.end()) { return errStellarObjectIDClash; } stellarObjects[obj->StellarID()]=obj;

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[coroutine] Launch a thread in a coroutine
by Pierre Talbot 18 Jan '14

18 Jan '14

Hi, Is it possible to launch a thread in a coroutine? Such that this code would work: #include <iostream> #include <thread> #include <boost/coroutine/all.hpp> std::thread t; void push_data2(boost::coroutines::coroutine<std::string>::push_type sink) { sink("test2"); } void push_data(boost::coroutines::coroutine<std::string>::push_type& sink) { sink("test1"); t = std::thread(push_data2, std::move(sink)); } int main() { boost::coroutines::coroutine<std::string>::pull_type source(push_data); auto b = boost::begin(source); auto e = boost::end(source); std::cout << *b << std::endl; ++b; std::cout << *b << std::endl; t.join() return 0; } Output: test1 parser: /usr/local/include/boost/smart_ptr/intrusive_ptr.hpp:162: T* boost::intrusive_ptr<T>::operator->() const [with T = boost::coroutines::detail::push_coroutine_base<std::basic_string<char> >]: Assertion `px != 0' failed. Aborted (core dumped)

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[chron] time_point convertible?
by Oliver Kowalke 17 Jan '14

17 Jan '14

are the time_point-types of the clock-types from boost.chrono convertible into each other? chrono::system_clock::time_point t = convert_fun( chrono::steady_clock::now() ) etc. ?

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[serialization] test_dll_exported in VS2012
by Stefan Gradinger 17 Jan '14

17 Jan '14

Hi! I am currently trying to run the test_dll_exportet test in Visual Studio 2012, with polymorphic_derived2.cpp in a DLL and test_dll_exportet.cpp in the executable. Compiling and Linking works fine, but when I run the test, I get an "unregistered void cast class polymorhpic_derived2<-polymorhpic_base" error at line 85 of test_dll_exportet.cpp. Running the same test using the library_test tool (library_test --toolset=msvc-11.0) yields no errors. Does anybody have an idea what the cause for this problem might be? -- View this message in context: http://boost.2283326.n4.nabble.com/serialization-test-dll-exported-in-VS201… Sent from the Boost - Users mailing list archive at Nabble.com.

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Re: [Boost-users] [msm] [mpl] wrong number of template arguments (21, should be 20)
by Kamel Zaarouri, Mr 17 Jan '14

17 Jan '14

Hi, I added a new transition to my statemachine that is built around boost::msm and I got this error when compiling. error: wrong number of template arguments (21, should be 20) /boost/mpl/aux_/sequence_wrapper.hpp:154: error: provided for 'template<class T0, class T1, class T2, class T3, class T4, class T5, class T6, class T7, class T8, class T9, class T10, class T11, class T12, class T13, class T14, class T15, class T16, class T17, class T18, class T19> struct boost::mpl::vector' I went to add in the beginning of the header file before any boost includes: #define BOOST_MPL_LIMIT_LIST_SIZE 30 But that didn't fix it. I also tried adding in the makefile.am AM_CFLAGS = \ -DBOOST_MPL_LIMIT_LIST_SIZE=30 \ But that didn't fix it either. And then I hacked boost/mpl/limits/list.hpp and I changed the default value of BOOST_MPL_LIMIT_LIST_SIZE from 20 to 30 and I still have this error. Any idea? Thanks, Kamel

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[enable_if] Problem with conversion operator in VS2012
by dariomt＠gmail.com 17 Jan '14

17 Jan '14

Hi all, I'm trying to follow the example given in http://www.boost.org/doc/libs/1_55_0/libs/utility/enable_if.html#sec:enable… But VS2012 compiler gives: error C4519: default template arguments are only allowed on a class template Is this supposed to work with VS2012? Is there some other way to use enable_if in a conversion operator with VS2012? Thnaks!

