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

Design for boost::serialization of STL iterators.
by Carlo Wood 23 May '09

23 May '09

On Sat, Mar 11, 2006 at 11:45:36PM +0200, Peter Dimov wrote: > Carlo Wood wrote: > > > 1) WHY does boost::serialization not support serialization > > of iterators? > > It's very hard, if not impossible, in general. It is either impossible or possible. When it is possible, it can't be hard :p I think that at the moment of serialization, the actual container needs to be known. So, only concentrating on the syntax of the code that serializes an iterator, the following cannot work: ar & iter; However, the container will be known at that point (or at least, we might as well assume that). Therefore, I could imagine a syntax like: ar & foobar(container, iter); where 'foobar' is some template function (that will be part of boost::serialization in the future). Lets start with the last one (have to start somewhere). In order to deserialize the iterator (and taken into account that we already have the container) -- which makes me think that it might be better to pass a functor to operator& above. In other words, (at least for writing), use: template<class Container> struct Foobar { Foobar(Container const&, typename Container::const_iterator& iter) : M_container(container), M_iter(iter); private: Container const& M_container; Container::const_iterator& M_iter; }; and then assign to M_iter, whatever we find in M_container. > If you have access to the container to which the iterator i refers: > > a) if the container is a map, you can serialize i->first, then on > deserialization look up the key in the map using .find(); > > b) if the container is a sequence, and it has the same contents on > deserialization as it does on serialization, you can serialize the index of > the element - distance( c.begin(), i ). I don't think that it is a requirement that the whole container has to be read: either it's a map or set, in which case later insertions will not invalidate the container, or it is a vector, in which case we use an index, from which we can construct the end iterators before the whole container is reconstructed. Therefore, the following syntax can work imho: ar & FooBar(container, iter); Would you agree? There are a zillion questions and implementation details open - but I'd like to get anyones feedback about this type of interface for iterators before continuing. Current questions: What is a good name for Foobar? Am I right when I think that Foobar needs to be declared in boost::serialization? Now the hard part (for me) is that part that involves the internals of the boost library. At the moment one tries to serialize an iterator, it is possible (though not necessarily) that the object that the iterator points to is already serialized. In the case that we are dealing with an associative container (map or set etc), we don't want to store the contents of the object (or key part, in the case of a map) again: I'd like to just store that once, and store a reference in the archive at the other place. How can I make the library store an object only the first time and the store a reference the second time? This would be for an object of arbitrary type thus. I think that it is only feasible to do this when it's actually the same object (same memory address), which is the case; but while storing the object element of the container, the address of it isn't stored as well, is it? Is there a way to make: std::set<SomeData> s; [...] ar << s; Store the address of s (&s) along with the contents of s? And would that then automatically cause the library to not store that same object again when I do: std::set<SomeData>::iterator iter = s.find(...); [...] ar << *iter; Because then, &*iter would again be the same memory address as what was stored before. -- Carlo Wood <carlo(a)alinoe.com>

3 2

[BGL] Is it possible to control algorithm's behavior by visitor?
by Li Ning 23 May '09

23 May '09

In some complex application, I need to control algorithm's behavior according to edge's property. It seems all visitor are used to "visit" the predefined place in a algorithm but it can not "control". All functions in visitor has void return type, so it can't give algorithm anything. Why there is no STL-like functor which can control algorithm's behavior? -- View this message in context: http://www.nabble.com/-BGL--Is-it-possible-to-control-algorithm%27s-behavio… Sent from the Boost - Users mailing list archive at Nabble.com.

