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[iterator] Does the base of iterator_adaptor need a const version of operator* ?
by Andre Massing 04 Sep '09

04 Sep '09

Hi, I am trying to wrap our kind of iterators (for meshes) with the iterator_adaptor class template, something like class CellBoostIterator : public boost::iterator_adaptor< CellBoostIterator //Derived , CellIterator //Base , Cell //Value , boost::forward_traversal_tag // CategoryOrTraversal > { ... }; Since the base class CellIterator already provides a operator* and a operator-> (both non-const version) I did not redefine any of these within the CellBoostIterator class. If I now want to use with code-snippet typedef Mesh_2::CellBoostIterator MIT; MIT mit; Mesh_2 mesh_2(omega1); for (MIT mit = mesh_2.begin(); mit != mesh_2.end(); ++mit) { std::cout << mit->index() <<std::endl; } I get a compile error /usr/include/boost/iterator/iterator_adaptor.hpp:312: error: passing ‘const dolfin::CellIterator’ as ‘this’ argument of ‘dolfin::Cell& dolfin::CellIterator::operator*()’ discards qualifiers I looked at the corresponding line /usr/include/boost/iterator/iterator_adaptor.hpp:312: typename super_t::reference dereference() const { return *m_iterator; } So it seems to me that I have to provide a const version of operator*, or do I get something wrong? I am a bit confused, since I have not found this kind of requirements in the documentation. Any enlightening, hints or pointers are greatly appreciated! Greetings, Andre

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1.40 and pch - gcc problems?
by Jonathan Brannan 04 Sep '09

04 Sep '09

I just got 1.40 and tried building. I kept having some pieces fail with a complete build, sometimes I had gcc that ran until resources exausted, sometimes the compiler would segfault. Eventaully I tracked it down to the math library. After noticing the many errors from the gch (things like : error _REENTERANT not defined or used diffrent -fpic). I disabled pch for the math library (actually the boost project and the libs/math/test) and I did not have any more issues. This is how I compiled it: ./bootstrap.sh --without-icu --prefix=ID_1_40_0 ./bjam install stage --prefix=/path/to/install -j 16 --buildid=ID_1_40_0 --layout=tagged --build-type=complete --stagedir=/path/to/install The system is sles (suse enterprise) 11. It's an 8 core intel machine. gcc version 4.3.2 [gcc-4_3-branch revision 141291] (SUSE Linux) I did not figure out how to disable this via the command line, so I did this: *** boost_1_40_0-compiled/Jamroot 2009-08-23 12:17:37.000000000 -0400 --- boost_1_40_0-new/Jamroot 2009-09-03 13:25:05.000000000 -0400 *************** *** 177,182 **** --- 177,183 ---- # Disable auto-linking for all targets here, primarily because it caused # troubles with V2. <define>BOOST_ALL_NO_LIB=1 + <toolset>gcc:<pch>off # Used to encode variant in target name. See the 'tag' rule below. <tag>@$(__name__).tag <conditional>@handle-static-runtime *** boost_1_40_0-compiled/libs/math/test/Jamfile.v2 2009-07-23 05:45:33.000000000 -0400 --- boost_1_40_0-new/libs/math/test/Jamfile.v2 2009-09-03 13:24:40.000000000 -0400 *************** *** 23,28 **** --- 23,29 ---- <toolset>intel:<linkflags>-nologo #<toolset>intel-linux:<pch>off <toolset>intel-darwin:<pch>off + <toolset>gcc:<pch>off <toolset>msvc:<warnings>all <toolset>msvc:<asynch-exceptions>on <toolset>msvc:<cxxflags>/wd4996

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date_time formatting issues
by ariasgore＠gmx.de 04 Sep '09

04 Sep '09

Hi, I have been trying to format a simple posix date time for string representation. The basic part is plain and simple: ---------------------------------------------- #include <boost/date_time/posix_time/posix_time.hpp> namespace ps = boost::posix_time; ps::ptime t(ps::second_clock::local_time()); std::string foo = ps::to_simple_string(t); ---------------------------------------------- But how can I format this returned string? I think the facets are required but as mentioned here : http://www.boost.org/doc/libs/1_40_0/doc/html/date_time/date_time_io.html#d… I tried something with the boost::date_time::date_input_facet: e.g ---------------------------------------------- ps::date_input_facet("%A"); ps::ptime t(ps::second_clock::local_time()); std::string foo = ps::to_simple_string(t); ---------------------------------------------- by using it before the simple_string call. I am sure this is wrong but I wouldn't like to use streams in addition to that to simply rearange some parts of a date for that reason. thanks sam -- Jetzt kostenlos herunterladen: Internet Explorer 8 und Mozilla Firefox 3 - sicherer, schneller und einfacher! http://portal.gmx.net/de/go/chbrowser

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[Boost-Serialization] Problem with BOOST_CLASS_EXPORT
by Soumen 03 Sep '09

03 Sep '09

Hi, I'm getting conflicting declaration with BOOST_CLASS_EXPORT and I think I've got the reason. But I'm not aware of clean solution to overcome this. Let me explain the problem here. Say in FileAB.h, I've class A, class B defined. I've a FileSExportAB.h where I've BOOST_CLASS_EXPORT(A) at line say 10 and BOOST_CLASS_EXPORT(B) at line 11. Similarly I've class C and class D defined FileCD.h. And FileSExportCD.h has BOOST_CLASS_EXPORT(C) @ line 10 and BOOST_CLASS_EXPORT(D) @ line 11. And while building, I get error like following: ------------------------------------------------------------------------------------------------ FileSExportCD.h:10: error: conflicting declaration ‘const boost::archive::detail::guid_initializer<C>& <unnamed>::boost_serialization_guid_initializer_10’ FileSExportAB.h:10: error: ‘<unnamed>::boost_serialization_guid_initializer_10’ has a previous declaration as ‘const boost::archive::detail::guid_initializer & <unnamed>::boost_serialization_guid_initializer_10’ ------------------------------------------------------------------------------------------------ All A, B, C and D are in same namespace. Putting things at different namespace is overkill on legacy code. Is using BOOST_CLASS_EXPORT_GUID only better solution? Is it not pssible for boost to resolve it automatically with BOOST_CLASS_EXPORT macro? Regards, ~ Soumen -- View this message in context: http://www.nabble.com/-Boost-Serialization--Problem-with-BOOST_CLASS_EXPORT… Sent from the Boost - Users mailing list archive at Nabble.com.

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cycle iterators
by Neal Becker 03 Sep '09

03 Sep '09

I use these regularly. Work for me.

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[iterator_adaptor] Does the base need a const version of operator* ?
by Andre Massing 03 Sep '09

03 Sep '09

Hi, I am trying to wrap our kind of iterators (for meshes) with the iterator_adaptor class template, something like class CellBoostIterator : public boost::iterator_adaptor< CellBoostIterator //Derived , CellIterator //Base , Cell //Value , boost::forward_traversal_tag // CategoryOrTraversal > { ... }; Since the base class CellIterator already provides a operator* and a operator-> (both non-const version) I did not redefine any of these within the CellBoostIterator class. If I now want to use with code-snippet typedef Mesh_2::CellBoostIterator MIT; MIT mit; Mesh_2 mesh_2(omega1); for (MIT mit = mesh_2.begin(); mit != mesh_2.end(); ++mit) { std::cout << mit->index() <<std::endl; } I get a compile error /usr/include/boost/iterator/iterator_adaptor.hpp:312: error: passing ‘const dolfin::CellIterator’ as ‘this’ argument of ‘dolfin::Cell& dolfin::CellIterator::operator*()’ discards qualifiers I looked at the corresponding line /usr/include/boost/iterator/iterator_adaptor.hpp:312: typename super_t::reference dereference() const { return *m_iterator; } So it seems to me that I have to provide a const version of operator*, or do I get something wrong? I am a bit confused, since I have not found this kind of requirements in the documentation. Any enlightening, hints or pointers are greatly appreciated! Greetings, Andre

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BGL new graph type implementation trouble
by Sebastian Weber 03 Sep '09

03 Sep '09

Hi! I am currently trying to implement a new graph type which I want to use with the BGL. The graph implements the Incidence Graph concept and should work out of the box with DFS algorithm of the BGL. However, I had to find out that the edge_descriptor must obey an EqualityComparison concept which keeps DFS from compiling. My current edge_descriptor is just a typedef to std::pair<vertex_descriptor, vertex_descriptor>. The vertex_descriptor itself is a custom object I wrote myself. Another problem turns out to appear with the copy-graph algorithm. This algorithm tries to copy vertex_all-property maps and edge_all property maps which I simply do not have defined in my custom graph as I only support the vertex_index mechanism. So what to do here? How can I tell copy-graph that these maps are not existent? Any help would be great here as I have the impression to hit limits of the documentation (the Equality-thing is not mentioned in the docs, at least I did not find it...). Greetings, Sebastian

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compile boost thread lib for iphone failed! the darwin g++ cant find head files for STL (string, cstddef)..how to solve this problem?
by terryc tang 03 Sep '09

03 Sep '09

i do the work as following: 0.install bjam 1. down boost_1_40_0 2. untar to disk root directory 3. ./bootstrap.sh ---with-library=thread 4. configure user-config.jam as following: using darwin : 4.2.1~iphone : /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/g++ : <striper> : <architecture>arm <target-os>iphone <macosx-version>iphone-2.1 ; using darwin : 4.2.1~iphonesim : /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/g++ : <striper> : <architecture>x86 <target-os>iphone <macosx-version>iphonesim-2.1 ; 5. command at console: bjam --prefix=/usrLibs/boostiPhoneDev toolset=darwin architecture=arm target-os=iphone macosx-version=iphone-2.1 define=_LITTLE_ENDIAN link=static install ... ... .... .. Any setting missing ? how to deal with it? In file included from ./boost/config.hpp:40, from ./boost/thread/detail/config.hpp:10, from libs/thread/src/pthread/thread.cpp:8: ./boost/config/select_stdlib_config.hpp:17:19: error: cstddef: No such file or directory In file included from ./boost/config/select_stdlib_config.hpp:33, from ./boost/config.hpp:40, from ./boost/thread/detail/config.hpp:10, from libs/thread/src/pthread/thread.cpp:8: ./boost/config/no_tr1/utility.hpp:21:21: error: utility: No such file or directory In file included from ./boost/thread/pthread/thread_data.hpp:9, from ./boost/thread/thread.hpp:17, from libs/thread/src/pthread/thread.cpp:10: ./boost/thread/exceptions.hpp:19:18: error: string: No such file or directory ./boost/thread/exceptions.hpp:20:21: error: stdexcept: No such file or directory In file included from ./boost/smart_ptr/shared_ptr.hpp:27, from ./boost/shared_ptr.hpp:17, from ./boost/thread/pthread/thread_data.hpp:10, from ./boost/thread/thread.hpp:17,

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[proto] char vs. int behaviour when matching
by Maurizio Vitale 03 Sep '09

03 Sep '09

Proto behaves in a different way when matching terminal<char> and terminal<int>. The only difference I'm aware is that it is implementation defined whether 'char' means 'signed char' or 'unsigned char' but it has to mean one of the two. I was surprised to hit the following: struct char_grammar : proto::or_< proto::terminal<signed char>, proto::terminal<unsigned char> > {}; struct extended_char_grammar : proto::or_< proto::terminal<char>, proto::terminal<signed char>, proto::terminal<unsigned char> > {}; struct int_grammar : proto::or_< proto::terminal<signed int>, proto::terminal<unsigned int> > {}; int main() { // WHY _NOT? BOOST_MPL_ASSERT_NOT ((proto::matches<proto::terminal<char>, char_grammar>)); BOOST_MPL_ASSERT ((proto::matches<proto::terminal<char>, extended_char_grammar>)); // GIVEN THAT: BOOST_MPL_ASSERT ((proto::matches<proto::terminal<int>, int_grammar>)); return 0; } Is this behaviour intentional? Regards, Maurizio

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[Unordered] [Multi-Index] Set lookup from something else than key_type
by Dominique Devienne 02 Sep '09

02 Sep '09

We currently have a unordered_map< Uid, shared_ptr<Identity> >, where Identity already contains the Uid. So I thought I could avoid the duplicated Uid by using an unordered_set< shared_ptr<Identity>, MyHash, MyPred > to hash/compare by the internal Uid, but unlike a Multi-Index hashed_index [1], unordered doesn't seem to provide: "lookup operations accepting search keys different from the key_type of the index, which is a specially useful facility when key_type object are expensive to create." Any reason why unordered cannot allow similar "compatible key" lookups? What kind of overhead is there (memory use, runtime), if any, in using Multi-Index as opposed to unordered_set in this scenario? Using Multi-Index yields a more complex type and slower compiles it seems due to its meta-programming uses I guess. Thanks for any insight. --DD [1] http://www.boost.org/doc/libs/1_40_0/libs/multi_index/doc/tutorial/basics.h…

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Boost::bind: compiling error from sample code in book
by Boost lzw 02 Sep '09

02 Sep '09

Hi there, I am testing the following sample code on page 264 of the book "Beyond the C++ Standard Library" and got an error msg: "result_type' : is not a member of '`global namespace'' from MSVC 2008 Pro compiler. Can anyone point out what is wrong with it? Thanks. ------------ #include<iostream> #include<string> #include<map> #include<vector> #include<algorithm> #include "boost/bind.hpp" class print_size { typedef std::map<std::string, std::vector<int> > map_type; public: typedef void result_type; result_type operator()(std::ostream& os, const map_type::value_type& x) const { os << x.second.size() << '\n'; } }; int main() { typedef std::map<std::string, std::vector<int> > map_type; map_type m; m["Strange?"].push_back(1); m["Strange?"].push_back(2); m["Wierd?"].push_back(3); m["Wierd?"].push_back(4); m["Wierd?"].push_back(5); std::for_each(m.begin(), m.end(), boost::bind(&print_size(), boost::ref(std::cout), _1)); } ------------

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[GIL] GIL and FreeImage interaction sample code suggestions ?
by Nicolas Lelong 02 Sep '09

02 Sep '09

Hi, FWIW I'm considering boost GIL to implement the few image algorithms I need, and I need proper image I/O on top of that. As I'm using FreeImage in my current codebase, I thought about exposing FreeImage image memory layout to GIL. You can find the, quite simplistic, source code here : http://code.google.com/p/rotoglup-scratchpad/source/browse/trunk/rtgu/image… http://code.google.com/p/rotoglup-scratchpad/source/browse/trunk/rtgu/image… http://code.google.com/p/rotoglup-scratchpad/source/browse/trunk/rtgu/image… I created a 'borrowed_image' class that mimics the behaviour of gil::image : it is not allocating memory itself, it takes an existing memory buffer and a 'deleter' (under the form of a boost::shared_ptr<void>) as input. This allows to use directly the memory allocated by FreeImage, avoiding extra copy, in case of file input. Feel free to use the code as a starting point, if you have similar needs, and I'd be glad to have comments about the concept of 'borrowed_image' class, and about its interface, as I feel I'm missing something. Cheers, Nicolas.

