September 2006 - Boost-users - lists.preview.boost.org

Lock pointer implementation
by Mattias Brändström 11 Sep '06

11 Sep '06

Hello! I have a small class that I would like to get some feedback on. If you have the time. =) What I would like to do is to protect an instance of some class T with a mutex. It seems to me that I would be able to do this with a smart pointer that returns a proxy class, from operator->(), that locks a mutex in its constructor and unlocks it in its destrcutor. This is my intitial implementation of such a class: #include <boost/shared_ptr.hpp> #include <boost/thread.hpp> template <typename T> class LockPointer { public: class LockProxy { public: LockProxy(boost::shared_ptr<T> p, boost::shared_ptr<boost::recursive_mutex> mutex) : p_(p), lock_(new boost::recursive_mutex::scoped_lock(*mutex)) { } boost::shared_ptr<T> operator->() { return p_; } private: boost::shared_ptr<T> p_; boost::shared_ptr<boost::recursive_mutex::scoped_lock> lock_; }; LockPointer(boost::shared_ptr<T> o) : p_(o), mutex_(new boost::recursive_mutex()) { } LockProxy operator->() { return LockProxy(p_, mutex_); } private: boost::shared_ptr<T> p_; boost::shared_ptr<boost::recursive_mutex> mutex_; }; What do you think? Would this work? Would this be equivalent to locking a member mutex in each method of T (as long as all calls to an instance of T is invoked via the same LockPointer)? For some reason this is the kind of thing I would expect to find in boost, but I have not been able to. Have I missed some part of boost that I should know about? Regards, Mattias

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Properties (newbie)
by Olivier Tournaire 10 Sep '06

10 Sep '06

Hi all, I am a new boost user (2 days old ...). I just want to know a few things. 1. I use an adjacency_list with my own properties to store my graph. I just want to know if it is possible to manipulate directly the properties' values. At the moment, I use get(...) to obtain the property, make my change, and use put(...) to set the new value. 2. My graph cannot contain parallel edges, so I use a setS. However, the documentation says that listS or vecS is more efficient in time and space complexity. Is it possible to use std::vector or std::list and to disallow parallele edges ? Thanks in advance Olivier

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[string_algo] wildcard support?
by Richard Dingwall 10 Sep '06

10 Sep '06

Hi, I was wondering if boost string algorithms library has any support for "wildcard" characters (eg * and ?). If not... then I'm open to suggestions :) Cheers, Richard

4 5

having a problem seeding random number generator.
by Jim Ingram 10 Sep '06

10 Sep '06

I'm just starting out with boost, and I'm playing around with the random library. I'm writing a class that is supposed to simulate a six-sided die. It compiles and everything works, except seeding the mt19937. Every time I try testing this class, I get the same numbers, no matter what value I call my seed method with. If I use the constructor that takes a seed value, I get different numbers, but reseeding the object still doesn't seem to have any effect. Any ideas? #include <boost/random.hpp> class D6 { typedef boost::mt19937 engine_t; typedef boost::uniform_int<> dist_t; typedef boost::variate_generator<engine_t, dist_t> gen_t; public: D6() : engine(), six(1, 6), die(engine, six) { } D6(boost::uint32_t s) : engine(s), six(1, 6), die(engine, six) { } int roll() { return die(); } // This method seems to do nothing. void seed(boost::uint32_t s) { engine.seed(s); } private: engine_t engine; dist_t six; gen_t die; };

3 5

Graph library read_graphviz linker problem Visual C++ 7.1
by hadi khani 10 Sep '06

10 Sep '06

Hi everybody, First I want to point out that I am very immature with Boost library, and my problem may seem very simple for you; but I would be grateful if you help me. I am trying to use Graph library especially read_graphviz function to load a DOT file. I accomplished the following steps in Visual C++ 7.1 1. Download boost_1_33_1 2. Download bjam file for windows 3. Building libbgl-viz.lib by run "bjam "-sTOOLS=vc-7_1"" command in \boost_1_33_1\libs\graph\build folder 4. Setting path for libbgl-viz.lib and other Header file in the proper dialog Tools>Options>VC++ Directories 6. At this point I try to Build and compile one of Garaph example, cc-internet.cpp, I got a linker error for read_graphviz. Any help would be appreciated. Hadi Khani Hadi Khani --------------------------------- Get your own web address for just $1.99/1st yr. We'll help. Yahoo! Small Business.

