March 2005 - Boost-users - lists.boost.org

RE: [Boost-users] Weird behaviour when changing states in boost::fsm
by Darryl Green 02 Mar '05

02 Mar '05

Hi Jan, > -----Original Message----- > [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Jan Eickmann > Subject: [Boost-users] Weird behaviour when changing states > in boost::fsm > > I have a parent state which has two substates. One is basicly > a noop as > InnerInitial, the other is and OptionsDialog. > Now, in a custom_reaction's react function in the parent > state, I call > transit<OptionsDialog> in order to go to the OptionsDialog-substate. > What happens is that the parentstate itself is destroyed and > reentered, > then it enters the OptionsDialog state. > Something similar happens when I use transit<ParentState> to > go back to > the ParentState (which should automatically enter the InnerInitial, > no?). It exits the OptionsDialog, then exits ParentState and reenters > ParentState (I haven't checked if it enters the InnerInitial). > If in the OptionsDialog, I do a transit<NoOpInnerInitial> it > just goes > there without first destroying the parent-state (just exits > OptionsDialog but not ParentState). > > Is this the expected behaviour, if so, could someone explain > how to get > the desired behaviour? Yes it is expected. See transit() in reference. In summary, calling transit will always exit the current state, and keep exiting back to the icos of the current state and the final state, then work in again from there to reach the destination state. Note tht exit = destruct, enter = construct. There isn't enough information to properly answer your question. For a start I don't properly understand your fsm, or whether this is just a minimal example to illustrate your problem. The obvious answer is that you should just make the inner states react to the event you currently have the parent reacting to. Using the form of custom reaction that allows a transition context and member function to be specified, you can make the transition context the parent state and a member function of the parent can perform action. Of course, if your reason for using a custom reaction is to implement some form of guard, this won't entirely solve the problem. The other way to look at this is to see if you can replace the guard with more states/events (the reaction to the original event conditionally produces the appropriate more specific event to cause the correct action and final state). hth Darryl. ########################################################################## This e-mail is for the use of the intended recipient(s) only. If you have received this e-mail in error, please notify the sender immediately and then delete it. If you are not the intended recipient, you must not use, disclose or distribute this e-mail without the author's prior permission. We have taken precautions to minimise the risk of transmitting software viruses, but we advise you to carry out your own virus checks on any attachment to this message. We cannot accept liability for any loss or damage caused by software viruses. ##########################################################################

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Debugging a graph visitor
by Stephen Torri 02 Mar '05

02 Mar '05

I am using the default depth_first_search visitor with an graph setup as follows: typedef property< vertex_index_t, uint32_t, property< vertex_name_t, boost::shared_ptr<Component> > > VertexProperty; typedef adjacency_list<setS, // OutEdgeList setS, // VertexList directedS, // Directed VertexProperty> // VertexProperties Graph_Type; typedef graph_traits<Graph_Base::Graph_Type>::vertex_descriptor Vertex; typedef graph_traits<Graph_Base::Graph_Type>::edge_descriptor Edge; The graph contains Component class objects. I want to visit each Component and execute the function run(). The test graph I have is a simple two node graph: node A ---> node B When I use the depth_first_search with my visitor I see that it only visits node A. I do not know why this is the case. I have only implemented the discover_vertex function in it. I have std::cout messages for telling me various steps of run() have been done. I cannot see how to have the visitor say what its doing (e.g. "I'm in node A. Executing run(). Considering moving to node B). What I need assistance on is how do I debug my visitor? I am only sending the graph and the visitor to my call to depth_first_search: // Let Graph Visitor run through the Graph // (visit Input graph) depth_first_search (test_graph_ptr->get_Graph(), visitor(vis)); Stephen

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Re: bjam seg faulting on mac os x 10.3.8
by Andy Espenscheid 02 Mar '05

02 Mar '05

yep, I discovered the $TOP issue yesterday. Had it set as a convienence for another project. Good to know I'm not alone. Thanks for the reply. Andy. > > Message: 1 > Date: Mon, 28 Feb 2005 10:59:40 -0800 > From: "junyi.sun(a)supportlinux.net" <junyi.sun(a)supportlinux.net> > Subject: re: [Boost-users] bjam seg faulting on mac os x 10.3.8 > To: boost-users(a)lists.boost.org > Message-ID: <5.1.0.14.2.20050228104802.00b90540(a)10.0.0.63> > Content-Type: text/plain; charset="us-ascii"; format=flowed > > I saw bjam got segmentation fault with bjam 3.1.10 + boost 1.32 + gcc 3.3.3 > + fedora 2. > After playing it around on different environment, I found that I can always > reproduce the problem when I set environment variable $TOP for my own > development CVS. Once I removed the environment variable $TOP ( I was using > bash shell: run "unset TOP" ), the problem is gone. > I hope this might help. > - Junyi Sun > > From: boost-users-bounces(a)lists.boost.org > [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Andy Espenscheid > Sent: Sunday, February 27, 2005 8:46 PM > To: boost-users(a)lists.boost.org > Subject: [Boost-users] bjam seg faulting on mac os x 10.3.8 > > I am trying to compile boost 1.32.0 on MacOSX 10.3.8 and getting a > Segmentation Fault immediately from bjam immediately. I'm using gcc 3.3. > bjam is crashing with a EXC_BAD_ADDRESS exception. I compiled bjam from the > boost distribution but it has the same behavior. Any pointers would be > greatly appreciated. Seems like I'm doing somehthing dumb. Also, are > binaries available via fink? I seached with fink 0.71 but couldn't find > anything. Thx. >

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Strange error...
by Jason House 01 Mar '05