4 11

date_time question
by Amadeus W.M. 23 May '09

23 May '09

I have a file with tab separated entries like this: 1230735660 12/31/2008 10:01:00 8.94 277880 1230735729 12/31/2008 10:02:09 8.95 279693 1230735791 12/31/2008 10:03:11 8.95 284743 etc. I don't assume which column represents the date so I read one line at the time and test each token if it's a date in the format "%m/%d/%Y %H:%M:%S". However, when I process the first token (1230735660) date_time thinks it's a date in my format and returns 5660-Dec-07 00:00:00 How come? It seems to think that 3 is a separator. Could anyone please shed some light? Thanks! Here is a short program that exemplifies the problem: // g++ -g -Wall -o dateIO -I/usr/local/include/boost-1_38 -L/usr/local/ lib/ dateIOTest.C -lboost_date_time-gcc43-mt-1_38 #include <iostream> #include <sstream> #include <cstdlib> #include <string> #include <boost/date_time/posix_time/posix_time.hpp> using namespace std; using namespace boost::posix_time; int main(int argc, char * argv[]) { ptime pt; string datestr("1230735660"); istringstream INSTR(datestr); time_input_facet * tifacet=new time_input_facet("%m/%d/%Y %H:%M:%S"); locale loc(INSTR.getloc(),tifacet); INSTR.imbue(loc); INSTR >> pt; cout << pt << endl; return 0; }

1 0

Including Xutil.h on Fedora breaks BOOST_FOREACH
by Tron Thomas 22 May '09

22 May '09

Compiling this: #include <X11/Xutil.h> #include <boost/shared_ptr.hpp> #include <vector> #include <cstdlib> #include <boost/foreach.hpp> #include <iostream> using std::ostream; class Value { public: explicit Value(int amount) : m_amount(amount) {} void WriteTo(ostream& stream) const { stream << m_amount; } private: int m_amount; }; ostream& operator <<(ostream& stream, const Value& value) { value.WriteTo(stream); return stream; } int main() { typedef boost::shared_ptr<Value> ValuePtr; std::vector<ValuePtr> valueBuffer; for(int count = 0; 10 > count; ++count){ valueBuffer.push_back(ValuePtr(new Value(::rand()))); } BOOST_FOREACH(ValuePtr value, valueBuffer){ std::cout << *value << std::endl; } return 0; } on Fedora 10 (Intel) produces error output like: /usr/include/boost/foreach.hpp:223: error: expected nested-name-specifier before ‘int’ /usr/include/boost/foreach.hpp:223: error: two or more data types in declaration of ‘parameter’ /usr/include/boost/foreach.hpp:224: error: default template arguments may not be used in function templates Value.cpp: In function ‘int main()’: Value.cpp:34: error: no matching function for call to ‘not_(boost::is_array<std::vector<boost::shared_ptr<Value>, std::allocator<boost::shared_ptr<Value> > > >*)’ Value.cpp:34: error: no matching function for call to ‘not_(boost::foreach::is_noncopyable<std::vector<boost::shared_ptr<Value>, std::allocator<boost::shared_ptr<Value> > > >*)’ Value.cpp:34: error: no matching function for call to ‘not_(boost::is_array<std::vector<boost::shared_ptr<Value>, std::allocator<boost::shared_ptr<Value> > > >*)’ Value.cpp:34: error: no matching function for call to ‘not_(boost::foreach::is_noncopyable<std::vector<boost::shared_ptr<Value>, std::allocator<boost::shared_ptr<Value> > > >*)’ Value.cpp:34: error: no matching function for call to ‘not_(boost::is_array<std::vector<boost::shared_ptr<Value>, std::allocator<boost::shared_ptr<Value> > > >*)’ Value.cpp:34: error: no matching function for call to ‘not_(boost::foreach::is_noncopyable<std::vector<boost::shared_ptr<Value>, std::allocator<boost::shared_ptr<Value> > > >*)’ If the first included header file is removed from the code, it builds successfully. Even though the code in this example doesn't technically need that first header file included, it is representative of code that does. What is needed so this code can build successfully while including all the header files?