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Re: [Boost-users] [mpl, units] rational and static_rational
by Matthias Schabel 02 Sep '09

02 Sep '09

> I am looking for a template library that can handle compile time > rationals, ideally with a similar interface to mpl::int_ and that > plays well with boost::rational (the dynamic type). > > First I found boost/mpl/math/rational_c.hpp but soon I realized that > it doesn't work with basic operations like mpl::plus, it doesn't even > simplify reducible fractions (i.e. 2/4 -> 1/2), in fact it looks like > it is just the storage of two (static) integers. Is this something > that will be developed in the future or am I using it in the wrong > way? > > Then I found boost::units::static_rational which is more promising, > because it simplifies fractions and works with mpl::plus, but it is > not integrated with boost::rational nor has an interface similar to > that of mpl metatypes. > > Is there a way of extending mpl::math::rational_c with the existing > libraries in boost, or a simple way to make > boost::units::static_rational have an interface similar to mpl and > also have a value type that returns it runtime boost::rational value? I certainly would have no objection to repackaging the static_rational type used in Boost.Units as an MPL type that plays nicely with Boost.Rational. My advice would be to put together a functional implementation and propose it for a mini-review. We could easily typedef units::static_rational -> mpl::rational_ in the units library. Matthias

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Equality comparison of boost::function<>
by Zachary Turner 02 Sep '09

02 Sep '09

Is this possible? I always get ambiguities when I try it. Here's some sample code: class foo { public: typedef enum { lost, reset } device_event; typedef boost::function<void (window&, device_event)> device_listener; void add_listener(const device_listener& listener) { std::list<device_listener>::const_iterator iter = std::find(listeners_.begin(), listeners_.end(), listener); if (iter == listeners_.end()) listeners_.push_back(listener); } private: std::list<device_listener> listeners_; }; The above is slightly simplified from my actual code, but when I do this I get the following: I'm using Visual C++ 9.0 SP1 1>f:\dev\testing\window.h(42) : error C2666: 'operator ==' : 4 overloads have similar conversions 1> q:\include\boost\1.39.0\boost\function\function_template.hpp(995): could be 'void boost::operator ==<R,T0,T1>(const boost::function2<R,T0,T1> &,const boost::function2<R,T0,T1> &)' [found using argument-dependent lookup] 1> with 1> [ 1> R=void, 1> T0=zg::window &, 1> T1=zg::window::device_event 1> ] 1> q:\include\boost\1.39.0\boost\function\function_base.hpp(791): or 'bool boost::operator ==<zg::window::device_listener>(Functor,const boost::function_base &)' [found using argument-dependent lookup] 1> with 1> [ 1> Functor=zg::window::device_listener 1> ] 1> q:\include\boost\1.39.0\boost\function\function_base.hpp(782): or 'bool boost::operator ==<zg::window::device_listener>(const boost::function_base &,Functor)' [found using argument-dependent lookup] 1> with 1> [ 1> Functor=zg::window::device_listener 1> ] 1> or 'built-in C++ operator==(void (__thiscall boost::function2<R,T0,T1>::dummy::* )(void), void (__thiscall boost::function2<R,T0,T1>::dummy::* )(void))' 1> with 1> [ 1> R=void, 1> T0=zg::window &, 1> T1=zg::window::device_event 1> ] 1> while trying to match the argument list '(const zg::window::device_listener, const zg::window::device_listener)' 1

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[BGL] reducing memory requirements for adjacency list
by Soeren Meyer-Eppler 02 Sep '09

02 Sep '09

Hi, I'm using adjacency_list< vecS, vecS, bidirectionalS ... > extensively. I have so many graphs loaded at once that memory becomes an issue. I'm doing static program analysis and store the callgraph and flowgraphs of the disassembled binary in boost graphs. Thus I can have several ten thausand functions==flowgraphs and one gigantic callgraph. I'd really like to reduce memory usage for my graphs while still using the BGL. Since my graphs are static after loading and edge and vertex counts are known beforehand I see huge potential for optimization. For example, I'd like to allocate a single buffer for all vertices/edges of a single graph and let the graph just store indices into that buffer. more questions: 1) what's the memory overhead of using vertex and edge properties? I have quite a few of them. 2) is it possible to convince the BGL to use the shrink to fit idiom? As I understand it the adjacency lists use push_back to add edges. Is it possible to reduce memory usage by swapping the resulting vector with a copy of itself? Maybe by copying the whole graph? 3) Is it possible to use boost pool allocators with the BGL? As far as I can tell the BGL currently performs lots of small allocations - I'd really like to avoid that for space and runtime efficiency reasons. Did anyone already build a BGL version optimized for memory usage? Should I try using the existing graph structures and augment it with custom allocators or somesuch or is it more fruitful to write my own implementation and try to stay interface compatible with the BGL so I may continue to use it's algorithms? best regards, Sören

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Template mailing list / forum
by Ryan McConnehey 02 Sep '09

02 Sep '09

What is a good template forum or mailing list so that I don't clutter the boost mailing list with non boost questions? Ryan

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how to know which libraries to link?
by pedro chaparro 02 Sep '09

02 Sep '09

HI, im newbie with boost, i have a doubt about how to know which libraries u have to link when u compile a cpp file, in the example below for example which would be the libraries to link? i do for example c++ -I boostdirectory myfile.cpp -o myfile [ and here? ]. Im working with ubuntu, and boost 4.0 thanks // // timer.cpp // ~~~~~~~~~ // // Copyright (c) 2003-2008 Christopher M. Kohlhoff (chris at kohlhoff dot com) // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // #include <iostream> #include <boost/asio.hpp> #include <boost/date_time/posix_time/posix_time.hpp> int main() { boost::asio::io_service io; boost::asio::deadline_timer t(io, boost::posix_time::seconds(5)); t.wait(); std::cout << "Hello, world!\n"; return 0; } -- Ing Pedro Alonso Chaparro Valero Ciudad Politecnica de la Innovación iTEAM - Mobile Communications Group Polytechnic University of Valencia C\ Camino de Vera S/N, Edificio 8G 46022 Valencia, Spain

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[Interprocess] assertion while destroying inexistent named instance
by Rui Pedro Fernandes 02 Sep '09

02 Sep '09

Hi, During my tests I found that if I change the managed shared memory index from the default iset_index to map_index the test fails when a process tries to destroy an already inexistent named instance, using its name. With map_index, an assertion fails when the object is found not to be present. Shouldn't it behave like in the case of iset_index ? Thank you. Rui

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Re: [Boost-users] Boost and autocompletion
by dhruva 02 Sep '09

02 Sep '09

Hello, > On Tue, Sep 1, 2009 at 11:24 AM, Germ?n Diagowrote: > > try eclipse with eclipse cdt plugin. In www.eclipse.org you can find a > > bundle of "eclipse for c/c++ developers". > > That's the one you need. > > Yea, that is the best I have seen so far, but nothing gets anywhere > close to the quality of Visual Assist + MSVC sadly, that is my only > main tie to still programming on Windows, the IDE is just so much > better. Might see if it works in wine... Slightly off topic, GNU Global is pretty good in creating the good cross reference. I use it in my project with full boost being indexed. Emacs + Global is my development environment that works on both windoze and gnu/linux. I like the references feature of global which lists all potential locations where the symbol is referred (using pattern match only, same named functions appear even if it is totally unrelated to the symbol you are trying to explore) -dhruva Love Cricket? Check out live scores, photos, video highlights and more. Click here http://cricket.yahoo.com

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Re: [Boost-users] [Spirit] Creating a vector of structs
by Lindley M French 02 Sep '09

02 Sep '09

> On Tue, Sep 1, 2009 at 4:38 PM, Lindley M French<lfrench1(a)gmu.edu> > wrote:> I'm playing around with Spirit for a particular parsing > task. I could do this manually, but I figured this was a good > chance to learn what Spirit had to offer. > > > > The trouble is this. While Spirit offers ready-made semantic > actions for parsing primitives, it doesn't seem to offer anything > terribly useful for compound statements. As far as I can tell, you > can define your own semantic actions but they simply take in the > matched string as an argument----there's no way to get at the > values parsed on that level. > > > > For example, let's say I have a type > > struct Person > > { > > ? string name; > > ? double height; > > ? int age; > > ? Person(string n, double h, int a) > > ? : name(n), height(h), age(a) > > }; > > > > And I have a document containing > > > > 5.5 15 Henry > > 4.6 32 Jane > > 6.1 21 Bob > > > > I could parse this using > > > > rule<> personrule = strict_real_p >> int_p >> ~eol_p; > > parse(str, *(personrule[WhatGoesHere] >> eol_p) >> end_p); > > > > But how can I build a vector<Person> out of this? I can write my > own functor to do the push_back, but I need to get at the parsed > values of name, age, and height for each personrule somehow. > > > > I suppose I *could* just run another parse() on the input the > semantic action for that specific person....but that really seems > like it shouldn't be necessary. > > You are using Spirit.Classic, you should use Spirit.QI (Boost trunk, > docs are at: > http://svn.boost.org/svn/boost/trunk/libs/spirit/doc/html/index.html) then you can do it easy, like so: > > BOOST_FUSION_ADAPT_STRUCT(Person > (double,height) > (int,age) > (string,name) > ) > > rule<YourIteratorType> personrule; > personrule %= double_ >> int_ >> raw[lexeme[*(char_-eol)]]; > std::vector<Person> theVec; > parse(str.begin(),str.end(), *personrule, theVec); > > This is also better to ask on the spirit mailing list. :) Unfortunately for the moment I'm stuck with Boost 1.35, which I don't believe has Spirit 2. I'll try asking on the Spirit list.

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[Spirit] Creating a vector of structs
by Lindley M French 01 Sep '09

01 Sep '09

I'm playing around with Spirit for a particular parsing task. I could do this manually, but I figured this was a good chance to learn what Spirit had to offer. The trouble is this. While Spirit offers ready-made semantic actions for parsing primitives, it doesn't seem to offer anything terribly useful for compound statements. As far as I can tell, you can define your own semantic actions but they simply take in the matched string as an argument----there's no way to get at the values parsed on that level. For example, let's say I have a type struct Person { string name; double height; int age; Person(string n, double h, int a) : name(n), height(h), age(a) }; And I have a document containing 5.5 15 Henry 4.6 32 Jane 6.1 21 Bob I could parse this using rule<> personrule = strict_real_p >> int_p >> ~eol_p; parse(str, *(personrule[WhatGoesHere] >> eol_p) >> end_p); But how can I build a vector<Person> out of this? I can write my own functor to do the push_back, but I need to get at the parsed values of name, age, and height for each personrule somehow. I suppose I *could* just run another parse() on the input the semantic action for that specific person....but that really seems like it shouldn't be necessary.

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Boost and autocompletion
by Hassan Syed 01 Sep '09

01 Sep '09

Hello All, I've been trying to get autocompletion to work under Unix. I do not mind which editor I use really. I was hoping to get the quality of visual studio code completion. I have tried VIM/Ctags/Omnicompletion, Netbeans and Eclipse. The first option does not work well since ctags has a problem indexing boost, the smallest index I could build is 56 mb (after excluding the vector*.hpp files). Netbeans works well however it is dog slow. Eclipse doesn't work at all (perhaps I've done something wrong). Is there a combination for a posix system that will work well with boost (or other template heavy libraries) or do I need to code in visual studio and just recompile under a posix system ?. I guess what I could do is hide the boost code I use behind my own objects in visual studio and then resume development on Posix where it can index my objects nicely. It's depressing how bad the code completion engines are in non-Microsoft editors for C++ :(. Are there any mechanisms in c++0x to make the template code easier to parse for naive code-completion engines ? Regards Hassan

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lock-free shared_ptr on solaris
by Frank Meerkötter 01 Sep '09

01 Sep '09

Hello, from looking at [1] i understood that there is no lock-free implementation of shared_ptrs on solaris. When snooping around in the source i noticed that there is a ./smart_ptr/detail/atomic_count_solaris.hpp It is using the solaris specific <atomic.h> to implement an atomic counter. frank@dexter:~/boost_1_40_0/boost$ find -type f | xargs grep atomic_count_solaris.hpp ./smart_ptr/detail/atomic_count_solaris.hpp:// boost/detail/atomic_count_solaris.hpp But apparently it is not in use. I am currently wondering why? KR, Frank [1] http://www.boost.org/doc/libs/1_40_0/libs/smart_ptr/shared_ptr.htm

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Re: [Boost-users] [msm] Acceptance into boost?
by christophe henry 01 Sep '09

01 Sep '09

>I really admire the Boost.MSM library currently in the vault. I like it a lot better than the original FSM. Are there any plans to integrate the msm library into >an official Boost release?> >--------- >Robert Dailey Thanks for the feedback! I'm happy that you like it! Msm is right now in the review queue but I need a review manager and I have been very busy with msm 2.0 and therefore had no time to look for one. So I'd like to use the chance to ask if some experienced boost'ler would accept to be the review manager for msm and help me speed up the process a little. If someone would also be interested in playing with msm 2 as beta tester please contact me too :) Christophe _________________________________________________________________ More than messages–check out the rest of the Windows Live™. http://www.microsoft.com/windows/windowslive/

1 0

[Test] data_access_test && common_layer::const_string && missing std::out_of_range exception
by Dmitry V. Krivenok 01 Sep '09

01 Sep '09

Hello! I'm trying to build boost-1.40.0 and have problems with Boost::Test. Please take a look at build log: ------------------------------------------------------------------------ common.mkdir /home/krivenok/dev_builds/boost_1_40_0_build/boost/bin.v2/libs/test/example/const_string_test.test common.mkdir /home/krivenok/dev_builds/boost_1_40_0_build/boost/bin.v2/libs/test/example/const_string_test.test/gcc-4.4 common.mkdir /home/krivenok/dev_builds/boost_1_40_0_build/boost/bin.v2/libs/test/example/const_string_test.test/gcc-4.4/debug gcc.compile.c++ /home/krivenok/dev_builds/boost_1_40_0_build/boost/bin.v2/libs/test/example/const_string_test.test/gcc-4.4/debug/const_string_test.o gcc.link /home/krivenok/dev_builds/boost_1_40_0_build/boost/bin.v2/libs/test/example/const_string_test.test/gcc-4.4/debug/const_string_test testing.capture-output /home/krivenok/dev_builds/boost_1_40_0_build/boost/bin.v2/libs/test/example/const_string_test.test/gcc-4.4/debug/const_string_test.run ====== BEGIN OUTPUT ====== Running 6 test cases... ../../libs/test/example/const_string_test.cpp(71): error in "data_access_test": exception std::out_of_range is expected *** 1 failure detected in test suite "const_string test" EXIT STATUS: 201 ====== END OUTPUT ====== LD_LIBRARY_PATH="/usr/local/bin:/usr/local/lib:/usr/local/lib32:/usr/local/lib64:$LD_LIBRARY_PATH" export LD_LIBRARY_PATH "/home/krivenok/dev_builds/boost_1_40_0_build/boost/bin.v2/libs/test/example/const_string_test.test/gcc-4.4/debug/const_string_test" > "/home/krivenok/dev_builds/boost_1_40_0_build/boost/bin.v2/libs/test/example/const_string_test.test/gcc-4.4/debug/const_string_test.output" 2>&1 status=$? echo >> "/home/krivenok/dev_builds/boost_1_40_0_build/boost/bin.v2/libs/test/example/const_string_test.test/gcc-4.4/debug/const_string_test.output" echo EXIT STATUS: $status >> "/home/krivenok/dev_builds/boost_1_40_0_build/boost/bin.v2/libs/test/example/const_string_test.test/gcc-4.4/debug/const_string_test.output" if test $status -eq 0 ; then cp "/home/krivenok/dev_builds/boost_1_40_0_build/boost/bin.v2/libs/test/example/const_string_test.test/gcc-4.4/debug/const_string_test.output" "/home/krivenok/dev_builds/boost_1_40_0_build/boost/bin.v2/libs/test/example/const_string_test.test/gcc-4.4/debug/const_string_test.run" fi verbose=0 if test $status -ne 0 ; then verbose=1 fi if test $verbose -eq 1 ; then echo ====== BEGIN OUTPUT ====== cat "/home/krivenok/dev_builds/boost_1_40_0_build/boost/bin.v2/libs/test/example/const_string_test.test/gcc-4.4/debug/const_string_test.output" echo ====== END OUTPUT ====== fi exit $status ...failed testing.capture-output /home/krivenok/dev_builds/boost_1_40_0_build/boost/bin.v2/libs/test/example/const_string_test.test/gcc-4.4/debug/const_string_test.run... ...failed updating 1 target... ...updated 174 targets... ------------------------------------------------------------------------ The problem is: ../../libs/test/example/const_string_test.cpp(71): error in "data_access_test": exception std::out_of_range is expected I looked at line 71 in const_string_test.cpp: BOOST_CHECK_THROW( cs1.at( cs1.length() ), std::out_of_range ); This code is used to ensure that std::out_of_range is thrown in case of out of bound access to the string. However, common_layer::const_string doesn't provide such validation. operator[] and at() are identical in const_string: char operator[]( size_t index ) const { return m_begin[index]; } char at( size_t index ) const { return m_begin[index]; } I commented BOOST_CHECK_THROW out and now Boost::Test compiles w/o any errors. I think implementation of const_string::at() should be fixed.

