October 2012 - Boost-users - lists.preview.boost.org

[units] Missing quantity operator++, operator%
by Nathan Crookston 25 Oct '12

25 Oct '12

All, I'm in the process of switching my homegrown units system over to boost units. Some operators which I'm missing are the modulus and the pre and post increment operators. Looking through the archives I note an original review[1] which mentioned the absence of those operators. One response claimed that quantity<si::length, int> t = 5. ...; t++; was nonsensical as writing 5 m + 1, and the reviewer eventually agreed, citing possible confusion if the quantity type converted the … [View More]

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Errors when linking a CXX executable to boost static libraries, using gcc4.7 and boost 1.51.0
by camille chambon 25 Oct '12

25 Oct '12

Hello, I'm trying to link a CXX executable to boost static libraries. My environment is: - Fedora 17 64bit - gcc 4.7 - boost 1.51.0 built with gcc 4.7 I then get the following errors : `.text._ZN5boost16exception_detail19error_info_injectorINS_16bad_lexical_castEED2Ev' referenced in section `.text._ZN5boost16exception_detail19error_info_injectorINS_16bad_lexical_castEED1Ev[_ZN5boost16exception_detail19error_info_injectorINS_16bad_lexical_castEED1Ev]' of /home/cchambon/libs/lib/libpgma.a(… [View More]

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Re: [Boost-users] Occasional blocking with tcp::socket::receive
by Stuart Siegel 25 Oct '12

25 Oct '12

I have read the documentation :-) My understanding is that it's blocking if there's no data left to be read and you ask it to read from the socket. In my case, the server has sent the data and it's there waiting for it to read. I've confirmed this via wireshark and, as I mentioned, the plain POSIX call to read (which is also blocking by the way) works as expected. ________________________________ From: nullable.type <nullable.type(a)gmail.com> To: boostusers(a)googlegroups.com Cc: "… [View More]

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Are shared_mutex's recursive?
by John M. Dlugosz 25 Oct '12

25 Oct '12

Clearly recursive acquiring of a shared (reading) lock is natural. But what about an exclusive lock? Can the owning thread acquire the write lock recursively, or even read locks recursively?

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Memory usage of adjacency_list
by Ed Linde 24 Oct '12

24 Oct '12

Hi, Is it possible to get a ballpark figure of the maximum memory required for an adjacency_list, given its settings? I need these statistics to report how much memory is being used initially when reading in a large graph and then after vertex removal operations and edge removal operations, how much reduction is got in this memory finally. Do I have to write something of my own to do this? Thanks, Ed -- View this message in context: http://boost.2283326.n4.nabble.com/Memory-usage-of-… [View More]

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Is it possible to put a std::unique_ptr into a mulit_index container?
by Josh Quigley 24 Oct '12

24 Oct '12

Hi all, Is it possible to put a std::unique_ptr into a mulit_index container? In particular, the following fails. typedef std::pair<int, std::unique_ptr<int> > ValueT; typedef boost::multi_index_container< ValueT, boost::multi_index::indexed_by< boost::multi_index::hashed_unique< BOOST_MULTI_INDEX_MEMBER(ValueT, int, first) > > > HashMap; … [View More]

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[spirit] Parsing quoted string
by Giampiero Gabbiani 24 Oct '12

24 Oct '12

Hi together, I have to parse the following row: "a_token": true|false, the last comma is optional. Testing the following: bool value; test_parser(" \"orig_bool\": true,", qi::lit('"') >> *(ascii::alnum | qi::char_('_')) >> qi::lit('"') >> qi::lit(':') >> boost::spirit::qi::bool_[phx::ref(value)=_1] >> -(qi::lit(','))); it works, but with the following instead the program compile but hangs ... bool value; test_parser(" \"orig_bool\": true,", qi::lit('"') … [View More]

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Re: [Boost-users] asio: how to handle disk IO, recommendations
by Avi Bahra 24 Oct '12

24 Oct '12

> Currently I has a single threaded server based on boost ASIO. > This works correctly most of the time. > However on systems where i know that the disk's are slow. > , the server grinds to a halt, when dealing with the blocking > disk IO. > > I could not find any examples or documentation in ASIO, in > how to get round these issues. It appears that ASIO does > not provide any support for async' disk IO. > > So I assume this is handled by use of threads ? > … [View More]

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serialization
by Larry E. Ramey 24 Oct '12