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Compress to buffer
by Kenneth Adam Miller 16 Jan '14

16 Jan '14

I have an object for which operator << is defined, myobj. I want to compress into a buffer, and I know that this can be done with boost. I would prefer a buffer that dynamically resizes, but that only allocates new space, preferably treating discontiguous space brought on by new allocations as though the whole buffer was one piece; I don't want to find that it's copying data at all. So vector won't work as a buffer; there's no need for it to be contiguous, just as fast as possible. I've been trying to do this with filtering_istreambuf by pushing a bzip2_compressor (any compression filter will work). So far, it's giving me a lot of trouble. I did find an example where a string was passed to a function, but they went through a process where they first moved the string into an stringstream. I don't want to settle for that extra copy either. What would be nice is to be able to do something like compressor << myobj compressor.buf(); //returns compressed myobj output

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Boost.Heap (i.e fibonacci_heap) handle_type handles are persistent across calls?
by Tassos Souris 16 Jan '14

16 Jan '14

Hello to everyone When i use, say a fib_heap fb1 and fib_heap fb2. I add some data to fb1 using the push method and keep the handles returned from those calls. I do the same with fb2. Then i do some modification to the heaps. Lets say i do fb1.merge(fb2). Can i use the handles i obtained from the push calls on fb2 to update the data that was originally in fb2 and now in fb2?? That is the first time i obtain a handle_type from the push() method, it remains valid until the item is removed from the heap?? I tested the above scenario and seems to work but the documentation doesn't say anything and i would like another opinion. Thanks

1 0

Trying to extract sub library from Boost using BCP
by Colin Burn 16 Jan '14

16 Jan '14

I'm trying to extract "just what I need" from Boost to reduce the checkin footprint. So far I'm doing the following (On Windows): bootstrap.bat b2 tools/bcp md extract dist\bin\bcp boost/thread.hpp boost/shared_ptr.hpp boost/enable_shared_from_this.hpp boost/asio.hpp boost/thread/thread.hpp boost/bind.hpp boost/thread/lock_types.hpp boost/thread/condition_variable.hpp .\extract cd extract ..\b2but this gives me an error: boostcpp.jam: No such file or directory link.jam: No such file or directory Jamroot:137: in modules.load ERROR: rule "boostcpp.set-version" unknown in module "Jamfile<C:\temp\boost_1_55_0\extract>". C:/temp/boost_1_55_0/tools/build/v2/build\project.jam:311: in load-jamfile C:/temp/boost_1_55_0/tools/build/v2/build\project.jam:64: in load C:/temp/boost_1_55_0/tools/build/v2/build\project.jam:145: in project.find C:/temp/boost_1_55_0/tools/build/v2\build-system.jam:535: in load C:\temp\boost_1_55_0\tools\build\v2/kernel\modules.jam:289: in import C:\temp\boost_1_55_0\tools\build\v2/kernel/bootstrap.jam:139: in boost-build C:\temp\boost_1_55_0\boost-build.jam:17: in module scopeWhat am I doing wrong? What is the correct way to compile the extracted sub-library? Thanks Colin

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[Geometry] Calculating the centre of a rectangle
by Sean Farrow 16 Jan '14

16 Jan '14

Hi All, I'm in the process of needing to calculate the centre point of a rectangle, given the top left and bottom right co-ordinates. Before I write this myself, I was wondering whether boost Geometry already has something to do this. Any help appreciated. Cheers Sean.

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Re: [Boost-users] [Asio] signal_set not blocking/queueing signals on shutdown (Slava)
by Marat Abrarov 16 Jan '14

16 Jan '14

> >> I've written an io_service+signal_set signal handling implementation > >> in a thread of my application that triggers an orderly shutdown when > >> (among other things) the user presses Ctrl+C. > >> > > I first hear about asio signals, but I believe purpose of these signal > facility in asio is only to help you to implement *waiting* for signals, > like SIGCHLD, or SIGUSR{12}, whateverer you may choose for your IPC > communication. You should not misuse asio for general signal handling. > Normally signals are instantaneous things to be delivered right now right > here without any regard in which state the target is. I personally agree with Benjamin and think that the main goal of asio::signal_set is to provide the Asio way to handle signals. Look at the Asio examples (http://www.boost.org/doc/libs/1_55_0/doc/html/boost_asio/examples/cpp03_exa mples.html) - the "HTTP Servers" series. They use asio::signal_set for the same goal/reason as Benjamin does. Regards, Marat Abrarov.

