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

[units]
by Robert Ramey 16 Sep '13

16 Sep '13

I have an urgent and definite need for the functionality which boost.units is meant to provide. The concept is quite simple so I had expected it to be relatively easy to use. I had anticipated spending a few hours perusing the documentation and examples, adding code to my application and moving on. T'was not to be. I'm now on day 3 (or 4?) trying to figure this thing out. The main hurdle is that the documentation is indecipherable. There are a number of templated classes defined which depend upon each other. I expect to find a page for each of the templates along with a description of what the template arguments should be. (Ideally these should be backed up with concept checking classes). Ideally there would be a small example showing how one would use these templates. It seems that the library is layered from low level ideas to higher level ones. The documentation touches on this - but its not really formalized. Theres a reference section which includes scores of things like base_units types for wide variety of units - but no where is there any indication how these should be used - not even in the examples are they used. There is a concept of "system" (of dimensions?) and the idea of mixing units from different systems and the idea that the same dimension (eg length) have multiple renderings in the system (nautical vs metric). I realize I've likely got this wrong and I'm not asking for anyone to explain this to me here - my point is that what should be very simple is incredibly confusing. I still haven't figured out whether it's only the documentation which is incomplete or if it is the actual logical design of the library itself is what's flawed. I'm still working on this. I don't remember much traffic on this list regarding this library and if I google information on boost C++ units library I don't get a whole lot of hits. This could mean that that the library is so easy to use no one ever needs to ask about it or it could be that almost no one every uses it. In Boost we don't gather statistics on usage by library so I don't which of these it might be. So my question is: Has anyone had good success with this library? How much effort did it take? What did you have to do to make it work. I would be curious about any other user feed back in these questions. Robert Ramey

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Re: [Boost-users] [Boost] Command Line to run a specific Boost Test Case using BOOST_AUTO_TEST_CASE_TEMPLATE
by Hemanth Choudary M V (RBEI/ETA1) 16 Sep '13

16 Sep '13

Hi Gennadiy, I have tried the same with the Boost 1.54.0 (Release Version) and it is not working. Looking forward to the next version which supports this. Mit freundlichen Grüßen / Best Regards, Hemanth Choudary MV RBEI/ETA1

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Overhead in boost IPC
by nithesh salian 16 Sep '13

16 Sep '13

Hi, I am interested in knowing the overhead associated with using boost message queue and shared memory. i.e., What is the latency associated with using these mechanisms for IPC? Thanks in advance. -- Regards, Nithesh Gangadhar Salian .

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Re: [Boost-users] [units]
by Kelly, Dan 16 Sep '13

16 Sep '13

I have had much the same experience as you. The library seems to hold a lot of promise and is from what I can see very sophisticated. But I had the same problems with the documentation and examples. I struggled for some time to figure out the difference between units and base units (and dimensions and base dimensions) and when you would use each. If someone could put together a decent tutorial I'm sure I would use this library quite frequently. -----Original Message----- From: Robert Ramey [ramey(a)rrsd.com<mailto:ramey@rrsd.com>] Sent: Sunday, September 15, 2013 01:14 PM Eastern Standard Time To: boost-users(a)lists.boost.org Subject: [Boost-users] [units] I have an urgent and definite need for the functionality which boost.units is meant to provide. The concept is quite simple so I had expected it to be relatively easy to use. I had anticipated spending a few hours perusing the documentation and examples, adding code to my application and moving on. T'was not to be. I'm now on day 3 (or 4?) trying to figure this thing out. The main hurdle is that the documentation is indecipherable. There are a number of templated classes defined which depend upon each other. I expect to find a page for each of the templates along with a description of what the template arguments should be. (Ideally these should be backed up with concept checking classes). Ideally there would be a small example showing how one would use these templates. It seems that the library is layered from low level ideas to higher level ones. The documentation touches on this - but its not really formalized. Theres a reference section which includes scores of things like base_units types for wide variety of units - but no where is there any indication how these should be used - not even in the examples are they used. There is a concept of "system" (of dimensions?) and the idea of mixing units from different systems and the idea that the same dimension (eg length) have multiple renderings in the system (nautical vs metric). I realize I've likely got this wrong and I'm not asking for anyone to explain this to me here - my point is that what should be very simple is incredibly confusing. I still haven't figured out whether it's only the documentation which is incomplete or if it is the actual logical design of the library itself is what's flawed. I'm still working on this. I don't remember much traffic on this list regarding this library and if I google information on boost C++ units library I don't get a whole lot of hits. This could mean that that the library is so easy to use no one ever needs to ask about it or it could be that almost no one every uses it. In Boost we don't gather statistics on usage by library so I don't which of these it might be. So my question is: Has anyone had good success with this library? How much effort did it take? What did you have to do to make it work. I would be curious about any other user feed back in these questions. Robert Ramey _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users ________________________________ IMPORTANT: The information contained in this email and/or its attachments is confidential. If you are not the intended recipient, please notify the sender immediately by reply and immediately delete this message and all its attachments. Any review, use, reproduction, disclosure or dissemination of this message or any attachment by an unintended recipient is strictly prohibited. Neither this message nor any attachment is intended as or should be construed as an offer, solicitation or recommendation to buy or sell any security or other financial instrument. Neither the sender, his or her employer nor any of their respective affiliates makes any warranties as to the completeness or accuracy of any of the information contained herein or that this message or any of its attachments is free of viruses.

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[coroutine] Resuming of coroutine from another thread
by Jason Roehm 16 Sep '13

16 Sep '13

I'm thinking up a design for a task-processing system that uses Boost.Asio and Boost.Coroutine. As part of that design, I would have a pool of worker threads executing work items. During processing of a particular work item, it's possible that the worker might need to wait on some other operation (e.g. I/O) to complete. However, while it waits, I'd like to put that thread to work doing something else useful from the queue. I was thinking of using coroutines to provide the ability to suspend the processing of one task, restarting it later when it is ready to move forward again. In my hypothetical framework, the thread that finishes the work might not be the same one that started it in the first place. I recently came across this Stack Overflow question: http://stackoverflow.com/questions/8557067/thread-safe-coroutines-with-asio which inquired as to the safety of creating a coroutine in one thread and then resuming it in another. The answers there indicate that this is not supported, and they link to Boost.Coroutine documentation that explains the underlying problems and why it isn't supported. However, that documentation was from the original Boost.Coroutine by Giovanni Deretta (which I'm not sure was ever actually accepted into Boost). The latest version by Oliver Kowalke indicates that it is a follow-up on that library, but doesn't have any specific caveats in the documentation regarding the interaction between threads and coroutines. Does the contemporary Boost.Coroutine have the same limitation, or is it safe to create a coroutine in one thread and then resume it in another? Jason

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Max Boost Fusion tuple parameters
by Rodrigo Madera 15 Sep '13

15 Sep '13

Hello, What is the maximum Boost Fusion tuple param count? I was thinking of using it for about 200-300 elements. Anyone done this? I've heard of defines for this, but never actually *knew* of anyone actually doing it. Thanks, Rodrigo Madera

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Too many EOF's using boost::asio
by ustulation 13 Sep '13

