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[serialization] tuples and portable_binary_archive
by Richard Ulrich 19 Aug '10

19 Aug '10

I used boost serialize with some smaller projects, which always worked nicely. But now I want to use it on a bigger one. And I wonder why some things seem to be missing. - tuple: There is code on the Internet in various places for bridging boost::serialize with boost::tuple. But why isn't there an official version in either boost::serialize or boost::tuple? - portable_binary_archive: There are also some implementations around, one even in the examples of boost::serialization. But why is it not in the official library itself? Sure I could use the code I found, but it would feel better if it was part of the library. That's especially true for serialization where I want to be 99.99999999% sure, the data can always be read back in. Rgds Richard

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[serialization] Different behaviors between archive and its polymorphic variant
by Maxime van Noppen 19 Aug '10

19 Aug '10

Hi, I'm trying to make a custom archive class that works either with the template flavor or via the polymorphic_archive. It compiles but produces a different behavior and I can't find why. Basically I did a trivial oarchive class that overloads (via save_override) how are treated NVP. When used with the template version it works, whereas with the polymorphic version it doesn't. The code is attached. There is a preprocessor switch to choose the template or polymorphic version (-DPOLY). $ g++ poly.cc -lboost_serialization && ./a.out <name=u><name=id_>42</name=id_> </name=u> $ g++ -DPOLY poly.cc -lboost_serialization && ./a.out 42 This is with Boost 1.43 and g++ 4.5.0. I looked at various archive implementations but couldn't find any code that I could relate to this problem. Thanks, -- Maxime

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A problem in using "prim_minimum_spanning_tree.hpp"
by 王伟 19 Aug '10

19 Aug '10

Hi, I'm studying MST algorithms in GPU recently.I need BGL implementation as coparison,But I have a problem in using prim_minimum_spanning_tree.hpp.The problem is:when I use large input(e.g. >1M),the result is wrong,all the parent of vertices is "no parent".But when the input(e.g. 1K) is small,the result is noproblem. I haven't found know the reason yet.My complier is gcc 4.1.2,OS is RHEL5. Help would be appreciated. Thanks in advance. Wang wei The complete code is: #include <iostream> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/prim_minimum_spanning_tree.hpp> #include <fstream> #include <string.h> using namespace std; int main() { using namespace boost; typedef adjacency_list < vecS, vecS, undirectedS, property<vertex_distance_t, long>, property < edge_weight_t, int > > Graph; typedef std::pair < long, long >E; //read graph data from file long num_nodes,num_edges,u,v; int w; ifstream infile; infile.open("convertResult.txt"); if(!infile) { cerr<<"error:unable to open file."<<endl; return -1; } infile>>num_nodes>>num_edges; E edges[num_edges]; int weights[num_edges]; for(long i=0;i<num_edges;i++) { infile>>u>>v>>w; edges[i] = make_pair(u,v); weights[i] = w; } //construct input parameters Graph g(edges, edges + sizeof(edges) / sizeof(E), weights, num_nodes); property_map<Graph, edge_weight_t>::type weightmap = get(edge_weight, g); std::vector < graph_traits < Graph >::vertex_descriptor > p(num_vertices(g)); //call the BGL PRIM prim_minimum_spanning_tree(g, &p[0]); //output the result ofstream outfile; outfile.open("primResult.txt"); for (std::size_t i = 0; i != p.size(); ++i) if (p[i] != i) outfile<< "parent[" << i << "] = " << p[i] << std::endl; else outfile<< "parent[" << i << "] = no parent" << std::endl; return EXIT_SUCCESS; }

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[Serialization] serializing derived class through base class pointer
by Dante Stroe 19 Aug '10

19 Aug '10

Hi, I have a problem with serializing a derived classes through a pointer to a base class. I tried registering with the syntax from the documentation: |ar.template register_type<derived_one>(); | , which works well in case the derived class has a default constructor (just like the example). I just don't know what the syntax is for the case where the derived class does not have a default constructor (if I use the same syntax to register the derived class then I get a compilation error about the fact that there is no. I can provide an example in case this is not clear enough. Or, is it an absolute requirement for all derived classes to have a default constructor? Thank you and best regards, Dante

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[Filesystem] is_directory( ) for a non-existent path.
by Robert Jones 19 Aug '10

19 Aug '10

This is probably something of a shot in the dark, but somewhere between 1.33.1 and 1.37 the behaviour of is_directory() for a non-existent directory changed from failing (or throwing) in 1.33.1 to simply returning false (1.37). Can anyone enlighten me when this was. Trac references would be lovely. Thx - Rob.