2 1

Bizarre behaviour with Microsoft compiler
by Eric Fowler 10 Sep '06

10 Sep '06

I have a fraction of code using BGL that the MS compiler has for some reason optimized into oblivion. While this is not a boost problem per se, since it appears in a compiler I have not had problems with, I suspect all those templates are confusing the MS compiler somehow. The symptom is that when I get a property of an edge, then test on that property and branch, the test is removed from the compiled assembly. Here is the code: //header typedef property<edge_weight_t, unsigned> EdgeCountProperty; typedef adjacency_list<vecS, vecS, bidirectionalS, no_property, EdgeCountProperty> Graph; typedef graph_traits<Graph>::out_edge_iterator OutEdgeIter; ..... //code property_map<Graph, edge_weight_t>::type wgt = get(edge_weight, g); OutEdgeIter ei, ee, eMax; unsigned nTopWgt = 0; unsigned nChk = 0; for(tie(ei, ee) = out_edges(v, g), eMax = ee; ei != ee; ++ei) { nChk = wgt[*ei]; ////////This 'if' is skipped, the code acts like nChk > nTopWgt is always TRUE, even when it ain't!! if(nChk > nTopWgt); { nTopWgt = nChk; eMax = ei; } } Here is the assembly: OutEdgeIter ei, ee, eMax; 00420514 lea ecx,[ei] 00420517 call boost::detail::out_edge_iter<std::vector<boost::detail::sei_<unsigned int,std::list<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> >,std::allocator<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> > > >::iterator,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> >,std::allocator<boost::detail::sei_<unsigned int,std::list<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> >,std::allocator<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> > > >::iterator,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> > > >::iterator,unsigned int,boost::detail::edge_desc_impl<boost::bidirectional_tag,unsigned int>,int>::out_edge_iter<std::vector<boost::detail::sei_<unsigned int,std::list<boost::list_edge<unsigned int,boost::property<enum boost::e 0042051C lea ecx,[ee] 0042051F call boost::detail::out_edge_iter<std::vector<boost::detail::sei_<unsigned int,std::list<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> >,std::allocator<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> > > >::iterator,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> >,std::allocator<boost::detail::sei_<unsigned int,std::list<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> >,std::allocator<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> > > >::iterator,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> > > >::iterator,unsigned int,boost::detail::edge_desc_impl<boost::bidirectional_tag,unsigned int>,int>::out_edge_iter<std::vector<boost::detail::sei_<unsigned int,std::list<boost::list_edge<unsigned int,boost::property<enum boost::e 00420524 lea ecx,[eMax] 00420527 call boost::detail::out_edge_iter<std::vector<boost::detail::sei_<unsigned int,std::list<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> >,std::allocator<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> > > >::iterator,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> >,std::allocator<boost::detail::sei_<unsigned int,std::list<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> >,std::allocator<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> > > >::iterator,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> > > >::iterator,unsigned int,boost::detail::edge_desc_impl<boost::bidirectional_tag,unsigned int>,int>::out_edge_iter<std::vector<boost::detail::sei_<unsigned int,std::list<boost::list_edge<unsigned int,boost::property<enum boost::e unsigned nTopWgt = 0; 0042052C mov dword ptr [nTopWgt],0 unsigned nChk = 0; 00420533 mov dword ptr [nChk],0 for(tie(ei, ee) = out_edges(v, g), eMax = ee; ei != ee; ++ei) 0042053A mov eax,dword ptr [g] 0042053D push eax 0042053E mov ecx,dword ptr [v] 00420541 mov edx,dword ptr [ecx] 00420543 push edx 00420544 lea eax,[ebp-198h] 0042054A push eax 0042054B call @ILT+5420(??