13 Sep '13

I have a TCP server and client with following read and write functions: ----------------- Writes ---------------------- void SomeClass::startWrite() { //m_writeBuffer is boost::asio::streambuf..m_writeQueue is std::deque<std::string> m_writeBuffer.sputn(&m_writeQueue.at(0)[0], m_writeQueue.at(0).size()); //m_objStrandWrite is boost::asio::strand boost::asio::async_write( getSocket(), m_writeBuffer, m_objStrandWrite.wrap([this](const boost::system::error_code &e, std::size_t bytesTxd){writeHandler(e, bytesTxd);}) ); } void SomeClass::writeHandler(const boost::system::error_code &refErrorCode, std::size_t bytesTxd) { if(!m_bIsStopped) { m_writeQueue.pop_front(); if(refErrorCode) { if(refErrorCode != boost::asio::error::operation_aborted) { std::cerr << "Write Error: " << refErrorCode.message() << std::endl; stop(); } } else { if(!m_writeQueue.empty()) { startWrite(); } } } } ------------------- Reads ----------------- void SomeClass::startRead() { //m_readBuffer is boost::asio::streambuf..m_objStrandRead is boost::asio::strand boost::asio::async_read_until( getSocket(), m_readBuffer, m_szTermString, m_objStrandRead.wrap([this](const boost::system::error_code &e, std::size_t bytesRxd){readHandler(e, bytesRxd);}) ); } void SomeClass::readHandler(const boost::system::error_code &refErrorCode, std::size_t bytesRxd) { if(!m_bIsStopped) { if(refErrorCode) { if(refErrorCode != boost::asio::error::operation_aborted) { std::cerr << "Read error: " << refErrorCode.message() << std::endl; stop(); } } else { if(bytesRxd) { std::string szRxdData; szRxdData.resize(bytesRxd); m_readBuffer.sgetn(&szRxdData[0], bytesRxd); } startRead(); } } } I get very frequent End Of File (EOF) error on client's read. It is not always but frequent. I am running a threadpool by asking multiple std::threads to execute io_service::run() which never quits until io_service::stop() is called. The data given by the server is almost never more than 5MB. As you see in the code, for any error I call stop() which shuts down the connection gracefully. <Q> *Is there something wrong I'm doing because I see no reason for EOF error. Why should the server close/shutdown the connection?* The code does not do that explicitly. Anyway it is random - out of 10 times maybe 5 are successful reads and 5 become EOF's and I have to restart my client executable to connect again in each of those cases. Other sockets don't do that - eg., I've tested with QTcpSocket of Qt framework and it works all the time (no randomness). -- View this message in context: http://boost.2283326.n4.nabble.com/Too-many-EOF-s-using-boost-asio-tp465117… Sent from the Boost - Users mailing list archive at Nabble.com.

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using boost with net-snmp
by moshe levi 12 Sep '13

12 Sep '13

I wrote an example on how to integrate net-snmp with boost. please checkout http://blog-moshe.blogspot.co.il/

2 1

ICMP Ping example running problem
by shunguang 12 Sep '13

12 Sep '13

Hi all, When i run *ping.cpp * at .\boost_1_53_0\doc\html\boost_asio\example\icmp, it comes with the error message: "Exception: open: An attempt was made to access a socket in a way forbidden by its access permissions". Debug shows that it comes from calling ",* socket_ (io_service , icmp::v4() )*" in the constructor. Google says the running computer must have administrator right, i do have it. i also checked my firewall settings, it looks fine to me also. Does anyone can give a help? Thanks, -shunguang -- View this message in context: http://boost.2283326.n4.nabble.com/ICMP-Ping-example-running-problem-tp4651… Sent from the Boost - Users mailing list archive at Nabble.com.

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[coroutine] help with code from docs
by Jeff Flinn 12 Sep '13

12 Sep '13

I'm trying to understand coroutine usage with boost 1.53.0. I'm getting an assertion when running the code snippet from the docs "Creating a coroutine" from http://www.boost.org/doc/libs/1_53_0/libs/coroutine/doc/html/coroutine/coro… #include <boost/coroutine/all.hpp> #include <string> typedef boost::coroutines::coroutine< int (std::string const&) > coro_t; // void f( boost::coroutine< std::string const&( int) > & ca) void f( coro_t::caller_type & ca) { std::string str( ca.get() ); // asserts here! ca(7); } int main(int argc, char* argv[]) { std::string str("abc"); coro_t c(f); c(str); // pass argument int res = c.get(); // returned value return 0; } Asserts in coroutine_get.hpp line 43: BOOST_ASSERT( static_cast< D const* >( this)->impl_->result_); Is the snippet from the doc incorrect or am I doing something else wrong. Thanks, Jeff

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boost::tr1::tuple or boost::tuple? how to compile the same code with both -std=c++98 and -std=c++11?
by Frédéric Bron 12 Sep '13

12 Sep '13

This small program compiles nicely with g++ 4.6.4 and -std=c++98 and boost 1.52.0: #include <iostream> #include <boost/math/tools/roots.hpp> #include <boost/tr1/tuple.hpp> std::tr1::tuple<double, double> f(double x) { return std::tr1::tuple<double, double>(x, 1.); } int main() { std::cout<<boost::math::tools::newton_raphson_iterate(f, 10., -9., +20., 10); return 0; } Now, I would like to be able to compile that program also with g++ 4.8.1 and -std=c++11 (I changed also boost to 1.53.0). If I do not change anything, std::tr1::tuple is replaced by std::tuple and I get the following error (see attached log): path/to/boost/include/boost/math/tools/roots.hpp:202:32: error: no match for 'operator=' (operand types are 'std::tuple<double&, double&>' and 'boost::fusion::tuple<double, double>') I tried to replace <boost/tr1/tuple.hpp> and std::tr1::tuple by <boost/tuple/tuple.hpp> and boost::tuple without any success. What should I do to have the same code compile with both -std=c++98 and -std=c++11? Regards, Frédéric

1 0

Regex on Windows2012
by Michael Xanadu 11 Sep '13

11 Sep '13

Hi guys, I developed a little application called MyProgram.exe (Win7, VS2008 SP1, Qt 4.8.4) and a little DLL called MyLibrary.dll. The DLL uses BOOST's regex engine 1.5. The executable calls the DLL via couple of functions, one function inside the DLL uses the regex engine. I've tested the environment on Windows7 and all is OK. BUT: If I copy the application and the DLL to Windows2012 I see that the executable crashes if I use it. I took a closer look to the issue and found out that the cause for the crash seems to be the regex engine inside the DLL. If regex functions will be called inside the DLL, it crashes and also the application does. AND: The strange thing is, that this problem seems to occur only on Windows2012 and only if the regex engine is inside a DLL. If I use Windows7 instead or uses the regex engine inside an executable on Windows2012 - everything works fine. I've already tried a lot to solve the problem, including using different linking approaches (BOOST as shared DLL etc.). I wonder if anybody had similar issues or can give me a hint of what went wrong? Regards, Michael

1 0

syntax error reporting from imported python modules
by Richi Lists 11 Sep '13

11 Sep '13

Hi, when I execute a python script that contains errors, I get nice and complete information from boost::python::error_already_set about the error and it's location. If the script that contains a syntax error is not executed directly, but imported from the main script, I don't get that exception. Instead it returns from the function as if everything was successful. When I check the result, the tasks from the other files were performed, just the stuff from the erroneous file is missing. Do I need to somehow attach the error reporting to the imported files? Rgds Richard

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[BOOST]BOOST_AUTO_TEST_CASE_TEMPLATE usage
by Hemanth Choudary M V (RBEI/ETA1) 11 Sep '13

