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

Re: [Boost-users] [FunctionTypes] Getting functor/lambda parameters (VS2012)
by Mateusz Loskot 12 Oct '13

12 Oct '13

On 11 October 2013 22:46, Stzpz <newstzpz(a)gmail.com> wrote: > I am not sure what is lacking in VS2012, but there is some way to overcome > this problem. > > template<class T, int argNo> > struct FunctorParameterType > { > static auto init() -> typename decltype(&T::operator()) > { > typedef typename decltype(&T::operator()) func_type; > return func_type(); > } > typedef typename decltype(FunctorParameterType<T, argNo>::init()) func_type; > typedef boost::function_types::parameter_types<func_type> parameter_types; > > typedef typename boost::mpl::at_c<parameter_types, argNo>::type type; > }; Nice one, thanks! I'll give it a try when I need it again. Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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[system] Default error codes
by Gavin Lambert 10 Oct '13

10 Oct '13

boost/system/error_code.hpp defines "errc" as a collection of standard error codes (based on posix). It also defines a constructor for error_code and error_condition that allows them to accept a single parameter of an enum type when is_error_code_enum is defined to true for that enum type. It does not, however, actually do this for its own errc enum. As a result, code such as this fails to compile: boost::system::error_code ec(boost::system::errc::operation_canceled); Is there some good reason for this, or is it an oversight? It's certainly more annoying to have to explicitly specify the generic_category().

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[iostreams] - Using sparse Windows files
by Byrne, Kevin 10 Oct '13

10 Oct '13

Hello, I am trying to write cross-platform Boost code that utilizes sparse files on Windows7 and FreeBSD. I already have Windows code that creates and accesses a sparse file. I am of the understanding that Boost code cannot create a Windows7 sparse file for me so I am trying to create the file using the Windows code and then replace my ReadFileEx() and WriteFileEx() with Boost streams. I have had luck with using iostreams::file to access an existing Windows sparse file but it fails when I have to read a sparse area thinking it is at the end of the file. I tried creating a stream using an existing HANDLE but was not successful in reading or writing file content. Before I proceed further I thought I would ask first if Boost is capable of using Windows7 sparse file technology. If it is capable I would appreciate some guidance on how. I have done a bit of searching on the web with not much helpful information. Regards, Kevin

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1.55.0 beta 1 release candidates available for testing
by Marshall Clow 10 Oct '13

10 Oct '13

Release candidate files for 1.55.0 beta 1 are available at http://boost.cowic.de/rc/ As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. This helps ensure the candidates build OK before we push them out to SourceForge. The files (and associated md5s) are: 9fa020efb06f5485628c646451b927c6 *boost_1_55_0b1_rc1.tar.gz 02d26b038ac96f19c3478d0c45a63c9b *boost_1_55_0b1_rc1.tar.bz2 de5f7d60b2387c4fe3d03eb327f095a9 *boost_1_55_0b1_rc1.zip 7deb9063846873452e6ec6918cb75a87 *boost_1_55_0b1_rc1.7z Thanks, --The release managers

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[type_traits] ice_or / ice_and not documented but recommended in coding guidelines
by Adam Romanek 10 Oct '13

10 Oct '13

Hi, I have a concern about the usage of boost::type_traits::ice_or and boost::type_traits::ice_and. I've seen it used in many places and it's even recommented in Coding Guidelines for Integral Constant Expressions [1]. The question is: why isn't it documented? Is there any reason for it? Is there any "public" (documented) equivalent? WBR, Adam Romanek [1] - http://www.boost.org/development/int_const_guidelines.html

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How to choose which library version to choose?
by Michael Kragh Pedersen 10 Oct '13

10 Oct '13

I have downloaded and built the Boost library, as according to these instructions: http://theseekersquill.wordpress.com/2010/08/24/howto-boost-mingw/ I need to use the serialization library, so I looked at the stage\lib folder, only to 16 different library files! Some are named mt, some sd, some s or d, and some a combination thereof, all this following libboost_serialization-mgw48. Some are dll files and some are a files. I tried using –lboost_serialization, as I have seen this mentioned on a lot of forums, but Eclipse says it can’t find that library. So how on Earth am I supposed to figure out which of the many files to link to?!

