October 2008 - Boost-users - lists.preview.boost.org

Meaning of "unspecified" arguments (scoped_lock constructors)
by Mark Reginald James 31 Oct '08

31 Oct '08

Hello, I haven't been able to discover the meaning of "unspecified" in things like scoped_lock constructor parameters: http://www.boost.org/doc/libs/1_36_0/doc/html/boost/interprocess/scoped_loc… I'm trying to lock a scoped lock only if the mutex is not null. It looks like I need to use one of these "unspecified" constructors to assign the mutex but not lock it, so that I can then lock it in an "if" statement if the mutex is not null. I'd be grateful for any help.

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[boost::pool] using many pools in the application
by Roman Shmelev 31 Oct '08

31 Oct '08

Hi, Are there any thoughts if using many boost::pool objects ( from 50 to 1000 to maybe 5000 ) in my application will be efficient or not? During the "long" run my program just allocates new chunks, and the deletion of them is done in the end of the program. The reason I use boost::pool is that my simple tests showed me that boost::pool allocates memory 10x faster than standard _new_ operator. But I'm suffering that 1000 pools will cause some kind of memory fragmentation or smth like that... so maybe it will be better to use _new_ operator? I can make some another test for multiple pools, but we know that real application will act in some other way, and I cannot make a decision. P.S.:MS VS2005, XpSp2_x86, boost 1.35 (if any ideas, I'll upgrade to the newest boost version) thank you!

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[graph] predecessor_recorder and VertexList=listS
by trashing＠gmx.net 31 Oct '08

31 Oct '08

Hello list members, I've following graph: typedef adjacency_list<vecS, listS, bidirectionalS, property<vertex_distance_t, unsigned int, VertexContainer >, cPose> BGLGraph typedef graph_traits<BGLGraph>::vertex_descriptor BGLVertexDescriptor; with VertexList=listS, two vertex properties (distance map and a bundled property VertexContainer) and a bundled edge property cPose. Now I try to create a predecessor map with the predecessor_recorder but I'm not able to create a map that obtains the predecessor informations. I know I can't use std::vector<BGLVertexDescriptor> like the example (http://www.boost.org/doc/libs/1_35_0/libs/graph/example/bfs.cpp) because I use VertexList=listS. HenceI tried std::map<BGLVertexDescriptor, BGLVertexDescriptor> but this leads to another compiler error. What I'm doing wrong? greetz, Manuel -- Ist Ihr Browser Vista-kompatibel? Jetzt die neuesten Browser-Versionen downloaden: http://www.gmx.net/de/go/browser

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[Graph] newbie to graph
by Lior Weizman 31 Oct '08

31 Oct '08

I am a newbie to boost. I am trying to build a graph and to compute the max_flow using boost/graph/kolomogorov_max_flow.hpp. Blow is my code: -------------------------------------------------------------CODE------------------------------------------------------------------------------- #include <boost/config.hpp> #include <iostream> #include <string> #include <boost/graph/kolmogorov_max_flow.hpp> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/write_dimacs.hpp> int main() { using namespace boost; typedef adjacency_list_traits<vecS, vecS, directedS> Traits; typedef adjacency_list<vecS, vecS, directedS, property<vertex_name_t, std::string>, property<edge_capacity_t, long, property<edge_residual_capacity_t, long, property<edge_reverse_t, Traits::edge_descriptor> > > > Graph; typedef graph_traits <Graph>::edge_descriptor edge_descriptor; typedef Traits::vertex_descriptor vertex_descriptor; typedef std::pair<edge_descriptor, bool> EdgePair; typedef std::pair<int,int> Pair; Graph g; long flow; property_map<Graph, vertex_name_t>::type name = get(vertex_name, g); property_map<Graph, edge_capacity_t>::type capacity = get(edge_capacity, g); property_map<Graph, edge_reverse_t>::type rev = get(edge_reverse, g); property_map<Graph, edge_residual_capacity_t>::type residual_capacity = get(edge_residual_capacity, g); vertex_descriptor s, t; Pair edge_array[6] = { Pair(0,1), Pair(0,2), Pair(0,3), Pair(2,4), Pair(1,3), Pair(4,3), }; EdgePair edge_desc_obj; EdgePair edge_from_first=add_edge(edge_array[0].first,edge_array[0].second,g); put(capacity,edge_from_first.first,1); for (int i = 1; i < 5; ++i){ edge_desc_obj=add_edge(edge_array[i].first, edge_array[i].second,g); put(capacity,edge_desc_obj.first,i+1); } EdgePair edge_to_last=add_edge(edge_array[5].first,edge_array[5].second,g); put(capacity,edge_to_last.first,4); char str[2]; for (int i=0;i<5;++i) { sprintf(str,"%d",i); put(name,i,str); } edge_descriptor from_s,to_t; from_s=edge_from_first.first; to_t=edge_to_last.first; s=source(from_s,g); t=target(to_t,g); flow = kolmogorov_max_flow(g, s, t); return 0; } ---------------------------------------------------------------------END OF CODE--------------------------------------------------------------- The compilation output of the code above includes errors and can be found here: http://www.cs.huji.ac.il/~lweizm45/compile_output.txt if I remove the call to kolmogorv_max_flow, everyting is fine. If I replace the call to kolmogorov_max_flow with the line: write_dimacs_max_flow(g, capacity, identity_property_map(),s, t, std::cout); The output is: -------------------------------------- OUTPUT ------------------------------------------------------ c DIMACS max-flow file generated from boost::write_dimacs_max_flow p max 5 6 n 1 s n 4 t a 1 2 1 a 1 3 2 a 1 4 3 a 2 4 5 a 3 5 4 a 5 4 4 ---------------------------------------- END OF OUTPUT -------------------------------------------------- Which means that the graph was created correctly. Calling the example "libs/graph/example/kolmogorov-eg.cpp" with the dimacs output above as input, also works fine. This fact leads me to the assumption that my graph is fine. Does anyone know what is wrong with my graph when I perform a direct call to kolmogorov_max_flow? Thanks, Lior