$out_edges@Uconfig@?$adj_list_gen@ V?$adjacency_list@UvecS@boost@@U12@UbidirectionalS@2@Uno_property@2@U ?$property@W4edge_weight_t@boost@@IUno_property@2@@2@U42@UlistS@2@@boost@@ UvecS@2@U32@UbidirectionalS@2@Uno_property@2@U?$property@ W4edge_weight_t@boost@@IUno_property@2@@2@U52@UlistS@2@@detail@boost@@ U?$bidirectional_graph_helper_with_property@Uconfig@?$adj_list_gen@ V?$adjacency_list@UvecS@boost@@U12@UbidirectionalS@2@Uno_property@2@U ?$property@W4edge_weight_t@boost@@IUno_property@2@@2@U42@UlistS@2@@boost@@ UvecS@2@U32@UbidirectionalS@2@Uno_property@2@U?$property@ W4edge_weight_t@boost@@IUno_property@2@@2@U52@UlistS@2@@detail@boost @@@4@@boost@@YA?AU?$pair@U?$out_edge_iter@Viterator@?$vector@ V?$sei_@IViterator@?$list@U?$list_edge@IU?$property@W4edge_weight_t@boost@@ IUno_property@2@@boost@@@boost@@V?$allocator@U?$list_edge@ IU?$property@W4edge_weight_t@boost@@IUno_property@2 @@boost@@@boost@@@std@@@std@@U?$property@W4edge_weight_t@boost@@ IUno_property@2@@boost@@@detail@boost@@V?$allocator@ 00420550 add esp,0Ch 00420553 push eax 00420554 lea ecx,[ee] 00420557 push ecx 00420558 lea edx,[ei] 0042055B push edx 0042055C lea eax,[ebp-1A8h] 00420562 push eax 00420563 call @ILT+4705(??$tie@U?$out_edge_iter@Viterator@?$vector@ V?$sei_@IViterator@?$list@U?$list_edge@IU?$property@W4edge_weight_t@boost@@ IUno_property@2@@boost@@@boost@@V?$allocator@U?$list_edge@ IU?$property@W4edge_weight_t@boost@@IUno_property@2 @@boost@@@boost@@@std@@@std@@U?$property@W4edge_weight_t@boost@@ IUno_property@2@@boost@@@detail@boost@@V?$allocator@V ?$sei_@IViterator@?$list@U?$list_edge@IU?$property@W4edge_weight_t@boost@@ IUno_property@2@@boost@@@boost@@V?$allocator@U?$list_edge@ IU?$property@W4edge_weight_t@boost@@IUno_property@2 @@boost@@@boost@@@std@@@std@@U?$property@W4edge_weight_t@boost@@ IUno_property@2@@boost@@@detail@boost@@@std@@@std@@ IV?$edge_desc_impl@Ubidirectional_tag@boost@@I@detail@boost@@H@detail @boost@@U123@@tuples@boost@@YA?AV?$tuple@AAU ?$out_edge_iter@Viterator@?$vector@V?$sei_@IViterator@?$list@U?$list_edge@IU ?$property@W4edge_weight_t@boost@@IUno_property@2@@boost@@@boost@@ V?$allocator@U?$list_edge@IU?$property@W4edge_weight_t@boost@@ IUno_property@2@@boost@@@boost@@@std@@@std@ 00420568 add esp,0Ch 0042056B mov ecx,eax 0042056D call @ILT+2355(??$?4U?$out_edge_iter@Viterator@?$vector@ V?$sei_@IViterator@?$list@U?$list_edge@IU?$property@W4edge_weight_t@boost@@ IUno_property@2@@boost@@@boost@@V?$allocator@U?$list_edge@ IU?$property@W4edge_weight_t@boost@@IUno_property@2 @@boost@@@boost@@@std@@@std@@U?$property@W4edge_weight_t@boost@@ IUno_property@2@@boost@@@detail@boost@@V?$allocator@V ?$sei_@IViterator@?$list@U?$list_edge@IU?$property@W4edge_weight_t@boost@@ IUno_property@2@@boost@@@boost@@V?$allocator@U?$list_edge@ IU?$property@W4edge_weight_t@boost@@IUno_property@2 @@boost@@@boost@@@std@@@std@@U?$property@W4edge_weight_t@boost@@ IUno_property@2@@boost@@@detail@boost@@@std@@@std@@ IV?$edge_desc_impl@Ubidirectional_tag@boost@@I@detail@boost@@H@detail @boost@@U012@@?$tuple@AAU?$out_edge_iter@Viterator@?$vector@ V?$sei_@IViterator@?$list@U?$list_edge@IU?$property@W4edge_weight_t@boost@@ IUno_property@2@@boost@@@boost@@V?$allocator@U?$list_edge@ IU?$property@W4edge_weight_t@boost@@IUno_property@2 @@boost@@@boost@@@std@@@std@@U?