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boost and Obj-C++ ("id" variables)
by Manfred Schwind 07 May '10

07 May '10

Hi, in some headers, boost is using "id" as variable name. This makes is impossible to use those headers in Obj-C (or better Obj-C++) code, because "id" has a special meaning there. I worked around by renaming these id variables in the boost headers for every new boost release (hoping that it will be fixed in the next release), but this is ugly. Now I looked into the boost trac, and found that this problem was reported - and fixed! - multiple times. I can read from the trac that it SHOULD haven been fixed in the latest 1.43.0 (if I read that correct). It's fixed and it's Milestone is 1.43.0. So I downloaded boost 1.43.0 - but the problem is still there. Still "id" variables. How can this be? Doesn't this mean there are serious problems in source code control? Or hasn't the fix just not made its way into 1.43 - where can I read in which version a fix really appears? If I read it right, it should have been fixed in boost 1.37.0: https://svn.boost.org/trac/boost/ticket/2306 https://svn.boost.org/trac/boost/changeset/48751 But appeared again and should now be fixed in boost 1.43.0: https://svn.boost.org/trac/boost/ticket/4132 https://svn.boost.org/trac/boost/ticket/4191 https://svn.boost.org/trac/boost/changeset/61789 Any ideas what happens here? Regards, Mani -- http://mani.de - friendly software iVolume - listen to music hands-free LittleSecrets - the encrypted notepad Sahara - sand in your pocket Watchdog - baffle the curious

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[units] easier "power" of units generation
by alfC 07 May '10

07 May '10

Hi, I have a custom units, for example, angstrom: typedef scaled_base_unit<si::meter_base_unit, scale<10, static_rational<-10> > > angstrom_base_unit; typedef metric::angstrom_base_unit::unit_type angstrom_unit; static const angstrom_unit angstrom; and I have a quantity quantity<angstrom_unit> L=1.*angstrom; and I want to have a variable that has dimensions of volume and angstrom^3 units: ??? V = pow<3>(L); ¿how can I generate the type of V, given angstrom_unit? I found this complicated way: quantity<unit< volume_dimension, make_system<angstrom_base_unit>::type > > V = pow<3>(L); Is there a more compact way or a way that doesn't explicitly mention angstrom_base_unit?, something like quantity<static_power<angstrom_unit, 3>::unit> V = pow<3>(L); // not working In other words, what are the metafunctions necessary to generate the typeof(pow<3>(L)) from angstrom_unit. Thank you, Alfredo

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how to compare fusion adapted structures
by Olaf Peter 07 May '10

07 May '10

Hi, in my project I do have a lot of fusion adapted structures (due to use for/with spirit). Now I want to compare them. How to reuse the informations? In the example attached, I show the (imo) complicated way using fusion::vector_tie. I would like reuse the BOOST_FUSION_ADAPT_STRUCT macro since it generates tag_of<>, struct_member<>, struct_member_name<> , struct_size<> etc. At http://www.boost.org/doc/libs/1_42_0/libs/fusion/doc/html/fusion/extension/… there is the full blown feature shown how to adapt the structure for a fusion iterator. What do I really need for simple comparing? Is it the way to use? Even simpler one? Since the project is involving, a simple and && combine of the members isn't save - easy to lost one ... Thanks, Olaf

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Re: [Boost-users] [Serialization] Newbie question
by Brian Wood 07 May '10

07 May '10

Robert Ramey: >David Aldrich wrote: >> >> Perhaps later we could install Boost in full . >> > Your strategy of getting started by just including some headers is > a good one - that's how I got started with boost. Unfortunately it > won't get you access to the serialization library. > One note: Assuming you decide to bite the bullet and do the > build of boost on your system, remember it's generally a one > time thing. That is, once you have the libraries and dlls built > you VS projects just include headers and the library directory. It's a one time thing for every release you wish to use and there's a possibility of needing patches between releases. Brian Wood http://webEbenezer.net (651) 251-9384

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shared_ptr usage
by Hicham Mouline 06 May '10

06 May '10

Hello, I have a class that stores a private member a shared_ptr<T> that points to a dynamically allocated instance of T. A getter member function returns T&. I now realise that in a snippet, I would like to store a new shared_ptr<T> to that returned object. T& t = myinstance.getT(); I would like to store t in a shared_ptr, ie increment the count of shared pointers Do I do: shared_ptr<T> desiredPointer( &t ); will this increment the count of shared pointers to t? Regards,