24 Oct '12

I've got a system where class A { A(); A(const string&); virtual ~A(); }; class C : public A { C(); C(const A&, float); virtual ~C(); }; BOOST_CLASS_EXPORT( A ) BOOST_CLASS_EXPORT( C ) main() { ... const A* a = new a("stuff"); const C* c = new c(*a, 52.54390f); { ofstream ofs("dump.bin"); boost::archive::text_oarchive oa(ofs); oa<<a<<… [View More]

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adding 'blackberry' to boost build
by Gottlob Frege 23 Oct '12

23 Oct '12

I work for RIM (ie BlackBerry), and am trying to make using boost as easy as possible to use for BB developers. So I would like to make building boost for BB as easy as possible. I would also like to make building boost work "as expected" for anyone who understands Boost.Build. It is the "as expected" part that I'm not sure of. ie should I just offer a blackberry-config.jam? should Boost.Build be changed to auot-detect the BB NDK? should blackberry be a toolset? a target-os? ...? how would … [View More]you *expect* it hook into Boost.Build? (And note that I expect that developers *also* use the same boost for Windows, etc, so I don't want to replace/affect the simple build for the host machine.) - And finally, it would be nice if this was upstreamed back into boost build (if people think that makes sense), so that boost "just works" on BlackBerry. Here's what I have so far: from the command line, you run something like: b2 install --prefix=C:\boost\ --user-config=blackberry-config.jam --layout=system toolset=gcc target-os=qnxnto I'd prefer it if they didn't need to type so much. And the config file looks like basically the rest of this email: import os ; # these env vars are set by installing the BB NDK QNX_TARGET_ARCH = [ os.environ QNX_TARGET_ARCH ] ; QNX_TARGET = [ os.environ QNX_TARGET ] ; QNX_HOST = [ os.environ QNX_HOST ] ; if ! $(QNX_TARGET) || ! $(QNX_HOST) { ECHO error: ; ECHO error: BlackBerry build of Boost requires QNX_TARGET and QNX_HOST env variables. Did you run bbndk-env.bat? ; ECHO error: ; EXIT ; } if $(QNX_TARGET_ARCH) = x86 { dashVOpt = gcc_ntox86_cpp ; linkArchDir = x86 ; } else { dashVOpt = gcc_ntoarmv7le_cpp ; linkArchDir = armle-v7 ; } using qcc # Version : # C++-compile-command : $(QNX_HOST)/usr/bin/QCC -V$(dashVOpt) # Compiler options : <compileflags>"-D__QNX__" <compileflags>"-D__QNXNTO__" # Add -D__USE_ISOC99 for rounding control mechanism (boost/numeric/interval/hw_rounding.hpp) <compileflags>"-D__USE_ISOC99" <compileflags>"-I$(QNX_TARGET)/usr/include" # Prevent this from being output: "note: the mangling of 'va_list' has changed in GCC 4.4" <compileflags>"-Wno-psabi" # Add -fPIC to link without error to LibTestNativeLibTuTest.o (for statechart tests) <compileflags>"-fPIC" # Requested by BBM team <compileflags>"-fno-strict-aliasing" # Functions like sync_val_compare_and_swap and sync_fetch_and_add aren't available <compileflags>"-DBOOST_SP_NO_SYNC" <linkflags>"-L$(QNX_TARGET)/$(linkArchDir)/usr/lib -L$(QNX_TARGET)/$(linkArchDir)/lib" ; import option ; option.set keep-going : false ; ------------------------ Thanks in advance, Tony [View Less]

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building universal boost binaries (MacOS)
by Nick Zavaritsky 23 Oct '12

23 Oct '12

Hi! Boost.build docs says that to build 'fat' binaries on the Mac two options exist: architecture=combined and/or address-model=32_64. The first one builds a binary with PowerPC and x86 code. The second one builds a binary with 32 and 64bit code. The doc further states that architectire= and address-model= are independent: one can use the first one alone or the second one alone or both simultaneously yielding different results. (http://www.boost.org/boost-build2/doc/html/bbv2/reference/tools.… [View More]

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Re: [Boost-users] [EXTERNAL] Re: [MPI] missing symbols using serialization's static library design
by Robert Ramey 23 Oct '12