3 2

Re: [Boost-users] Boost-users Digest, Vol 2003, Issue 6
by Tron Thomas 22 May '09

22 May '09

> > Date: Fri, 22 May 2009 22:42:05 +0100 From: "Pete Bartlett" > <pete(a)pcbartlett.com> Subject: Re: [Boost-users] Including Xutil.h on > Fedora breaks BOOST_FOREACH To: <boost-users(a)lists.boost.org> > Message-ID: <4CBFD915E6B84833BC9CE588386CDD04@P2> Content-Type: > text/plain; charset="us-ascii" Tron Thomas wrote: >> >#include <X11/Xutil.h> >> > > A quick search on Google Codesearch shows that Xutil.h includes Xlib.h which > has the following > > " > #define Bool int > #define Status int > #define True 1 > #define False 0 > " > > (around line 112 in the version I am looking at). > > This breaks Boost.ForEach's (legitimate) attempt to use "Bool" as the name > for a template type. How to fix? Some possibilities > > a) Stop using libraries that employ such bad practices, or > b) Wrap the include in your own header that tidies up after X11 with some > #undefs, or > c) include X11 after Boost ?! > > I doubt Boost.ForEach would be the only library the X11 include would foul > up Thanks Pete. I was able to get the code to compile now.

1 0

[BIL] BIL & AOP
by Jonathan Leonard 22 May '09

22 May '09

Hello, I'm trying to do aspect-oriented programming in C++ and found this library which is almost up to speed to do it (but not quite). The documentation is rather incomplete (with respect to AOP at least) but the relevant code itself seems pretty complete (although I can't quite figure out how to use it for AOP :)). http://www.cdiggins.com/bil.html Does anyone here have experience with the BIL and/or AOP in C++? The specific problem I'm having is using an 'interface' as a 'pointcut'. The docs seem to indicate that an interface is a pointcut, but when I try substituting it in as the 'aspect' class' pointcut_type, I get this error: 1>c:\expedia\ems\ads\lib\boost\boost_1_37\boost\interfaces\crosscut.hpp(59) : error C2039: 'generator' : is not a member of 'Ic' 1> c:\expedia\ems\devs\v-jleonard\aspect_test\aspect_test\aspect_test.cpp(12) : see declaration of 'Ic' 1> c:\expedia\ems\ads\lib\boost\boost_1_37\boost\mpl\aux_\preprocessed\plain\apply_wrap.hpp(39) : see reference to class template instantiation 'boost::interfaces::detail::crosscut_impl<Aspects>::generator_impl<Derived,Flags,Base>::merge::apply<Aspect>' being compiled 1> with 1> [ 1> Aspects=boost::mpl::list<log_aspect,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na>, 1> Derived=boost::interfaces::crosscut_interface<c,log_aspect>, 1> Flags=boost::interfaces::flags::default_, 1> Base=boost::interfaces::detail::empty_base, 1> Aspect=boost::interfaces::aspect<Ic,log_advice> 1> ] 1> c:\expedia\ems\ads\lib\boost\boost_1_37\boost\mpl\aux_\preprocessed\plain\apply.hpp(43) : see reference to class template instantiation 'boost::mpl::apply_wrap1<F,T1>' being compiled 1> with 1> [ 1> F=boost::interfaces::detail::crosscut_impl<boost::mpl::list<log_aspect,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na,boost::mpl::na>>::generator_impl<boost::interfaces::crosscut_interface<c,log_aspect>,boost::interfaces::flags::default_,boost::interfaces::detail::empty_base>::merge, 1> T1=boost::interfaces::aspect<Ic,log_advice> 1> ] It seems that interface_base has a 'generator' member, but the BOOST_IDL_END macro derives interfaces from interface_base::type instead. I realize this isn't yet an official boost library, but it deals with a great many of the same techniques/ideas [and relies on a lot of underlying boost functionality] so any help you can offer would be much appreciated! [My code is attached and the BIL code can be downloaded here: http://www.coderage.com/interfaces/] Thanks, Jonathan P.S. if anyone knows of alternate ways of pulling off AOP in C++, I'd be open to that too!