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Serialization unsupported version, going from 1.47.0 to 1.54.0
by Robert Bielik 10 Oct '13

10 Oct '13

Hi all, Just updated to using boost 1.54.0 and I've gotten problems with my application serializing data with 1.54.0 and a server application deserializing with 1.47.0, using text archives. I noticed the thread http://stackoverflow.com/questions/6015339/boost-serialization-archive-unsu… however it seems only to be issue with binary archives ?? Ideas ? TIA /Rob

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Example calc4.cpp for others grammars
by Olivier Austina 10 Oct '13

10 Oct '13

Hi all, I would like to customize the example calc4.cpp at http://www.boost.org/doc/libs/1_47_0/libs/spirit/example/qi/compiler_tutori… the following grammar: G-------> { A+; C} A--------> {B; C} B--------->E (like arithmetic expression grammar in calc4.cpp) How to modifier this boost variant instruction for this grammar or there no need to change it: typedef boost::variant< nil , unsigned int , boost::recursive_wrapper<signed_> , boost::recursive_wrapper<program> > In general what to put in boost variant for specific grammar (or AST). Any suggestion is welcome. Thank you. Regards Olivier

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[Fusion] Simple transform not working in 1.54?
by Andrew 10 Oct '13

10 Oct '13

Hi, Can anyone shed any light on why this simple test case results in an instantiation of ‘struct inspect<boost::fusion::vector2<boost::fusion::detail::apply_transform_result<int>...' instead of the expected 'struct inspect<boost::fusion::vector2<int, int(double)>>' ? Sorry about the use of pastebin, boost.codepad.org is down. http://pastebin.com/kctYLfag

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Re: [Boost-users] Boost range iterator pointing to wrong element
by Giorgos Sermaidis 09 Oct '13

09 Oct '13

Dear Nate and Gavin, Thank you so much for such a detailed explanation! It is very clear now. boost-users-request(a)lists.boost.org wrote: >Send Boost-users mailing list submissions to > boost-users(a)lists.boost.org > >To subscribe or unsubscribe via the World Wide Web, visit > http://lists.boost.org/mailman/listinfo.cgi/boost-users >or, via email, send a message with subject or body 'help' to > boost-users-request(a)lists.boost.org > >You can reach the person managing the list at > boost-users-owner(a)lists.boost.org > >When replying, please edit your Subject line so it is more specific >than "Re: Contents of Boost-users digest..." > > >Today's Topics: > > 1. [thread] Test if a thread is running (Patrick Steele) > 2. Re: [thread] Test if a thread is running (Kim Barrett) > 3. Re: [thread] Test if a thread is running > (christoph.kliemt(a)pgxml.net) > 4. Type Erasure: Infinite loop when accessing an element of a > container of any<>, where the element is another container > (Alexandre Pretyman) > 5. Re: [boost] [1.55.0] Beta 1 Available (Rich E) > 6. Re: Boost range iterator pointing to wrong element (Nathan Ridge) > 7. Re: [thread] Test if a thread is running (Patrick Steele) > > >---------------------------------------------------------------------- > >Message: 1 >Date: Tue, 8 Oct 2013 17:15:05 +0100 >From: Patrick Steele <steele.patrick(a)gmail.com> >To: boost-users(a)lists.boost.org >Subject: [Boost-users] [thread] Test if a thread is running >Message-ID: > <CAFXDkHyrnTqijUc09otuNs7w+DwXSTue5eLh0-HZBvq+RH=HSg(a)mail.gmail.com> >Content-Type: text/plain; charset="iso-8859-1" > >boost = 1.54 >OS = Windows 7 >compiler = Visual Studio 2005 > >Hi, >in order to test if a boost.thread is running I used timed_join as per >http://stackoverflow.com/questions/1667420/how-can-i-tell-reliably-if-a-boo…, >which recommended that I should be able to call timed_join with a wait time >of 0 ie >bool isThreadRunning = ! m_Thread.timed_join( boost::get_system_time() ); >I have just upgraded to boost 1.54 to see that this no longer appears to >work and that the timed_join function is being deprecated. >Can you tell me how I should now check whether a thread is running please? >Thanks, >Patrick >

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Type Erasure: Infinite loop when accessing an element of a container of any<>, where the element is another container
by Alexandre Pretyman 09 Oct '13