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[Asio] signal_set not blocking/queueing signals on shutdown
by Benjamin Shadwick 16 Jan '14

16 Jan '14

I've written an io_service+signal_set signal handling implementation in a thread of my application that triggers an orderly shutdown when (among other things) the user presses Ctrl+C. According to the Boost.Asio documentation for signal_set ( http://www.boost.org/doc/libs/1_55_0/doc/html/boost_asio/reference/signal_s…) just having a signal_set (with inherent dependency on an io_service) with registered signals and not in a wait state is supposed to be enough to cause signals to be blocked/queued. After I stop the io_service and cancel the wait state on the signal_set, however, it appears that signal blocking/queueing is no longer occurring. I say this because hitting Ctrl+C during orderly shutdown after the io_service has stopped causes my application to instantly terminate (and in one case generate a core file). Is there something about stopping the io_service and/or canceling the async wait on the signal_set that is causing the note about signal queueing in the signal_set documentation to no longer apply? Thanks in advance.

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[boost::shared_ptr] Easy to violate the One Definition Rule / C++11 / Check für standard used to compile Boost
by beet 15 Jan '14

15 Jan '14

Hi there, from what I can see, boost::shared_ptr has a different definition, depending on whether Boost is compiled in C++98 oder C++11 mode. For example, in C++11-mode, shared_ptr has a move-constructor. By default, however, Boost seems to be compiled in C++98 mode, even with a compiler like gcc 4.8 (Ubuntu 13.10 / 64 bit / Boost 1.55), that is perfectly capable of compiling in C++11 mode. So, while boost::shared_ptr is header-only, all Boost libraries that use boost::shared_ptr will assume the C++98 version. The build-environment of one of my applications checks the compiler (currently gcc and CLang) and, depending on the version, activates C++11 support, so that I can use some C++11-checks (such as override), that can easily be #defined away for C++98 . So what may happen here is that my main application uses a different boost::shared_ptr than the Boost libraries I want to link with. To me this seems to violate the one-definition rule (and may happen with other Boost libraries as well). Indeed I'm seeing some strange errors, where "if(!p) {raise_error();}" triggers for a shared_ptr<derived_class> p, but I can still access member functions of a base_class that derived_class is derived from. Now, while I'm not yet sure that the above is the cause of this problem, I'd like to make sure that my build system chooses the appropriate C++ standard for compilation. Hence: Is there any way I can check (e.g. through some #define provided by Boost) what C++ standard it has been compiled with ? Thanks and Best Regards, Beet

2 1

[Units] conversion between double and millimeter
by Richel Bilderbeek 15 Jan '14

15 Jan '14

Hello Boost.Units users, When I convert a double to a unit (e.g. meter) and back, this works as expected. When I convert a double to a prefixed unit (e.g. millimeter) and back, this fails to compile. The code below shows how I'd expect it to work. What do I overlook? Thanks, Richel Bilderbeek const double x_in_mm = 1.0; const Length x(x_in_mm * milli * meter); //This works as expected: const double x_again_in_m = x / meter; //Why doesn't this: const double x_again_in_mm = x / (milli * meter); //Fails

2 1

[log] Default logging configuration for trivial logger
by Ben Pope 15 Jan '14

15 Jan '14

Hi, I'm using the trivial logging interface, but I need to tweak the default configuration. I want to be able to flush after every log entry, and I also want to be able to do file rolling. As far as I can tell, in order to configure it this way, I pretty much need to configure the whole thing from scratch including formatters, but I can't find the code that sets up the default logger to replicate it. Any pointers? Cheers, Ben

1 0

boost.log: how to view open log files
by Georg.Kellerer＠lfu.bayern.de 14 Jan '14

14 Jan '14

Hi, currently i am writeng a windows service and use the boost.log library for logfile creation. The serive should run long and I want to view the log files when the service is running. At the moment the logfile is written to the disk when the service ends and the file always has a size of 0 bytes. Is there a way to configure boost.log in a way that the log entries are written to disk immideately and that the logfile is not locked for reading by another application so that I can view my logfile? Thanks a lot, Georg

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Thread_group semantics
by Kenneth Adam Miller 14 Jan '14

14 Jan '14

When a thread_group is assigned a task using post, does that task get executed sequentially? Is there a list, so that, when too many posts are added to it, it keeps track of them?