11 Sep '13

Hi, In the code snippet below, The 3rd parameter in the BOOST_AUTO_TEST_CASE_TEMPLATE is a boost::mpl::list. Is the 3rd parameter restricted only to boost::mpl::list or anything else can also be used? #define BOOST_TEST_MODULE example #include <boost/test/included/unit_test.hpp> #include <boost/test/test_case_template.hpp> #include <boost/mpl/list.hpp> //____________________________________________________________________________// typedef boost::mpl::list<long long,unsigned char> test_types; BOOST_AUTO_TEST_CASE_TEMPLATE( my_test, T, test_types ) { BOOST_CHECK_EQUAL( sizeof(T), (unsigned)4 ); } //_ Mit freundlichen Grüßen / Best Regards, Hemanth Choudary MV RBEI/ETA1

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shared_ptr to this
by Gonzalo Garramuno 10 Sep '13

10 Sep '13

I have an application where I need to pass "this" in a callback belonging to a class to a function using a shared_ptr in another thread In code: struct Data { Data( void* p ) : ptr( p ) { } boost::shared_ptr<void> ptr; }; void threadA( Data* d ) { boost::shared_ptr<void> ptr( d->ptr ); delete d; // use ptr } class A { void init_thread() { Data* data = new Data( this ); boost.thread t( boost::bind( threadA, data ) ); } }; The problem is obvious. Once threadA closes, the shared ptr is destroyed as its count is 0 and as it points to the this of class A this gets deleted too. However my class A is still active and should not get deleted. How can I work around this?

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[wave] Wave macro expansion problem
by Edward Diener 10 Sep '13

10 Sep '13

The code: // test_macros_o.cpp #define f(a) f(x + (a)) #define x 2 #define g f #define h g(~ int main() { #pragma wave trace(enable) h 5); #pragma wave trace(disable) return 0; } In the latest C++ standard at 16.3.5 paragraph 5 the expansion of 'h 5)' is given as: f(2 * (~5)) but the wave.exe driver gives: C:\Programming\VersionControl\boost\libs\vmd\test\test_macros_o.cpp:11:3: h C:\Programming\VersionControl\boost\libs\vmd\test\test_macros_o.cpp:4:9: see macro definition: h [ g(~ rescanning [ C:\Programming\VersionControl\boost\libs\vmd\test\test_macros_o.cpp:3:9: see macro definition: g [ f rescanning [ f ] ]

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[wave] Wave driver --c++0x option
by Edward Diener 10 Sep '13

10 Sep '13

After building the Wave driver tool from the latest Boost source on trunk, if I pass the --c++0x option to the Wave.exe driver I get: wave: exception caught: unrecognised option '--c++0x' Do I have to build the wave driver with some option to support the --c++0x option when running it ?

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Re: [Boost-users] [BOOST.PREPROCESSOR] Use BOOST_PP_REPEAT in macros?
by Sergey Zhuravlev 10 Sep '13

10 Sep '13

I foolishly undef ARGS_AMOUNT after using. It is habit, because not wrote global macros earlier. Thanks, Edward Diener.

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[BOOST.PREPROCESSOR] Use BOOST_PP_REPEAT in macros?
by Sergey Zhuravlev 10 Sep '13

10 Sep '13

Write code: ////////////////// #define ARGS_AMOUNT 9 #define INTERNAL_GENERATE_MEMBER_APPLY_CLASS(_, ARG_COUNTER, MemberName)\ template<class TClassWithMember BOOST_PP_COMMA_IF(ARG_COUNTER) BOOST_PP_ENUM_PARAMS(ARG_COUNTER, class TArg)>\ result_type operator()(\ TClassWithMember& classWithMember BOOST_PP_COMMA_IF(ARG_COUNTER)\ BOOST_PP_ENUM_BINARY_PARAMS(ARG_COUNTER, TArg, &arg)) const\ {\ classWithMember.MemberName(BOOST_PP_ENUM_PARAMS(ARG_COUNTER, arg));\ } #define DECLARE_MEMBER_APPLY_CLASS(TMemberApplyClassName, MemberName)\ template<class TResultType>\ struct TMemberApplyClassName\ {\ typedef TResultType result_type;\ BOOST_PP_REPEAT(ARGS_AMOUNT, INTERNAL_GENERATE_MEMBER_APPLY_CLASS, MemberName)\ }; #undef ARGS_AMOUNT ////////////////// DECLARE_MEMBER_APPLY_CLASS(TClassName, MemberName) declare class template closer to boost::apply, but my declared class call member MemberName: f.MemberName(args...); opposite f.operator()(args...) at boost::apply. Code not work correctly, because ARGS_AMOUNT not replaced to number 9 internally. ARGS_AMOUNT preserved after all macros substitution. If manualy replace text "ARGS_AMOUNT" at "call" for BOOST_PP_REPEAT in macros DECLARE_MEMBER_APPLY_CLASS to 9, then code generated and work correctly. Why it does? How preserve valuable name of const ARGS_AMOUNT? Now temporarily maualy replace ARGS_AMOUNT to 9 and write comment about this hardcoded const 9: BOOST_PP_REPEAT(9 /*max amount of arguments for MemberName*/, INTERNAL_GENERATE_MEMBER_APPLY_CLASS, MemberName)\

2 1

[thread] release lock before cond.var. notified?
by Thomas M 09 Sep '13

09 Sep '13

Hi, Consider a boolean variable, a mutex and a condition variable: // simplified code snippet begin bool Continue = false; boost::mutex someMutex; boost::condition_variable someCondVar; // simplified code snippet end A number of (boost-)threads check if the boolean variable is set to true in order to continue execution, or otherwise wait for this to happen: // simplified code snippet begin boost::unique_lock<boost::mutex> threadLock(someMutex); while (Continue == false) { someCondVar.wait(threadLock); } // simplified code snippet end and a single controller thread is responsible for setting Continue to true (see snippets below). Now the question: Is there a strong point pro or against releasing controllerLock before the notify_all-signal is sent? E.g. is there preference for the first or second variant as below (see placement of curly brackets!), or even a need for one to ensure correctness? // simplified code snippet begin - Variant 1 // notify_all is issued while controllerLock is still being held { boost::unique_lock<boost::mutex> controllerLock(someMutex); Continue = true; someCondVar.notify_all(); } // simplified code snippet end // simplified code snippet begin - Variant 2 // notify_all is issued when controllerLock has already been released { boost::unique_lock<boost::mutex> controllerLock(someMutex); Continue = true; } someCondVar.notify_all(); // simplified code snippet end Thanks for your input and help, Thomas

4 5

Memory Leak with flat_map.insert(Iterator,Iterator)
by Adam Baxter 09 Sep '13

09 Sep '13

Hello, I'm experiencing a memory leak using the flat_map.insert(Iterator, Iterator) function. The leak goes away if I do regular for loop and use flat_map.insert(*Iterator). Is this a known issue? If not, what would be helpful for a bug report? Adam