09 Oct '13

Hi Boost list! After watching Sean Parent's lightning-talk "Inheritance is the base class of Evil" ( http://channel9.msdn.com/Events/GoingNative/2013/Inheritance-Is-The-Base-Cl…) I decided to try a similar example with Boost's Type Erasure library, but did not succeed. I created a vector of any<.., ostreamable<>,...>, implemented the stream operator to print this vector type and I can print its' elements. A problem arises, however, when I insert this vector as an element of a second vector. When I print the second vector I encounter an infinite loop ending with a stack overflow when accessing the vector type when it is an element of second vector. The example which demonstrates this behaviour follows attached on this message. I am using Boost 1.55 from the trunk with clang 3.2 from Apple, compiling it with the flags "-std=c++11 -stdlib=libc++" and linking with "-stdlib=libc++". I would be grateful if anyone could try this on your local boost version and compiler. Can anyone shed some light on why this happens? Regards, -- Alexandre Pretyman

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[thread] Test if a thread is running
by Patrick Steele 09 Oct '13

09 Oct '13

boost = 1.54 OS = Windows 7 compiler = Visual Studio 2005 Hi, in order to test if a boost.thread is running I used timed_join as per http://stackoverflow.com/questions/1667420/how-can-i-tell-reliably-if-a-boo…, which recommended that I should be able to call timed_join with a wait time of 0 ie bool isThreadRunning = ! m_Thread.timed_join( boost::get_system_time() ); I have just upgraded to boost 1.54 to see that this no longer appears to work and that the timed_join function is being deprecated. Can you tell me how I should now check whether a thread is running please? Thanks, Patrick

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Re: [Boost-users] [boost] 1.55.0 beta 1 release candidates available for testing
by Akira Takahashi 09 Oct '13

09 Oct '13

2013/10/8 Domagoj Saric <dsaritz(a)gmail.com> > On 3.10.2013. 18:19, Marshall Clow wrote:> Release candidate files for > 1.55.0 beta 1 are available at > > > http://boost.cowic.de/rc/ > > > > As always, the release managers would appreciate it if you download > > the candidate of your choice and give building it a try. Please report > > both success and failure, and anything else that is noteworthy. > > With MSVC12 RC: > * 1.54 and 1.55 b1 RC - lots of: > .\boost/iterator/detail/**facade_iterator_category.hpp(**166) : error > C2039: 'assert_not_arg' : is not a member of 'boost::mpl' > This issue fixed by this commit. http://lists.boost.org/boost-commit/2013/05/46330.php However, not merge to release branch yet.

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(Better) Compile time strings
by Rodrigo Madera 09 Oct '13

09 Oct '13

Is there any roadmap for the inclusion of C++11 compile time strings into Boost MPL (or a separate library) as mentioned in Abel Sinkovics and Dave Abrahams' article [1]? If so, any ideas for non-C++11 uses? Thanks, Rodrigo [1] http://cpp-next.com/archive/2012/10/using-strings-in-c-template-metaprogram…

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Utree tutorial
by Olivier Austina 09 Oct '13

09 Oct '13

Hi, I would like to learn how to build AST with utree. I am looking for some basic starting points as newbie in boost. Any suggestion is welcome. Thank you. Regards Olivier

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Boost range iterator pointing to wrong element
by Giorgos Sermaidis 09 Oct '13

09 Oct '13

Hi all, I have a vector<pair<bool, int>> from which I need to read (and possibly write) only the vector elements for which the boolean value of the pair is true. I am using boost range filter and reverse adaptors to do that. However, I noticed that the order of the adaptors, ie whether I use reversed | filtered or filtered | reversed produces different results. In fact, for the latter when I use an iterator to the transformed range to change the boolean value of the pair, then the iterator after the change points to a different vector element. This does not happen when I use reversed | filtered. Below is the code demonstrating the issue. Any ideas as to why this is happening are much appreciated! #include <boost/range/adaptors.hpp> #include <vector> #include <utility> #include <iostream> using namespace boost::adaptors; using container_type = std::vector<std::pair<bool,int>>; struct to_include { bool operator()(const std::pair<bool,int>& x) { return x.first; } }; int main() { container_type container; /* element0: 1, 1 */ /* element1: 1, 2 */ /* element2: 1, 3 */ for(size_t i=0; i!=3; ++i) container.push_back(std::make_pair(true, i+1)); container_type container_cpy = container; /* filter and then reverse */ auto fr = container | filtered(to_include()) | reversed; auto fr_it1 = fr.begin(); auto fr_it2 = std::next(fr_it1); fr_it2->first = false; std::cout << "FILTER AND THEN REVERSE\n"; std::cout << fr_it2->first << " " << fr_it2->second << '\n'; /* prints (1,1) instead of (0,2) */ /* reverse and then filter */ auto rf = container_cpy | reversed | filtered(to_include()); auto rf_it1 = rf.begin(); auto rf_it2 = std::next(rf_it1); rf_it2->first = false; std::cout << "\nREVERSE AND THEN FILTER\n"; std::cout << rf_it2->first << " " << rf_it2->second << '\n'; /* prints (0,2) */ return 0; }