2 1

[serialization] loading a map having a const mapped value type
by Marco Canini 01 Sep '09

01 Sep '09

Hi all, I'm unable to address this use case of the serialization library. I have a standard map in which the mapped value is const: map<string, const Protocol *> _table; My serialize is very simple: ar & _table; (the test case source code is attached) However, this can't be compiled as I get many errors related to the loading code inside boost::serialization: /usr/include/boost/archive/detail/iserializer.hpp:488: error: reinterpret_cast from type 'const Protocol**' to type 'void**' casts away constness /usr/include/boost/archive/detail/iserializer.hpp:491: error: no matching function for call to 'boost::archive::detail::load_pointer_type<boost::archive::text_iarchive, const Protocol*>::pointer_tweak(const boost::serialization::extended_type_info&, const Protocol*&, const Protocol&)' /usr/include/boost/serialization/access.hpp:109: error: passing 'const Protocol' as 'this' argument of 'void Protocol::serialize(Archive&, unsigned int) [with Archive = boost::archive::text_iarchive]' discards qualifiers /usr/include/boost/archive/detail/iserializer.hpp: In member function 'void boost::archive::detail::pointer_iserializer<T, Archive>::load_object_ptr(boost::archive::detail::basic_iarchive&, void*&, unsigned int) const [with T = const Protocol, Archive = boost::archive::text_iarchive]': /usr/include/boost/archive/detail/iserializer.hpp:299: error: invalid conversion from 'const void*' to 'void*' /usr/include/boost/archive/detail/iserializer.hpp:307: error: invalid conversion from 'const void*' to 'void*' /usr/include/boost/archive/detail/iserializer.hpp:307: error: initializing argument 1 of 'void boost::archive::detail::basic_iarchive::next_object_pointer(void*)' /usr/include/boost/serialization/access.hpp:123: error: invalid conversion from 'const void*' to 'void*' /usr/include/boost/serialization/access.hpp:123: error: initializing argument 2 of 'void* operator new(size_t, void*)' /usr/include/boost/serialization/access.hpp:123: error: no matching function for call to 'Protocol::Protocol()' /usr/include/boost/archive/detail/iserializer.hpp:555: error: invalid application of 'sizeof' to incomplete type 'boost::STATIC_ASSERTION_FAILURE<false>' /usr/include/boost/archive/detail/iserializer.hpp:555: error: invalid application of 'sizeof' to incomplete type 'boost::STATIC_ASSERTION_FAILURE<false>' Can somebody share his wisdom on this please? Thanks! -- Marco Canini

3 6

[mpl::print] Making mpl::print<> function
by Robert Ramey 01 Sep '09

01 Sep '09

I have the following which I expect to produce a compile time warning which includes the type name but it fails to do so. I found this in the C++ Template Metaprogramming book - but not in the MPL documentation. What am I missing here? Robert Ramey #include <boost/mpl/print.hpp> template<class T> int f(){ boost::mpl::print<T>; //static int x = g<T::value>(); return x; } struct A { BOOST_STATIC_CONSTANT(bool, value = false); }; ... int x = f<A>();

3 2

[msm] Acceptance into boost?
by Robert Dailey 01 Sep '09

01 Sep '09

I really admire the Boost.MSM library currently in the vault. I like it a lot better than the original FSM. Are there any plans to integrate the msm library into an official Boost release? --------- Robert Dailey

1 0

Iterator behaving like an indirect_iterator and a filter_iterator
by Teto 01 Sep '09

01 Sep '09

Hi everyone, I wanted to know if it was possible to have an iterator behaving like both an indirect_iterator and a filter_iterator. I've tried to without success. Here is a minimal code that compiles but crashes. ===================================== class CTest { public: CTest(int Value,int Id) : value(Value),id(Id) {}; int id; int value; }; std::vector<CTest*> vec; vec.push_back(new CTest(4,7)); vec.push_back(new CTest(4,1)); //I want an iterator that I could use like iter->id / iter->value and not (*iter)->id / (*iter)->value struct SPredicate { bool operator()( C& x) { return (-1 < x.id); } }; typedef boost::filter_iterator<SPredicate, CTest*> FilterIterator; FilteredIterator end(*vec.end()); for(FilteredIterator iter(*vec.begin());start != end; iter++){ std::cout << "id" << iter->id << "\tValue" << iter->m << std::endl; } ===================================== I'm new to boost and is very impressed by its possibilites. Hope I can understand the code better later. thanx matt

3 2

[mem_fn] return type
by Lowell McLinskey 01 Sep '09

01 Sep '09

I am having trouble understanding the return type of mem_fn. Is it possible to create a vector of this type, analogous to how one can create a vector of type mem_fun_t to hold the return values of mem_fun()? Here is an example of what I'd like to do. Thanks in advance. #include <vector> #include <functional> #include "boost/shared_ptr.hpp" #include "boost/mem_fn.hpp" class A { public: A(const int a) : a_(a) {} const int get() const {return a_;} private: int a_; }; int main(int argc, char** argv) { // I can do this std::vector<std::const_mem_fun_t<const int, A> > v; v.push_back(std::mem_fun(&A::get)); int i = v[0](new A(4)); // and this boost::shared_ptr<A> p(new A(7)); int j = boost::mem_fn(&A::get)(p); // but how do I do this? // std::vector< WHAT GOES HERE > w; // w.push_back(boost::mem_fn(&A::get)); // int k = w[0](p); return 0; }

3 3

[asio] What happens when a deadline_timer is deleted
by Bjarne Laursen 01 Sep '09

01 Sep '09

If I have a deadline_timer in my class and my class is deleted, the compleetion function will be called (with error code). But as the destructor have already been run I guess that the 'this' pointer will be invalid! Is this safe? What if my compleetion function is virtual? timer.async_wait(boost::bind(&MyClass::OnTimer, this, boost::asio::placeholders::error)); --

2 1

[Units] Runtime dimension check
by Thomas Taylor 01 Sep '09

01 Sep '09

Hi all! Is there an easy way to check if two quantities have the same dimension? E. g. a user enters a weight in tons and asks for a conversion to kilograms. So now at run time I would like to know if tons and kilograms have the same dimensions (i. e. are convertable) or not (illegal conversion). Thanks, Thomas

2 1

Problem detecting python
by Philippe Fremy 01 Sep '09

01 Sep '09

Hi, bjam does not seem to pick my python installation on windows. This is running on Windows XP, toolset gcc, boost 1.39, compiling from source with no changes. D:\program\boost_1_39_0>bjam --debug-configuration -d+2 --debug-building [...] notice: [python-cfg] running command '"C:\Python25\python" -c "from sys import *; print 'version=%d.%d\nplatform=%s\nprefix=%s\nexec_prefix=%s\nexecutable=%s' % (version_info[0],version_info[1],platform,prefix,exec_prefix,executable)" 2>&1'notice: [python-cfg] ...does not invoke a working interpreter notice: [python-cfg] No working Python interpreter found. The strange thing is that if I run the same command line, it works perfectly: D:\program\boost_1_39_0>"C:\Python25\python" -c "from sys import *; print 'version=%d.%d\nplatform=%s\nprefix=%s\nexec_prefix=%s\nexecutable=%s' % (version_info[0],version_info[1],platform,prefix,exec_prefix,executable)" 2>&1 version=2.5 platform=win32 prefix=C:\Python25 exec_prefix=C:\Python25 executable=C:\Python25\python.exe Any idea what confuses bjam ? I could not find any log file to see more details of what is going wrong... cheers, Philippe

5 8

Latex
by Dmitry Bufistov 01 Sep '09

01 Sep '09

\renewcommand{\baselinestretch}{0.98}

1 1

[MPL] Front of a set of types
by Marco Guazzone 01 Sep '09

01 Sep '09

Dear all, Consider this: ---[code]--- #include <boost/mpl/front.hpp> #include <boost/mpl/set.hpp> #include <boost/type_traits/is_same.hpp> #define BOOST_TEST_MODULE "boost::mpl::set tests" #define BOOST_TEST_DYN_LINK #define BOOST_TEST_MAIN #include <boost/test/unit_test.hpp> BOOST_AUTO_TEST_CASE( mpl_set ) { typedef boost::mpl::set<int,long,char> s; BOOST_CHECK( (boost::is_same<int, boost::mpl::front<s>::type>::value) ); // Test #1 BOOST_CHECK( (boost::is_same<long, boost::mpl::front<s>::type>::value) ); // Test #2 BOOST_CHECK( (boost::is_same<char, boost::mpl::front<s>::type>::value) ); // Test #3 } ---[/code]--- Reading the docs http://www.boost.org/doc/libs/1_40_0/libs/mpl/doc/refmanual/set.html the "front" of a set<t1,t2,...,tn> return the first element type in s which for me is t1 So what I expect is the test to fail on tests #2 and #3 and hence to succeed on test #1 Instead the test fails on tests #1 and #2 and succeeds on test #3. Looking inside the code I find out this is OK since a setN<T1,..,TN> is defined from TN and set{N-1}<T1,...,T{N-1}>, resulting in TN be the very front element Anyway, in my opinion this is counterintuitive. Maybe a note in the document would be helpful. What do you think? Thank you very much! Cheers, -- Marco

2 7

problem with asio
by pedro chaparro 01 Sep '09

01 Sep '09

hi everyone, i'm new with boost, i've try some examples and they work well but spacifically with programs that use asio libraries i've got some error when i try to compile them, below the line i use to compile, ill apreciate some help thnaks pdro7@ubuntu:~/Desktop$ c++ -I /home/pdro7/Desktop/boost_1_40_0 asio1.cpp -o asio1 /usr/lib/libboost_system-gcc43-mt-1_35.a /usr/lib/libboost_thread-gcc43-mt-1_35.a /usr/lib/libboost_date_time-gcc43-mt-1_35.a /usr/lib/libboost_regex-gcc43-mt-1_35.a /usr/lib/libboost_serialization-gcc43-mt-1_35.a // timer.cpp // ~~~~~~~~~ // // Copyright (c) 2003-2008 Christopher M. Kohlhoff (chris at kohlhoff dot com) // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // #include <iostream> #include <boost/asio.hpp> #include <boost/date_time/posix_time/posix_time.hpp> int main() { boost::asio::io_service io; boost::asio::deadline_timer t(io, boost::posix_time::seconds(5)); t.wait(); std::cout << "Hello, world!\n"; return 0; } -- Ing Pedro Alonso Chaparro Valero Ciudad Politecnica de la Innovación iTEAM - Mobile Communications Group Polytechnic University of Valencia C\ Camino de Vera S/N, Edificio 8G 46022 Valencia, Spain

2 1

[Math] Fractional binomial_coefficient
by Ralf M. 01 Sep '09

01 Sep '09

Hi, the binomial coefficients are usually used with integers, but it is also possible to get the binomial coefficient of real values (cf. http://en.wikipedia.org/wiki/Binomial_coefficient ). Maybe this could be added to the boost math library. Here's a sample implementation using standard g++: template <class T> T Choose(T n, T k) { return exp(lgamma(n + 1.0) - lgamma(k + 1.0) - lgamma(n - k + 1.0)); } Examples using double or long double type: C(10.000000, 3.000000) = 120.000000000000 C(10.000000, 3.250000) = 143.236519908866 C(10.000000, 3.500000) = 166.719334273254 C(10.000000, 3.750000) = 189.361086655990 C(10.000000, 4.000000) = 210.000000000000 C(10.500000, 3.000000) = 141.312500000000 C(10.500000, 3.250000) = 171.461136142499 C(10.500000, 3.500000) = 202.979003906250 C(10.500000, 3.750000) = 234.620815915449 C(10.500000, 4.000000) = 264.960937500000

2 1

[BGL] backward warning
by Ralf Goertz 01 Sep '09

01 Sep '09

When compiling with gcc4.3 I get a backward warning from adjacency_list.hpp because it includes hash_set instead of unordered_set (Boost 1.39.0). Will this be fixed soon? Ralf

2 2

[serialization] binary archiver with generic primitive types
by Florent Teichteil 31 Aug '09

31 Aug '09

Hi all, The binary_oarchive and binary_iarchive classes serialize an object to a stream whose buffer type is streambuf=basic_streambuf<char>. It means that the serialized object is translated into an array of chars. It is fine if you can work with an array containing chars. Unfortunately, some libraries need serialized objects that are translated into arrays whose type is different from char. For instance, I'm using a library that requires an array of unsigned chars. For that reason, I have defined generic (templated) tbinary_oarchive and tbinary_iarchive classes based on the ones provided by the boost serialization library. It is straightforward since the original boost serialization classes use the std::ostream type that is just an instantiation of the generic basic_ostream class with the char type (ostream=basic_ostream<char>). For instance, the tbinary_oarchive class is now defined as follows: // CODE BEGIN template <class Tdata> class tbinary_oarchive : public binary_oarchive_impl< tbinary_oarchive<Tdata>, typename std::basic_ostream<Tdata>::char_type, typename std::basic_ostream<Tdata>::traits_type > { public: tbinary_oarchive(std::basic_ostream<Tdata> & os, unsigned int flags = 0) : binary_oarchive_impl< tbinary_oarchive, typename std::basic_ostream<Tdata>::char_type, typename std::basic_ostream<Tdata>::traits_type >(os, flags) {} tbinary_oarchive(std::basic_streambuf<Tdata> & bsb, unsigned int flags = 0) : binary_oarchive_impl< tbinary_oarchive, typename std::basic_ostream<Tdata>::char_type, typename std::basic_ostream<Tdata>::traits_type >(bsb, flags) {} }; // CODE END Then, when I need to use a binary archiver with the type unsigned char, I just put the following lines in my code: // CODE BEGIN typedef boost::archive::tbinary_oarchive<unsigned char> BinaryOBArchive; typedef boost::archive::tbinary_iarchive<unsigned char> BinaryIBArchive; BOOST_SERIALIZATION_REGISTER_ARCHIVE(BinaryOBArchive) BOOST_SERIALIZATION_REGISTER_ARCHIVE(BinaryIBArchive) // CODE END This compiles fine except that I get some linker errors concerning the basic_binary_oarchive and the basic_binary_oprimitive classes. For instance: undefined reference to `boost::archive::basic_binary_oprimitive<boost::archive::tbinary_oarchive<unsigned char>, unsigned char, std::char_traits<unsigned char> >::~basic_binary_oprimitive()' It seems that parts of the serialization library's code is outside the definition classes, preventing to extend it with different binary types... Is there a workaround? Thank you very much for your patience reading this e-mail entirely, Florent.