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[program-options] Line width ignored on add()-ed options_description?
by Rhys Ulerich 13 Jan '14

13 Jan '14

I've got a "primary" options_description instance to which I add() other "secondary" options_description instances. I want operator<< to print the primary and all secondary instances with the primary instance's line width. I expect that this should happen automagically because, after construction, I cannot adjust the private m_line_length member of the secondary instances through any public means. However, it does not. A small re-create follows my signature. In my applications, I do not control the construction of the secondary instances and so I cannot adjust the secondary instance's construction-time width setting. Is this behavior a deliberate design decision? Some minor rework to options_description::print(...) within src/options_description.cpp would make it possible. Thanks, Rhys #include <iostream> #include <boost/program_options.hpp> int main() { static const char lengthy[] = "123456789 123456789 123456789 123456789 " "123456789 123456789 123456789 123456789 " "123456789 123456789 123456789 123456789 " "123456789 123456789 123456789 123456789 " "123456789 123456789 123456789 123456789 " "123456789 123456789 123456789 123456789 " "123456789 123456789 123456789 123456789 "; boost::program_options::options_description foo(255); // Linewidth 255 foo.add_options() ( "foo", lengthy ); boost::program_options::options_description bar; // Default line width bar.add_options() ( "bar", lengthy ); // foo should either dictate bar's line width, or... // I should be able to change it via a public interface... // ... but I seemingly cannot. foo.add(bar); // Option --foo has a nice long width, // but option --bar is truncated. std::cout << foo; }

1 0

UDP bind problems
by ustulation 13 Jan '14

13 Jan '14

{Windows 7, MinGW 4.8, boost 1.55} I'm having some problems with UDP binds. I've a client that broadcasts datagrams for listeners listening on specific port and binds to a port itself if the listeners want to communicate something back. The port on which the client needs to bind is X and the servers are listening on Y. Problem: If I simulate a client-crash (eg., by causing segmentation fault by dereferencing a nullptr) after binding the UDP socket to the port, then once the client application is no longer running (no longer listed in Windows Task Manager) netstat -ano | find "X" still shows that someone is bound to port X and ip address of 0.0.0.0 (the client had specified the IP address as any address). The PID cannot be found in Windows Task Manager. However when I downloaded application TCPView I can see that a *<non-existent>* process is still bound to 50000. On starting the client (without making it crash this time) subsequently I get two behaviors: <1> On some machines the client is unable to bind to the socket again (although reuse_address option is set to true) and the error message is: An attempt was made to access a socket in a way forbidden by its access permissions. <2> On other machines the client binds successfully but the read handler is not called and the client does not receive any datagram on port X although the servers are unicasting to the client port X. Infact <2> is true even for launching multiple instances of the client on the same machine even if none of the clients were deliberately made to crash and exist as zombie processes. Only the 1st one gets datagrams. Here is how client socket is set up: if(!m_udpSocket.is_open()) { m_udpSocket.open(m_localEndpoint.protocol(), errorCode); //m_localEndpoint is address 0.0.0.0 and port X if(errorCode) { std::cerr << "Unable to open socket: " << errorCode.message() << std::endl; } else { m_udpSocket.set_option(boost::asio::socket_base::reuse_address(true), errorCode); if(errorCode) { std::cerr << "Reuse address option set failure. " << errorCode.message() << std::endl; } m_udpSocket.set_option(boost::asio::socket_base::broadcast(true), errorCode); if(errorCode) { std::cerr << "Socket cannot send broadcast. " << errorCode.message() << std::endl; } else { m_udpSocket.bind(m_localEndpoint, errorCode); if(errorCode) { std::cerr << "Socket cannot bind...!! " << errorCode.message() << std::endl; } } } } Can you explain why do I get <1> and <2> and what can I do to avoid them and make socket bind even if there is some other process bound to that socket? I need to support Windows, Linux and MAC -- View this message in context: http://boost.2283326.n4.nabble.com/UDP-bind-problems-tp4657731.html Sent from the Boost - Users mailing list archive at Nabble.com.

