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boost regex support for 64-bit
by itay 12 May '04

12 May '04

does boost regex support 64-bit for SunOS 5.8, HP-UX 11i (native compilers), WIN (MSVC-6) ? we are using an old(?) version - regexpp version 3.12. Is it recommended to upgrade to the latest version ? Is it essential to upgrade to the latest version with relevance to 64-bit compilation ? thanks, Itay

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BGL: record tree-edges of MST during prim_minimum_spanning_tree
by boost＠spyderworks.de 12 May '04

12 May '04

Hi, I'm looking for a possibility to record the tree edges in the minimum spanning tree (like the result of kruskal_minimum_spanning_tree). But unfortenuatley I depend on using the prim_minimum_spanning_tree function, because the root of the tree has to be defined. My first idea was, to use a dijkstra visitor and do something with the edge_relaxed respectivley edge_not_relaxed events, but this doesn't work, because these events doesn't give me an unique edge state. Maybe anyone has another hint? best regards Stefan Rauch

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AW: [Boost-users] BGL: using an edge_descriptor as key in a map
by boost＠spyderworks.de 12 May '04

12 May '04

Hi Doug, [...] > > I intend to write a visitor class which sets a boolean to each edge, and > > therefore I need the edge as key. > > Common ways to do this include using internal properties and maintaining your > own edge_index (internal) property so that you can build property maps out of > vectors. [...] I don't know, if I understand correctly? Would I request the edges' index in the callback member function of the visitor and use this as index to a vector? Maybe you can give me an example? I'm pretty new to boost. Thanks Stefan Rauch

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Re: Boostifying GluCat
by Paul C. Leopardi 11 May '04

11 May '04

Hi all, Back in January last year, I asked if there was any documentation which could help me to Boostify GluCat: http://lists.boost.org/MailArchives/boost-users/msg02787.php Since then I have been very busy, but in the next few months I may be able to find the time to get this done right, so I'm asking again: GluCat is a new numeric template class library, hopefully destined for promotion to Boost. I would like to know where there is some documentation on how to: 1. Add concepts. Is there such a thing as a non-commutative multiplication concept? How do I check concepts? 2. Add numeric limits. Limits of U<T> would default to limits of T. 3. Add numeric promotion_traits. What are promotion_traits ? There is a discussion on ublas-dev mailing list about promotion_traits within uBLAS. 4. Add numeric type_traits. Also, is there a set of documented procedures which explain what is required for a library to be included in Boost? GluCat uses uBLAS. Should I take these questions to ublas-dev? Thanks

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Re: is_sequence
by Rozental, Gennadiy 11 May '04

11 May '04

> It already works. If you want to detect STL sequence-ness, you'll > have to try some nasty hacks. I'm have doubts about whether it's even > possible to approximate that metafunction in portable code. Wouldn't something about these lines work? template<typename T> char test( T const&, long ); template<typename T> int test( std::list<T> const&, int ); template<typename T> struct is_list { static T t; enum { value = sizeof( test( t, 0 ) ) == 4; } }; Gennadiy.

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[BGL] graph constness and vertex/edge iterators
by Cyrille Damez 11 May '04

11 May '04

Hi all, I'm currently trying to write a wrapper in order to use the BGL algorithms and visitors on a home-made graph class. If I'm not mistaken, this requires me to write (amongst other things) a couple functions that will return iterators over my graph edges and vertices, eg: std::pair<graph_traits<MyGraph>::out_edge_iterator, graph_traits<MyGraph>::out_edge_iterator > out_edges(graph_traits<MyGraph>::vertex_descriptor u, const MyGraph& g) and similarly in_edges(...) , vertices(...) and edges(...) functions. However, it seems that this function profile forces me to do a const_cast on g when implementing the function body since the out_edge_iterators are not const iterators, though they point to internal elements of g. I had a look at the example given in the documentation (dealing with converting LEDA graphs to the BGL), but I didn't see anything helping me on this particular issue (also, the example in the doc is a bit outdated since it uses the deprecated Boost iterator adaptors). Am I forced to rely on const_cast in these functions, or is there a way to declare my graph edges, vertices and the corresponding iterators as const in my graph_traits class ? I'm a newbie with the BGL, and more generally with this whole traits/template specialization style of programming, so please excuse me if I overlooked something obvious. Cheers.

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is_sequence
by Wolfgang Meyer 11 May '04

11 May '04

Is boost::mpl::is_sequence supposed to work with gcc 3.2.2 ? I'm trying to use it, but get "false" for boost::mpl::is_sequence<std::list<int> >::value using boost 1.31.0. The same happens with boost::mpl::has_begin. I'm working with FreeBSD 5.1. Any hints how to get it to work would be greatly appreciated. Wolfgang Meyer

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BOOST_NO_MEMBER_TEMPLATE_FRIENDS
by Witz 11 May '04

11 May '04

if the following code is commented out from visualc.hpp the standard streaming operators become available for mersenne_twister - and they seem to work fine. is this a bug or have i just been fortunate in my experimentation? #if _MSC_VER <= 1310 # define BOOST_NO_MEMBER_TEMPLATE_FRIENDS #endif ian whittley

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BGL: using an edge_descriptor as key in a map
by boost＠spyderworks.de 11 May '04

11 May '04

Hi, is it possible to use an edge_descriptor (boost::graph_traits<G>::edge_descriptor) as key in a map? I intend to write a visitor class which sets a boolean to each edge, and therefore I need the edge as key. The result of my first try is, that the compiler complains about the missing '<' operator of the key in the map. Best regards Stefan Rauch

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RE: [Boost-users] help: boost::thread and compile error
by Ben Hutchings 10 May '04

10 May '04

Guillermo Martony <gmartony(a)cue.com.uy> wrote: > Greetings, > The following code taken from an example compiles without errors: > > #include <boost/thread/thread.hpp> > #include <boost/thread/xtime.hpp> > #include <iostream> > class thread_alarm > { <snip> > }; > > int main() > { > int secs = 5; > std::cout << "setting alarm for 5 seconds..." << std::endl; > thread_alarm alarm(secs); > boost::thread thrd(alarm); > thrd.join(); > return 0; > } > > But adding a std::fstream varible to the thread_alarm class: <snip> > Results in the following compilation error: > > c:\opt\include\boost\function\function_template.hpp(289): > error C2664: 'void > boost::function0<R,Allocator>::assign_to(Functor)' : cannot convert > parameter 1 from 'const thread_alarm' to 'thread_alarm' > with > [ > R=void, > Allocator=int, > Functor=thread_alarm > ] The boost::thread constructor copies its argument, so the thread_alarm class needs to be copiable, but std::fstream is not copiable. You might be better off using Boost.Bind to produce a lightweight functor.

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