4 4

[Graph] Error in cuthill_mckee_ordering in 1.40
by Ryan W. Frenz 31 Aug '09

31 Aug '09

I am attempting to upgrade to boost 1.40 and have found an issue with cuthill_mckee_ordering.hpp. The following code demonstrates the issue. #include <boost/graph/adjacency_matrix.hpp> #include <boost/graph/cuthill_mckee_ordering.hpp> int main() { typedef boost::property<boost::vertex_name_t, std::string> VertexProperty; typedef boost::adjacency_matrix<boost::undirectedS, VertexProperty> MyGraph; typedef boost::graph_traits<MyGraph>::vertex_descriptor Vertex; MyGraph graph(0); // Fill graph with nodes, etc.... // Perform reverse cuthill mckee... std::vector<Vertex> inv_perm(boost::num_vertices(graph)); { boost::cuthill_mckee_ordering(graph, inv_perm.rbegin()); // 'has_no_vertices' error... // do stuff with ordered graph... } return 0; } This code builds cleanly against 1.36 (my previous version) but fails when built against 1.40 with the following: ....boost/graph/cuthill_mckee_ordering.hpp(172): 'has_no_vertices': identifer not found Looking at the code, the function boost::cuthill_mckee_ordering is calling has_no_vertices (with no specified namespace). has_no_vertices (in graph_utility.hpp) lives in the boost::graph namespace. Changing the line to graph::has_no_vertices fixes the compiler error. Is this possibly a bug in 1.40 or am I doing something wrong? Thanks, Ryan

2 2

fast_pool_allocator, std::multi_map and purge_memory
by Soeren Meyer-Eppler 31 Aug '09

31 Aug '09

Hi, I have written a small test program to measure the performance benefit of using a boost::fast_pool_allocator vs the default system allocator in conjunction with a std::multi_map. Memory overhead is ~16% lower and the boost allocator is ~4x faster - sweet. However, I can't release the allocated memory via the singleton_pool interface as described in the documentation. In my test program quoted below the call to purge_memory always returns 0 and according to window's task manager the memory has not been released. An even simpler test just using an allocator for ints and allocating/relasing/purging 10.000.000 ints works as expected. What am I doing wrong? cheers, Sören PS: I'm using boost 1.39 with MSVC2008 #include <map> #include <iostream> #include <boost/pool/pool_alloc.hpp> int main( int, char ** ) { typedef boost::fast_pool_allocator< std::pair< int, void * > > TPoolAllocator; typedef std::multimap< int, void *, std::less< int >, TPoolAllocator > TMap; { TMap map; for ( int i = 0; i < 10000000; ++i ) map.insert( std::make_pair( rand() % 100, (void *)0 )); } std::cout << boost::singleton_pool< boost::fast_pool_allocator_tag, sizeof( TPoolAllocator::value_type ) >::purge_memory(); return 0; }

2 2

Cannot file tickets for 1.40
by Roland Bock 31 Aug '09

31 Aug '09

Hi, I would like to file a few tickets for version 1.40, but TRAC does not know version 1.40 yet. Regards, Roland

2 1

Linker errors with boost's threading and python libs, OSX
by Shamyl Zakariya 31 Aug '09

31 Aug '09

Hi, Yesterday I upgraded boost to 1.4, from 1.36. A big jump, but hey why not. I'm running OSX, 10.6 with the most recent dev tools ( Xcode 3.2, GCC 4.2, etc ) and used the bjam build system as described on the website. Vanilla install to /usr/local/ giving me the static and dynamic libs in /usr/local/lib. Two (related) questions: 1) My project ( built in Xcode ) uses mostly header-based libs, but does link against libboost_thread.a -- and now it throws all sorts of linker errors when it worked just fine linking against 1.36 For example: "boost::thread::~thread()", referenced from: void boost::checked_delete<boost::thread>(boost::thread*)in QTFrameTransfer.o /// many many more And for reference, I really *am* linking against libboost_thread.a 2) My related followup question -- I've *never* been able to link against libboost_python.a. So in the past I added the full source from $BOOST/libs/python/src to a sub-target of my project and manually build my own libboost_python.a which I then linked against. That worked fine. But I don't understand why I can't link against /usr/ local/lib/libboost_python.a I have to assume something's wonky with the way bjam is building these libraries. But I'm following the out-of-the-box install instructions. Finally, I assume I could just build my own local boost the way I used to build boost's python. But I'd rather use the versions in /usr/local/ lib... shamyl zakariya - squamous and rugose

3 2

Advise sought for container type
by Archie14 30 Aug '09

30 Aug '09

given the class like the one below: template <typename T> class animal { public: animal (const char* ofname) : _name(ofname) {} private: typedef T _T; std::string _name; _T behavior; } class MeatEater {}; class GrassEather {}; animal<MeatEater> bear ("bear"); animal<GrassEater> rabbit ("rabbit"); How to store "bear" and "rabbit" instances in a vector? Advise is greatly appreciated.

3 4

Chain of Responsibility Pattern in a boost library
by Ryan McConnehey 30 Aug '09

30 Aug '09

Is there a boost library that implements the Chain of Responsibility Pattern? Ryan

1 0

[mapreduce] Prim Calculator
by Christian Henning 30 Aug '09

30 Aug '09

Hi there, first of all, I'm not sure if boost user list should be used for boost-sandbox libraries. Anyone? Now, I would like create a new example for the mapreduce lib. How can I, for instance, setup a system that computes the prim numbers for 0 to 1,000,000,000. For this, I need to create the input for the map function on the fly, rather than reading some files from the hard drive. How is that possible? The documentation is a bit spare so far. Thanks, Christian

2 22

[proto] folding a proto tree in reverse
by Maurizio Vitale 30 Aug '09

30 Aug '09

I need to traverse a proto tree from right to left so that given the statement: (a, b, c) = expr; I can assign in order c then b and lastly a. A fragment that does the order a,b,c (and work, but not very efficiently, which is why I want to go the other way) is: template<typename E> struct assign_aux { assign_aux (const E& rhs) : m_rhs (rhs) {} typedef int result_type; template<typename T> int operator()(const T& t, int offset) const { int next_offset = offset - actual_width_transform () (t); int value = systemc_eval (m_rhs.range (offset,next_offset+1)); const_cast<T&>(t) = value; return next_offset; } const E& m_rhs; }; template <typename E> struct assign<E, proto::tag::comma> { template<typename RHS> const E& doit (const E& e, const RHS& rhs) { int width = actual_width_transform () (e); fusion::fold(proto::flatten (const_cast<systemc_expression&>(e)), width-1, assign_aux<RHS> (rhs)); return e; } }; template<typename E> const systemc_expression& operator = (const E& e) const { BOOST_MPL_ASSERT ((proto::matches<systemc_expression, lhs_systemc_grammar>)); return assign<systemc_expression>().doit (*this, e); return *this; } I've tried to use fusion::reverse_view to invert the fusion sequence, but failed. I also suspect that the resulting code wouldn't be as good as it could be, which in my application is critical. So I looked at alternatives and tried proto::reverse_fold_tree. Here's my attempt: struct assign_terminal : proto::callable { typedef int result_type; template<typename T, typename O, typename R> int operator () (T& t, O o, const R& r) const { int width = actual_width_transform () (t); const_cast<T&>(t) = r.range (1,0); return o+width; } }; template <typename E> struct assign<E, proto::tag::comma> { template<typename RHS> const E& doit (const E& e, const RHS& rhs) { proto::reverse_fold_tree<_, int() , assign_terminal (_, proto::_state, proto::_data)>() (e, rhs); return e; } }; template<typename E> const systemc_expression& operator = (const E& e) const { BOOST_MPL_ASSERT ((proto::matches<systemc_expression, lhs_systemc_grammar>)); return assign<systemc_expression>().doit (*this, e); return *this; } But this doesn't seem to pass the data (rhs) to assign_terminal::operator () (expr, state, data). There're really very few examples on how to use proto::fold_tree and even fewer using the data parameter, so I don't have much to go on. Would anybody whose name is Eric tell me why I'm this stupid? TIA, Maurizio

3 3

boost::multi_index_container vector-like O(1) time indexing question
by zap.foster 30 Aug '09

30 Aug '09

I originally posted this to the wrong group, but I intended it for this group. I have a boost::multi_index question. My current container has looked like the following for a very long time: typedef std::map<double,int> mtype_t; What I am looking for is a way to index the mtype_t::value_type.first value so that, syntactically, it appears like a vector. For example, the container I need would let me do something like: { container_t c; c.insert( container_t::value_type( keycount_t( 1.414,88) )); c.insert( container_t::value_type( keycount_t( 3.141,77) )); c.insert( container_t::value_type( keycount_t( 23.000,99) )); for(int index=0; index<c.size(); ++index) printf("%d\n",c[index].second); } You can see that I want to be able to index into the container much like one would do with a vector. But I want my indexing to be O(1) and not O(n). Now I still need to be able to iterate the container, and I need to be able to do efficient insertions, and yes, the contents of the container will get bigger and smaller and the values vary quite a lot. A basic sketch of the multi_index container (but without the vector-like index) would be: typedef struct { double key; int count; } keycount_t; struct by_key{}; typedef boost::multi_index_container< keycount_t, boost::multi_index::indexed_by < boost::multi_index::ordered_unique < boost::multi_index::tag<by_key>, boost::multi_index::member< keycount_t,double,&keycount_t::key > > > > container_t; This gives me the basics. But I cannot think of a way to add a secondary index that would give me the O(1) vector-like indexing. A use-case of the grammar I am after would be something like the following: void useless_function(container_t& c) { for(container_t::iterator i = c.begin(); i!=c.end(); ++i) print("key=%f\tval=%d\n",i->first,i->second); for(index=0; index<c.size(); ++index) print("key=%f\tval=%d\n",c[index].first,c[index].>second); } Here's WHY I need this: I have a stream of floating point values coming in (fixed to 5 significant digits). I need to keep count of how often any one of the floating point values is repeated. Very often I need to respond to requests as to the contents of the container at the Nth position. The slow O(n) method would be: const keycount_t& get_nth_record(int index,const container_t& c) { container_t::const_iterator i; for(i=c.begin(); i!=c.end(); ++i) if(--index==0 ) break; return( *i ); } But again, I need O(1) time, so I need some sort of index added to my container_t. Has anyone done this sort of thing before, and met the O(1) positional index requirement? Many thanks! -zap

2 1

Intercommunicators with Boost.MPI ?
by Ashika Umanga Umagiliya 30 Aug '09

30 Aug '09

Greeting all, I am completly new to Boost and this is my very first post here . I have used Boost.Serialization and Boost.MPI to send user-defined-datatypes across MPI processes. (I use OpenMPI 1.3.3 ) Now, I want to spawn processes (MPI_Comm_spawn) and send across these objects among newly created child processes. How can I handle Intercommunicators with Boost.MPI ? Thanks in advance, umanga

1 0

circular_buffer: How to make push_back() increase capacity?
by Robert Dailey 30 Aug '09

30 Aug '09

Hello, I have a list of colors that I need to be able to cycle through, either by rotating the container or by using an iterator that will rotate (i.e. return to the beginning when I increment at the end, and vice-versa). The goal is to be able to iterate through the container in a circular way and process all of the colors repeatedly. I chose a boost::circular_buffer for this job, I assumed it was the perfect tool for the job. It works great, except I would like to be able to call push_back() to add all of my colors to the buffer without having to call set_capacity() on it first. It's a minor thing, but omitting the call to set_capacity() would make it slightly more scalable/manageable since I won't have to keep incrementing the size of the capacity each time I want to add colors to the buffer. How can I achieve this? --------- Robert Dailey

4 3

[boost-users][Variant] Sequence instantiation
by Ryan McConnehey 30 Aug '09

30 Aug '09

I have a sequence of types defined with the Loki library. I believe the equivalent would be boost::mpl::vector. The sequence is used to cause compile time asserts for unsupported types being passed to template functions. Boost variant can be created with a given list of types. typedef boost::variant< int, std::string, short, long > type_list; | <boost/variant.html>| Is it possible to create a variant from a sequence by either passing the sequence or iterating through each value in the sequence? This would reduce the code duplication of having one sequence for assert checking and the other for variants. Ryan

3 12

Using BGL::read_graphml()
by Ramapriya Rangachar 30 Aug '09

30 Aug '09

Hello Boost users, I have managed to build the latest version (1.40.0) under Windows/MSVC. Could someone kindly point me to a working example that complements the link below, for read_graphml()? http://www.boost.org/doc/libs/1_40_0/libs/graph/doc/write_graphml.html Best regards, Ram _________________________________________________________________ Windows Live: Make it easier for your friends to see what you’re up to on Facebook. http://windowslive.com/Campaign/SocialNetworking?ocid=PID23285::T:WLMTAGL:O…

1 0

[asio] DTR serial port option?
by Robert Dailey 30 Aug '09

30 Aug '09

Hello, I'm rewriting a C# program in C++. This C# program previously was communicating with a device via serial port. One thing in particular it was doing was setting the DTR flag to enabled. The MSDN article on this option is here: http://msdn.microsoft.com/en-us/library/system.io.ports.serialport.dtrenabl… <http://msdn.microsoft.com/en-us/library/system.io.ports.serialport.dtrenabl…>I do not see an option in the Boost.Asio documentation that is identical to this C# option. Can anyone comment on this? How can I enable DTR through Boost Asio's serial_port? --------- Robert Dailey

4 10

Re: [Boost-users] [Graph] Problems with adjacency_matrix
by Juan Antonio Farré Basurte 29 Aug '09

29 Aug '09

> > > Hello, > I have a problem with adjacency_matrix template. > It claims to implement VertexAndEdgeListGraphConcept, BidirectionalGraphConcept and MutablePropertyGraphConcept. > But when I try to compile, it complains about using the next functions with an adjacency_matrix: > > num_vertices(graph) > vertices(graph) > num_edges(graph) > edges(graph) > source(edge_descriptor, graph) > target(edge_descriptor, > graph) > > and also with > > get(&V::property, graph), where V is a vetex bundled-properties type get(&E::property, > graph), where E is an edge bundled-properties type > > (these get functions should return a property map for the corresponding bundled property > and they work correctly for adjacency_list, just like the rest). > > Is this a bug or an error in the documentation? > > Thanks a lot, > > Juan > Mmmm... I just tried to include adjacency_matrix.hpp and now I don't get errors about those functions anymore. It's strange to have to inclue this header in a template library that doesn't explicitly deal with any concrete implementations of graph concepts. In fact, I don't need to include adjacency_list.hpp for it to work with adjacency_list. I just need to include graph_concepts.hpp and graph_traits.hpp. Anyway, I'm still getting lots of errors in a code that perfectly compiles and works with adjacency lists. If anybody is interested, I can send the listing of compiler errors. Thanks again, Juan

9 20

[1.40] Release of PDF docs for Boost-1.40 now available.
by John Maddock 29 Aug '09

29 Aug '09

For those who prefer printable docs, PDF builds of the docs from Boost-1.40 are now available from the usual sourceforge download site: https://sourceforge.net/projects/boost/files/ (look under the boost-docs subtree). Direct links are as follows: zip (19.2Mb): https://sourceforge.net/projects/boost/files/boost-docs/1.40.0/boost_pdf_1_… tgz (19.7Mb): https://sourceforge.net/projects/boost/files/boost-docs/1.40.0/boost_pdf_1_… 7z (17.9Mb): https://sourceforge.net/projects/boost/files/boost-docs/1.40.0/boost_pdf_1_… Please note that not all libraries have documentation suitable for automatic PDF generation yet, libraries covered are: Accumulators Any Array Asio Bimap Bjam Boost.Build Range Boostbook TR1-complex number algorithms Concepts Config Conversion Date_time Foreach Function FunctionTypes Fusion Hash Interprocess Intrusive Iterator Lambda Math (special functions and distributions) Math-gcd MPI Octonion Optional Phoenix ProgramOptions Proto Python tutorial Quaternion Quickbook Ref Regex ScopeExit Signals Signals2 StaticAssert StringAlgo Thread TR1 Tribool TypeTraits Typeof Units Unordered Variant Xpressive Enjoy! John Maddock.