1 0

Compile errors using BOOST_FOREACH on Fedora Linux
by Tron Thomas 22 May '09

22 May '09

I have a class defined like this: class SomeObject { public: ... virtual void Method(); ... private: typedef boost::shared_ptr<AnotherObject> AnotherObjectPtr; ... std::vector<AnotherObject> m_objects; ... }; void SomeObject::Method() { ... BOOST_FOREACH(AnotherObjectPtr object, m_objects){ object->DoSomething(); } } The code compiles fine using Boost 1.39.0 on Mac OS X 10.5 (PowerPC). However, when I compile the same code on Fedora 10 (Intel), I get compile errors like: .../boost_1_39_0/boost/foreach.hpp:221: error: expected nested-name-specifier before ‘int’ .../boost_1_39_0/boost/foreach.hpp:221: error: two or more data types in declaration of ‘parameter’ .../boost_1_39_0/boost/foreach.hpp:222: error: default template arguments may not be used in function templates .../SomeObject.cpp: In member function ‘virtual void SomeObject::Method()’: .../SomeObject.cpp:110: error: no matching function for call to ‘not_(boost::is_array<std::vector<boost::shared_ptr<AnotherObject>, std::allocator<boost::shared_ptr<AnotherObject> > > >*)’ .../SomeObject.cpp:110: error: no matching function for call to ‘not_(boost::foreach::is_noncopyable<std::vector<boost::shared_ptr<AnotherObject>, std::allocator<boost::shared_ptr<AnotherObject> > > >*)’ .../SomeObject.cpp:110: error: no matching function for call to ‘not_(boost::is_array<std::vector<boost::shared_ptr<AnotherObject>, std::allocator<boost::shared_ptr<AnotherObject> > > >*)’ .../SomeObject.cpp:110: error: no matching function for call to ‘not_(boost::foreach::is_noncopyable<std::vector<boost::shared_ptr<AnotherObject>, std::allocator<boost::shared_ptr<AnotherObject> > > >*)’ .../SomeObject.cpp:110: error: no matching function for call to ‘not_(boost::is_array<std::vector<boost::shared_ptr<AnotherObject>, std::allocator<boost::shared_ptr<AnotherObject> > > >*)’ .../SomeObject.cpp:110: error: no matching function for call to ‘not_(boost::foreach::is_noncopyable<std::vector<boost::shared_ptr<AnotherObject>, std::allocator<boost::shared_ptr<AnotherObjecth> > > >*)’ These error are quite puzzling, and I'm not sure what is causing the problem especially since the code compiled fine on another platform, which suggests it might be fine. What is needed to fix this problem so the code will compile successfully?

2 2

1.35 -> 1.39 update
by Terry.Rankine＠csiro.au 22 May '09

22 May '09

Hi I am updating some code from 1.35 to 1.39 and i am stuck on this http://www.boost.org/doc/libs/1_38_0/boost/enable_shared_from_this.hpp vs http://www.boost.org/doc/libs/1_39_0/boost/smart_ptr/enable_shared_from_thi… The code i have to update is making calls like this: _internal_weak_this.expired() this is now private in 1.39, but i cant see a way of replicating its actions. Terry Rankine

2 1

Re: [Boost-users] Boost-users Digest, Vol 2003, Issue 1
by Tron Thomas 22 May '09

22 May '09

> > Tron Thomas wrote: >> > I have a class defined like this: >> > >> > class SomeObject >> > { >> > public: >> > ... >> > >> > virtual void Method(); >> > >> > ... >> > >> > private: >> > typedef boost::shared_ptr<AnotherObject> AnotherObjectPtr; >> > >> > ... >> > >> > std::vector<AnotherObject> m_objects; >> > >> > ... >> > }; >> > >> > void SomeObject::Method() >> > { >> > ... >> > >> > BOOST_FOREACH(AnotherObjectPtr object, m_objects){ >> > object->DoSomething(); >> > } >> > } >> > >> > The code compiles fine using Boost 1.39.0 on Mac OS X 10.5 (PowerPC). >> > > That's surprising since m_objects is a vector of AnotherObject, not a > vector of AnotherObjectPtr. (Hint: *always* post the actual code that is > failing.) > > -- Eric Niebler BoostPro Computing http://www.boostpro.com Yes, the declaration of m_objects should have been: std::vector<AnotherObjectPtr;> m_objects; That is consistent with the actual code where the problem is happening. Given that what do people know about how to fix the compiler error?

