- Boost-users - lists.boost.org

execution order of slots (signals)
by oliver.kowalke＠t-online.de 02 Aug '04

02 Aug '04

Hello, if I create a signal sig with n slots (slots are ordered by group). What happens if : - I call sig(); and the first called slot removes the slot which is its successor - I call sig(); and the first slot connects a new slot to signal which has a higher priority (group -> higher values are executed at first) with best regards, Oliver -- "Der Spezialist ist ein Barbar, dessen Unwissenheit nicht allumfassend ist." Master's Voice, S.LEM

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RE: [Boost-users] Window API
by Ben Hutchings 02 Aug '04

02 Aug '04

Dr Jekyll <drjekyll(a)empirics.net> wrote: > Hi, > I use a library, which itself use Boost. This library define > > #define Handle boost::shared_ptr Ugh. > But because I intende to use WINAPI , this definition results > in a conflict > > c:\Program Files\Microsoft Visual Studio .NET > 2003\Vc7\PlatformSDK\Include\WinUser.h(3282): error C2751: > 'boost::shared_ptr' : the name of a function parameter cannot > be qualified <snip> > What should I do, if I have to keep the #define line in my library... Don't use that library. Its code quality is so low that you will probably waste more time working around its bugs then you can save by using it. If you disagree with this assessment, perhaps you could write and use a wrapper header that does something like: #ifndef LIBRARY_WRAPPER_H #define LIBRARY_WRAPPER_H #include "library.h" #undef Handle // undefine any other unwanted macros #endif // !defined(LIBRARY_WRAPPER_H)

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lambda and shared_ptr
by Vladimir Krasovsky 02 Aug '04

02 Aug '04

Hello boost-users(a)lists.boost.org, It seems to me that currently lambda's bind does not support shared_ptr as a second argument to bind, when first argument is a pointer-to-member. But boost::bind handles it perfectly. It would be nice for me to be able to write something like this: using namespace boost::lambda; struct SomeClass { int member1; }; boost::shared_ptr<SomeClass> ptr(new SomeClass); (bind(&SomeClass::member1, ptr) = _1)(5); Is it possible with current implementation of lambda? Or I have missed something important? -- Best regards, Vladimir mailto:vkrasovsky@yandex.ru

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[Help on implementation of boost regex]
by hackervalley 02 Aug '04

02 Aug '04

Hello, I try to use boost regex . I don't have a lot of experience of using boost regex . Boost regex examples aren't so explicit for me. So I need some help to parse this example file. Point(1) = {0,0,0,0.1}; Point(2) = {1,0,0,0.1}; Point(3) = {0,1,0,0.1}; Point(4) = {1,1,0,0.1}; Line(1) = {1,2}; Line(2) = {2,4}; Line(3) = {4,3}; Line(4) = {3,1}; Line Loop(5) = {2,3,4,1}; Plane Surface(6) = {5}; I can't read each informations to use it after. I can't match for use IdentificationNumber of Point(IdentificationNumber). Actually my code look so : /* g++ -Wall -O2 -o ifstream ifstream.cc */ #include <iostream> #include <fstream> #include <string> /* boost regex header */ #include <boost/regex.hpp> using namespace std; using namespace boost; int main (int argc, char argv[]) { char buffer[256]; string filename; string inputstring; cout << "Input filename "; cin >> filename; ifstream readfile (filename.c_str (), ios::in); if (!readfile.is_open ()) { cout << "Error opening file" << endl; return 0; } regex exPoint ("Point"); regex exLine ("Line"); regex IdentificationNumber ("[:digit:]"); while (!readfile.eof ()) { readfile.getline (buffer, 200); inputstring = buffer; if (regex_search (inputstring, exPoint)) { cout << "Point" << endl; smatch result; if (regex_search (inputstring, result, IdentificationNumber)) { cout << "Identification Number " << result << endl; } else cout << "Error regex_match" << endl; } if (regex_search (inputstring, exLine)) { cout << "Line" << endl; } cout << buffer << endl; } readfile.close (); return (0); } Thank you for help. Best regards hackervalley http://hackervalley.free.fr

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Accessing Internal Properties
by Jeffrey Holle 02 Aug '04

02 Aug '04

I'm using BGL checked out of CVS on Tue Jun 29 05:25:17 EDT 2004. Also using gcc 3.4.1 on a linux machine. I've a question of how to access internal properties. It appears that there are basically two templated function families for this: get - returns a value get_property_iter_range - returns iterator range get_property - returns a reference Are there more? I'm interested in the later. I've seen in the examples get_property being used to access properties global to a graph, but not edge or vertex properties. What I'd like to see is a varient of get_property (or equivalent) that takes an edge descriptor, so it provides access to a particular edge's named property. Does what I'm looking for exist?