2 2

ASIO - Using IO service from main program in a .so loaded with dlopen, dlsym, etc.
by J.W.F. Thirion 29 Aug '09

29 Aug '09

Dear Community, I've got an application that loads a .so using dlopen, dlsym, etc. It also starts up an IO service pool and manages them. The application implements a socket server, that starts a thread for each incoming connection. Inside each of the threads started, a .so function is called based on information received on the socket. Inside the function of the .so, I want to connect to a remote server using the IO service in the main program (that called the dlopen, etc.). It seems, however, that if I use an IO service not created inside the .so, the handle_connect never gets called by ASIO. Is anyone aware of this problem. I suppose I'm just doing something stupid w.r.t. shared object usage (maybe permissions, etc.). Or is the ASIO library not initialised inside the DLL? When I create an IO service pool inside the .so, everything works, but obviously this is not ideal as the pool starts threads that execute the run() method on the io service. Interesting thing is that I can actually pass a session object (from the socket server accept operation) from my main program to the .so function and have messages read and written on the socket. But when I try and create a new connection using the session's IO service (e.g. from a sock.get_io_service() call), then I never get the handle_connect. I've even tried: #pragma GCC visibility push(default) #include <boost/asio.hpp> #include <boost/bind.hpp> #include <boost/thread.hpp> #pragma GCC visibility pop around the boost includes, but no luck. Any help on this would be greatly appreciated. Kind regards, Derik Thirion

2 2

implementing a new Range
by Alex Flint 29 Aug '09

29 Aug '09

Hi there, I'm using a math library that provides a Vector class, but it does not have begin() or end() method, or any other normal container methods. I would like to pass it to functions that take a Range object as a parameter. How can I do this? Cheers, Alex

6 10

[Fwd: Re: [interprocess] shared_memory_object design]
by Ion Gaztañaga 29 Aug '09

29 Aug '09

2 1

pkg-config and FreeBSD
by Roman Shmelev 29 Aug '09

29 Aug '09

Hi! I've downloaded boost 1.38 from the official site and successfully build it. I was able to compile the program that uses regexes. OS is FreeBSD 7.2. gcc is 4.2.1. The question is: how can I do something like this: pkg-config --libs boost-regex I'm new to FreeBSD, so I guess I really miss something basic. Googling for subject gave me a lot but not instructions how to do what I want. Thank you

3 10

Boost C++ Math Toolkit
by Paul A. Bristow 29 Aug '09

29 Aug '09

I am pleased to announce publication of the Boost Math Toolkit PDF documentation as a book (in CD format initially). Boost C++ Math Toolkit, ISBN 0-9504833-2-X John Maddock, Paul A. Bristow, Hubert Holin, Xiaogang Zhang, Bruno Lalande, Johan Råde, Gautam Sewani, Thijs van den Berg Publisher: hetp Publication date: 1 Sep 2009 Suggested Classification 519.2-dc22 If you are using this software, and writing academic or scholarly articles, you can reference it as above. (If you an author you can add it to your CV ;-) In the unlikely event that anyone would like this as a CD, I can of course provide it (at a modest cost) - but then you can download everything for free from www.boost.org or www.sourceforge.net. The CD also includes a Windows Installer program for the Distribution Explorer (but you can also download from http://distexplorer.sourceforge.net/) Please tell me if you would like to be able to buy a printed version. Thank you. Paul --- Paul A. Bristow Prizet Farmhouse Kendal, UK LA8 8AB +44 1539 561830, mobile +44 7714330204 pbristow(a)hetp.u-net.com

1 0

[BGL] possible Bug in property handling
by Ralf Goertz 29 Aug '09

29 Aug '09

Hi, I'm new to BGL (and generic programming) so this may well not be a bug but I don't know how this could be intended. Consider the following program: #include <string> #include <iostream> #include <boost/graph/graph_traits.hpp> #include <boost/graph/properties.hpp> #include <boost/graph/adjacency_list.hpp> using namespace boost; typedef property<vertex_name_t, std::string> VertexProp; //this crashes typedef adjacency_list < vecS, vecS, undirectedS,VertexProp, no_property > graph_t; //this doesn't //typedef adjacency_list < vecS, listS, undirectedS,VertexProp, no_property > graph_t; typedef graph_traits < graph_t >::vertex_descriptor vertex_descriptor; typedef property_map<graph_t, vertex_name_t>::type id_name_map_t; typedef graph_traits<graph_t>::vertex_iterator vi_t; std::pair<vi_t,vi_t> vi; int main(){ graph_t g; vertex_descriptor vd; id_name_map_t name_map; vd=add_vertex(g); put(name_map,vd,"foo"); for (vi=vertices(g); vi.first!=vi.second;++vi.first) { std::cout<<get(name_map,*vi.first)<<std::endl; } return EXIT_SUCCESS; } From what I read in the BGL book the storage type of the edges shouldn't matter. But here using vecS gives a segfault whereas listS works fine. This is the backtrace of a gdb session: Program received signal SIGSEGV, Segmentation fault. #0 0x00007ffff79316e6 in std::string::assign(char const*, unsigned long) () from /usr/lib64/libstdc++.so.6 #1 0x00000000004016ef in boost::put<boost::vec_adj_list_vertex_property_map<boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, boost::property<boost::vertex_name_t, std::string, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, boost::property<boost::vertex_name_t, std::string, boost::no_property>, boost::no_property, boost::no_property, boost::listS>*, std::string, std::string&, boost::vertex_name_t>, std::string&, unsigned long, char [4]> ( pa=@0x7fffffffdcc0, k=0, v=@0x403693) at /usr/include/boost/property_map.hpp:321 #2 0x0000000000400ee8 in main () at bug.cc:26 Version information boost-devel 1.39.0 $: g++ -v Using built-in specs. Target: x86_64-suse-linux Configured with: ../configure --prefix=/usr --infodir=/usr/share/info --mandir=/usr/share/man --libdir=/usr/lib64 --libexecdir=/usr/lib64 --enable-languages=c,c++,objc,fortran,obj-c++,java,ada --enable-checking=release --with-gxx-include-dir=/usr/include/c++/4.3 --enable-ssp --disable-libssp --with-bugurl=http://bugs.opensuse.org/ --with-pkgversion='SUSE Linux' --disable-libgcj --disable-libmudflap --with-slibdir=/lib64 --with-system-zlib --enable-__cxa_atexit --enable-libstdcxx-allocator=new --disable-libstdcxx-pch --enable-version-specific-runtime-libs --program-suffix=-4.3 --enable-linux-futex --without-system-libunwind --with-cpu=generic --build=x86_64-suse-linux Thread model: posix gcc version 4.3.2 [gcc-4_3-branch revision 141291] (SUSE Linux)

3 5

boost::asio::io_service and posix message queues
by Sergio Martinez 28 Aug '09

28 Aug '09

I'm working on a project where we want a single thread to asynchronously interact with posix message queues, TCP sockets and drivers. From what I've read, boost::asio::io_service provides a common framework dealing with asynchronous IO. It looks like there's a asio library for TCP and posix::stream_descriptor could be used for interacting with a driver file descriptor. What I don't see is support for posix message queues. The io_service documentation states the following: "The io_service class also includes facilities intended for developers of custom asynchronous services.". I was thinking of adding a custom service for posix message queues. Has anyone already done this? Is there any fundamental reason why it could not be done? (i.e. message queues are not byte streams, etc.) Thanks, Sergio

1 1

[proto] I'm lost
by Mail Delivery System 28 Aug '09

28 Aug '09

I need a transform property_b that evaluates another transform property_a and returns what property_a returns+1. Simple enough, here's what I do: struct property_a : proto::or_< proto::when< proto::terminal<_>, mpl::int_<42>()> > {}; struct property_b : proto::or_ < proto::when< _, mpl::next<property_a(_) >() > > {}; The complete file is attached at the end of this message as "Working example". But when I move to my real application (of which I attach a very condensed version as "Non-working example") I cannot manage to make it compile. The code in #ifdef BUG...#endif gives an error, the #else branch doesn't (but doesn't compute what I need, which makes the fact it compiles secondary). I cannot see differences, other than my terminals now being in their own domain. H E L P TIA, Maurizio --=-=-= Content-Type: text/x-c++src Content-Disposition: inline; filename=test_transforms.cpp Content-Description: Working example #include <iostream> #include <boost/mpl/int.hpp> #include <boost/mpl/assert.hpp> #include <boost/mpl/min_max.hpp> #include <boost/proto/core.hpp> #include <boost/proto/context.hpp> #include <boost/proto/transform.hpp> namespace mpl = boost::mpl; namespace proto = boost::proto; using proto::_; template<typename T> struct data { typedef T type; }; proto::terminal<data<mpl::int_<42> > >::type a; struct property_a : proto::or_< proto::when< proto::terminal<_>, mpl::int_<42>()> > {}; struct property_b : proto::or_ < // proto::when< _, property_a> proto::when< _, mpl::next<property_a(_) >() > > {}; int main(int argc, char *argv[]) { std::cout << "property A = " << property_a () (a) << std::endl; std::cout << "property B = " << property_b () (a) << std::endl; return 0; } /// Local Variables: /// mode:c++ /// comment-column:60 /// fill-column:150 /// compile-command:"g++ -I. -I./boost -o test_transforms test_transforms.cpp" /// c-macro-cppflags:"-C -I. -I./boost" /// c-backslash-column:120 /// c-backslash-max-column:149 /// End: --=-=-= Content-Type: text/x-c++src Content-Disposition: inline; filename=width.cpp Content-Description: Non-working example //* Includes #include <iostream> //#include <iomanip> //#include <sstream> #include <limits.h> #define BOOST_PROTO_MAX_LOGICAL_ARITY 15 #include <boost/proto/proto.hpp> #include <boost/utility.hpp> // for enable_if #include <boost/mpl/min_max.hpp> #include <boost/type_traits/is_same.hpp> #include <boost/type_traits/is_arithmetic.hpp> #include <boost/integer_traits.hpp> #include <boost/mpl/assert.hpp> #include <boost/typeof/typeof.hpp> namespace quicksilver { namespace mpl = boost::mpl; namespace fusion = boost::fusion; namespace proto = boost::proto; using proto::_; template<typename E> class my_expression; template<typename R> struct data; template<typename B> struct representation_traits; template<int L, int R> struct bounds_c; template<typename E> int left (const E&); // template<typename E> struct result_of_expression; // template<typename E> struct representation_of_expression; struct actual_width_transform; struct unspecified {}; struct builtin_types_grammar : proto::or_ < proto::terminal<bool>, proto::terminal<int>, proto::terminal<unsigned int>, proto::terminal<long>, proto::terminal<unsigned long>, proto::terminal<long long>, proto::terminal<unsigned long long> > {}; struct my_grammar : proto::or_ < proto::terminal<data<_> >, proto::unary_expr<_, my_grammar>, proto::binary_expr<_, my_grammar, my_grammar>, builtin_types_grammar > {}; struct my_domain : proto::domain<proto::generator<my_expression>, struct my_grammar> {}; template <typename Expr> struct my_expression : proto::extends<Expr, my_expression<Expr>, my_domain> { typedef proto::extends<Expr, my_expression<Expr>, my_domain> base_type; my_expression (Expr const& expr_ = Expr()) : base_type (expr_) {} }; struct left_bound_transform : proto::or_< proto::when<proto::terminal<data<_> >, mpl::int_<42>() > > {}; struct actual_width_transform : proto::or_< //#define BUG #ifdef BUG mpl::next<left_bound_transform (_)>() #else left_bound_transform #endif > {}; template<typename L, typename R, typename I=short> struct bounds { typedef L meta_left; }; template<int L, int R> struct bounds_c : bounds<mpl::int_<L>, mpl::int_<R> > {}; template<typename Bounds> struct representation_traits { typedef Bounds bounds; }; template<typename R> struct data : R::bounds { typedef R representation; }; template<typename R> struct number : my_expression<typename proto::terminal<data<R> >::type> { typedef my_expression<typename proto::terminal<data<R> >::type> base_type; number () : base_type (base_type::proto_base_expr::make (data<R> ())) {} }; } // end of namespace quicksilver #include <boost/test/included/unit_test_framework.hpp> using namespace boost::unit_test; using namespace quicksilver; void test_width_transform () { typedef number<representation_traits<bounds_c<6,0> > > number_type; number_type i7; BOOST_MPL_ASSERT ((proto::matches<number_type, left_bound_transform>)); BOOST_MPL_ASSERT ((proto::matches<number_type, actual_width_transform>)); std::cout << "left (i7) = " << left_bound_transform () (i7) << std::endl; BOOST_ASSERT (left_bound_transform () (i7) == 6); std::cout << "width (i7) = " << actual_width_transform () (i7) << std::endl; } test_suite* init_unit_test_suite (int, char**) { test_suite* test= BOOST_TEST_SUITE( "Quicksilver" ); test->add (BOOST_TEST_CASE (&test_width_transform)); return test; } /// Local Variables: /// mode:c++ /// comment-column:60 /// fill-column:150 /// compile-command:"g++ -I. -I./boost -o width width.cpp -lgmpxx -lgmp" /// c-macro-cppflags:"-C -I. -I./boost" /// c-backslash-column:120 /// c-backslash-max-column:149 /// End: --=-=-=--

3 2

Boost ASIO on Windows Mobile 5, asynchronous functions not working
by James Pritts 28 Aug '09

28 Aug '09

I was able to compile boost asio for Windows Mobile 5 using VC 9.0 and STL Port 5.2.1. The synchronous socket functions seem to be working, but the asynchronous functions never call the provided handlers. Does anyone know if asio's asunchronous socket functions work on WinMo5? I know that WinMo 5 does not have i/o completion ports, but the reactors don't seem to be working either. Is asynchronous i/o not possible on Windows Mobile ?. I used the following functions: client_socket_.async_connect(...); client_socket_.async_read_some(...); The async_connect call establishes a connection, but my connect handler is never called. Thanks, Jimmy.

2 2

[serialization] Linker errors in trunk
by Hartmut Kaiser 28 Aug '09

28 Aug '09

Since the latest changes in trunk I'm seeing linker errors while linking with the serialization library (VS2005 SP1, boost_serialization-vc80-mt-gd-1_40.lib): runtime_support.obj : error LNK2001: unresolved external symbol "__declspec(dllimport) public: __thiscall boost::archive::archive_exception::archive_exception(enum boost::archive::archive_exception::_exception_code,char const *,char const *)" (__imp_??0archive_exception@archive@boost@@QAE@W4_exception_code@012@PBD1@Z) (note the leading underscore in _exception_code) Which is really strange as this symbol is the only missing one. OTOH, the library exports the symbol: boost::archive::archive_exception::archive_exception( enum boost::archive::archive_exception::exception_code, char const *,char const *); (note the missing underscore in exception_code) If I change the first parameter of the archive_exception constructor to be a 'int' everything builds fine. Any clues? Compiler issue? Regards Hartmut

1 0

[lambda] Can I use lambda::bind to a functor with a parametric return type?
by Jesse Perla 28 Aug '09

28 Aug '09

Thanks for the rapid response on the previous question. Now for my real question: I am using an autodifferentiation library and want to use lambda's bind, but still return a generic type. Is this possible? Here is the function I wrote : struct test_function_impl { //result_of supprt template<typename Sig> struct result; template<typename This, typename Arg1, typename Arg2> struct result<This(Arg1, Arg2)> { typedef typename boost::remove_reference<Arg1>::type::value_type type; }; template<typename Vector, typename IntT> typename Vector::value_type //The type in the vector... can be a double or AD type operator()(const Vector& x, IntT y) const{ return x[0] * x[0] + y; } }; The function works on its own, and now std::tr1::result_of seems to work as well. However, I cannot bind to this: using namespace boost::lambda; ublas::bounded_vector<double, 1> x; x[0] = 1.0; int int_value = 1; //THIS FAILS! Not sure if lambda's bind is using result_of? Obviously, can't use the ret<> approach here. auto f = bind(test_function_impl(), _1, int_value); Does lambda support this usage, or should I turn to Phoenix (if so, I am recognizing a trend here). -Jesse

2 1

: Re: How to use the "type" member template pattern for using result_of?
by Jesse Perla 28 Aug '09

28 Aug '09

Thanks to all, Now I was playing around with Phoenix on my binding problem here as well (which is part of the reason for my confusion)... am I right to think that phoenix has a "result" template incompatible with result_of? The following seems to work when using Phoenix lazy functions, etc., but the standard result template did not. struct test_function_impl { //For phoenix... not sure if necessary for template<typename Arg1, typename Arg2> struct result { //typedef typename Arg1::value_type type; }; template<typename Vector, typename IntT> typename Vector::value_type //The type in the vector... can be a double or AD type operator()(const Vector& x, IntT y) const{ return x[0] * x[0] + y; } }; Thanks, Jesse

2 1

Formal Review of Boost.Polygon is halfway through and no actual reviews so far
by Fernando Cacciola 28 Aug '09

28 Aug '09

Dear Developers, The formal review of the Boost.Polygon is halfway through and, while there was some useful discussion, there are still no "actual" reviews (where you clearly vote for inclusion and rejection). If you are interested in a geometric oriented library please try to make the time to post a formal review by the end of September 2 :) Best regards Fernando Cacciola Review Manager

1 0

Linux build of boost using Intel C++ compiler 11.1 or 11.0 and g++ 4.3.3
by Bill O'Hara 28 Aug '09