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[1.43.0] Release notice
by Beman Dawes 19 Aug '10

19 Aug '10

Release 1.43.0 of the Boost C++ Libraries is now available. These open-source libraries work well with the C++ Standard Library, and are usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use. This release contains two new libraries (functional/factory, functional/forward), a major range library upgrade, plus numerous enhancements and bug fixes for other libraries. For details, including download links, see http://www.boost.org/users/news/version_1_43_0 The release can also be downloaded directly from SourceForge. See http://sourceforge.net/projects/boost/files/ To install this release on your system, see http://www.boost.org/doc/libs/1_43_0/more/getting_started/index.html Thanks to all who contributed, --The Boost release team

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[BGL] adjacency_list.hpp requires to link with serialization lib in 1.44?
by Oliver Koenig 19 Aug '10

19 Aug '10

Hello, when trying to update Boost from 1.43 to 1.44 in our code we noticed that in 1.44 we need to link to the serialization lib as soon as boost/graph/adjacency_list.hpp is included. Is this correct behavior or is this a bug? To reproduce this it is sufficient to build the following test program hello_adjacency_list.cpp (tested with MSVC-9.0): #include <iostream> #include <boost/graph/adjacency_list.hpp> int main(){ std::cout << "hello adjacency_list\n"; return 0; } With the boost build rule "exe hello_adjacency_list : hello_adjacency_list.cpp ;" compilation fails with: compile-c-c++ ..\..\..\bin\even_utils\test\graph\msvc-9.0\release\address-model-64\threading-multi\hello_adjacency_list.obj hello_adjacency_list.cpp msvc.link ..\..\..\bin\even_utils\test\graph\msvc-9.0\release\address-model-64\threading-multi\hello_adjacency_list.exe LINK : fatal error LNK1104: cannot open file 'libboost_serialization-vc90-mt-1_44.lib' Using the build rule "exe hello_adjacency_list : hello_adjacency_list.cpp /boost//serialization : <link>shared<define>BOOST_SERIALIZATION_DYN_LINK ;" everything works fine. Sincerely ok -- -------------------------------------------- Oliver Koenig Dr.sc.techn. ETH Email: koenig(a)even-ag.ch EVEN - Evolutionary Engineering AG Technoparkstrasse 1 CH-8005 Zurich Tel : +41 (0)44 500 93 60 Fax : +41 (0)44 500 93 61 Mail : info(a)even-ag.ch WWW : www.even-ag.ch -------------------------------------------- -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.

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how to detect TCP communication problems on time with synchronous operations
by Gözde Bahar KOŞ 19 Aug '10

19 Aug '10

Hello, I'm using synchronous TCP communication via asio sockets. I have following problems: First problem; When I unplug ethernet cable, "eth0: Link is Down" is written in the console, but socket.write_some command does not detect link down failure. Second problem; During socket.connect command, if I plug ethernet cable, connect command does not detect this till "Connection timed out" error occurs. If I run socket.connect again, it detects the connection. How can I detect these plug/unplug events as soon as the event occurs? Best Regards, Gözde Koş ###################################################################### Dikkat: Bu elektronik posta mesaji kisisel ve ozeldir. Eger size gonderilmediyse lutfen gondericiyi bilgilendirip mesaji siliniz. Firmamiza gelen ve giden mesajlar virus taramasindan gecirilmekte, guvenlik nedeni ile kontrol edilerek saklanmaktadir. Mesajdaki gorusler ve bakis acisi gondericiye ait olup Aselsan A.S. resmi gorusu olmak zorunda degildir. ###################################################################### Attention: This e-mail message is privileged and confidential. If you are not the intended recipient please delete the message and notify the sender. E-mails to and from the company are monitored for operational reasons and in accordance with lawful business practices. Any views or opinions presented are solely those of the author and do not necessarily represent the views of the company. ######################################################################

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Re: [Boost-users] Placeholders and iterator arithmetic in MPL
by Rob Platt 18 Aug '10

18 Aug '10

Steven Watanabe wrote: > After I included all the right headers, it compiled for me. > The only problem is that you're dereferencing past the > end of the sequence. Indeed, thank you! One of my previous attempts was written to avoid the past-the-end, or so I thought... But [slaps forehead] I somehow was thinking that reverse_iter_fold would give reverse_iterators, like those found in the STL. Whereas, next<> and prior<> always operate forwards. So, I had them mixed up. This little example does the job neatly: template<class T> struct works : reverse_iter_fold< T, vector_c<long>, push_front<_1, if_<empty<_1>, long_<0>, deref< next<_2> > > > > {}; It substitutes a long_<0> for the first step of the reverse_iter_fold, when next<> would be past the end. It could be adapted to iter_fold when using prior<>. Dave Abrahams wrote: > stylistically, may I suggest > > struct fails : reverse_iter_fold< .... > {}; You're right to correct me -- I should know that since I have the (your) book! Thank you both for your help, Rob

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Dynamic Properties and Removing Edges/Vertex
by ef 18 Aug '10

18 Aug '10

Hello, I am pretty new and inexperienced so forgive me if any of this is incorrect, any corrections would be appreciated. I am currently using Dot/Graphviz libaries of boost to create a graph. However my graph is huge, to the point where memory will run out. I have devised an algorithm to remove edges/and vertex that are unused when I am done with them. When an vertex/edge is added using read_graphviz function the following happens: the vertex/edge is added to some data structures, as well as the function add_vertex and add_edge are called. I think memory management is pretty straight forward for those situation. The issues that I think will be of some concern is that in order to map names and properties of these vertex, data is added via dynamic properties. >From what I have seen there is no way of removing information from these dynamic properties. (So even if I remove the vertex/edges there is still some residue left in the dp). My question is this correct? Are there functions to remove a certain vertex/edge dynamic property or is this done using the function remove_vertex/edge. From the source code I have seen there is no such thing. Do I need to edit the dynamic property class and make a special delete function, or am I incorrect in my thinking? Any Advice is appreciated, Thanks! EF

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