01 Mar '05

Code that was compiled and tested on windows is now getting ported to unix (by another organization). I'm a bit puzzled by the following error message they are getting: /op_models/FCS_SOSv1.0_Scenarios_v10.5/FCS_SDD/CabWnwSrwPoP.opt32.s1.nt.so: symbol __1cFboostGdetailUsp_counted_base_impl4CpnXtransaction_reservation4nHslot_id_nYchannel_reservation_type___n0APchecked_deleter4n0E____G__vtbl_: referenced symbol not found I believe that it is looking for the implementation of boost::shared_ptr<transaction_reservation<slot_id,channel_reservation_type> Any hints as to what could be wrong? I did not include source code because I suspect the problem is more basic than that. When I asked which compiler was used, he replied "All I know is that we are using SunPro 5.4 for the compiler." -- Jason. 732-578-6378

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[serialization] problem with Borland C++ Builder 6
by Pablo Aguilar 01 Mar '05

01 Mar '05

Hi, I've just started using the serialization library, and am trying to do so with BC++6. If I'm right, it should work just as long as I remove support for xml archives (because Spirit doesn't work on BC++) I've a class Cliente which has an appropriate serialize member fxn. And a manager class called Clientes which stores a std::vector<boost::shared_ptr<Cliente> > When doing: void Clientes::serialize(Archive& ar, unsigned const version) { ar & m_imp->m_clientes; // where m_imp is a pimpl-style struct // m_clientes is of the type specified above } (this is trimmed down code, I can post the original if required) I get the following error: [C++ Error] serialization.hpp(121): E2015 Ambiguity between 'boost::serialization::void serialize< boost::archive::text_iarchive , boost::shared_ptr<cc::servidor::Cliente> > ( boost::archive::text_iarchive & , _STL::vector<boost::shared_ptr<cc::servidor::Cliente> > & , const unsigned int )' and 'boost::serialization::void serialize< boost::archive::text_iarchive , _STL::vector<boost::shared_ptr<cc::servidor::Cliente> > >( boost::archive::text_iarchive & , _STL::vector<boost::shared_ptr<cc::servidor::Cliente> > & , const unsigned int )' (I removed the allocator parts to make the message clearer) So the question is, how do I remove the ambiguity? Thanks for your help... Pablo Aguilar

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boost::indirect_iterator
by Matthias Kaeppler 01 Mar '05

01 Mar '05

Consider this code: vector<int> coll; // ... push back some values vector<int*> ptrcoll; // ... push back pointers to the values of coll indirect_iterator< vector<int*>::iterator > begin(ptrcoll.begin()), end(ptrcoll.end()); sort( begin, end, less<int> ); -- My question: After the sort statement, coll is sorted, right? (and ptrcoll is not). However, I need to sort a vector of pointers according to a predicate which applies to non-pointers. In this case, I want to sort ptrcoll, according to the less-relation on the pointees in coll. How can I achieve that? -- Matthias Kaeppler

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[optional] new assignmet semantic and references
by Fernando Cacciola 01 Mar '05

01 Mar '05

{This is copy of a message on the developers list that needs attention from Boost.Optional Users} Hello people, A few days ago, a problem with Boot.Optional's assignment not properly handling aliasing scenarios (like self assignment) was pointed out. We concluded that the solution was to use T's operator=() directly instead of the Destroy+Construct pattern that I was using. I changed the code, tested it, and I was updating the documentation when I recalled the following long-standing issue: Currently, with the Destroy+Construct pattern, references are re-bound in case of assignment: int a = 123 ; int b = 456 ; int& ra = a ; int& rb = rb ; optional<int&> ora(ra); optional<int&> orb(rb); ora = orb ; // now 'ora' contains a reference to 'b' instead of 'a' b = 789 ; cout << *ora ; Prints 789 cout << a ; Prints 123 This is not the way assignment of reference types work in C++: ra = rb ; // The value of 'a' referenced by 'ra' is changed, not the reference itself. cout << a ; Prints 789 This error in the way optional<T&> treated assignment of reference types was pointed out by Joel de Guzman long ago when he started using Optional in Spirit. However, at the time, Joel explicitely asked me not to change this and keep the current rebinding semantics in order to minimize any impact in Spitit itself (which certainly has, o had, a much larger user base). If I change the code now to use T's operator=(), assignment of optional<T&> will have a _radically_ different semantics. A correct one, that's for sure, but end user code might be fundamentally impacted. Note: if you look at Optional documentation you will discover that assignment is only documented for T not being of reference type. This was intentional.. I left this undocumented becasue I knew back then that the current semantics were wrong but I couldn't fix it at the time because Spirit was (or could be) depending on it; yet I didn't want other users to depend on it as well... Of course, users could have "discovered" the (incorrect) semantics themselves and now rely on it, but I hope that the intentionally missing documentation served to keep the amount of users depending on this incorrect semantics very low. [At least it served _me_ to remember about this since I had forgotten] I really want to 'fix' this, i.e, give it correct semantics, so unless Joel or anyone else speaks now I'll move on, finish the documentation updates and commit the new version. Best, Fernando Cacciola P.S: Joel already agreed in the developers list that this needs to be fixed.

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at<AssocSeq,Key,Default>
by Lemings, Eric B. (Contr) 01 Mar '05

01 Mar '05

Where is at<AssocSeq,Key,Default>' defined in MPL? I can't find the header file that defines it. Thanks, Eric.

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date_time: UTC to local time conversion
by Cory Nelson 01 Mar '05

01 Mar '05

Is there a function in date_time to do UTC to local time conversions? -- Cory Nelson http://www.int64.org

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