2 1

Regex comparision
by Prakash Reddy Bande 09 Sep '13

09 Sep '13

Hi, I would like to change a regular expression in a compatible way. Here is the use case. Initially, in the configuration I defined a reg-exp for validation of data before persisting it. Some data was created and persisted, later the reg-exp required a change, however, the change must be done is such a way that existing data should not become invalid. Example: Initial validation says "no ; (semi-colon) and : (colon) in the text". However, later we decide to relax the constraint and want to allow : (colon). By allowing this we are not invalidating any existing data and hence this change should be allowed. However, we should not be changing the configuration and add additional constraint, like now I don't want to allow _ (underscore) since there will be existing data that has _ (underscore). I am using: boost_1_46_1 Pseudo-code of APIs I am using: #include <boost/xpressive/xpressive.hpp> string regexPattern("^[^\\/?%*:|\"<>\.]+$"); boost::xpressive::sregex tmpRegex = boost::xpressive::sregex::compile(regexPattern); bool match = boost::xpressive::regex_match("value to validate", tmpRegex); Now I decide that I would start allowing . (dot) from now on. Is there a way that will allow me to validate that whatever successfully matches the old expression will also match the new expression Regards, Prakash Bande Director - Hyperworks Enterprise Software Altair Eng. Inc. Troy MI Ph: 248-614-2400 ext 489 Cell: 248-404-0292 My Secure Drop Box: https://ftam1.altair.com/dropbox/~Ursfnk

1 0

[thread] Internal compiler error when trying to make movable future
by Gavin Lambert 09 Sep '13

09 Sep '13

Am I doing something wrong in the following code? #include <boost/thread/future.hpp> template<typename T> struct test_node { BOOST_THREAD_MOVABLE_ONLY(test_node) typedef boost::unique_future<test_node> future_node; T value; future_node next; }; (In the "real code" I've defined move constructors etc as well of course, but they don't affect the result so I've omitted them for brevity.) Using boost v1.53 with BOOST_THREAD_VERSION==2 and VS2008 (non C++11 compiler), the above code produces an internal compiler error: 1>t:\boost\boost_1_53_0\boost\type_traits\is_convertible.hpp(484) : fatal error C1001: An internal error has occurred in the compiler. 1>(compiler file 'msc1.cpp', line 1411) 1> To work around this problem, try simplifying or changing the program near the locations listed above. 1>Please choose the Technical Support command on the Visual C++ 1> Help menu, or open the Technical Support help file for more information 1> t:\boost\boost_1_53_0\boost\thread\detail\is_convertible.hpp(22) : see reference to class template instantiation 'boost::is_convertible<From,To>' being compiled 1> with 1> [ 1> From=test_node<int> &, 1> To=boost::detail::thread_move_t<test_node<int>> 1> ] 1> t:\boost\boost_1_53_0\boost\mpl\if.hpp(63) : see reference to class template instantiation 'boost::thread_detail::is_convertible<T1,T2>' being compiled 1> with 1> [ 1> T1=test_node<int> &, 1> T2=boost::detail::thread_move_t<test_node<int>> 1> ] 1> t:\boost\boost_1_53_0\boost\thread\future.hpp(519) : see reference to class template instantiation 'boost::mpl::if_<T1,T2,T3>' being compiled 1> with 1> [ 1> T1=boost::thread_detail::is_convertible<test_node<int> &,boost::detail::thread_move_t<test_node<int>>>, 1> T2=boost::detail::thread_move_t<test_node<int>>, 1> T3=const test_node<int> & 1> ] 1> t:\boost\boost_1_53_0\boost\thread\future.hpp(1398) : see reference to class template instantiation 'boost::detail::future_traits<T>' being compiled 1> with 1> [ 1> T=test_node<int> 1> ] 1> s:\tests\nodetest.cpp(26) : see reference to class template instantiation 'boost::unique_future<R>' being compiled 1> with 1> [ 1> R=test_node<int> 1> ] 1> s:\tests\nodetest.cpp(56) : see reference to class template instantiation 'test_node<T>' being compiled 1> with 1> [ 1> T=int 1> ] The internal error goes away if I remove the MOVABLE_ONLY macro or the future_node instance field. The equivalent move code (using boost::detail::thread_move_t directly) for boost 1.47 compiles and works successfully (but crashes again if I switch to boost 1.53). Is this a regression in boost or am I doing something incorrect somewhere? Does anyone know of a workaround? Note that it does not matter if I try to use Boost.Move syntax instead, as unique_future<> internally uses Boost.Thread's move implementation, which is where things seem to be failing. One possible issue is that I'm trying to declare a future to an incomplete type (because it's self-referential), which is possibly confusing some of the internal checks it wants to do. But again, this usage used to work, and I'm not sure how to fix it given the new boost version. At least not without introducing pointers and heap allocation, which I really didn't want to do.

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[accumulators] Help with accumulator-based typedef
by Michael Powell 09 Sep '13

09 Sep '13

Hello, I am trying to setup a "simple" weighted_mean accumulator for a struct I want to accumulate. It goes something like this. Let's call it a float for sake of example. It's actually a struct with mathematical comprehension: addable, subtractable, multipliable, dividable, and so on. typedef accumulator_set<float, stats<tag::rolling_mean>, features<tag::count, tag::weighted_mean> > my_float_accumulator_set; However, I am getting obscenely long errors complaining about AccumulatorSet, etc, etc. Can someone direct me to a (somewhat) complete example of a weighted_sum accumulator in action? Am I even on the right track type-defining my accumulator ahead of time? Regards, Michael Powell

1 1

Re: [Boost-users] cross-compilation x86_64-w64-ming32: undefined reference to `InterlockedIncrement'
by Frédéric Bron 08 Sep '13

08 Sep '13

> I have exactly the same issue with MinGW-builds gcc-4.8.1-x86_64-posix-seh > building boost 1.54.0. It also crashes cxx1plus.exe as I build it (which is > probably another problem). > Did you manage to construct a workaround? Well I stopped working on that. I was expecting that somebody could help with the content of <boost/detail/interlocked.hpp> but got no answer. I imagine that extern "C" long InterlockedIncrement( long volatile * ); should be extern "C" __attribute__((dllimport)) long __attribute__((__stdcall__)) InterlockedIncrement( long volatile * ); as it is in 32 bits. I have now looked a bit further: among the preprocessor variable checked in <boost/detail/interlocked.hpp>, here are the differences when compiling with i686-w64-mingw32-g++ or x86_64-w64-mingw32-g++: 1. in both cases, the following variables are undefined: WIN32 __CYGWIN__ MINGW64 _M_IA64 BOOST_MSVC BOOST_INTEL_WIN _WIN32_WCE _MSC_VER 2. in both cases, the following variables are defined with value 1: _WIN32 __WIN32 3. variable _M_AMD64 is undefined with i686-w64-mingw32-g++ and defined with value 100 with x86_64-w64-mingw32-g++. Does this help? In particular, is it normal that _WIN32 and __WIN32 are defined when targetting win64? Is it normal that MINGW64 is always undefined although I use a W64 compiler? Frédéric

3 6

[accumulators] Moving mean expiry
by Michael Powell 08 Sep '13

08 Sep '13

Hello, I am looking for a moving window mean accumulator. Could roll my own, but I know there's a pretty good one in Boost. Need to know, does it comprehend the notion of Expiration? That is, values dropping off after a predetermined window of time? Preferably depending on the boost::chrono::high_resolution_clock. Thank ye... Regards, Michael Powell

1 1

[Serialization and possibly others] Serialization library built with Clang symbol export errors on link
by Kim 07 Sep '13