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using boost::shared_ptr with boost::signal
by oliver.kowalke＠t-online.de 01 Aug '04

01 Aug '04

Hi, I want to use boost::shared_ptr with boost::signal. class A { private: int _i; public: A() : _i( 0) {} void operator()( int, std::string & s) { i+= 1; } void operator()( std::string & s, int) { i+= 2; } }; boost::shared_ptr< A > a( new A() ); boost::signal< void( int, std::string &) > rsig; boost::singal< void( std::string &, int) > lsig; rsig.connect( a); lsig.connect( a); rsig(0,"called from right side"); lsig("called from left side",0); Because a is a smart_ptr this code would not compile because operator() is not a member function. If I dereference the smart pointer when I connect to signal, changes of a are never know by the other signal instance. Maybe I can use a proxy class which aggregates the smart pointer but maybe there is a better solution?! with best regards, Oliver -- "Der Spezialist ist ein Barbar, dessen Unwissenheit nicht allumfassend ist." Master's Voice, S.LEM

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boost.graph external properties question.
by Jeffrey Holle 01 Aug '04

01 Aug '04

HI, I'm starting a project that uses boost.graph and I'm trying to decide if I should use internal or external properties. My code that implements external properties is like, for example: typedef boost::graph_traits <GraphT>::vertex_descriptor Vertex; typedef std::map<Vertex,Vertex_Datum,ltDescriptor<Vertex> > VertexData; My question is: Given my use of Vertex as a key of a std::map, it needs to be unique. Is this uniqueness quality maintained across different graphs? That is, can I instanciate 2 GraphT objects and populate both, but maintain only one VertexData container? Assume that I am not defining any internal properties in GraphT.

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Vertex properties in BGL
by Ralph Wessel 01 Aug '04

01 Aug '04

I would like to use the BGL for a project I'm working on, but I haven't been able to find a particular piece of information. The system I'm modeling can be easily represented by a directed graph, but it seems that an essential vertex property can only be calculated on the fly based on the current in-edge and out-edge as the graph is traversed. Can this be supported in the BGL in a way which can feed this vertex property to the supplied algorithms?

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[HELP]How can I print a name of a node in a graph?
by Daniele Carlucci 01 Aug '04

01 Aug '04

Hi everybody, I wanna to print a graph but instead the id I want to print the name of the same. How can I make? I have token the list of the nodes from a list i. In i.name I have the name of the node. The code that I used to initialize the graph is: template <class Graph> void print(Graph& g) { typename Graph::vertex_iterator i, end; typename Graph::out_edge_iterator ei, edge_end; for(boost::tie(i,end) = vertices(g); i != end; ++i) { if (*i!=0){ cout<< *i << " --> "; for (boost::tie(ei,edge_end) = out_edges(*i, g); ei != edge_end; ++ei) cout << target(*ei, g) << " "; cout << endl;} } } void Main() { int nodo, cont, a; nodo=1; typedef graph_traits < file_dep_graph >::vertices_size_type size_type; size_type n_vertices; //Setta n_vertices con il numero di nodi n_vertices=id; // legge il numero di nodi file_dep_graph g(n_vertices); for (i=list.begin(); i != list.end(); ++i) { size_type k; for (cont=0; cont<(*i).v.size(); cont++) { a=(*i).v[cont]; //Connection between node "cont" and all the other nodes add_edge((*i).PID, a, g); } } print(g); Thanks Daniele

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Re: Way to print a route between two nodes
by Gustavo Sÿffffe1nchez 01 Aug '04

01 Aug '04

I don't know exactly how you are traversing those nodes in the path, - ie how do find the path -, but as far as I know you have to use a visitor with an algorithm such as dijisktra shortest paths, so you define the event point, on_finish_vertex for example where you want the visitor to be called. This algorithm also stores in a vector the minimum weight pahts encountered from an specific origin vertex so you can go over those paths from the last vertex to this origin. Hope to be of help ------------------------------ Message: 10 Date: Thu, 29 Jul 2004 15:33:34 +0200 From: Daniele Carlucci Subject: [Boost-users] Way to print a route between two nodes To: boost-users(a)lists.boost.org Message-ID: <4108FCAE.8040301(a)email.it> Content-Type: text/plain; charset=us-ascii; format=flowed Hi all, there is a way to print a route between two nodes? If I have for ie: 8 nodes. A possible route is 1->3->2->6->8 How can I print it? I have only seen that it's used the way to print for every node, all the nodes near that one. Thanks Daniele ------------------------------ ---------------------------------

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