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Fast IPC between Linux and Windows on the same host
by U.Mutlu 13 Jan '14

13 Jan '14

Hi, what is the fastest cross-platform IPC mechanism between Linux and Windows on the same physical host? Additional info: Host OS is Linux (Debian), Windows XP is hosted in VirtualBox. Of course TCP/IP sockets is a possibility, but I need something much faster. My preference would be to use shared memory, but is it possible in such an heterogene environment? And: can Boost.Interprocess be used for this scenario? Thx -- U.Mutlu DACOS Notdienstanlagen GmbH, Germany

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using iterator_range with wchar_t
by Sean Farrow 13 Jan '14

13 Jan '14

Hi All, I'm sorry if this has already been covered. I'm trying to use iterator_range with a wchar_t. My code is as follows: std::wstring buttonName =L"jar:file:/C:/Program%20Files/diseMP/4.5.6/O2-LIVE/lib/client/ClientResources.jar!/branding/default/buttons/FindButtonActive.png"; bool isGraphical =false; isGraphical =boost::algorithm::starts_with(buttonName, L"jar:file:/") && boost::algorithm::ends_with(buttonName, L".png"); boost::iterator_range<wchar_t> range =boost::algorithm::find_last(buttonName, L"/"); I'm getting the following errors: 1>------ Build started: Project: TestApp, Configuration: Debug Win32 ------ 1> TestApp.cpp 1>c:\program files (x86)\boost\boost\iterator\iterator_traits.hpp(30): error C2039: 'value_type' : is not a member of 'boost::detail::iterator_traits<Iterator>' 1> with 1> [ 1> Iterator=wchar_t 1> ] 1> c:\program files (x86)\boost\boost\range\iterator_range_core.hpp(141) : see reference to class template instantiation 'boost::iterator_value<Iterator>' being compiled 1> with 1> [ 1> Iterator=wchar_t 1> ] 1> c:\work\panthion studios\o2\testapp\testapp.cpp(11) : see reference to class template instantiation 'boost::iterator_range<IteratorT>' being compiled 1> with 1> [ 1> IteratorT=wchar_t 1> ] 1>c:\program files (x86)\boost\boost\iterator\iterator_traits.hpp(30): error C2146: syntax error : missing ';' before identifier 'type' 1>c:\program files (x86)\boost\boost\iterator\iterator_traits.hpp(30): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int 1>c:\program files (x86)\boost\boost\iterator\iterator_traits.hpp(30): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int 1>c:\program files (x86)\boost\boost\range\iterator_range_core.hpp(141): error C2039: 'type' : is not a member of 'boost::iterator_value<Iterator>' 1> with 1> [ 1> Iterator=wchar_t 1> ] 1>c:\program files (x86)\boost\boost\iterator\iterator_traits.hpp(49): error C2039: 'difference_type' : is not a member of 'boost::detail::iterator_traits<Iterator>' 1> with 1> [ 1> Iterator=wchar_t 1> ] 1> c:\program files (x86)\boost\boost\range\iterator_range_core.hpp(145) : see reference to class template instantiation 'boost::iterator_difference<Iterator>' being compiled 1> with 1> [ 1> Iterator=wchar_t 1> ] 1>c:\program files (x86)\boost\boost\iterator\iterator_traits.hpp(49): error C2146: syntax error : missing ';' before identifier 'type' 1>c:\program files (x86)\boost\boost\iterator\iterator_traits.hpp(49): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int 1>c:\program files (x86)\boost\boost\iterator\iterator_traits.hpp(49): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int 1>c:\program files (x86)\boost\boost\range\iterator_range_core.hpp(145): error C2039: 'type' : is not a member of 'boost::iterator_difference<Iterator>' 1> with 1> [ 1> Iterator=wchar_t 1> ] 1>c:\program files (x86)\boost\boost\iterator\iterator_traits.hpp(36): error C2039: 'reference' : is not a member of 'boost::detail::iterator_traits<Iterator>' 1> with 1> [ 1> Iterator=wchar_t 1> ] 1> c:\program files (x86)\boost\boost\range\iterator_range_core.hpp(159) : see reference to class template instantiation 'boost::iterator_reference<Iterator>' being compiled 1> with 1> [ 1> Iterator=wchar_t 1> ] 1>c:\program files (x86)\boost\boost\iterator\iterator_traits.hpp(36): error C2146: syntax error : missing ';' before identifier 'type' 1>c:\program files (x86)\boost\boost\iterator\iterator_traits.hpp(36): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int 1>c:\program files (x86)\boost\boost\iterator\iterator_traits.hpp(36): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int 1>c:\program files (x86)\boost\boost\range\iterator_range_core.hpp(159): error C2039: 'type' : is not a member of 'boost::iterator_reference<Iterator>' 1> with 1> [ 1> Iterator=wchar_t 1> ] 1>c:\program files (x86)\boost\boost\type_traits\is_abstract.hpp(72): error C2139: 'boost::iterator_range<IteratorT>' : an undefined class is not allowed as an argument to compiler intrinsic type trait '__is_abstract' 1> with 1> [ 1> IteratorT=wchar_t 1> ] 1> c:\program files (x86)\boost\boost\type_traits\is_abstract.hpp(144) : see reference to class template instantiation 'boost::detail::is_abstract_imp<T>' being compiled 1> with 1> [ 1> T=boost::iterator_range<wchar_t> 1> ] 1> c:\program files (x86)\boost\boost\mpl\aux_\preprocessed\plain\or.hpp(51) : see reference to class template instantiation 'boost::is_abstract<T>' being compiled 1> with 1> [ 1> T=boost::iterator_range<wchar_t> 1> ] 1> c:\program files (x86)\boost\boost\mpl\if.hpp(63) : see reference to class template instantiation 'boost::mpl::or_<T1,T2>' being compiled 1> with 1> [ 1> T1=boost::is_abstract<boost::iterator_range<wchar_t>>, 1> T2=boost::is_array<boost::iterator_range<wchar_t>> 1> ] 1> c:\program files (x86)\boost\boost\range\iterator_range_core.hpp(174) : see reference to class template instantiation 'boost::mpl::if_<T1,T2,T3>' being compiled 1> with 1> [ 1> T1=boost::mpl::or_<boost::is_abstract<boost::iterator_range<wchar_t>>,boost::is_array<boost::iterator_range<wchar_t>>>, 1> T2=boost::iterator_range<wchar_t>, 1> T3=boost::iterator_range<wchar_t> 1> ] ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== Does anyone have any clues as to why this is happening or alternatively any working example? Help appreciated as always. Regards Sean.