1 0

Re: [Boost-users] posix_time::from_ftime versus DateTime.FromFileTime
by Anders Dalvander 22 May '09

22 May '09

Archie14(a)lists.boost.org wrote: > I will appreciate any help in sorting out following issue: > > There is a value dt of type long. Calling boost::posix::time::from_ftime in > c++ and > DateTime.FromFileTime with that value produce "slightly" different results: > > dt = 128822886020000000 > > c++: "2009-Mar-23 13:30:02" > c#: {3/23/2009 9:30:02 AM} > DateTime.FromFileTimeUtc will probably produce the same results as boost::posix::time::from_ftime. Perhaps DateTime.SpecifyKind are needed as well. Regards, Anders Dalvander

2 1

boost::iterator_property_map causes run-time fatal error in debug mode on VS2008
by Artyom 22 May '09

22 May '09

Dear all, Noticed some strange behaviour in Debug mode today using boost::iterator_property_map. Not sure whether this is a bug so decided to post here. Here is a how property map is instantiated: template< class Graph, class Vertex, class Edge, class VertexIterator, class EdgeIterator > class PathRecorder { typedef typename boost::property_map< typename Graph, boost::vertex_index_t >::type VertexId_PMap; typedef boost::iterator_property_map< typename std::vector< Edge >::iterator, VertexId_PMap, typename Edge, typename Edge & > PredEdgeMap; /// relevant members std::vector< Edge > edges; VertexId_PMap vertex_id; PathRecorder( void ) : /*** some instantiations here ***/ predEdgeMap( edges.begin(), vertex_id ) { } /** @desc Update an entry inside a map ( fatal error happens here ) **/ void put( Vertex target, Edge e ) { boost::put( predEdgeMap, target, e ); } } In Release mode everything works fine but in Debug mode put method causes a fatal error. It fails in property_map.hpp (351): inline R operator[](key_type v) const { return *(iter + get(index, v)) ; } iter seems to be equal to 0... Which is extremely suspicious. Could anyone think whether I am doing something wrong? I can provide more information if this isn't enough. Arty

3 3

[asio] io_service performance
by Rusty Koonce 22 May '09

22 May '09

First, I'm a noob to the mailing list -- you all need a "search" option on the archives... perhaps it's there, but I didn't see it. I gave up on my O(N) search after making it through the last 3 or 4 months of archives. :) My question is rather simple... Is it better to have a single io_service with multiple threads sharing it calling poll()/poll_one(), or have each thread own its own io_service and calling run()? I saw the HTTP example that did the latter -- each thread owned its own io_service and called run(). My worry there would be if one handler takes a long time to execute it essentially blocks all others behind it. But it seems a single io_service with multiple threads calling poll() or poll_one() would prevent one expensive handler from holding up processing of others behind it (but there could be much more contention on the handler queue). Without a better understanding of the underlying architecture, I'm not sure which way would yield the best performance as traffic scales up on the server. Thanks! -Rusty

2 1

bootstrap.sh questions (compiling v1.39)
by Raymond Wan 22 May '09

22 May '09

Hi all, I'm hadn't been following the development of Boost's installation process and just went from 1.38 to 1.39 and realized the steps that I had written down no longer work. :-) I'm glad that the process was being looked into, but could someone help me with a couple of things? First, I use mpi and use to edit $BOOST/user-config.jam and put "using mpi ;" at the end to get it to compile. I didn't do this and I got a similar warning as before even though I ran: ./bootstrap.sh --with-libraries=graph,mpi,program_options,serialization Does "mpi" in it have no effect? After it finished, it seems the other 3 were made, but not mpi. Should I add "using mpi ;" still? [In $BOOST, I now notice there is no user-config.jam but a project-config.jam.] And the other thing I use to do was to edit the Makefile by adding "--layout=system" so that the generated libraries do not indicate the compiler version. (I did read the discussion earlier this month and I'm now wondering if it's bad practice to do this? I would like libboost_program_options-mt.so instead of libboost_program_options-gcc43-mt.so .) How do I do this with bootstrap.sh/bjam? Thank you! Ray