07 Sep '13

Hey guys, I'm trying to link my program to the boost serialization library built using clang w/ the mingw STL headers on Windows and I get a lot of symbol not found errors. Any help is most appreciated since I really want to get this working with Clang. If I need to provide more information please let me know. C:\MinGW\bin>g++ -shared script.o libboost_serialization-clang34-mt-1_54.lib -o script.dll Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_iarchiveEEEE12get_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_iarchiveEEEE12is_destroyedEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_iarchiveEEEE18get_const_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_iarchiveEEEE20get_mutable_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_iarchiveEEEE8instanceE: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_oarchiveEEEE12get_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_oarchiveEEEE12is_destroyedEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_oarchiveEEEE18get_const_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_oarchiveEEEE20get_mutable_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_oarchiveEEEE8instanceE: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_19naked_text_iarchiveEEEE12get_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_19naked_text_iarchiveEEEE12is_destroyedEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_19naked_text_iarchiveEEEE18get_const_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_19naked_text_iarchiveEEEE20get_mutable_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_19naked_text_iarchiveEEEE8instanceE: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_13typeid_system27extended_type_info_typeid_0ENS3_12type_compareESaIS6_EEE12get_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_13typeid_system27extended_type_info_typeid_0ENS3_12type_compareESaIS6_EEE12is_destroyedEv: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_13typeid_system27extended_type_info_typeid_0ENS3_12type_compareESaIS6_EEE18get_const_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_13typeid_system27extended_type_info_typeid_0ENS3_12type_compareESaIS6_EEE20get_mutable_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_13typeid_system27extended_type_info_typeid_0ENS3_12type_compareESaIS6_EEE8instanceE: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_18extended_type_infoENS0_6detail11key_compareESaIS5_EEE12get_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_18extended_type_infoENS0_6detail11key_compareESaIS5_EEE12is_destroyedEv: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_18extended_type_infoENS0_6detail11key_compareESaIS5_EEE18get_const_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_18extended_type_infoENS0_6detail11key_compareESaIS5_EEE20get_mutable_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_18extended_type_infoENS0_6detail11key_compareESaIS5_EEE8instanceE: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_iarchiveEEEE12get_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_iarchiveEEEE12is_destroyedEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_iarchiveEEEE18get_const_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_iarchiveEEEE20get_mutable_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_iarchiveEEEE8instanceE: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_oarchiveEEEE12get_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_oarchiveEEEE12is_destroyedEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_oarchiveEEEE18get_const_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_oarchiveEEEE20get_mutable_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_13text_oarchiveEEEE8instanceE: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_19naked_text_iarchiveEEEE12get_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_19naked_text_iarchiveEEEE12is_destroyedEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_19naked_text_iarchiveEEEE18get_const_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_19naked_text_iarchiveEEEE20get_mutable_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonINS_7archive6detail12extra_detail3mapINS2_19naked_text_iarchiveEEEE8instanceE: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_13typeid_system27extended_type_info_typeid_0ENS3_12type_compareESaIS6_EEE12get_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_13typeid_system27extended_type_info_typeid_0ENS3_12type_compareESaIS6_EEE12is_destroyedEv: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_13typeid_system27extended_type_info_typeid_0ENS3_12type_compareESaIS6_EEE18get_const_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_13typeid_system27extended_type_info_typeid_0ENS3_12type_compareESaIS6_EEE20get_mutable_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_13typeid_system27extended_type_info_typeid_0ENS3_12type_compareESaIS6_EEE8instanceE: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_18extended_type_infoENS0_6detail11key_compareESaIS5_EEE12get_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_18extended_type_infoENS0_6detail11key_compareESaIS5_EEE12is_destroyedEv: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_18extended_type_infoENS0_6detail11key_compareESaIS5_EEE18get_const_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_18extended_type_infoENS0_6detail11key_compareESaIS5_EEE20get_mutable_instanceEv: symbol not found Cannot export __ZN5boost13serialization9singletonISt8multisetIPKNS0_18extended_type_infoENS0_6detail11key_compareESaIS5_EEE8instanceE: symbol not found collect2.exe: error: ld returned 1 exit status C:\MinGW\bin>

1 1

[spirit] Qi-adapted-struct light bulb
by Michael Powell 07 Sep '13

07 Sep '13

Hello, A light bulb went on for me with regard to adapting structs into Qi parser grammars. Feel free to correct me if I'm wrong. The key is adapting a struct into your grammer's parser(s) using the BOOST_FUSION_ADAPT_STRUCT, which identifies the type (struct) and fields you are synthesizing out of the grammar. It doesn't mean that there can't be other (presumably) public variables, functions, etc, in the struct. It also doesn't mean there can't be private or protected or even a hierarchy of members. It just means that those are the *adapted* fields into which values will be synthesized. Need a style feedback as well. I am finding that I define both the struct and its parser grammar in the same header/source. Is there any reason to separate the two, really? Other than perhaps not everything needs to know about the grammer, just the struct, type thing. Thank you... Regards, Michael Powell

1 0

Boost program option parsing issue.
by Vivek Anand 07 Sep '13

07 Sep '13

Hi All, I am using program option for my program. Here is my code snippet string inputFile, outputFile; /* Populate command line arguments */ po::options_description desc("Usage: KDMGenerator [OPTIONS]"); { desc.add_options() ("help", "prints this message") ( "input-file", po::value<string>(&inputFile), "input file name" ) ( "output-file", po::value<string>(&outputFile), "output file name"); } po::variables_map vm; po::store(po::parse_command_line(argc, argv, desc), vm); po::notify(vm); if (vm.count("help") || !vm.size()) { cout <<desc; return 0; } if(vm.count("input-file")) { cout << "Input file :" << inputFile << '\n'; } if(vm.count("output-file")) { cout << outputFile << '\n'; } The issue I am facing is that if i I call my program without passing value for input file, something like ./myapp --input-file --output-file out.txt I get Input file: --output-file i.e the value "--output-file" get stored in inputFile and vm.count("output-file") returns zero. Is this the desired behavior? Is there any workaround for this? -- Vivek,

2 4

[spirit] qi pheonix struct adaptation
by Michael Powell 06 Sep '13

06 Sep '13

Hello, Need a little guidance when it comes to adapting structs. Let's say I've got a simple struct: struct data_t { int a; int b; int c; }; When I adapt it, I need to specify the fields into which the values are being consumed and subsequently synthesized? What happens for optional consumers, in one use-case? In another use-case, what happens if one value or another value or a third value can be consumed for that field? So, something like this, pardoning the pseudo-code: using qi::int_; using qi::lit; qi::rule<Iterator, data_t()> rule_; //a is optional, followed by b is mandatory, followed by c can be 1 | 2 | 3 rule_ %= -( int_ ) >> lit(',') >> int_ >> lit('.') >> ( int_(1) | int_(2) | int_(3) ); This is applying into a GPS NMEA parser domain, so along these lines for things like geo-spacial-coordinates, latitude/longitude, time, etc. Thank you... Regards, Michael Powell

1 0

compilation error
by Николай Кинаш 06 Sep '13

06 Sep '13

Hello all! My programm: `--# cat test_boost.hpp #include <boost/graph/adjacency_list.hpp> #include <boost/graph/rmat_graph_generator.hpp> #include <boost/random/linear_congruential.hpp> typedef boost::adjacency_list<>Graph; typedef boost::unique_rmat_iterator<boost::minstd_rand, Graph> RMATGen; int main() { boost::minstd_rand gen; // Create graph with 100 nodes and 400 edges Graph g(RMATGen(gen, 100, 400, 0.57, 0.19, 0.19, 0.05), RMATGen(), 100); return 0; } `--# mpic++ test_boost.hpp -I./boost/boost/graph/ -I./boost/ -I./boost/boost/random/ -o test_boost /usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/crt1.o: In function `_start': (.text+0x20): undefined reference to `main' collect2: error: ld returned 1 exit status what's wrong ?