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Newbie question filesystem
by Dan Bloomquist 06 May '10

06 May '10

I lost my copy of metaprogramming. I'm ordering another tomorrow. But here is what I'm up to. I've been doing the virtual path thing with old MFC classes and such, like: C:\\cpp\\RA_User_2_2\\$(TEST) or $(PATH)\$(TEST) etc. What I'm trying to do is derive from filesystem and wrap this virtual stuff around it to break away from the old stuff I have, (ugly stuff). I've gotten to the point where I'd like to snap different virtual sets in and don't want to build on the old stuff, filesystem is really cool. I have a client that has several clients and wants to set his configurations on the fly to handle them, I do it in code for myself, but it is not runtime. Anyway... So I started with: template<class String, class Traits> class basic_vpath; typedef basic_vpath< std::string, path_traits > vpath; template<class String, class Traits> class basic_vpath :public basic_path< String, Traits > { }; But I don't understand why I can just fine: CString strUserDirectory= _T("C:\\cpp\\RA_User_2_2\\$(TEST)"); path aPath( strUserDirectory ); But can't convert from CString, or even std::string with: CString strUserDirectory= _T("C:\\cpp\\RA_User_2_2\\$(TEST)"); vpath aPath( strUserDirectory ); I'm trying to extend what I see in path.hpp without success, and I've tried lots of stuff. Something to do with the converters? Thanks, Dan.

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Error "more than one instance of constructor" while using boost::assign::list_of
by Alexander Vinokur 06 May '10

06 May '10

Hi, I have the following problem with boost::assign::list_of HP-UX aCC: HP C/aC++ B3910B A.06.25 [Nov 30 2009] BOOST 1.34 boost2.cpp // ---------------------------- #include <boost/assign/list_of.hpp> #include <vector> int main() { const std::vector<int> primes = std::vector<int> (boost::assign::list_of(2)(3)(5)(7)(11)); return 0; } // --------------------------- > aCC +DD64 -AA -I$BOOST_HOME boost2.cpp "boost2.cpp", line 7: error #2309: more than one instance of constructor "std::vector<_TypeT, _Allocator>::vector [with _TypeT=int, _Allocator=std::allocator<int>]" matches the argument list: function "std::vector<_TypeT, _Allocator>::vector(const _Allocator &) [with _TypeT=int, _Allocator=std::allocator<int>]" function "std::vector<_TypeT, _Allocator>::vector(_Allocator::size_type) [with _TypeT=int, _Allocator=std::allocator<int>]" function "std::vector<_TypeT, _Allocator>::vector(const std::vector<_TypeT, _Allocator> &) [with _TypeT=int, _Allocator=std::allocator<int>]" argument types are: (boost::assign_detail::generic_list<int>) const std::vector<int> primes = std::vector<int> (boost::assign::list_of(2)(3)(5)(7)(11)); Thank. Alex Vinokur This message and the information contained herein is proprietary and confidential and subject to the Amdocs policy statement, you may review at http://www.amdocs.com/email_disclaimer.asp

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[Serialization] Newbie question
by David Aldrich 06 May '10

06 May '10

Hi I have a need to serialize some STL containers in our C++ application. We build for Linux and Windows but do not currently use Boost. Adoption of Boost would seem to demand that we install the complete Boost library on all our development machines. This is straightforward but would be a serious project decision. Would it be possible to use the Serialization library by just adding the Serialization header files to our project directory and compiling them with our project? Perhaps later we could install Boost in full ... Best regards David

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file_descriptor_sink vs. pclose
by Dan Stahlke 06 May '10