2 4

scoped_lock
by Space Ship Traveller 22 May '09

22 May '09

I think this is my own fault. I'm debugging some issues with multi-threading and using boost scoped_lock. My code looks like this: { // Enqueue the notification to be processed scoped_lock(m_notifications.lock); m_notifications.sources->push(note); } Am I correct in assuming this is not going to work as expected? The compiler might not even instantiate the lock given this code? I need to write it like this? { // Enqueue the notification to be processed scoped_lock locked(m_notifications.lock); m_notifications.sources->push(note); } Kind regards, Samuel

2 1

Re: [Boost-users] Error (runtime) assigning multi_array to multi_array with smaller dimensions
by Oei, YC 22 May '09

22 May '09

> //at class constructor > boost::multi_array<char, 2> array2d = new boost::multi_array<char, > 2>(boost::extents[x][y]); > //at class method > boost::multi_array<char, 1> array1d = array2d[0]; I tried out those two lines (minus the "new") here (see below), and they compile without complaints in g++ 4.1.2. Yung-Chin -- contents of test file -- #include <iostream> #include <boost/multi_array.hpp> int main() { size_t x = 5; size_t y = 7; boost::multi_array<char, 2> array2d = boost::multi_array<char, 2>(boost::extents[x][y]); std::cout << array2d.num_dimensions() << std::endl; std::cout << array2d[0].num_dimensions() << std::endl; boost::multi_array<char, 1> array1d = array2d[0]; std::cout << array1d.num_dimensions() << std::endl; return 0; } //main

2 3

Example of using posix_time with timezone
by Archie14 21 May '09

21 May '09

This post is related to my discovery of differences in behavior between posix_time::from_ftime and C# DateTime.FromFileTime methods (earlier post) Now I am trying to learn the proper usage of posix_time and time_zones. After reading the documentation I am still confused regarding usage of the timezone together with usage of classes/functions in posix_time namespace Is it possible to do smth.like this: First declare the time zone, like EST, CT ets and then all subsequent calls to posix_time namespace functions or classes will take this timezone as a base? I will really appreciate a simple example of specifying EST timezone for posix_time.

1 0

[multi_array] Looking for elegant way to convert between array and extent_gen objects
by Oei, YC 21 May '09

21 May '09

Dear list members, I've been working with multi_array lately, and am trying to exclusively use boost::arrays as the indexing object when accessing multi_arrays, in order to keep my code dimension-independent. There is a little issue however, in that not all multi_array methods take arrays as parameters; e.g. multi_array::resize() only takes an extent_gen parameter. I've come up with a workaround, which converts an array to the corresponding extent_gen object, and this works.... but it is an ugly amount of code for such a little task. I was hoping I might ask if you have better suggestions? Is there a way to make extents-notation dimension-independent? The content of the header file with my current solution is pasted below to illustrate what I'm trying to achieve - a (somewhat overly trivial) use case is as follows: #include "ArrayToExtentGen.h" [...] boost::multi_array<SomeValueType, SomeNumberOfDimensions> array; [...] boost::array<boost::multi_array_types::index, SomeNumberOfDimensions> position = {{0, 0, 0, 0, 0, 0, 0, 0}}; array.resize(ArrayToExtentGen(position)); [...] Thanks for your thoughts! Yung-Chin -- ArrayToExtentGen.h -- #ifndef GUARD_ArrayToExtentGen_h #define GUARD_ArrayToExtentGen_h #include <boost/array.hpp> #include <boost/multi_array.hpp> namespace YungChin { //! Helper class for ArrayToExtentGen() to recurse through dimensions template < size_t NumDimsIn, size_t NumDimsOut> class ArrayToExtentGenRecurse; //! Convert boost::array (used for addressing on multi_array) into extent_gen template<size_t NumDims> boost::detail::multi_array::extent_gen<NumDims> ArrayToExtentGen( const boost::array<boost::multi_array_types::index, NumDims>& array) { return ArrayToExtentGenRecurse<NumDims, NumDims>::Apply(array); } //ArrayToExtentGen template < size_t NumDimsIn, size_t NumDimsOut> class ArrayToExtentGenRecurse { public: static boost::detail::multi_array::extent_gen<NumDimsOut> Apply( const boost::array<boost::multi_array_types::index, NumDimsIn>& array) { return ArrayToExtentGenRecurse<NumDimsIn, NumDimsOut-1> ::Apply(array)[array[NumDimsOut-1]]; } //Apply }; //ArrayToExtentGen //! Partial specialisation of the above, to stop recursing at 0 dimensions template <size_t NumDimsIn> class ArrayToExtentGenRecurse<NumDimsIn, 0> { public: static boost::detail::multi_array::extent_gen<0> Apply( const boost::array<boost::multi_array_types::index, NumDimsIn>& array) { return boost::detail::multi_array::extent_gen<0>(); } //Apply }; //ArrayToExtentGen } //namespace YungChin #endif