$property@W4edge_w 00420572 mov ecx,dword ptr [ee] 00420575 mov dword ptr [eMax],ecx 00420578 mov edx,dword ptr [ebp-24h] 0042057B mov dword ptr [ebp-34h],edx 0042057E jmp foo+0B8h (420588h) 00420580 lea ecx,[ei] 00420583 call boost::iterator_facade<boost::detail::out_edge_iter<std::vector<boost::detail::sei_<unsigned int,std::list<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> >,std::allocator<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> > > >::iterator,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> >,std::allocator<boost::detail::sei_<unsigned int,std::list<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> >,std::allocator<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> > > >::iterator,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> > > >::iterator,unsigned int,boost::detail::edge_desc_impl<boost::bidirectional_tag,unsigned int>,int>,boost::detail::edge_desc_impl<boost::bidirectional_tag,unsigned int>,boost::random_access_traversal_tag,bo 00420588 lea eax,[ee] 0042058B push eax 0042058C lea ecx,[ei] 0042058F push ecx 00420590 call boost::operator!=<boost::detail::out_edge_iter<std::vector<boost::detail::sei_<unsigned int,std::list<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> >,std::allocator<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> > > >::iterator,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> >,std::allocator<boost::detail::sei_<unsigned int,std::list<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> >,std::allocator<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> > > >::iterator,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> > > >::iterator,unsigned int,boost::detail::edge_desc_impl<boost::bidirectional_tag,unsigned int>,int>,boost::detail::edge_desc_impl<boost::bidirectional_tag,unsigned int>,boost::random_access_traversal_tag,boost:: 00420595 add esp,8 00420598 movzx edx,al 0042059B test edx,edx 0042059D je foo+114h (4205E4h) { nChk = wgt[*ei]; 0042059F lea eax,[ebp-180h] 004205A5 push eax 004205A6 lea ecx,[ei] 004205A9 call boost::iterator_facade<boost::detail::out_edge_iter<std::vector<boost::detail::sei_<unsigned int,std::list<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> >,std::allocator<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> > > >::iterator,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> >,std::allocator<boost::detail::sei_<unsigned int,std::list<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> >,std::allocator<boost::list_edge<unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> > > >::iterator,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property> > > >::iterator,unsigned int,boost::detail::edge_desc_impl<boost::bidirectional_tag,unsigned int>,int>,boost::detail::edge_desc_impl<boost::bidirectional_tag,unsigned int>,boost::random_access_traversal_tag,bo 004205AE sub esp,0Ch 004205B1 mov ecx,esp 004205B3 mov edx,dword ptr [eax] 004205B5 mov dword ptr [ecx],edx 004205B7 mov edx,dword ptr [eax+4] 004205BA mov dword ptr [ecx+4],edx 004205BD mov eax,dword ptr [eax+8] 004205C0 mov dword ptr [ecx+8],eax 004205C3 lea ecx,[wgt] 004205C6 call boost::adj_list_edge_property_map<boost::bidirectional_tag,unsigned int,unsigned int &,unsigned int,boost::property<enum boost::edge_weight_t,unsigned int,boost::no_property>,enum boost::edge_weight_t>::operator[] (41E2E3h) ;;LOOK MA! NO 'cmp' INSTRUCTION! WHERE'D IT GO?!!? 004205CB mov ecx,dword ptr [eax] 004205CD mov dword ptr [nChk],ecx if(nChk > nTopWgt); { nTopWgt = nChk; 004205D0 mov eax,dword ptr [nChk] 004205D3 mov dword ptr [nTopWgt],eax eMax = ei; 004205D6 mov eax,dword ptr [ei] 004205D9 mov dword ptr [eMax],eax 004205DC mov ecx,dword ptr [ebp-14h] 004205DF mov dword ptr [ebp-34h],ecx } } I repeat that this is not a boost issue per se but this bug might show up more often when compiling all those templates ... Eric