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auto_link.hpp
by Ryan McConnehey 31 Oct '08

31 Oct '08

Currently, the auto_link.hpp helps users declare a library in their header files. For example: #define BOOST_LIB_NAME boostlibrary #define BOOST_AUTO_LINK_NOMANGLE #include <boost/config/auto_link.hpp> The header file that declares this will search the library include path for a boostlibrary.lib. This is great if all versions of one's libraries have the same name. This would mean the libraries would need to be separated into different folders. To be able to place all of the versions of a library into the same folder, one would need to turn the mangling off and search for the library. The header would then be as follows: #define BOOST_LIB_NAME boostlibrary #include <boost/config/auto_link.hpp> This means one would rely on how boost mangles the name of the library. For the most part, I don't mind how this is done, however, I would like to specify my own version number for the library. Is there a way to do this or do I need to copy the entire file into my own directory and replace BOOST_LIB_VERSION with another define for my library? Ryan

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Asio Protocol Decoder interfaces/templates
by Rodrigo Madera 31 Oct '08

31 Oct '08

Hello all, I was wondering if Boost Asio has any plans to have a structure such as Apache MINA's xxxEncoder/xxxDecoder (which are for Java). This kind of interface (for those who don't know them yet) allow you to write code such as: (Warning: very bad {and simplistic} example ahead) class commands::echo : public message_decoder { somewhere("echo"); } class commands::cls : public message_decoder { somewhere("cls"); } ... class commands::exit : public message_decoder { somewhere("exit"); } class my_protocol_decoder : public protocol_decoder { ctor() { add(echo); add(cls); ... add(exit); } }; And that would give us a nice protocol decoder that we can plug into a family of "decoding-friendly" classes. Apache MINA does a great job doing this and maybe there is something that can be extracted into Boost Asio. Please tell me what you think or if I'm completely mad to want this or even if I'm asking on the wrong place. Thank you all!! Rodrigo Madera =o)

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Main thread not exiting
by developer1 31 Oct '08

31 Oct '08

Hi, I have created a thread pool library which maintains a worker thread queue and a work queue. Any Application class using this library passes functors to ThreadPool. I am using a ThreadGroup to manage all threads. I use the thread_group.join_all(), to wait for all threads to finish before the main thread exits. But on joining the threads in the thread_group, the main thread fails to exit. Am i missing something. -- View this message in context: http://www.nabble.com/Main-thread-not-exiting-tp20264225p20264225.html Sent from the Boost - Users mailing list archive at Nabble.com.

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How to find: best integer type for processor
by Daryle Walker 31 Oct '08

31 Oct '08

Is there a macro and/or typedef that will tell me bit-length used for a processor and/or the best integer type for said processor? The "int" type is supposed to be that type, and it was in the 16- and 32- bit eras. (I learned C programming with the former in the... early 1990s!) However, the powers-that-be decided, for "backwards compatibility," to freeze "int" and "long" at 32 bits and use a new type, "long long," for 64 bits, which should be the optimized integer type for 64-bit processors. (If they kept to the plan, "int" would be 64 bits, "long" either 64 or 128, "short" up to 32, and the new type will be "short short" at 16.) I want to know the best type so, when I build multi-integer arrays for various purposes, I don't pick an element type that causes a slow down, whether to focus on a fraction of a register (if the chosen type is too small) to handle two registers at once (if the chosen type is too large). -- Daryle Walker Mac, Internet, and Video Game Junkie darylew AT hotmail DOT com

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[multi-index] Container of polymorphic pointers
by Daniel Dilts 31 Oct '08

31 Oct '08

I'm am using boost::multi_index to hold a set of polymorphic entities. Due to efficiency concerns, I have to be able sort the container based on actual type. I was planning on sorting based on the return result of typeid. When I try this I get errors in <functional>. I am using VC++ 2005 Standard Edition SP1. What am I doing wrong, or, what is a better way of accomplishing what I am trying to do? #ifndef ENTITIES_ENTITYCONTAINER_H_ #define ENTITIES_ENTITYCONTAINER_H_ #include <boost/multi_index_container.hpp> #include <boost/multi_index/ordered_index.hpp> #include "Entity.h" namespace Entities { struct type{}; struct extractType { typedef const type_info& result_type; result_type operator()(const Entity * r)const // operator() must be const { return typeid(*r); } }; typedef boost::multi_index::multi_index_container< Entity *, boost::multi_index::indexed_by< boost::multi_index::ordered_non_unique<boost::multi_index::tag<type>, extractType> > > EntityContainer; }; #endif

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warning C4005: 'AF_IPX' : macro redefinition" +"ws2def.h" (converting from MS 6.0 to MS 2008 (9.0))
by Joseph Marks 30 Oct '08

30 Oct '08

RE: http://lists.boost.org/boost-users/2007/11/31965.php I don't see any public answer to this. What is the best solution. On another site, someone recommended: #define WIN32_LEAN_AND_MEAN And/or #define _WINSOCKAPI_ However, this solution did not work for me. Has anyone solved this problem? Thanks in Advance, Joseph [brand new to this list] The preceding e-mail message (including any attachments) contains information that may be confidential, or constitute non-public information. It is intended only for the designated recipient. If you are not the named addressee, you should not disseminate, distribute or copy this e-mail. If you have received this e-mail by mistake, please notify the sender immediately by replying to this message and delete this e-mail from your system. Use, dissemination, distribution or reproduction of this message by unintended recipients is not authorized and may be unlawful.

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