28 Aug '09

Hi, I guess this may be a known problem but I wonder if there is any straightforward workaround. I need to install boost on our development machines which run Linux and have g++ 4.3.3 installed. We are wondering about also support the Intel c++ compiler (version 11.1). When trying to build boost 1.39 we get many errors during compilation due to g++ builtins like __builtin_isfinite not being found. Example below. Perhaps I've missed something but using the intel toolset when building still seems to involve using these g++ specific features. Is there a workaround? Thanks Bill For example: "icpc" -c -xc++ -O3 -w1 -inline-level=2 -pthread -fPIC -DBOOST_ALL_NO_LIB=1 -DBOOST_MATH_TR1_DYN_LINK=1 -DNDEBUG -I"." -c -o "bin.v2/libs/math/build/intel-linux-11.1/release/threading-multi/lround.o" "libs/math/build/../src/tr1/lround.cpp" ...failed intel-linux.compile.c++ bin.v2/libs/math/build/intel-linux-11.1/release/threading-multi/lround.o... intel-linux.compile.c++ bin.v2/libs/math/build/intel-linux-11.1/release/threading-multi/nextafter.o /usr/include/c++/4.3.3/cmath(522): error: identifier "__builtin_isfinite" is undefined return __builtin_isfinite(__type(__f)); ^ detected during: instantiation of "__gnu_cxx::__enable_if<std::__is_arithmetic<_Tp>::__value, int>::__type std::isfinite(_Tp) [with _Tp=double]" at line 262 of "./boost/math/special_functions/fpclassify.hpp" instantiation of "bool boost::math::detail::isfinite_impl(T, const boost::math::detail::native_tag &) [with T=double]" at line 310 of "./boost/math/special_functions/fpclassify.hpp" instantiation of "bool boost::math::isfinite(T) [with T=double]" at line 56 of "./boost/math/special_functions/next.hpp" instantiation of "T boost::math::float_next(const T &, const Policy &) [with T=double, Policy=c_policies::c_policy]" at line 153 of "./boost/math/special_functions/next.hpp" instantiation of "T boost::math::nextafter(const T &, const T &, const Policy &) [with T=double, Policy=c_policies::c_policy]" at line 27 of "libs/math/build/../src/tr1/c_policy.hpp" instantiation of "T c_policies::nextafter(const T &, const T &) [with T=double]" at line 15 of "libs/math/build/../src/tr1/nextafter.cpp" compilation aborted for libs/math/build/../src/tr1/nextafter.cpp (code 2)

4 4

Re: [Boost-users] [ANN] Boost 1.39.0
by Tom Kent 28 Aug '09

28 Aug '09

I've built windows libraries (vc7.1, vc8, vc9) off of this, if you want them, you can get them from my website: http://boost.teeks99.com Tom > Subject: [Boost-users] [ANN] Boost 1.39.0 > From: Beman Dawes (bdawes_at_[hidden]) > Date: 2009-05-02 16:57:10 > > Boost 1.39.0 is available for download from SourceForge. > > See > http://sourceforge.net/project/showfiles.php?group_id=7586&package_id=8041&… > > New Libraries: Signals2. > > Updated Libraries: Asio, Flyweight, Foreach, Hash, Interprocess, > Intrusive, Program.Options, Proto, PtrContainer, Range, Unordered, > Xpressive. > > Updated Tools: Boostbook, Quickbook. > > Plus the usual bug fixes to numerous libraries. > > Please report any problems to the Boost users or developers mailing > list. > > Thanks, > > --Beman Dawes, Daniel James, and all the other Boosters who help get > releases out

1 1

How to use the "type" member template pattern for using result_of?
by Jesse Perla 28 Aug '09

28 Aug '09

Take the following function: struct test_function { template<typename Vector, typename IntType> typename Vector::value_type operator()(const Vector& x, IntType bound_value) const{ return x[0] * x[0] + bound_value; } }; I wasn't sure exactly how the "type" member template pattern works so that result_of will work. I tried the following, but can't figure out how to extract the type of the arguments or convert to an MPL sequence? Is there some trick I am missing? struct test_function { template<typename Args> struct result { //HOW TO CONVERT TO MPL SEQUENCE OR ANOTHER APPROACH? typedef typename boost::mpl::at_c<Args, 0 >::type::value_type type; }; template<typename Vector, typename IntType> typename Vector::value_type //The type in the vector... can be a double or AD type operator()(const Vector& x, IntType bound_value) const{ return x[0] * x[0] + bound_value; } }; Thanks, Jesse

3 2

[interprocess] remove
by Moritz 28 Aug '09

28 Aug '09

Hi, I have a question concerning the remove function of managed_shared_memory. Actually I am not able to remove a segment of shared memory. See the following example. It writes 0 to the output stream. But why? #include <boost/interprocess/managed_shared_memory.hpp> #include <iostream> int main() { boost::interprocess::managed_shared_memory * managed_shm; managed_shm = new boost::interprocess::managed_shared_memory(boost::interprocess::open_or_create, "TestMem", 1024); delete managed_shm; std::cerr << boost::interprocess::shared_memory_object::remove("TestMem") << std::endl; }

2 3

boost::function unusable as overloadable function argument
by Peter Soetens 28 Aug '09

28 Aug '09

Hi, I had this situation in a bigger program, where a user could supply a string or a function object: <code> #include <boost/function.hpp> #include <string> void foo1(int i, std::string a); void foo1(int i, boost::function<void(void)> foo ); int main(int argc, char** argv) { //boost::function<void(void)> foo = "hello"; // this line won't compile foo1( 3, "hello" ); //error: call of overloaded ‘foo1(int, const char [6])’ is ambiguous return 0; } </code> Although constructing a boost::function from a C string is nonsense, the compiler does consider it as an alternative when trying to find the right foo1. Is there any work around to keep the overloads without requiring the user to write foo1(3, string("hello")); or is this a compiler bug (g++ (Ubuntu 4.3.3-5ubuntu4) 4.3.3)? Thanks for any insights, Peter

3 3

[unit_test_framework] checkpoints for BOOST_CHECK*?
by rozelak＠volny.cz 28 Aug '09

28 Aug '09

Hallo, I need to write an unit test checking several various inputs. As there may be larger number of the inputs, I thought about a loop. The problem is how to know the input for which the test failed (if it failed). I wanted to write something like this: .... BOOST_AUTO_TEST_CASE(....) { // each tested_variant may be quite complicated structure for (tested_variants::iterator i) { BOOST_TEST_CHECKPOINT("variant:" << i); // not usable for what I need :-( BOOST_CHECK_EQUAL(i.expected, tested_method(i.data)); } } .... However, BOOST_TEST_CHECKPOINT() does not work in this situation (well, according to the documentation it works for exceptions only). Is there a way how to achieve what I am looking for? Thank you very much, Dan T.

3 3

Copy of a C++ object extended with Boost.Python
by 4ian 28 Aug '09

28 Aug '09

I have a simple C++ object, exposed to python with Boost.python, like this : ------------------------------------------------- BOOST_PYTHON_MODULE(MyModule) { class_<MyObject>("MyObject")... } ------------------------------------------------- I call then python, making an instance of MyObject accessible : ------------------------------------------------- MyObject anInstance; object main_module((handle<>( borrowed( PyImport_AddModule ( "__main__" ) ) ) ) ); object main_namespace = main_module.attr( "__dict__" ); object myModule( (handle<>(PyImport_ImportModule("MyModule"))) ); main_namespace["anInstance"] = ptr(&anInstance); try { handle<> ignored(( PyRun_String( "anInstance.aNewMember = 1;print anInstance.aNewMember;", Py_file_input, main_namespace.ptr(), main_namespace.ptr() ) ) ); } catch ( error_already_set ) { PyErr_Print(); } ------------------------------------------------- You can observe that I've added a member ( aNewMember ) to MyObject instance. But if I make a copy of my object : ------------------------------------------------- MyObject anotherInstance = anInstance; main_namespace["anotherInstance"] = ptr(&anotherInstance); try { handle<> ignored(( PyRun_String( "print anotherInstance.aNewMember;", Py_file_input, main_namespace.ptr(), main_namespace.ptr() ) ) ); } catch ( error_already_set ) { PyErr_Print(); } ------------------------------------------------- I have a error saying that MyObject hasn't any "aNewMember" member. What I have added with python has not been copied/transfered. Is there a workaround to add permanently some new members to wrapped objects ?

2 6

pathological regex?
by Michał Nowotka 28 Aug '09

28 Aug '09

Hello, I use boost regex v 1.37 on Ubuntu 9.04, g++-4.3. Because of performance issues i replaced defaut matching algorithm to BOOST_REGEX_RECURSIVE but then my program dont't work properly. So, is this expression pathological: (https?://)?([^/@]*[\\.@])?google.com[/\\?&#]* ? -- Regards Michał Nowotka

4 7

Define a callback member function inside the object instance
by Daniele Barzotti 28 Aug '09

28 Aug '09

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, I would ask you a suggestion. In according with the FAQ (http://www.parashift.com/c++-faq-lite/pointers-to-members.html#faq-33.2) is better to not set a non-static member function like a callback. But If I need to pass that callback inside my object, I'm pretty sure that the object itself exist! So if I have a callback signature like this: int my_callback(void *outputBuffer, void *inputBuffer, unsigned int nFrames, double streamTime, int status, void *userData ) And I want to bind it to a member function: int MyObject::my_callback(....) Now, inside the object I have something like: MyObject::OneMethod() { p_AnotherObject->SetCallBack( ???? ); } How can I pass my MyObject::my_callback to SetCallBack using boost::function and/or boost::bind? Thanks! Daniele. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (MingW32) iD8DBQFKl65//l+kMioSZwgRAkA8AKCdk44mlTXESXQJUG7vzqVnUHFoXgCghGW5 Icf+E8uX8cLwwfkdnCFmoKs= =s1nk -----END PGP SIGNATURE-----

2 2

Problem with serialization, load_wrapper
by Mikael Carlsson 28 Aug '09

28 Aug '09

Dear group, I am working with a observer pattern in a simulator and would like to restore the simulators state. This means that I need to restore the pointers to the observers in the subject. My simple example contains a composite that holds pointers to base class of the observers. The observable hold one of the observers using a base class pointer. The save part is OK but when I introduce restore I get compile time errors. Compiling (dbg) main.cpp obj/main.o /home/ecarmik/boost/include/boost-1_39/boost/archive/detail/iserializer.hpp: In function 'void boost::archive::load(Archive&, const T&) [with Archive = boost::archive::text_iarchive, T = composite]': /home/ecarmik/boost/include/boost-1_39/boost/archive/detail/common_iarchive.hpp:59: instantiated from 'void boost::archive::detail::common_iarchive<Archive>::load_override(T&, int) [with T = const composite, Archive = boost::archive::text_iarchive]' /home/ecarmik/boost/include/boost-1_39/boost/archive/basic_text_iarchive.hpp:62: instantiated from 'void boost::archive::basic_text_iarchive<Archive>::load_override(T&, int) [with T = const composite, Archive = boost::archive::text_iarchive]' /home/ecarmik/boost/include/boost-1_39/boost/archive/text_iarchive.hpp:65: instantiated from 'void boost::archive::text_iarchive_impl<Archive>::load_override(T&, int) [with T = const composite, Archive = boost::archive::text_iarchive]' /home/ecarmik/boost/include/boost-1_39/boost/archive/detail/interface_iarchive.hpp:61: instantiated from 'Archive& boost::archive::detail::interface_iarchive<Archive>::operator>>(T&) [with T = const composite, Archive = boost::archive::text_iarchive]' main.cpp:24: instantiated from here /home/ecarmik/boost/include/boost-1_39/boost/archive/detail/iserializer.hpp:560: error: no matching function for call to 'load_wrapper(boost::archive::text_iarchive&, const composite&, boost::serialization::is_wrapper<composite>)' make: *** [obj/main.o] Error 1 Is it possible to re-create objects during restore from file. Please note that composite class only contains base class pointers. Do I need to create a separate load to do this with constructors? Where can I read about this or even better, find an example? Please find the files included. / Mikael

1 0

[asio] serial_port::async_read_some() and scalable buffers
by Robert Dailey 28 Aug '09

28 Aug '09

Hello, I have a std::vector of bytes that I am passing into boost::asio::buffer(). The vector originally is of size 0. Basically, I want the vector to be resized by asio depending on how much data is read in. I don't want to choose an arbitrary upper-limit for the buffer. Is this possible? Below is an example of what I am doing: std::vector<boost::uint8_t> stream; m_port.async_read_some( boost::asio::buffer( stream ), boost::bind( &SerialClient::ReadCompleted, this, stream, error, bytes_transferred ) ); However, the above code will never read any data because my vector is 0 and it expects it to have a size. --------- Robert Dailey

3 3

Generically comparing structs
by Bill Buklis 28 Aug '09

28 Aug '09

Frequently I have to write comparison functions (usually of the "less" variety) that involve multiple keys or members of a struct. For example: struct s { A a; B b; C c; D d; // there may be other members not used in the comparison }; // operator< function or an equivalent function object bool operator<( const s& lhs, const s& rhs ) { if( lhs.a < rhs.a ) return(true); else if( lhs.a == rhs.a ) { if( lhs.b < rhs.b ) return(true); else if( lhs.b == rhs.b ) //and so on... } return(false); } This gets quite repetitive, especially if I have to write alternate sort orders (e.g. b,a,c,d or c,d,a,b) I'm thinking there has to an easier way to do this or a way to do a generic algorithm for this. Is there anything in boost that would help? I had an idea that one might be able to fill a vector with binders for each element and then call lexicographical_compare, but I'm not sure how to make it work.

3 7

[iostreams] problems with operator<<
by Robert Dailey 28 Aug '09

28 Aug '09

Hello, I'm using the container_device class provided in the documentation. I'm creating my stream and device like so: typedef boost::iostreams::stream< container_device<std::vector<boost::uint8_t > > > ByteStream; ByteStream stream; stream << "Hello"; This compiles fine, however when I run this code I get an assertion deep inside of the << operator, which is in the std namespace. I thought that boost::iostreams would have its own global << and >> operators? I was expecting the << operator to directly call my device's write() method, but it doesn't. Perhaps I just don't understand how this works. I'm trying to write out binary data. The string should translate to a series of bytes in the container. The assertion I'm hitting is in optional.hpp in Boost. I'm using MSVC9 as my compiler: T& operator*() { assert(initialized_); return *static_cast<T*>(address()); } Above contains the code snippet where the assertion is happening. I have no idea what this assert means. Below is my callstack: > VFDTester.exe!boost::iostreams::detail::optional<boost::iostreams::detail::concept_adapter<container_device<std::vector<unsigned char,std::allocator<unsigned char> > > > >::operator*() Line 55 + 0x1f bytes C++ VFDTester.exe!boost::iostreams::detail::indirect_streambuf<container_device<std::vector<unsigned char,std::allocator<unsigned char> > >,std::char_traits<unsigned char>,std::allocator<unsigned char>,boost::iostreams::seekable>::obj() Line 104 + 0x19 bytes C++ VFDTester.exe!boost::iostreams::detail::indirect_streambuf<container_device<std::vector<unsigned char,std::allocator<unsigned char> > >,std::char_traits<unsigned char>,std::allocator<unsigned char>,boost::iostreams::seekable>::overflow(long c=72) Line 301 + 0x15 bytes C++ VFDTester.exe!std::basic_streambuf<unsigned char,std::char_traits<unsigned char> >::sputc(unsigned char _Ch='H') Line 163 + 0x4c bytes C++ VFDTester.exe!std::operator<<<unsigned char,std::char_traits<unsigned char> >(std::basic_ostream<unsigned char,std::char_traits<unsigned char> > & _Ostr={...}, const char * _Val=0x0074a7b0) Line 679 + 0x32 bytes C++ VFDTester.exe!MainFrame::OnConnectPressed(wxCommandEvent & event={...}) Line 82 + 0x36 bytes C++ --------- Robert Dailey

2 1

[boost.function] conflict with tr1::function shipped with VC++10
by Tan, Tom (Shanghai) 28 Aug '09

28 Aug '09

Hi, I found a problem in using boost.function with VC++ 10, the code below reproduces the problem: #include <boost/function.hpp> #include <vector> typedef std::vector<int> test_type; template<class T> struct S { void test_g() { typedef S<T> this_class; boost::function<void (this_class*, test_type)> s(&this_class::g); } void g(test_type){} }; int main() { S<int> s; s.test_g(); } This code is OK with VC++ 2008, but with VC++ 2010, it yields the following message. Is there anything that I can do to solve the ambiguity? Thanks. C:\Boost\include\boost-1_39_0\boost/function/function_template.hpp(538) : error C2668: 'boost::mem_fn' : ambiguous call to overloaded function C:\Boost\include\boost-1_39_0\boost/bind/mem_fn_cc.hpp(25): could be 'bo ost::_mfi::mf1<R,T,A1> boost::mem_fn<void,S<int>,test_type>(R (__thiscall S<int> ::* )(A1))' with [ R=void, T=S<int>, A1=test_type ] C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xxmem_fn(32): o r 'std::tr1::_Mem_fn2<_Rx,_Pmf,_Arg0,_Arg1> std::tr1::mem_fn<void,S<T>,tes t_type>(_Rx (__thiscall S<T>::* )(_Arg1))' [found using argument-dependent looku p] with [ _Rx=void, _Pmf=void (__thiscall S<int>::* )(test_type), _Arg0=S<int>, _Arg1=test_type, T=int ] while trying to match the argument list '(void (__thiscall S<T>::* )(tes t_type))' with [ T=int ] .....