2 1

[filesystem] path destructor crash
by Patrick Steele 06 Sep '13

06 Sep '13

boost = 1.54 IDE = Visual Studio 2005 / 2012 OS = Windows 7 Hi, I have a 32-bit application that I am upgrading from Visual Studio 2005 to 2012. If I place the following code at the beginning of the application: { //test 1 boost::filesystem::path blahPath; } { //test 2 boost::filesystem::path blahPath = _T( "C:\\ProgramData\\blah" ); } { //test 3 boost::filesystem::path blahPath; std::wstring text = _T( "C:\\ProgramData\\blah" ); blahPath = text; } then it works fine in Visual Studio 2005, however test 3 crashes in Visual Studio 2012 with: --------------------------- Microsoft Visual C++ Runtime Library --------------------------- Debug Assertion Failed! File: f:\dd\vctools\crt_bld\self_x86\crt\src\dbgdel.cpp Line: 52 Expression: _BLOCK_TYPE_IS_VALID(pHead->nBlockUse) and this callstack: msvcr110d.dll!operator delete(void * pUserData) Line 52 C++ boost_filesystem-vc110-mt-gd-1_54.dll!std::allocator<wchar_t>::deallocate(wchar_t * _Ptr, unsigned int __formal) Line 586 C++ boost_filesystem-vc110-mt-gd-1_54.dll!std::_Wrap_alloc<std::allocator<wchar_t> >::deallocate(wchar_t * _Ptr, unsigned int _Count) Line 888 C++ boost_filesystem-vc110-mt-gd-1_54.dll!std::basic_string<wchar_t,std::char_traits<wchar_t>,std::allocator<wchar_t> >::_Tidy(bool _Built, unsigned int _Newsize) Line 2265 C++ boost_filesystem-vc110-mt-gd-1_54.dll!std::basic_string<wchar_t,std::char_traits<wchar_t>,std::allocator<wchar_t> >::~basic_string<wchar_t,std::char_traits<wchar_t>,std::allocator<wchar_t> >() Line 965 C++ boost_filesystem-vc110-mt-gd-1_54.dll!boost::filesystem::path::~path() C++ blah.exe!CPlanarApp::InitInstance() Line 152 C++ mfc110ud.dll!AfxWinMain(HINSTANCE__ * hInstance, HINSTANCE__ * hPrevInstance, wchar_t * lpCmdLine, int nCmdShow) Line 37 C++ blah.exe!wWinMain(HINSTANCE__ * hInstance, HINSTANCE__ * hPrevInstance, wchar_t * lpCmdLine, int nCmdShow) Line 26 C++ blah.exe!__tmainCRTStartup() Line 528 C blah.exe!wWinMainCRTStartup() Line 377 C kernel32.dll!75ce33aa() Unknown [Frames below may be incorrect and/or missing, no symbols loaded for kernel32.dll] ntdll.dll!76f09ef2() Unknown ntdll.dll!76f09ec5() Unknown The boost::filesystem::path destructor is being called and is causing a crash. I do not understand how the first two tests can pass yet there is a problem with the third test. Is there something that I am doing wrong here or does anyone have any advice please? Thanks, Patrick

3 7

[BGL] Having a cost function as weight map
by Maxime van Noppen 06 Sep '13

06 Sep '13

Hi, I can't find how to do this pretty basic thing : having a function instead of a field to compute the cost of edges for various path finding algorithms. I couldn't find the answer in the documentation and Google was of no help. Did I miss something obvious ? Example : ------------------- #include <boost/graph/dijkstra_shortest_paths.hpp> #include <boost/graph/graph_traits.hpp> #include <boost/graph/adjacency_list.hpp> struct my_edge { double cost() const { return cost_ * 2; } double cost_; }; struct my_node { }; int main() { typedef boost::adjacency_list< boost::vecS, boost::vecS, boost::directedS, my_node, my_edge > graph_t; typedef boost::graph_traits<graph_t>::vertex_descriptor vertex_t; graph_t graph; vertex_t v /*= ... */; using boost::weight_map; // Works : boost::dijkstra_shortest_paths(graph, v, weight_map(boost::get(&my_edge::cost_, graph))); // Doesn't compile : //boost::dijkstra_shortest_paths(graph, v, // weight_map(boost::get(&my_edge::cost, graph))); } ------------------- Thanks ! -- Maxime

4 8

How to build Boost binary libraries on Windows X64 using GCC
by guxiaobo1982 06 Sep '13

06 Sep '13

Hi, We are trying to develop a custom R package, which will utilize Boost and RCPP. We are using R 3.0.1 64bit, and the corresponding RTools3 toolchain, which can be downloaded from CRAN, such as http://cran.at.r-project.org/bin/windows/Rtools/Rtools31.exe. Upon our environment we can build test R packages which with C++ srouces and without any other third-part denpendencies, and can use Eclipse C++ IDE to develop demo C++ programes. When comes to Boost, there is a problem to build the binary libraries such as regex, we found a guide at http://fischerlaender.de/development/using-boost-c-libraries-with-gcc-g-und…, it only tells how to use a pre-built Boost binary, and we have tried the steps at http://stackoverflow.com/questions/5299468/unable-to-build-boost-libraries-… 1. cd to toos\build\v2\engine (there is not a src directory) 2. build.bat gcc 3. put the new bjam.exe and b2.exe into the root the boost 4. execute b2 under root of boost It seems boost still looks for cl (which is from the visual studio toolchain) So do you have a pre-built boost library for windows and gcc, or what's the wright way? Thanks. Xiaobo Gu

1 0

[spirit] Qi rule for GPS NMEA
by Michael Powell 06 Sep '13

06 Sep '13

Hello, I'm digging into a qi rule for GPS NMEA and want to approach it as a kind of 2-pass parser. First pass to extract the message and hex-formatted checksum. Next pass to parse out the actual messages from the message. I believe I comprehend how to go about the second pass. For the first pass, I want to parse $XYZ*HH\r\n. That's the literal '$', and everything between there and the literal '*', followed by the two hex characters, as a complete field, followed by the terminal CR+LF. How do I express the "all characters excluding '*'" for the NMEA message? Then the hex field? Thanks... Regards, Michael Powell

3 9

[BGL] Cannot use vertex indices managed through bundled properties with r_c_shortest_path if EdgeList is listS
by potato_research 05 Sep '13

05 Sep '13

As per the thread topic. Given the following minimal (not-)working example: http://pastebin.com/6zpwCb4X I receive the following compilation error: /usr/local/include/boost/graph/r_c_shortest_paths.hpp:244:50: error: invalid conversion from 'boost::graph_traits<boost::adjacency_list<boost::listS, boost::listS, boost::bidirectionalS, VertexProperty, EdgeProperty> >::vertex_descriptor {aka void*}' to 'int' [-fpermissive] int i_cur_resident_vertex_num = cur_label->resident_vertex; If I change my graph from: adjacency_list<listS, listS, bidirectionalS, VertexProperty, EdgeProperty> to adjacency_list<listS, vecS, bidirectionalS, VertexProperty, EdgeProperty> everything seems to be working fine. However, I need to use listS in my code for iterator validity purposes. Is it possible to use r_c_shortest_paths with a graph with listS EdgeList? If so, how? Thanks. -- View this message in context: http://boost.2283326.n4.nabble.com/BGL-Cannot-use-vertex-indices-managed-th… Sent from the Boost - Users mailing list archive at Nabble.com.