1 0

posix_time::from_ftime versus DateTime.FromFileTime
by Archie14 21 May '09

21 May '09

I will appreciate any help in sorting out following issue: There is a value dt of type long. Calling boost::posix::time::from_ftime in c++ and DateTime.FromFileTime with that value produce "slightly" different results: dt = 128822886020000000 c++: "2009-Mar-23 13:30:02" c#: {3/23/2009 9:30:02 AM} What I am doing wrong? c++ code: typedef signed __int64 int64; int64 dt = 128822886020000000; datetime = boost::posix_time::from_ftime<boost::posix_time::ptime>(dt); std::string testdt = boost::posix_time::to_simple_string(datetime); C# code: Int64 dt = 128822886020000000; startdate = DateTime.FromFileTime(dt);

2 1

Re: [Boost-users] Boost.Unordered throws 64-bit portability warnings
by JOAQUIN M. LOPEZ MUÑOZ 21 May '09

21 May '09

________________________________________ De: boost-users-bounces(a)lists.boost.org [boost-users-bounces(a)lists.boost.org] En nombre de Daniel James [daniel_james(a)fmail.co.uk] Enviado el: jueves, 21 de mayo de 2009 21:36 Para: boost-users(a)lists.boost.org Asunto: Re: [Boost-users] Boost.Unordered throws 64-bit portability warnings 2009/5/21 Dominique Devienne <ddevienne(a)gmail.com>: > > > > FWIW, I'm getting these as well when using > > boost::hash_combine(hash_value(this->member_)); to implement hashes > > for my classes. We also use VS2005 with the compiler switch that > > raises these warnings. My work around below is not pretty... --DD > > > > #if ACME_SIZEOF_SIZE_T == 4 > > // Avoid warning C4267: 'argument' : > > // conversion from 'size_t' to 'unsigned int', possible loss of data > > boost::hash_combine( > > seed, static_cast<unsigned int>(hash_value(member_)) > > ); > > #else > > boost::hash_combine(seed, hash_value(member_)); > > #endif > > Doesn't 'boost::hash_combine(seed, member_)' work? > > I'll have a look at the warning when I get the chance, but AFAICT > they're wrong since when compiling for 64-bit a different overload or > template resolution would be chosen. Is this maybe related to http://lists.boost.org/boost-users/2007/03/26388.php ? Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

1 0

iterators must go
by Neal Becker 21 May '09

21 May '09

Interesting presentation: http://www.boostcon.com/site- media/var/sphene/sphwiki/attachment/2009/05/08/iterators-must-go.pdf

8 13

Persisting __int64 (or long long) with boost::serialization?
by Sandy Walsh 21 May '09