06 May '10

I've been having difficulty using iostreams::file_descriptor_sink with popen in Linux. The problem is that popen() requires a matching pclose() rather than a close(). Now, file_descriptor_sink has a close_on_exit flag that, when set to false, supposedly prevents it from calling close() on the underlying file descriptor, but it calls close() anyway. Is this a bug in boost or am I doing it wrong? As a workaround I can call flush () on the iostream and then pclose() on the filehandle, but it seems like it would be better to actually close the iostream. I've tested the example below using boost 1.39 and using 1.43 from subversion. The result in both cases is: pclose returned error (test A): Bad file descriptor pclose returned error (test B): Bad file descriptor Hello Hello ------------------------- #include <stdexcept> #include <iostream> #include <boost/iostreams/device/file_descriptor.hpp> #include <boost/iostreams/stream.hpp> #include <stdio.h> #include <string.h> #include <errno.h> typedef boost::iostreams::stream<boost::iostreams::file_descriptor_sink> boost_stream; int main() { bool close_on_exit = false; FILE *pout = popen("cat", "w"); { boost_stream bs(fileno(pout), close_on_exit); bs << "Hello\n"; // destructor calls close(fileno(pout)) } if(pclose(pout)) { char *err = strerror(errno); std::cerr << "pclose returned error (test A): " << err << std::endl; } pout = popen("cat", "w"); boost_stream bs(fileno(pout), close_on_exit); bs << "Hello\n"; // bs.close() calls close(fileno(pout)) // without the bs.close(), there would be no pclose() error bs.close(); // If bs.close() is not used, bs.flush() can be used to flush data to // pipe before calling pclose(). //bs.flush(); if(pclose(pout)) { char *err = strerror(errno); std::cerr << "pclose returned error (test B): " << err << std::endl; } }

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[Asio] Infinite epoll_wait?
by Joaquim Pedro França Simão 06 May '10

06 May '10

Hello, I have a proxy that uses Boost.Asio, everything normal so far, only began to appear a strange problem. Sometimes, the proxy stops responding. I make a connection to it, send the request and it returns nothing. Sometimes he does not 'accept' the connection, it seems that goes into some waiting list. Could generate a core dump when it is 'locked', follows the text of the gdb backtrace. Attached the 'backtrace full'. _____ #0 0x00002adcec8a9cd8 in epoll_wait () from /lib/libc.so.6 #1 0x00000000005dedd3 in boost::asio::detail::epoll_reactor<false>::run (this=0x2adcf0000c90, block=true) at /usr/include/boost/asio/detail/epoll_reactor.hpp:470 #2 0x00000000005db050 in boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor<false> >::do_one (this=0x1ed4650, lock=..., this_idle_thread=0x2adced580ee0, ec=...) at /usr/include/boost/asio/detail/task_io_service.hpp:260 #3 0x00000000005d6c71 in boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor<false> >::run (this=0x1ed4650, ec=...) at /usr/include/boost/asio/detail/task_io_service.hpp:103 #4 0x00000000005d392d in boost::asio::io_service::run (this=0x1ed4a60) at /usr/include/boost/asio/impl/io_service.ipp:68 #5 0x000000000060fe6b in boost::_mfi::mf0<unsigned long, boost::asio::io_service>::call<boost::shared_ptr<boost::asio::io_service> > (this=0x1ed6720, u=...) at /usr/include/boost/bind/mem_fn_template.hpp:40 #6 0x000000000060fdef in boost::_mfi::mf0<unsigned long, boost::asio::io_service>::operator()<boost::shared_ptr<boost::asio::io_service> > ( this=0x1ed6720, u=...) at /usr/include/boost/bind/mem_fn_template.hpp:55 #7 0x000000000060fd89 in boost::_bi::list1<boost::_bi::value<boost::shared_ptr<boost::asio::io_service> > >::operator()<unsigned long, boost::_mfi::mf0<unsigned long, boost::asio::io_service>, boost::_bi::list0> (this=0x1ed6730, f=..., a=...) at /usr/include/boost/bind/bind.hpp:243 #8 0x000000000060fd35 in boost::_bi::bind_t<unsigned long, boost::_mfi::mf0<unsigned long, boost::asio::io_service>, boost::_bi::list1<boost::_bi::value<boost::shared_ptr<boost::asio::io_service> > > >::operator() (this=0x1ed6720) at /usr/include/boost/bind/bind_template.hpp:20 #9 0x000000000060fcc2 in boost::detail::thread_data<boost::_bi::bind_t<unsigned long, boost::_mfi::mf0<unsigned long, boost::asio::io_service>, boost::_bi::list1<boost::_bi::value<boost::shared_ptr<boost::asio::io_service> > > > >::run (this=0x1ed65f0) at /usr/include/boost/thread/detail/thread.hpp:56 #10 0x00002adceb32c200 in thread_proxy () from /usr/lib/libboost_thread.so.1.42.0 #11 0x00002adcecb3873a in start_thread () from /lib/libpthread.so.0 #12 0x00002adcec8a969d in clone () from /lib/libc.so.6 #13 0x0000000000000000 in ?? () ____________ -- osmano807 Joaquim Pedro

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