23 Oct '12

"Barrett, Brian W" <bwbarre(a)sandia.gov> wrote in message news:<69A29AB53D57F54D81061A9E4E45B8FD239CC111(a)EXMB01.srn.sandia.gov>... > On 10/17/12 1:00 PM, "Robert Ramey" <ramey(a)rrsd.com> wrote: > > >Barrett, Brian W wrote: > >> > Unfortunately, I'm barely competent in using Boost.MPI and > Boost.Serialization. I'm definitely not in a position to be able to apply > a patch. > > What I'm getting from your responses and the general … [View More]

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[system] symbol visibility and GCC vs. Clang
by James Walker 23 Oct '12

23 Oct '12

When trying to link a bunch of libraries on OS X, I got this linker warning: ld: warning: direct access in boost::system::system_error::~system_error() to global weak symbol vtable for boost::system::system_error means the weak symbol cannot be overridden at runtime. This was likely caused by different translation units being compiled with different visibility settings. As far as I can tell, everything is compiled using the flags -fvisibility=hidden -fvisibility-inlines-hidden. I'm … [View More]

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Re: [Boost-users] Interesting article on stack-based TMP
by Thorsten Ottosen 23 Oct '12

23 Oct '12

On 23-10-2012 15:05, Larry Evans wrote: > On 10/22/12 07:26, Giovanni Piero Deretta wrote: > [snip] >> Now, to make this thread on-topic: is anybody working on a C++11 >> rewrite of Boost.MPL? >> > Anyone attempting such a rewrite and planning to use the > variadic template features might want to start from: > > http://svn.boost.org/svn/boost/sandbox/variadic_templates/boost/mpl/ > > However, using variadic templates may cause a slowdown in the > … [View More]

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asio: how to handle disk IO, recommendations
by Avi Bahra 23 Oct '12

23 Oct '12

Currently I has a single threaded server based on boost ASIO. This works correctly most of the time. However on systems where i know that the disk's are slow. , the server grinds to a halt, when dealing with the blocking disk IO. I could not find any examples or documentation in ASIO, in how to get round these issues. It appears that ASIO does not provide any support for async' disk IO. So I assume this is handled by use of threads ? Are there any examples of using ASIO with threaded disk IO, … [View More]

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Boost install creates no boost library files
by niallm 22 Oct '12

22 Oct '12

Hi guys, I'm running OS X 10.8.2 and I'm trying to install boost. I'm using Enthought python. So I've unpacked the tar file boost_1_51_0.tar.bz2 into usr/local. Then in the resulting directory boost_1_51_0, I do the following commands: $ ./bootstrap.sh --with-python=2.7 --with-python-root=../../Library/Frameworks/EPD64.framework /Versions/Current/bin/python then: $ ./b2 link=shared --with-python --with-math (I only need the python and math parts). This returns: he Boost C++ Libraries were … [View More]

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[graph] Extending bgl_named_params
by Philipp Moeller 22 Oct '12

22 Oct '12

Hi, I maintain a library that introduces its own graph properties for domain specific algorithms and provides it's own implementation of bgl_named_parameters by essentially mimicking bgl_named_parameters one-to-one. With the refactoring in 1.51 that implementation broke and I had to add another implementation of named parameters which essentially looks like this: enum my_property_t { my_property }; template <typename T, typename Tag, typename Base = boost::no_property> struct … [View More]foo_bgl_named_params : boost::bgl_named_params<T, Tag, Base> { typedef boost::bgl_named_params<T, Tag, Base> base; typedef foo_bgl_named_params self; foo_bgl_named_params(T v = T()) : base(v) {} foo_bgl_named_params(T v, const Base& b) : base(v, b) {} template <typename PMap> foo_bgl_named_params<PMap, my_property_t, self> my_property_map(const PMap& p) const { typedef foo_bgl_named_params<PMap, my_property_t, self> Params; return Params(p, *this); } }; // the respective free functions... template <typename PMap> foo_bgl_named_params<PMap, my_property_t, self> my_property_map(const Pmap& p) const { typedef foo_bgl_named_params<PMap, my_property_t, self> Params; return Params(p); } // partial specialization for lookup_named_param_def namespace boost { template <typename T, typename Tag, typename Base, typename Def> struct lookup_named_param_def<Tag, foo_bgl_named_params<T, Tag, Base>, Def> { typedef T type; static const type& get(const bgl_named_params<T, Tag, Base>& p, const Def&) { return p.m_value; } }; template <typename Tag1, typename T, typename Tag, typename Base, typename Def> struct lookup_named_param_def<Tag1, foo_bgl_named_params<T, Tag, Base>, Def> { typedef typename lookup_named_param_def<Tag1, Base, Def>::type type; static const type& get(const bgl_named_params<T, Tag, Base>& p, const Def& def) { return lookup_named_param_def<Tag1, Base, Def>::get(p.m_base, def); } }; } // boost This is brittle because it the type returned by the inherited functions is not the same and chaining will not work if one of those functions is called first, e.g. all custom properties have to be chained together first. >From the documentation it is not really obvious to me if other libraries are even supposed to provide their own properties and how/if they actually should be able to extend the named parameters API. Is that simply not an intended feature of the BGL or can that be done differently? Cheers, Philipp [View Less]