21 May '09

Hi, Sorry for the n00b question, but I'm trying to serialize some unsigned __int64 member variables using boost::serialization. I added the following to my header: namespace boost { namespace serialization { template<class Archive> void load(Archive & ar, unsigned __int64& big, const unsigned int version) { size_t size = sizeof(big); ar.load_binary(&big, size); } template<class Archive> void save(Archive & ar, unsigned __int64 big, const unsigned int version) { ar & sizeof(big); ar.save_binary(&big, sizeof(big)); } } }; But the compiler still complains that it doesn't know how to handle that right-hand operand. Is there something obvious here I'm missing? Thanks -S

4 6

Declare statistical distribution array: boost/math/distributions
by Alex Tsoi 21 May '09

21 May '09

Hi all, I am trying to write a MCMC algorithm by using boost's math distribution library, what I want to do is to first declare an array of length 10 of gamma distribution, and then run a for loop to declare each gamma distribution's parameters. However, boost does not allow me to declare the gamma distribution array without having defining the parameter in advance: gamma_distribution<double> mydist10[10]; error: no appropriate default constructor available. because the library requires to know the parameter of the gamma distribution in advance. Do you guys have any idea to overcome this ? Thanks a lot for any comment or suggestion. Alex- -- Lam C. Tsoi (Alex) Medical University of South Carolina

3 3

Boost'Con aftermath
by Joel Falcou 21 May '09

21 May '09

I wanted to know what will the paper submitted to boost'con become ? Is there any publication planned or not ? Just asking to know if I can quote the thing I did for Boost'Con 09 in other papers ;) Regards -- ___________________________________________ Joel Falcou - Assistant Professor PARALL Team - LRI - Universite Paris Sud XI Tel : (+33)1 69 15 66 35

2 2

boost::iostreams filter question
by plarroy 21 May '09

21 May '09

Hello, I have implemented a test SymmetricFilter and works ok. Although to my suprise I had to declare two different methods of filter differing only in the signature by the const char*& src_end. If I supress either of those i get a compile time error. Perhaps it is because it's being used as a bidirectional filter? as the two signatures might be the ones in boost/iostreams/filter/symmetric.hpp read and write? Pedro. Regards. My code: class smashing_filter_impl { public: typedef char char_type; smashing_filter_impl() { } bool filter(const char*& src_begin, char*& src_end, char*& dst_begin, char*& dst_end, bool flush) { bool eof = false; ptrdiff_t src_sz = src_end - src_begin; if( src_sz <= 0 ) return false; while(src_begin < src_end && dst_begin < dst_end) *dst_begin++ = tolower(*src_begin++); return true; } bool filter(const char*& src_begin, const char*& src_end, char*& dst_begin, char*& dst_end, bool flush) { bool eof = false; ptrdiff_t src_sz = src_end - src_begin; if( src_sz <= 0 ) return false; while(src_begin < src_end && dst_begin < dst_end) *dst_begin++ = tolower(*src_begin++); return true; } void close() {} private: }; struct smashing_filter : symmetric_filter<smashing_filter_impl> { public: typedef symmetric_filter<smashing_filter_impl> base_type; smashing_filter() : base_type(default_device_buffer_size) { } };

1 0

Boost Library on ThreadX RTOS
by Suraj Gupta, Gurgaon 21 May '09

21 May '09

Hi All, I want to use BOOST library (Test) on ThreadX Real Time Operating System. Can it be used on ThreadX? If possible, are there any guidelines those needs to be followed? Thanks, Suraj DISCLAIMER: ----------------------------------------------------------------------------------------------------------------------- The contents of this e-mail and any attachment(s) are confidential and intended for the named recipient(s) only. It shall not attach any liability on the originator or HCL or its affiliates. Any views or opinions presented in this email are solely those of the author and may not necessarily reflect the opinions of HCL or its affiliates. Any form of reproduction, dissemination, copying, disclosure, modification, distribution and / or publication of this message without the prior written consent of the author of this e-mail is strictly prohibited. If you have received this email in error please delete it and notify the sender immediately. Before opening any mail and attachments please check them for viruses and defect. -----------------------------------------------------------------------------------------------------------------------

1 0