1 0

using embedded stringstream on a single line.
by Avi Bahra 27 Aug '09

27 Aug '09

Is there anything in boost/design pattern that can help with following: std::stringstream ss; ss << "SUBMIT: Task(" << absPath << ") "; log( Log::DBG, ss ); The code I am working on does this all over the place, what I would like is : log( Log::DBG, "SUBMIT: Task(" << absPath << ") " ); Best regards, Ta, Avi

5 4

Feedback on units use
by Noah Roberts 27 Aug '09

27 Aug '09

Is there a better way to do the following? The purpose is to provide a conversion from a pressure to a head given the density of the fluid the head should be in. Head is "hydrostatic pressure" and is a measure of the length a fluid can be pushed up a column at pressure X. The value is a function of the fluid and of the pressure acted upon that fluid. Object is to do this in any system. Part of the equation is the constant "g", which is acceleration due to gravity. We're modeling objects on earth so the value of g is 9.80665 m/s^2. The conversion equation is very basic: h = p / (d * g) where h is the headloss in length, p is pressure, d is mass density, and g is the gravitational constant. #include <boost/units/quantity.hpp> #include <boost/units/physical_dimensions.hpp> template < typename T, typename System > struct acceleration_due_to_gravity; template < typename T, typename System > boost::units::quantity< boost::units::unit<boost::units::length_dimension, System>, T > pressure_to_head( boost::units::quantity< boost::units::unit<boost::units::pressure_dimension, System>, T > press , boost::units::quantity< boost::units::unit<boost::units::mass_density_dimension, System>, T> density) { return press / (density * acceleration_due_to_gravity<T,System>::value()); } #include <boost/units/systems/si.hpp> template < typename T > struct acceleration_due_to_gravity<T, boost::units::si::system> { typedef boost::units::si::system System; static boost::units::quantity< boost::units::unit< boost::units::acceleration_dimension, System>, T> value() { return boost::units::quantity<boost::units::unit< boost::units::acceleration_dimension, System>, T>::from_value(9.80665); } };

2 1

Re: [Boost-users] Compiling python extensions examples fail
by Dan Sanduleac 27 Aug '09

27 Aug '09

I had the same issue, trying to compile latest svn trunk of boost. When I bootstrap.sh-ed, it created project-config.jam which had my python configuration in it (I provided --with-python-root=). Now, I also had ~/user-config.jam which had the exact same line ("using python : 2.6 : /home/dan/stackless ;") and bjam wasn't sure which one of those to choose, even though they were identical. The solution for me was to remove the superfluous user-config.jam from my home directory. Sean Snyders wrote: > > Hi, > > I've compiled Boost 1.39 locally (to a folder > '/local1/installs/boost_1_39_0') such that I can try out building python > extensions without disrupting the current system setup. I compiled it with > gcc 4.3.3 64bit and with python 2.5.2 64bit. > > My system details are: > Ubuntu 7.04 > Linux 2.6.25.18-20081021 x86_64 GNU/Linux > > I've setup my jam configs as follows: > file: ~/boost-build.jam > containing: boost-build /local1/installs/boost_1_39_0/tools/build/v2 ; > > file: /local1/installs/boost_1_39_0/tools/build/v2/site_config.jam > containing: > using gcc : : /vol/apps/gcc-4.3.3_64/bin/g++ ; > using python : : /vol/apps/python-2.5.2_64/bin/python ; > > I'm trying to compile the python tutorial > 'boost_1_39_0/libs/python/example/tutorial' using bjam and get the > following errors when running it: > ------- > error: No best alternative for /python_for_extensions > next alternative: required properties: <python>2.5 <target-os>linux > matched > next alternative: required properties: <python>2.5 <target-os>linux > matched > /local1/installs/boost_1_39_0/tools/build/v2/build/property.jam:613: in > find-replace from module object(property-map)@1 > error: Ambiguous key <target-type>PYTHON_EXTENSION > .... > .. > . > ------ > > Here is the full output that is given with the '--debug-configuration' > option: > ---------------------------------------------- > ssnyders@machine:/local1/installs/boost_1_39_0/libs/python/example/tutorial > {650} > /local1/ssnyders/boost_1_39_0/bin/bjam --debug-configuration > notice: found boost-build.jam at > /local1/installs/boost_1_39_0/libs/python/example/boost-build.jam > notice: loading Boost.Build from > /local1/installs/boost_1_39_0/tools/build/v2 > notice: Searching /etc /usr/home/ssnyders > /local1/installs/boost_1_39_0/libs/python/example/../../../tools/build/v2 > /usr/share/boost-build /local1/installs/boost_1_39_0/tools/build/v2/kernel > /local1/installs/boost_1_39_0/tools/build/v2/util > /local1/installs/boost_1_39_0/tools/build/v2/build > /local1/installs/boost_1_39_0/tools/build/v2/tools > /local1/installs/boost_1_39_0/tools/build/v2/contrib > /local1/installs/boost_1_39_0/tools/build/v2/. for site-config > configuration file site-config.jam . > notice: Loading site-config configuration file site-config.jam from > /local1/installs/boost_1_39_0/tools/build/v2/site-config.jam . > notice: will use '/vol/apps/gcc-4.3.3_64/bin/g++' for gcc, condition > <toolset>gcc-4.3.3 > notice: using gcc libraries :: <toolset>gcc-4.3.3 :: > /vol/apps/gcc-4.3.3_64/bin /vol/apps/gcc-4.3.3_64/lib > /vol/apps/gcc-4.3.3_64/lib32 /vol/apps/gcc-4.3.3_64/lib64 > notice: using gcc archiver :: <toolset>gcc-4.3.3 :: ar > warning: toolset gcc initialization: can not find tool windres > warning: initialized from > /local1/installs/boost_1_39_0/tools/build/v2/build/project.jam:874 > notice: using rc compiler :: <toolset>gcc-4.3.3 :: as > notice: [python-cfg] Configuring python... > notice: [python-cfg] user-specified cmd-or-prefix: > "/vol/apps/python-2.5.2_64/bin/python" > notice: [python-cfg] Checking interpreter command > "/vol/apps/python-2.5.2_64/bin/python"... > notice: [python-cfg] running command > '"/vol/apps/python-2.5.2_64/bin/python" -c "from sys import *; print > 'version=%d.%d\nplatform=%s\nprefix=%s\nexec_prefix=%s\nexecutable=%s' % > (version_info[0],version_info[1],platform,prefix,exec_prefix,executable)" > 2>&1' > notice: [python-cfg] ...requested configuration matched! > notice: [python-cfg] Details of this Python configuration: > notice: [python-cfg] interpreter command: > "/vol/apps/python-2.5.2_64/bin/python" > notice: [python-cfg] include path: > "/vol/apps/python-2.5.2_64/include/python2.5" > notice: [python-cfg] library path: > "/vol/apps/python-2.5.2_64/lib/python2.5/config" > "/vol/apps/python-2.5.2_64/lib" > notice: Searching /usr/home/ssnyders > /local1/installs/boost_1_39_0/libs/python/example/../../../tools/build/v2 > /usr/share/boost-build /local1/installs/boost_1_39_0/tools/build/v2/kernel > /local1/installs/boost_1_39_0/tools/build/v2/util > /local1/installs/boost_1_39_0/tools/build/v2/build > /local1/installs/boost_1_39_0/tools/build/v2/tools > /local1/installs/boost_1_39_0/tools/build/v2/contrib > /local1/installs/boost_1_39_0/tools/build/v2/. for user-config > configuration file user-config.jam . > notice: Loading user-config configuration file user-config.jam from > /usr/home/ssnyders/user-config.jam . > notice: Searching ../../../.. for project-config configuration file > project-config.jam . > notice: Loading project-config configuration file project-config.jam from > ../../../../project-config.jam . > notice: [python-cfg] Configuring python... > notice: [python-cfg] user-specified version: "2.5" > notice: [python-cfg] user-specified cmd-or-prefix: > "/vol/apps/python-2.5.2_64" > notice: [python-cfg] Checking interpreter command > "/vol/apps/python-2.5.2_64/bin/python2.5"... > notice: [python-cfg] running command > '"/vol/apps/python-2.5.2_64/bin/python2.5" -c "from sys import *; print > 'version=%d.%d\nplatform=%s\nprefix=%s\nexec_prefix=%s\nexecutable=%s' % > (version_info[0],version_info[1],platform,prefix,exec_prefix,executable)" > 2>&1' > notice: [python-cfg] ...requested configuration matched! > notice: [python-cfg] Details of this Python configuration: > notice: [python-cfg] interpreter command: > "/vol/apps/python-2.5.2_64/bin/python2.5" > notice: [python-cfg] include path: > "/vol/apps/python-2.5.2_64/include/python2.5" > notice: [python-cfg] library path: > "/vol/apps/python-2.5.2_64/lib/python2.5/config" > "/vol/apps/python-2.5.2_64/lib" > notice: iostreams: using prebuilt zlib > notice: iostreams: using prebuilt bzip2 > error: No best alternative for /python_for_extensions > next alternative: required properties: <python>2.5 <target-os>linux > matched > next alternative: required properties: <python>2.5 <target-os>linux > matched > /local1/installs/boost_1_39_0/tools/build/v2/build/property.jam:613: in > find-replace from module object(property-map)@1 > error: Ambiguous key <target-type>PYTHON_EXTENSION <asynch-exceptions>off > <debug-symbols>on <exception-handling>on <extern-c-nothrow>off > <hardcode-dll-paths>true <host-os>linux <inlining>off > <install-dependencies>off <link>shared <main-target-type>PYTHON_EXTENSION > <optimization>off <os>LINUX <pch>on <preserve-test-targets>on > <profiling>off <python-debugging>off > <python.interpreter>/vol/apps/python-2.5.2_64/bin/python > <python.interpreter>/vol/apps/python-2.5.2_64/bin/python2.5 <python>2.5 > <rtti>on <runtime-debugging>on <runtime-link>shared <stdlib>native > <suppress-import-lib>true <symlink-location>project-relative > <target-os>linux <target>object(file-target)@408 <threadapi>pthread > <threading>single <toolset-gcc:version>4.3.3 <toolset>gcc > <user-interface>console <variant>debug <warnings-as-errors>off > <warnings>on > /local1/installs/boost_1_39_0/tools/build/v2/build/property.jam:590: in > object(property-map)(a)1.find from module object(property-map)@1 > /local1/installs/boost_1_39_0/tools/build/v2/build/type.jam:335: in > generated-target-ps-real from module type > /local1/installs/boost_1_39_0/tools/build/v2/build/type.jam:359: in > generated-target-ps from module type > /local1/installs/boost_1_39_0/tools/build/v2/build/type.jam:270: in > type.generated-target-suffix from module type > /local1/installs/boost_1_39_0/tools/build/v2/build/virtual-target.jam:501: > in virtual-target.add-prefix-and-suffix from module virtual-target > /local1/installs/boost_1_39_0/tools/build/v2/build/virtual-target.jam:460: > in _adjust-name from module object(file-target)@408 > /local1/installs/boost_1_39_0/tools/build/v2/build/virtual-target.jam:243: > in abstract-file-target.__init__ from module object(file-target)@408 > /local1/installs/boost_1_39_0/tools/build/v2/build/virtual-target.jam:553: > in object(file-target)(a)408.__init__ from module object(file-target)@408 > /local1/installs/boost_1_39_0/tools/build/v2/kernel/class.jam:88: in > class.new from module class > /local1/installs/boost_1_39_0/tools/build/v2/build/generators.jam:565: in > generator.generated-targets from module object(gcc-linking-generator)@403 > /local1/installs/boost_1_39_0/tools/build/v2/tools/builtin.jam:893: in > linking-generator.generated-targets from module > object(gcc-linking-generator)@403 > /local1/installs/boost_1_39_0/tools/build/v2/tools/unix.jam:67: in > generated-targets from module object(gcc-linking-generator)@403 > /local1/installs/boost_1_39_0/tools/build/v2/build/generators.jam:462: in > construct-result from module object(gcc-linking-generator)@403 > /local1/installs/boost_1_39_0/tools/build/v2/build/generators.jam:415: in > run-really from module object(gcc-linking-generator)@403 > /local1/installs/boost_1_39_0/tools/build/v2/build/generators.jam:390: in > generator.run from module object(gcc-linking-generator)@403 > /local1/installs/boost_1_39_0/tools/build/v2/tools/builtin.jam:808: in > linking-generator.run from module object(gcc-linking-generator)@403 > /local1/installs/boost_1_39_0/tools/build/v2/tools/unix.jam:41: in > unix-linking-generator.run from module object(gcc-linking-generator)@403 > /local1/installs/boost_1_39_0/tools/build/v2/tools/gcc.jam:506: in > object(gcc-linking-generator)(a)403.run from module > object(gcc-linking-generator)@403 > /local1/installs/boost_1_39_0/tools/build/v2/build/generators.jam:1000: in > try-one-generator-really from module generators > /local1/installs/boost_1_39_0/tools/build/v2/build/generators.jam:1062: in > try-one-generator from module generators > /local1/installs/boost_1_39_0/tools/build/v2/build/generators.jam:1274: in > construct-really from module generators > /local1/installs/boost_1_39_0/tools/build/v2/build/generators.jam:1346: in > generators.construct from module generators > /local1/installs/boost_1_39_0/tools/build/v2/build/targets.jam:1437: in > construct from module object(typed-target)@77 > /local1/installs/boost_1_39_0/tools/build/v2/build/targets.jam:1250: in > object(typed-target)(a)77.generate from module object(typed-target)@77 > /local1/installs/boost_1_39_0/tools/build/v2/build/targets.jam:710: in > generate-really from module object(main-target)@385 > /local1/installs/boost_1_39_0/tools/build/v2/build/targets.jam:682: in > object(main-target)(a)385.generate from module object(main-target)@385 > /local1/installs/boost_1_39_0/tools/build/v2/build/targets.jam:258: in > object(project-target)(a)74.generate from module object(project-target)@74 > /local1/installs/boost_1_39_0/tools/build/v2/build-system.jam:700: in load > from module build-system > /local1/installs/boost_1_39_0/libs/python/example/../../../tools/build/v2/kernel/modules.jam:283: > in import from module modules > /local1/installs/boost_1_39_0/libs/python/example/../../../tools/build/v2/kernel/bootstrap.jam:138: > in boost-build from module > /local1/installs/boost_1_39_0/libs/python/example/boost-build.jam:7: in > module scope from module > > ---------------------------------------------- > -- View this message in context: http://www.nabble.com/Compiling-python-extensions-examples-fail-tp24526932p… Sent from the Boost - Users mailing list archive at Nabble.com.