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Serial port example compiles in Makefile, but does not compile under Eclipse
by Ulf Samuelsson 07 Oct '13

07 Oct '13

Running Eclipse 3.7.2 on Ubuntu 12.10 (i386) with Boost 1.49 Trying to get a serial port running with a callback Found: http://www.webalice.it/fede.tft/serial_port/serial_port.html and the source: git clone: git://gitorious.org/serial-port/serial-port.git When I compile a serial port example 4 with g++ I do not get any problems. When I compile exactly the same class from Eclipse I get an error. thread t(boost::bind(&asio::io_service::run, &pimpl->io)); // Offending code ------------------------------------------------------------------ 'boost::bind' is ambiguous ' Candidates are: boost::_bi::bind_t<unsigned int,unsigned int (*)(boost::system::error_code &),boost::_bi::list1<boost::_bi::value<boost::asio::io_service *>>> bind(unsigned int (*)(boost::system::error_code &), boost::asio::io_service *) boost::_bi::bind_t<unsigned int,boost::_mfi::mf0<unsigned int,boost::asio::io_service>,boost::_bi::list1<boost::_bi::value<boost::asio::io_service *>>> bind(unsigned int (boost::asio::io_service::*)(), boost::asio::io_service *) ' AsyncSerial.cpp /nodeserver/src line 102 Semantic Error ------------------------------------------------------------------ pimpl->io is a boost::asio::io_service class AsyncSerialImpl: private boost::noncopyable { public: ... boost::asio::io_service io; ///< Io service object ... }; Someone suggest I declare a pointer to the run function, to resolve the problem, which I tried, but didnt get it right. How do I declare a variable, which can be assigned the io_service::run function? <?> myrun = &boost::asio::io_service::run; Any other ideas? Why compile and link in the makefile and not inside Eclipse? Tried on a Ubuntu 13.04 machine with the same problem. BR Ulf Samuelsson ==================================================================== Part of the code. ------------------------ void AsyncSerial::open(const std::string& devname, unsigned int baud_rate, asio::serial_port_base::parity opt_parity, asio::serial_port_base::character_size opt_csize, asio::serial_port_base::flow_control opt_flow, asio::serial_port_base::stop_bits opt_stop) { if(isOpen()) close(); setErrorStatus(true);//If an exception is thrown, error_ remains true pimpl->port.open(devname); pimpl->port.set_option(asio::serial_port_base::baud_rate(baud_rate)); pimpl->port.set_option(opt_parity); pimpl->port.set_option(opt_csize); pimpl->port.set_option(opt_flow); pimpl->port.set_option(opt_stop); //This gives some work to the io_service before it is started pimpl->io.post(boost::bind(&AsyncSerial::doRead, this)); --------------------------------------------------------------------------------------------------------------------------- thread t(boost::bind(&asio::io_service::run, &pimpl->io)); // Offending code --------------------------------------------------------------------------------------------------------------------------- pimpl->backgroundThread.swap(t); setErrorStatus(false);//If we get here, no error pimpl->open=true; //Port is now open } class AsyncSerialImpl: private boost::noncopyable { public: AsyncSerialImpl(): io(), port(io), backgroundThread(), open(false), error(false) {} boost::asio::io_service io; ///< Io service object boost::asio::serial_port port; ///< Serial port object boost::thread backgroundThread; ///< Thread that runs read/write operations bool open; ///< True if port open bool error; ///< Error flag mutable boost::mutex errorMutex; ///< Mutex for access to error /// Data are queued here before they go in writeBuffer std::vector<char> writeQueue; boost::shared_array<char> writeBuffer; ///< Data being written size_t writeBufferSize; ///< Size of writeBuffer boost::mutex writeQueueMutex; ///< Mutex for access to writeQueue char readBuffer[AsyncSerial::readBufferSize]; ///< data being read /// Read complete callback boost::function<void (const char*, size_t)> callback; };

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Using boost::iostreams::restrict without overconsuming the original stream
by Avi Kivity 07 Oct '13

07 Oct '13

Hi, I amy trying to split an incoming streams into multiple substreams (specifically, an incoming cpio stream into its individual files). After parsing the header in the incoming stream, I have the file size, and can use boost::iostreams::restrict to create a substream containing only the file data, which the user can subsequently consume. However some experiments with filtering_streambuf show that it will consume past the end of the substream. Will the same happen with restrict?