2 7

[chrono] this_thread::sleep_for milliseconds
by Michael Powell 05 Sep '13

05 Sep '13

Hello, I am working on a daemon that involves a sleep_for in the main loop, while worker-threads do the "heavier" lifting in the daemon. I have a couple of signals wired up to respond to terminal, kill or other requests, as per daemonization-guidelines. Question for the list, I gather that thread-sleeps are interrupted when these type of signals occur? Which is fine, I don't need to re-sleep, per se, as some examples seem to suggest. But I do guard a flag in a mutex-critical-section and flag whether to stop running the main loop, which then joins the worker threads. Is this about right as far as daemon, thread/sleep, worker thread approaches are concerned? It seems like it to me, but I thought I should run it past the list to see if there are any pearls of wisdom on the subject. Thank you... Regards, Michael Powell

2 1

[units] coulombs to milliamp-hours
by Michael Powell 05 Sep '13

05 Sep '13

Hello, I am looking for a Coulombs to mAh (milliamp-hours) converter. It's conversion is a ratio I think: 1000 / 3600 (A -> mA, seconds -> hours). Haven't checked yet, but does SI include Coulombs? Or for that matter Amperes, where Coulomb = A s, I think. Thank ye. Regards, Michael Powell

2 5

[multi_index] sorted iteration of values
by Mathieu Champlon 05 Sep '13

05 Sep '13

Hello, I'm trying to use Boost.MultiIndex to store my data. The idea is to have a kind of bidirectional multimap (I initially started with Boost.BiMap) which could model : std::multimap< SomeType*, std::set< int > > left; std::multimap< int, SomeType*> right; I'll need to : . insert obviously . remove all ints based on a SomeType* . remove one given (SomeType*,int) . for a given int iterate on all SomeType* . for a given SomeType* iterate in order on all ints What I have so far is : typedef SomeType* First; typedef int Second; struct Value { First first; Second second; }; boost::multi_index::multi_index_container< Value, boost::multi_index::indexed_by< boost::multi_index::ordered_unique< boost::multi_index::composite_key< Value, boost::multi_index::member< Value, First, &Value::first >, boost::multi_index::member< Value, Second, &Value::second > > >, boost::multi_index::ordered_non_unique< boost::multi_index::member< Value, Second, &Value::second > >, boost::multi_index::ordered_non_unique< boost::multi_index::member< Value, First, &Value::first > > > > data; This works, except for the ints iteration based on a given SomeType* because I need them to be sorted, and they're not, e.g. auto range = data.get< 2 >().equal_range( someTypePtr ); for( auto it = range.first; it != range.second; ++it ) ; does not iterate in a sorted order. Is there a way to achieve this without manually sorting the iterated values ? Thank you ! MAT.

2 5

boost::multiprecision::cpp_int encoding and decoding little endian byte arrays
by Steffen Heil (Mailinglisten) 05 Sep '13

05 Sep '13

Hello I need to decode/encode cpp_int values from/into byte arrays. The encoding must be shortest little endian two's complement representation of the value. For example: 00 = 0 01 = 1 ff = -1 ff:7f = 32767 01:80 = -32767 00:80:00 = 32768 00:80 = -32768 01:80:00 = 32769 ff:7f:ff = -32769 ff:ff:ef:9c:d2:40:43:da:4f:40:6b:06:6a:cd:92:c2:93:bf:a4:5c:c3:f1:29:63:1d = 184467440737095516151844674407370955161518446744073709551615 01:00:10:63:2d:bf:bc:25:b0:bf:94:f9:95:32:6d:3d:6c:40:5b:a3:3c:0e:d6:9c:e2 = -184467440737095516151844674407370955161518446744073709551615 I found a way to archive my goal (see below), but it seems way to complex and too inefficient. For encoding I basically converting the cpp_int to a uint8_t to get 8 bit and then shift the cpp_int by 8, creating a new cpp_int... Twice (once to compute it's length, again to encode it). For decoding I already shift the byte read to the "right" position and "|=" it into the existing cpp_int. Isn't there an easier way access the binary representation of an cpp_int? Regards, Steffen --- #include <iostream> #include <boost/multiprecision/cpp_int.hpp> using namespace std; using namespace boost::multiprecision; size_t binLength( cpp_int value ) { if ( value.is_zero() ) return 1; if ( value.sign() < 0 ) value = ~ value; size_t length = 0; uint8_t lastByte; do { lastByte = value.convert_to<uint8_t>(); value >>= 8; length ++; } while ( ! value.is_zero() ); if ( lastByte >= 0x80 ) length ++; return length; } void binEncode( cpp_int value, uint8_t* output, size_t length ) { if ( value.is_zero() ) *output = 0; else if ( value.sign() > 0 ) while ( length -- > 0 ) { *( output ++ ) = value.convert_to<uint8_t>(); value >>= 8; } else { value = ~ value; while ( length -- > 0 ) { *( output ++ ) = ~ value.convert_to<uint8_t>(); value >>= 8; } } } cpp_int binDecode( uint8_t* input, size_t length ) { boost::multiprecision::cpp_int result( 0 ); int bits = - 8; while ( length -- > 1 ) result |= (boost::multiprecision::cpp_int) *( input ++ ) << ( bits += 8 ); uint8_t a = *( input ++ ); result |= (boost::multiprecision::cpp_int) a << ( bits += 8 ); if ( a >= 0x80 ) result |= (boost::multiprecision::cpp_int) - 1 << ( bits + 8 ); return result; } void test( string s ) { cpp_int x( s ); uint8_t buffer[ 100 ]; size_t length = binLength( x ), index = 0; binEncode( x, buffer, length ); cpp_int y = binDecode( buffer, length ); cout << hex << setw( 2 ) << setfill( '0' ) << (int) buffer[ 0 ]; while ( -- length > 0 ) cout << ':' << setw( 2 ) << setfill( '0' ) << (int) buffer[ ++ index ]; cout << " = " << dec << setw( 1 ) << x << endl; if ( x != y ) cerr << "failed" << endl; } int main( int argc, const char* argv[] ) { test( "0" ); test( "1" ); test( "-1" ); test( "32767" ); test( "-32767" ); test( "32768" ); test( "-32768" ); test( "32769" ); test( "-32769" ); test( "184467440737095516151844674407370955161518446744073709551615" ); test( "-184467440737095516151844674407370955161518446744073709551615" ); }

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Re: [Boost-users] Why fusion::map<> types not the same?
by Sergey Zhuravlev 04 Sep '13

04 Sep '13

This is bug. You should add ticket to bugtracker. Try to use boost\fusion\result_of::as_map as workaround.