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Linking issue with Boost 1.44 and GCC 4.6
by Joseph Sulewski 21 Oct '12

21 Oct '12

Hi, I'm having a very strange compilation issue with Boost. I've used boost in other C++ projects in the past and have had no issues. I'm writing a program to compile against Hypertable which relies on the boost 1.44 version of the library. I'm writing this on Intel Linux and compiling with GCC 4.6.3 Here is my linker command. I removed the .o's from my application to make it simpler to read: g++ -L/opt/hypertable/current/lib -L/home/l3/development/libraries/boost_1_44_0/stage/lib -pthread -… [View More]

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[proto] transform with calling templates
by Felipe Magno de Almeida 21 Oct '12

21 Oct '12

Hello, I had the following transform and function object: struct bind_functions_transform : proto::when < proto::terminal<binding::placeholder::method_value<proto::_,proto::_> > , bind_method_call(proto::_value, proto::_data, proto::_state)> > struct bind_method_call : proto::callable { template <typename T> struct result { typedef typename boost::function_types::parameter_types<T>::type parameter_types; typedef typename boost::mpl::… [View More]next <typename boost::remove_reference <typename boost::mpl::at_c<parameter_types, 2u>::type>::type>::type type; }; template <typename Sig, typename F, std::size_t I, std::size_t N> boost::mpl::size_t<I+1> operator()(binding::placeholder::method_value<Sig, F>const& method , boost::fusion::vector<Class&, environment, binding::virtual_table<N>&>& data , boost::mpl::size_t<I> v) const { ... } }; So, I needed one more compile-time information which would be equal to all calls and transforms, so I made my transform into a template and also bind_method_call as follows: template <typename T> struct bind_functions_transform : proto::when < proto::terminal<binding::placeholder::method_value<proto::_,proto::_> > , bind_method_call<T>(proto::_value, proto::_data, proto::_state)> > template <typename T> struct bind_method_call : proto::callable [...] And then I received the following error: ../boost_1_50_0/boost/proto/transform/detail/preprocessed/construct_funop.hpp:24:33: error: no matching function for call to ‘jvb::binding::bind_method_call<hello_world>::bind_method_call(const jvb::binding::placeholder::method_value<void(), void (hello_world::*)()>&, boost::fusion::vector<jvb::class_&, jvb::environment, jvb::binding::virtual_table<1ul>&, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_>&, const mpl_::size_t<0ul>&)’ I've remembered the workaround for msvc with proto::call. Because it seemed that the transform was actually trying to construct instead of calling bind_method_call, so I changed to: template <typename PeerClass> struct bind_functions_transform : proto::when < proto::terminal<binding::placeholder::method_value<proto::_,proto::_> > , proto::call<bind_method_call<PeerClass>(proto::_value, proto::_data, proto::_state)> > And it worked. Well, my question is: is this a known limitation? I didn't find it in proto documentation. I'm using GCC 4.7.1 and x86_64 with Linux Regards, -- Felipe Magno de Almeida [View Less]

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Boost python, unique_ptr and abstract class
by Maxim Yegorushkin 19 Oct '12

19 Oct '12

I am using boost::python to expose a C++ API into Python. Here is what I am trying to do: #include <boost/python.hpp> #include <memory> struct Subscriber { virtual ~Subscriber() = 0; static std::unique_ptr<Subscriber> create(); }; template<class T> inline T* get_pointer(std::unique_ptr<T> const& p) { return p.get(); } BOOST_PYTHON_MODULE(subscriber) { // Expose the class. … [View More]

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Occasional blocking with tcp::socket::receive
by Stuart Siegel 19 Oct '12