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Boost MSM : Virtual Memory Exhausted: cannot allocate memory
by rahul baruah 06 Oct '13

06 Oct '13

Hello, I am using boost Meta - state machine. I have 19 state which is compiling ok. but whn i incease the number of state transition in Transition table(using internal_transition_table) i get this error: *"Virtual Memory Exhausted: cannot allocate memory"* * * * *Has anyone has face the same problem?? Regards Rahul

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Doc error?
by Larry 06 Oct '13

06 Oct '13

In the doc (1.54.0) for algorithms under C++14, the first code segment under both equal and mismatch, the last line (for equal here) shows std::equal ( seq1.begin (), seq1.end (), seq1.begin (), seq2.end ()); // false ^^^^^^ Shouldn’t that be std::equal ( seq1.begin (), seq1.end (), seq2.begin (), seq2.end ()); // false ^^^^^^ Similar for mismatch. Larry

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spirit::qi and Phoenix placeholder
by Olivier Austina 04 Oct '13

04 Oct '13

I am reading Spirit tutorial, at http://www.boost.org/doc/libs/1_54_0/libs/spirit/doc/html/spirit/qi/tutoria…. I am new to boost. It is not clear to me what the placeholder are and when using them. This is some of them: *Spirit.Qi specific Phoenix placeholders* _1, _2... , _N Nth attribute of p _val The enclosing rule's synthesized attribute. _r1, _r2... , _rN The enclosing rule's Nth inherited attribute. _a, _b... , _j The enclosing rule's local variables (_a refers to the first). _pass Assign false to _pass to force a parser failure. For example in this code : template <typename Iterator>bool parse_numbers(Iterator first, Iterator last, std::vector<double>& v){ using qi::double_; using qi::phrase_parse; using qi::_1; using ascii::space; using phoenix::push_back; using phoenix::ref; bool r = phrase_parse(first, last, // Begin grammar ( *double_[push_back(ref(v), _1)] >> *(',' >> double_[push_back(ref(v), _1)])* ) , // End grammar space); if (first != last) // fail if we did not get a full match return false; return r;} why using _1, (using qi::_1) instead of _2 (using qi::_2). Which parts of boost should I read before reading spirit. Any suggestion is welcome. Thank you. Regards Olivier

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Re: [Boost-users] 1.55.0 beta 1 release candidates available for testing
by Craig Henderson 04 Oct '13

04 Oct '13

On 4 October 2013 07:13, Ovanes Markarian <om_boost(a)keywallet.com> wrote: > Marshall, > > is there any link to what has been added/fixed in the new release. Would > be great to find it out before downloading the software. > See http://www.boost.org/users/history/version_1_55_0.html

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Re: [Boost-users] Boost.Coroutine + objects
by Van Pers 03 Oct '13

03 Oct '13

Nathan Ridge wrote: > You need to refer to member functions as '&Abc::first' rather than > just 'first', and you need to bind the implicit object parameter > to something (likekely 'this'): > bind(&Abc::first, this, _1) > Regards, > Nate Thank you Nathan, this works for me. Regards, Van

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[Exception] Duplicate symbol error when using errinfo_api_function in static library
by Georg Leidinger 03 Oct '13