1 0

Race condition with Boost::Thread
by Rob Yull 27 Aug '09

27 Aug '09

I've been writing a thread pool class as kind of an experiment with boost.threads, boost.bind, and boost.function. The code below is the worker thread, that will eventually pull jobs from a queue, execute them, then look and see if there is another job in the queue. I think I've got an interesting race condition. The problem I'm having is when the class goes out of scope. I'm getting an access violation from the run() member function (which is function being run by m_Thread). Right now, run() is just entering and leaving (no actual queue checking). By the time run() is getting executed, the class is starting to execute the destructor. I thought that having the join() call in the destructor should allow the thread to finish before the class data is destroyed. In Visual Studio 2005's debugger, when it is getting to run(), it looks like the object has already been destroyed (this = 0x7fffffff), so the access violation is coming from the assignment to the m_Running member variable. If I take out the assignment, and run the debug, when it is entering run(), the this pointer is still showing as invalid, but the function completes and ends up back at the join() in the destructor, where the this pointer in the destructor is valid again. So as far as the destructor seems to be conserned, the class hasn't been destroyed yet, but as far as the member class is, it has been destroyed already. If I do pad some instructions/time before the class goes out of scope, run() executes just fine (this pointer is valid). I have also tried moving the creation of m_Thread outside of the constructor to a separate member function call, but the result is the same. I know debugging multithreaded apps can be difficult. Is there right out something I'm doing wrong here or making some kind of bad assumpion about the execution of run()? #include <boost/config.hpp> #include <boost/thread.hpp> #include <boost/functional.hpp> class WorkerThread { public: typedef boost::function<void ()> JobType; WorkerThread() { m_Thread = boost::thread(boost::bind(&WorkerThread::run, boost::ref(this))); m_Running = true; } ~WorkerThread() { m_Thread.join(); } const bool isRunning() const { return m_Running; } private: volatile bool m_Running; boost::thread m_Thread; void run() { m_Running = false; // Access violation here } private: WorkerThread(const WorkerThread& rhs); WorkerThread& operator = (const WorkerThread& rhs); }; int main() { WorkerThread wt; // new thread should start executing here return 0; } -Rob Yull

4 6

generic programming : variadic virtual function
by Stephen Nuchia 27 Aug '09

27 Aug '09

I'm finally doing something nontrivial with templates and I've painted myself into an interesting corner. boost::enable_if looks like it might be a solution but I've not made it work yet. extracting the essence of the situation: template<typename S, typename W> class baseclass { virtual void operator()(S s, W w) = 0; } template<typename S> class baseclass<S,void> { virtual void operator()(S s) = 0; } template<typename S, typename W = void> class derived : public baseclass<S,W> { void operator()(S s); // if W is void void operator()(S s, W w); // otherwise } How can I make this work? MSVC9, if that makes a difference. I tried adapting some examples from the enable_if documentation but that led to wandering around aimlessly making random changes to the text. TIA, -swn

3 4

[serialization] skipping top node "<boost_serialization signature...>"
by Sebastian Mach 27 Aug '09

27 Aug '09

Good morning everyone I'd like to use boost::serialization for the generation of xml-files. The format of those files shall not be specific to or dependent of boost, i.e. I'd like boost to not write the root-node of "<boost_serialization signature="serialization::archive" version=...>". E.g., instead of <?xml version="1.0" encoding="UTF-8" standalone="yes" ?> <!DOCTYPE boost_serialization> <boost_serialization signature="serialization::archive" version="4"> <picogen-qt-scene class_id="0" tracking_level="0" version="0"> <comment>hello world!</comment> <fenum>two</fenum> </picogen-qt-scene> </boost_serialization> I would prefer <?xml version="1.0" encoding="UTF-8" standalone="yes" ?> <picogen-qt-scene class_id="0" tracking_level="0" version="0"> <comment>hello world!</comment> <fenum>two</fenum> </picogen-qt-scene> . I wonder if this is possible without tweakage of boost components (meaning that I would have to fork or write patches). I tried the serialization-documentation and google, but could not find appropriate information (or maybe I missed the right words). Best Regards Sebastian Mach http://picogen.org

3 5

[boost-users][python] Problem with lifetime of object?
by Germán Diago 27 Aug '09

27 Aug '09

Hello. I would like to know what's wrong with this: Object * create() { return new Object(); } void addToScene(const std::string & name, Object * o) { //Store object in a std::multimap<std::string, Object *> } BOOST_PYTHON_MODULE(mod) { def("createObject", &create, return_value_policy<reference_existing_object>()); .... } I start my application, it works ok and it uses addToScene and create: Now I try to add a new object to my application from python: >> obj = Object() >> addToScene("obj", obj) Should the problem have anything to do with object lifetime? Or the segmentation fault is because of another issue? Thanks in advance.

2 2

[asio] io_service::run() never returns and is blocking my thread
by Robert Dailey 27 Aug '09

27 Aug '09

Hello, I'm currently using a serial_port object to call async_read_some(). This results in io_service::run() blocking until at least 1 byte or more can be read from the serial port. If nothing is ever sent, then I can not safely exit the thread in which io_service::run() is executing in. In other words, a call to join() on that thread hangs indefinitely until data is received. My completion callback is not executed at all until data arrives for reading. How can I force run() to return when I interrupt my thread? --------- Robert Dailey

3 4

Problem when using Boost.Asio at Fedora 11
by Davi Vercillo C. Garcia 27 Aug '09

27 Aug '09

Hi all, I'm new at C++ and Boost and I'm with some problems when I try to use Boost.Asio library. I was trying to build the first example from Boost.Asio's tutorial. The code is like this: ===== CODE ===== #include <iostream> #include <boost/asio.hpp> #include <boost/date_time/posix_time/posix_time.hpp> int main( int argc, char **argv ) { boost::asio::io_service io; boost::asio::deadline_timer t(io, boost::posix_time::seconds(5)); t.wait(); std::cout << "Opa !" << std::endl; return 0; } ===== CODE ===== I'm trying to compile using this command: g++ -I/usr/include/boost/ example.cpp -o example", and I'm getting this error: ==== ERROR ==== /tmp/ccv68fST.o: In function `__static_initialization_and_destruction_0(int, int)': timer.cpp:(.text+0x51): undefined reference to `boost::system::get_system_category()' timer.cpp:(.text+0x5b): undefined reference to `boost::system::get_generic_category()' timer.cpp:(.text+0x65): undefined reference to `boost::system::get_generic_category()' timer.cpp:(.text+0x6f): undefined reference to `boost::system::get_generic_category()' timer.cpp:(.text+0x79): undefined reference to `boost::system::get_system_category()' /tmp/ccv68fST.o: In function `boost::asio::error::get_system_category()': timer.cpp:(.text._ZN5boost4asio5error19get_system_categoryEv[boost::asio::error::get_system_category()]+0x7): undefined reference to `boost::system::get_system_category()' /tmp/ccv68fST.o: In function `boost::asio::detail::posix_tss_ptr<boost::asio::detail::call_stack<boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor<false> > >::context>::~posix_tss_ptr()': timer.cpp:(.text._ZN5boost4asio6detail13posix_tss_ptrINS1_10call_stackINS1_15task_io_serviceINS1_13epoll_reactorILb0EEEEEE7contextEED2Ev[boost::asio::detail::posix_tss_ptr<boost::asio::detail::call_stack<boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor<false> > >::context>::~posix_tss_ptr()]+0xf): undefined reference to `pthread_key_delete' /tmp/ccv68fST.o: In function `boost::asio::detail::posix_tss_ptr<boost::asio::detail::call_stack<boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor<false> > >::context>::posix_tss_ptr()': timer.cpp:(.text._ZN5boost4asio6detail13posix_tss_ptrINS1_10call_stackINS1_15task_io_serviceINS1_13epoll_reactorILb0EEEEEE7contextEEC2Ev[boost::asio::detail::posix_tss_ptr<boost::asio::detail::call_stack<boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor<false> > >::context>::posix_tss_ptr()]+0x22): undefined reference to `pthread_key_create' collect2: ld returned 1 exit status ==== ERROR ==== I already installed Boost and Boost-devel packages. Does anyone know what is missing ? Thanks, -- Davi Vercillo C. Garcia B.Sc. Student - DCC-IM/UFRJ Fedora Project Contributor http://davivercillo.fedorapeople.org/ "If a million people say a foolish thing, it is still a foolish thing." - Anatole France

3 4

lock-free shared_ptr on solaris
by Frank Meerkötter 27 Aug '09

27 Aug '09

Hello, from looking at [1] i understood that there is no lock-free implementation of shared_ptrs on solaris. When snooping around in the source i noticed that there is a ./smart_ptr/detail/atomic_count_solaris.hpp It is using the solaris specific <atomic.h> to implement an atomic counter. frank@dexter:~/boost_1_40_0/boost$ find -type f | xargs grep atomic_count_solaris.hpp ./smart_ptr/detail/atomic_count_solaris.hpp:// boost/detail/atomic_count_solaris.hpp But apparently it is not in use. I am currently wondering why? KR, Frank [1] http://www.boost.org/doc/libs/1_40_0/libs/smart_ptr/shared_ptr.htm

1 0

Implementing a type-and-effect system
by david raila 27 Aug '09

27 Aug '09

I'm pondering the use of boost to implement a type-and-effect static checker which consists of: 1. a system to define and name annotations 2. a way to declare and associate class members with the annotations 3. a way to declare effects on methods that say how the method interacts with the annotation 4. a way to capture uses of the members in the methods and verify that the effects are satisfied A simple example might be logical heap partitioning and interference checking which in the *abstract* might look something like this: class foo { heapregion a; heapregion b; foo * left in a; foo *right in b; foo *link(); void update() reads a, writes b { right = a->link(); // ok left = /*anything*/ // fails, writing a } This is one very simple example, but hopefully illustrates the idea. Ideally this can be all done statically at compile time without any run-time overhead, even if that means a two-phase compilation process, a checking phase that instantiates the checking code, and an optimized compile phase that might not. If this can be done via metaprogramming then we can avoid writing a new refactoring tool and/or modifying an existing front end. I've been trying to determine whether to try and implement a custom system or use proto or is there something else that might help in this effort? Is anyone aware of similar uses of boost, other libraries, or have advice and/or feedback. Thanks. David

2 2

Boost release 1.40.0 is available
by Beman Dawes 27 Aug '09

27 Aug '09

Boost release 1.40.0 is available from SourceForge: http://sourceforge.net/projects/boost/files/ As always, the .7z and .zip files have Windows line endings, while the .bz2 and .gz files have POSIX line endings. Please download a file that has line endings appropriate for your platform. There are no new libraries in this release, but lots of libraries have been updated and had bugs fixed, including: * Accumulators * Asio * Circular Buffer * Filesystem * Foreach * Function * Fusion * Hash * Interprocess * Intrusive * MPL * Program Options * Proto * Python * Serialization * Unordered * Xpressive Enjoy! -- The Boost Release Managers

3 2

[serialization]
by Marco Canini 27 Aug '09

27 Aug '09

Hi all, I'm getting exhausted with trying to get a functioning test case. I'm attaching my code, which consits of two classses: the second class Route is having a const reference member to the first class Protocol. It seems that I am able to serialize the two classes correctly, however when I deserialize the reference member is set to NULL. What am I doing wrong? Further, I was trying to have save_construct_data(...const Route * t...) to access the private members of the class Route by making it friend of the class. However, doing so results in a compiler error. Any idea of how I am supposed to deal with that? Thank you very much! -- Marco Canini

1 0

Iterating over the seconds of a list of pairs
by Zachary Turner 27 Aug '09

27 Aug '09

I have an std::list<std::pair<double, float> > internal to a class. I'd like to expose begin() and end() functions from this class, that iterate over the second element of the list. So basically I want the user of the class to only see a sequence of floats. transform_iterator seems to fit the bill, but I think I'm seriously overcomplicating this. I've tried the following and it's not working. I feel like this pair_second / pair_first, and iterator should either already all be defined somewhere that I'm just not aware of, or be much shorter to write than this. template<class First, class Second> struct pair_second : public std::unary_function<std::pair<First, Second>, const Second&> { const Second& operator()(std::pair<First,Second>& pair) const { return pair.second; } }; template<class First, class Second> struct pair_first : public std::unary_function<std::pair<First, Second>, const First&> { const First& operator()(std::pair<First,Second>& pair) const { return pair.first; } }; template<class pair_type> struct first_iterator { typedef boost::transform_iterator< pair_first<typename pair_type::first_type, typename pair_type::second_type>, typename pair_type > type; }; template<class pair_type> struct second_iterator { typedef boost::transform_iterator< pair_second<typename pair_type::first_type, typename pair_type::second_type>, typename pair_type > type; }; typedef typename first_iterator<double_float_pair>::type float_iterator; float_iterator begin() { return float_iterator(items_.begin(), second_iterator<double_float_pair>()); } float_iterator end() { return float_iterator(items_.end(), second_iterator<double_float_pair>()); } Any advice would be appreciated. Thanks Zach

12 22

[date_time] cannot understand idea behind c_time::gmtime function
by Roman Shmelev 27 Aug '09

27 Aug '09

Hi! I've seen different behaviour under Windows and FreeBSD of the function boost::date_time::c_time::gmtime Looking inside it confused me: (Windows variant) inline static std::tm* gmtime(const std::time_t* t, std::tm* result) { // RESULT VALUE IS NOT USED. SO WHAT SENSE TO PASS ANYTHING HERE? result = std::gmtime(t); if (!result) boost::throw_exception(std::runtime_error("could not convert calendar time to UTC time")); return result; } Under FreeBSD everything is ok (gmtime_r is used). So, probably it is a bug? I mean, the idea of cross-platform library - is that functions will operate in similar way on different platforms. Also, please look at documentation http://www.boost.org/doc/libs/1_39_0/doc/html/boost/date_time/c_time.html it says c_time has 4 functions (as I understand, 2 functions were cloned :/ ) so it also seems to be a bug.

2 3

why send_to does not send all the packets..?
by Paolo Viotti 27 Aug '09

27 Aug '09

Hi, I'm using the boost asio library to create and manage a UDP socket. In my code I've a for loop in which I send some packets, as follows: for (it=refreshList.begin(); it !=refreshList.end(); it++){ [...] std::cout<<"___Refreshing: sent a KADEMLIA2_HELLO_REQ packet to "<< (*it)->getAddressString()<<":"<<(*it)->getUDPPort()<<std::endl; Packet* packet = new Packet(CList->getMyNodeID(),true); // KADEMLIA2_HELLO_REQ socket->send_to(boost::asio::buffer(packet->getPacket(), packet->getSize()), (*re)); } and actually it sends the packets, but just some of them: it stops sending after having sent about 30 packets out of 150, without throwing any exception or giving any error, while the loop continue and all the strings are regularly printed on std::cout. i'm really puzzled... is there any buffer to flush or any shutdown timer to take into account..? could it be due to another thread that is blocked on the receive_from function..? thanks, p_viotti

1 0

[interprocess] shared_memory_object design
by Christian Henning 27 Aug '09

27 Aug '09

Hi there, a colleague of mine is questioning the design decisions in the shared_memory_object class. The assignment operator and copy constructor are private. Why? Also the constructor takes a type instead of a value as the first parameter. In his eyes it makes it very inflexible since the creation of or attaching to shared_memory area has to known at compile time. A few pointers on why such a design was chosen would be very helpful. Regards, Christian

1 0

[assign] Inconvenience with list_of
by dariomt＠gmail.com 27 Aug '09

27 Aug '09

Hi list, I found a small inconvenience while trying to use boost::assign::list_of with the following code #include <vector> #include <boost/assign/list_of.hpp> struct A { // no implicit conversion from int explicit A(int i) {} // constructor from two ints A(int i, int j) {} }; void works_with_two_ints() { std::vector<A> v = boost::assign::list_of<A>(1,2)(3,4)(5,6); } #if 0 void does_not_work_with_one_int() { std::vector<A> v = boost::assign::list_of<A>(1)(2)(3); } #endif Looking into the code, it seems as if assign_detail::generic_list<A> had two slightly different versions of operator() generated with some preprocessor magic // 1) accepts a fully constructed A generic_list& operator()( const A& u ) { this->push_back( u ); return *this; } // 2) accepts two generic paramenters forwarding them to A's two parameter constructor template <typename U, typename V> generic_list& operator()(const U& u, const V& v) { this->push_back( A(u,v) ); return *this; } I'm missing another operator() that takes one generic parameter and forwards it to A's one parameter constructor, for the case where it is not implicitly convertible. // 3) accepts a generic paramenter forwarding it to A's one parameter constructor template <typename U> generic_list& operator()(const U& u) { this->push_back( A(u) ); return *this; } That saves me from typing A's everywhere std::vector<A> v = boost::assign::list_of(A(1))(A(2))(A(3)); Does this make sense? Thanks!

2 1