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Boost.Fiber review January 6-15
by Nat Goodspeed 13 Jan '14

13 Jan '14

Hi all, The review of Boost.Fiber by Oliver Kowalke begins today, Monday January 6th, and closes Wednesday January 15th. ----------------------------------------------------- About the library: Boost.Fiber provides a framework for micro-/userland-threads (fibers) scheduled cooperatively. The API contains classes and functions to manage and synchronize fibers similar to Boost.Thread. Each fiber has its own stack. A fiber can save the current execution state, including all registers and CPU flags, the instruction pointer, and the stack pointer and later restore this state. The idea is to have multiple execution paths running on a single thread using a sort of cooperative scheduling (versus threads, which are preemptively scheduled). The running fiber decides explicitly when it should yield to allow another fiber to run (context switching). Boost.Fiber internally uses coroutines from Boost.Coroutine; the classes in this library manage, schedule and, when needed, synchronize those coroutines. A context switch between threads usually costs thousands of CPU cycles on x86, compared to a fiber switch with a few hundred cycles. A fiber can only run on a single thread at any point in time. docs: http://olk.github.io/libs/fiber/doc/html/ git: https://github.com/olk/boost-fiber src: http://ok73.ok.funpic.de/boost.fiber.zip The documentation has been moved to another site; see the link above. If you have already downloaded the source, please refresh it; Oliver has added some new material. --------------------------------------------------- Please always state in your review whether you think the library should be accepted as a Boost library! Additionally please consider giving feedback on the following general topics: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? Nat Goodspeed Boost.Fiber Review Manager ________________________________