03 Oct '13

Dear readers, I encountered a problem in my project when using *Boost.Exception* with the predefined types errinfo_xyz in a library project. I have two classes ClassA and ClassB in my library which both throw a boost::exception with errinfo_api_function type in their implementation file (.cpp) These both classes are compiled into a static library with the C/C++-Flags -fvisibility=hidden. Then I have a main.cpp which creates an instance of ClassA and ClassB and links to the library which contains ClassA.o and ClassB.o. When I compile the main.cpp I get the linker error duplicate symbol for the errinfo_api_function object in ClassA.o and ClassB.o. If I remove the visibility=hidden flag, it links without problems. I am not an expert on the compiler flags, but I saw that many libraries use the visibility=hidden flag so I think it would be good, if my lib could also use it. For a better description I will show the sources for my project: ClassA.h ------------------------------------------------------------------------------------------------- #pragma once #include <boost/exception/all.hpp> struct my_errorA : virtual std::exception, virtual boost::exception {}; class ClassA { public: ClassA() {}; virtual ~ClassA() {}; virtual void doSomething(); }; ClassA.cpp ------------------------------------------------------------------------------------------------- #include "ClassA.h" void ClassA::doSomething() { BOOST_THROW_EXCEPTION( my_errorA() << boost::errinfo_api_function("doSomething") ); } ClassB.h ------------------------------------------------------------------------------------------------- #pragma once #include <boost/exception/all.hpp> struct my_errorB : virtual std::exception, virtual boost::exception {}; class ClassB { public: ClassB() {}; virtual ~ ClassB() {}; virtual void doSomething(); }; ClassB.cpp ------------------------------------------------------------------------------------------------- #include "ClassB.h" void ClassB::doSomething() { BOOST_THROW_EXCEPTION( my_errorB() << boost::errinfo_api_function("doSomething") ); } main.cpp ------------------------------------------------------------------------------------------------- #include "ClassA.h" #include "ClassB.h" int main(int argc, const char * argv[]) { ClassA A; ClassB B; return 0; } The Linker output: ----------------------------------------------------------------------------------------------------------------- *Ld /Users/georg/Library/Developer/Xcode/DerivedData/ExceptionTest-dcnvciwqbwqvciaokkjjaqchftll/Build/Products/Debug/ExceptionTest normal i386 cd /Users/georg/work/ExceptionTest setenv MACOSX_DEPLOYMENT_TARGET 10.8 /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++ -arch i386 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk -L/Users/georg/Library/Developer/Xcode/DerivedData/ExceptionTest-dcnvciwqbwqvciaokkjjaqchftll/Build/Products/Debug -F/Users/georg/Library/Developer/Xcode/DerivedData/ExceptionTest-dcnvciwqbwqvciaokkjjaqchftll/Build/Products/Debug -filelist /Users/georg/Library/Developer/Xcode/DerivedData/ExceptionTest-dcnvciwqbwqvciaokkjjaqchftll/Build/Intermediates/ExceptionTest.build/Debug/ExceptionTest.build/Objects-normal/i386/ExceptionTest.LinkFileList -mmacosx-version-min=10.8 /Users/georg/Library/Developer/Xcode/DerivedData/ExceptionTest-dcnvciwqbwqvciaokkjjaqchftll/Build/Products/Debug/libExceptionLib.a -o /Users/georg/Library/Developer/Xcode/DerivedData/ExceptionTest-dcnvciwqbwqvciaokkjjaqchftll/Build/Products/Debug/ExceptionTest duplicate symbol __ZTIPN5boost21errinfo_api_function_E in: /Users/georg/Library/Developer/Xcode/DerivedData/ExceptionTest-dcnvciwqbwqvciaokkjjaqchftll/Build/Products/Debug/libExceptionLib.a(ClassA.o) /Users/georg/Library/Developer/Xcode/DerivedData/ExceptionTest-dcnvciwqbwqvciaokkjjaqchftll/Build/Products/Debug/libExceptionLib.a(ClassB.o) duplicate symbol __ZTSPN5boost21errinfo_api_function_E in: /Users/georg/Library/Developer/Xcode/DerivedData/ExceptionTest-dcnvciwqbwqvciaokkjjaqchftll/Build/Products/Debug/libExceptionLib.a(ClassA.o) /Users/georg/Library/Developer/Xcode/DerivedData/ExceptionTest-dcnvciwqbwqvciaokkjjaqchftll/Build/Products/Debug/libExceptionLib.a(ClassB.o) ld: 2 duplicate symbols for architecture i386 clang: error: linker command failed with exit code 1 (use -v to see invocation)* ----------------------------------------------------------------------------------------------------------------- I hope I described the problem well enough and I hope someone can explain what the problem is? Thank a lot and best regards Georg

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[parameter] named template parameters
by ilya shlyakhter 03 Oct '13

03 Oct '13

Some questions about the Boost.Parameter library: - seems like it hasn't been updated in some time -- is it still supported? - when specifying type constraints for named template parameters, is it possible to specify constraints among several type parameters (the way graph_type is used in section 2.1.5.6.1 of the documentation) - are there any issues in the interaction of Boost.Parameter and template specialization, i.e. how do I specialize the template on the values of some of the named parameters? Thanks, ilya

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