19 Oct '12

The call to receive below will occasionally hang. All interactions are synchronous and single threaded. Things work perfectly if I use the alternative <sys/socket.h> (POSIX) implementation under the #else. Since I'm pretty new to boost::asio, I must be doing something wrong but after many hours of trying different things, I'm still stuck. Any advice would be appreciated. #if 1 namespace bas = boost::asio; remaining = X //(something typically about 5000 bytes of char data) bas::streambuf … [View More]

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[Boost.Functional.OverloadedFunction][C++03] Number of overloads in boost::overload_function<...>
by Felipe Magno de Almeida 19 Oct '12

19 Oct '12

Hello, Is there a way to know how many overloads are there in a overloaded_function without resorting to preprocessor metaprogramming in C++03? It doesn't seem to be a MPL sequence, for example. Regards, -- Felipe Magno de Almeida

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boost solution for transforming stl algorithms on proxy iterators?
by Oswin Krause 19 Oct '12

19 Oct '12

Hi, I often have problems which look a bit like this: //example code, only for problem statement //std::vector<bool> chosen only because it is no container :). If this is too silly for you, //think about a matrix interpreted as range of row-vectors. std::vector<bool> myContainer;//does only have proxy iterators. std::vector<double> myDistances; //stores for every element in myContainer a distance //now i want to to sort the elements of both … [View More]

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Using Adaptable Generator concept with generate_n and boost smart pointers
by Marco Craveiro 18 Oct '12

18 Oct '12

Hi boosters, I'm trying to create a class that models the concept of adaptable generator [1]. The idea is that it generates pointers to test data objects which I'd like to then put inside of smart pointers such as shared_ptr or scoped_ptr (or even std::shared_ptr) via generate_n, etc. This is a (non-compilable) example of my intentions: #include <algorithm> #include <iostream> #include <memory> #include <vector> #include <iterator> struct base { int i; }; struct … [View More]

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Generically connecting a signal to a member function
by Chris Stankevitz 18 Oct '12

18 Oct '12

Hello, I wrote a function called "Connect" which generically connects a signal to a member function. The pseudo-code for this function is: void Connect(Signal, MemberFunction, pClass) { Signal.connect(Signal::slot_type(MemberFunction, pClass)); } Problem: I had to create "overloads" for different number of signal arguments. This was somewhat expected and we see it in boost with things like boost::bind. What I did not expect was that each of my overloads had to have a different name. … [View More]This is because all overloads have the same function signature: one signal, one member function, one class pointer. Question: Is there a way to write a generic "Connect" that handles signals of different number of arguments? If overloading is involved, can it be done like bind such that all overloads have the same name? Below is my solution that exhibits the "problem" I described above. Thank you for your help, Chris === #include <boost/bind.hpp> #include <boost/signals2.hpp> #include <iostream> //------------------------------------- // Connect0 // // Generically connect a member // function to a signal producing zero // arguments. //------------------------------------- template < class TASignal, class TAMemberFunction, class TAClass> void Connect0( TASignal& Signal, TAMemberFunction MemberFunction, TAClass* pClass) { typedef typename TASignal::slot_type TDSlot; TDSlot Slot(MemberFunction, pClass); Signal.connect(Slot); } //------------------------------------- // Connect0 // // Generically connect a member // function to a signal producing one // arguments. //------------------------------------- template < class TASignal, class TAMemberFunction, class TAClass> void Connect1( TASignal& Signal, TAMemberFunction MemberFunction, TAClass* pClass) { typedef typename TASignal::slot_type TDSlot; TDSlot Slot(MemberFunction, pClass, _1); Signal.connect(Slot); } //------------------------------------- // Connect2 // // Generically connect a member // function to a signal producing two // arguments. //------------------------------------- template < class TASignal, class TAMemberFunction, class TAClass> void Connect2( TASignal& Signal, TAMemberFunction MemberFunction, TAClass* pClass) { typedef typename TASignal::slot_type TDSlot; TDSlot Slot(MemberFunction, pClass, _1, _2); Signal.connect(Slot); } //------------------------------------- //------------------------------------- struct TCClass { void f0() {} void f1(int) {} void f2(int, int) {} }; //------------------------------------- //------------------------------------- int main() { boost::signals2::signal<void()> Signal0; boost::signals2::signal<void(int)> Signal1; boost::signals2::signal<void(int, int)> Signal2; TCClass Class; Connect0(Signal0, &TCClass::f0, &Class); Connect1(Signal1, &TCClass::f1, &Class); Connect2(Signal2, &TCClass::f2, &Class); Signal0(); Signal1(1); Signal2(2, 2); return 0; } [View Less]

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