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[Log] How to use a channel that is constant per file?
by Timo Schmiade 03 Sep '13

03 Sep '13

Hi all, I want to use boost's log library to output messages to the console which feature a per-message severity and a per-file channel. I already tried two approaches, none of which was satisfying: === 1. approach === The class boost::log::sources::severity_channel_logger supports both severity and channel and I could define it in each source file like so: --- 8< --- BOOST_LOG_INLINE_GLOBAL_LOGGER_DEFAULT( log, boost::log::sources::severity_channel_logger< boost::log::trivial::severity_level, std::string > ) --- >8 --- Unfortunately, using it like this requires me to redundantly add the channel to each log message, which is very inconvenient because it is the same for all logs in the file. --- 8< --- // Message.cpp BOOST_LOG_CHANNEL_SEV(log, Message, trace) << "Hello, world"; --- >8 --- === 2. approach === I defined my logger like this: --- 8< --- BOOST_LOG_INLINE_GLOBAL_LOGGER_DEFAULT( log, boost::log::sources::severity_logger< boost::log::trivial::severity_level > ) --- >8 --- Then, in each file, I manually set the "Channel" attribute for the logger, like so: --- 8< --- // Message.cpp log::get().add_attribute( "Channel", boost::log::attributes::make_constant("Message")); --- >8 --- This works, but as the "log" object seems to be stored globally, I would have to "invent" new names for the logger object in each file. This is both insecure and prevents the usage of macros (I think). So here's the question: What would be the recommended / a convenient way to add a per-file constant channel to log messages? Thanks in advance! Timo

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Why fusion::map<> types not the same?
by niXman 03 Sep '13

03 Sep '13

Hi, Why 'type' is not same as 'expected' in the example below? using origin = boost::fusion::map< boost::fusion::pair<int, int> >; using expected = boost::fusion::map< boost::fusion::pair<int, int> ,boost::fusion::pair<char, char> >; using type = boost::fusion::result_of::push_back< origin ,boost::fusion::pair<char, char> >::type; static_assert(std::is_same<expected, type>::value, "error!"); The second question is, how can I get the same type as 'expected' when using 'result_of::push_back<>::type' ? -- Regards, niXman ___________________________________________________ Dual-target(32 & 64-bit) MinGW compilers for 32 and 64-bit Windows: http://sourceforge.net/projects/mingwbuilds/ ___________________________________________________ Another online IDE: http://liveworkspace.org/

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[asio][ssl] why the error of " decryption failed or bad record mac" happen?
by lx 03 Sep '13

03 Sep '13

I use the asio and ssl , the error message of " decryption failed or bad record mac" happen some tiems. What are the possible causes? Thank you

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[spirit] Parsing std::string phrase into attribute struct
by Michael Powell 03 Sep '13

03 Sep '13

Hello, Question re: parsing string into a Fusion-adapted struct. First, magic! Wow, I like it. Question about the immediate result, true/false. Let's say the operation fails for whatever reason. In our use-case, we'll be reading some text in from a Linux /sysfs -provided API. We'll parse the contents into a struct instance. If the operation fails for whatever reason, does not match the grammar, are any values mapped into the structure? My first guess, is possibly: a partial (though still failing) match, would partially populate the instance? I am using the employee-example as our boiler plate. http://www.boost.org/doc/libs/1_54_0/libs/spirit/example/qi/employee.cpp The outcome of which would be whether to consider the instance valid for reporting further into user-space, or what else to do with the outcome from there. Thank you... Regards, Michael Powell

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Changing format of program_options
by Heikki Virtanen 02 Sep '13

02 Sep '13

Hi, I have tried to read config file using boost::program_options where I have large floating pointing numbers like [test_section] test = 1.432e43 but seems that I get bad an error message "boost::bad_any_cast: failed conversion using boost::any_cast" when I am reading the value from program_options::variables_map. Reading works perfectly when I am using numbers like [test_section] a = 13.62 but scientific format fails. Should I tell to variables_map somehow what is the format of floating point numbers or should I do something else? -Heikki

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Using Boost.Thread with lowlevel system software: async interruption question
by Nikita V. Youshchenko 02 Sep '13

02 Sep '13

Hi I'm developing lowevel system software, that runs under linux and communicates with custom linux drivers for custom hardware. I'm evaluating possibility to switch from explicit use of pthread interface to Boost.Thread. After reading documentation, I can't understand if there is any solution for async thread interruption with Boost.Thread. First use case is - need to interrupt thread that is sleeping in custom dirver's ioctl() call. Drivers are well-written, in terms that any sleep inside ioctl()s is immediately interrupted on signal arrival. This perfectly couples with pthreads' PTHREAD_CANCEL_ASYNCHRONOUS cancellation type - which is based on signals. Thus, to make threads cancellable while sleeping inside ioctl(), it is enough to set cancellation type to PTHREAD_CANCEL_ASYNCHRONOUS before entering system call. Second use case is - need to interrupt thread that is running 3rd party legacy code. The only method I know to physically communicate termination request to thread running unaware code is signal. Again, this couples well with PTHREAD_CANCEL_ASYNCHRONOUS. Is it possible to solve these two use cases with Boost.Thread? Per Boost.Thread documentation, thread interrupts only in predefined interruption points. Which is similar to pthreads' PTHREAD_CANCEL_DEFERRED, and is not what I'm looking for. I imagine I could play with signal handler that does longjump() to some point where I manually raise boost::thread_interrupted exception. Will that work? Sure this will loose any destructor calls for objects created in call stack "below setjmp point" - but in first use case I can ensure that no cleanup below setjmp is required, and in second use case this looks unavoidable... Any better ideas? I do not have any portability needs in this software - drivers are linux-only anyway. So linux-only solution is perfectly ok. Nikita Yushchenko

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On line alternative
by Brian Wood 01 Sep '13

01 Sep '13

I've been watching some of the videos from the last C++Now conference, including one that talked about the serialization library in Boost. The presenter mentioned some alternatives to that library, but he didn't mention the C++ Middleware Writer (CMW). The CMW has support for some Boost libs: http://webEbenezer.net/supportedTypes.html If possibe we'll add to that list in the future. -- Brian Ebenezer Enterprises http://webEbenezer.net

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[chrono] float-based milliseconds?
by Michael Powell 31 Aug '13

31 Aug '13

Hello, Or any of the chrono-steady-clock-based time units... I am noticing some what appear to be rounding errors outputting resulting millisecond values using the boost::chrono::milliseconds(x). It's a design-decision, most if not all of our floating-point values are single-precision-float, don't need to be double-precision-float. When we output the milliseconds(x).count() values, however, what I am finding is that the values are sometimes inaccurate, the same value in 3.0, for instance, output as 2.99995, stuff like this. Is there a way to tell milliseconds what precision floating point it is? float or double? We are targeting ARM, BTW, without hardware floating point support, which is the main reason, I'd like to keep things single-precision float, if at all possible. Thank you... Regards, Michael Powell

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libboost_thread-vc80-mt-1_54.lib
by John Emmas 30 Aug '13

30 Aug '13

A few months ago I downloaded 'boost_1_54_0.zip' which I probably obtained from Sourceforge:- http://sourceforge.net/projects/boost/files/boost/1.54.0/ I'm using libboost with Visual C++ 8 and up to now the only things I've needed from it are 'boost::regex' and 'boost::shared_ptr'. However I'm now building a 3rd party library which seems to want to link to the above library (libboost_thread-vc80-mt-1_54.lib). I'm not sure whether it's a static library or the symbols library for a DLL. Either way, the zip file I downloaded doesn't seem to contain it (nor any other libs or DLLs AFAICT). Q1) Is there some other web site I need to visit in order to get the pre-built binaries? Q2) I know from past experience that pre-built boost binaries sometimes require quite obscure versions of the MSVC runtime. That was the case with boost::regex so after a bit of advice from this mailing list, I ended up making a VC project and building it myself. I don't mind doing the same thing for boost::thread - but I wondered if there was already a suitable project available somewhere? I don't want to re-invent the wheel if a VC project already exists! Thanks. John

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