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[Log 2.0] rotating files size limiation
by Ovanes Markarian 13 Jan '14

13 Jan '14

Hello *, I am a bit stuck to implement a very simple scenario with boost log. I need to limit the size of entire rotation log. My current logger configuration looks like that: void setup_logging( channel_settings_t const& settings , std::string const& log_file , std::string const& log_level ) { config_logger_attributes(logging::core::get(), settings, log_level); using namespace logging::aux::default_attribute_names; //add logging to file (which implicitly deletes the default console logger) logging::add_file_log ( keywords::auto_flush = true, keywords::open_mode = std::ios::out | std::ios::app, keywords::file_name = log_file+"_%N.log", keywords::rotation_size = 50 * 1024, // Just for test limit to 50K keywords::format = //"%TimeStamp%: [%Channel%] |ThreadId| <%Severity%> %Message%" expr::format("%1% : [%2%] |%3%| <%4%> %5%") % expr::attr< boost::posix_time::ptime >(timestamp()) % expr::attr<std::string>(channel()) % expr::attr<attrs::current_thread_id::value_type>(thread_id()) % trivial::severity % expr::smessage )->locked_backend()->set_file_collector ( sinks::file::make_collector ( keywords::target = "logs" , keywords::max_size = 200 * 1024 // just for test limit to 200K ) ) ; } Unfortunately, I can't find what the target keyword means, despite the fact that it is a target directory. Target directory relating to smth or should there be a full path? Should this target directory exist? I did a test and rotating log files just grow upon the 200K limit. I just want to have let's say 3 or 4 last rotated log files, the rest should be removed? We already ran into the situation, where the logger used all disc space and the server crashed :( Any help if very appreciated! Thanks, Ovanes

1 1

Does Boost.Test cover 'golden file approach'?
by Journeyer J. Joh 13 Jan '14

13 Jan '14

Hello, I know almost nothing about 'golden file approach'. http://weblogs.java.net/blog/alexeyp/archive/2007/02/testing_command.html >From this blog, you can find the term 'golden file approach'. I want to know if Boost.Test cover this kind of testing. Can I implement 'golden file approach' with Boost.Test? If so please provide me more information about it. Thank you very much. ---------------------------------------- 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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lockfree::queue restrictions and performance on linux
by Leon Mlakar 13 Jan '14

13 Jan '14

Hello, after quite a while I'm back to using Boost (and back to the list) and quite happy to see that it made significant progress since I last last used it. One of the libraries that got my attentions is lockfree, the lockfree::queue in particular, since it almost completely meets my needs. Except that I've been wondering why is it that it places the requirement for the trivial destructor on the items it stores? I mean, that really reduces its usability. Is this something inherent to its design? I guess that this has been discussed during the review but a quick digging through the archives didn't come up anything on this. The reason for asking is that I have forced the queue to accept std::shared_ptr and this seems to work almost fine, except that there seem to be an extra reference left to the item last popped, but that's something I can live with. Another thing was its performance - I ran a sort of quick benchmark (queue of shared_ptr's to item containing atomic<int> as a counter, items were popped from the queue and immediately pushed back after decrementing the counter) and its perfromance was next to stellar on OSX (with multiple consumers and producers something like forty times faster than std::queue with mutex) but very poor on Linux. While I can understand that locking runs fast on Linux due to its spinlock/futex implementation of mutexes, I have no explanation for the poor performance of lockless::queue (with two producer/consumer threads std::queue with mutex was about 15 times faster and about 20 times slower than when run on OSX on the similar hardware). Did anybody else observe the same poor performance behavior? I used Boost 1.54 and tested with both gcc 4.8 and clang 3.5 and got similar results with both. Regards, Leon

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