2 1

How to get a graph with edges sorted by weight (or some other property) ?
by Eric Fowler 09 Sep '06

09 Sep '06

Title says it all, I have a graph with weighted edges, and want to iterate through them in order of weights. To make it more interesting the edges are defined with setS and must be - actually, I could work around - but it would be more convenient to keep setS. A brief example would help. Thanks. Eric

2 1

[regex] Perl regex special characters
by Andriy Tylychko (mail.ru) 08 Sep '06

08 Sep '06

Hi <http://www.boost.org/libs/regex/doc/syntax_perl.html> http://www.boost.org/libs/regex/doc/syntax_perl.html says: Perl Regular Expression Syntax In Perl regular expressions, all characters match themselves except for the following special characters: .[{()\*+?|^$ Q: what about "]}" symbols? Best regards, Andriy Tylychko, telia(a)vichnavich.com www.vichnavich.com <http://www.vichnavich.com/>

3 3

How to get a graph that does not accept parallel edges?
by Eric Fowler 08 Sep '06

08 Sep '06

How do I declare a graph that does not allow parallel edges? I have come up with this but IMO it is sort of, well, kludgey: typedef adjacency_list<setS, vecS, bidirectionalS> Graph; This works because std::set does not like multiple entries. But what if for performance reasons (say) I want a listS or vecS instead of setS? In adjacency_list.hpp I find: template <> struct parallel_edge_traits<setS> { typedef disallow_parallel_edge_tag type; }; Which suggest the existence of a more elegant mechanism. Anybody know what that is? Eric

3 2

Re: [Boost-users] How to use bind/lambda in a conditional
by Baranowski, Daniel 08 Sep '06

08 Sep '06

> From: "Andriy Tylychko > > Baranowski, Daniel > > std::for_each(myVector.begin(), myVector.end(), > boost::lambda::if_then(boost::lambda::_1 == 3, [...])); > > Best regards, > Andriy Tylychko Thanks Andriy! That definitely got me on the correct track! It still took me awhile, but I got it! It looks so simple now. Anyhow, since I'm sure I'm not the only person that will ever have this problem when learning to use bind and lambda, here is a sample program that I wrote in vc8 to figure out the solution: #include <vector> #include <iostream> #include <conio.h> #include <boost/lambda/lambda.hpp> #include <boost/lambda/if.hpp> #include <boost/lambda/bind.hpp> #include <algorithm> using namespace std; using namespace boost; using boost::lambda::_1; using boost::lambda::if_then; struct MyObjectClass { MyObjectClass(int Data) : MyData(Data) { }; int GetData() const { return MyData; }; int MyData; }; class TestClass { typedef vector<MyObjectClass> t_ObjVector; t_ObjVector myVector; void PrintObj(const MyObjectClass & MyObj) { cout << MyObj.GetData() << endl; } void PrintInt(int MyInt) { cout << MyInt << endl; } public: TestClass() { myVector.push_back( MyObjectClass(1) ); myVector.push_back( MyObjectClass(2) ); myVector.push_back( MyObjectClass(2) ); myVector.push_back( MyObjectClass(3) ); myVector.push_back( MyObjectClass(3) ); myVector.push_back( MyObjectClass(4) ); } void RunTest() { // regular for loop t_ObjVector::iterator end = myVector.end(); t_ObjVector::iterator itr = myVector.begin(); for(itr; itr != end; ++itr) { if((*itr).GetData() == 3) PrintObj(*itr); } // for_each using lambda concepts for_each(myVector.begin(), myVector.end(), if_then(bind(&MyObjectClass::GetData, _1) == 3, bind(&TestClass::PrintObj, this, _1) ) ); } }; int main (int argc, char **argv) { TestClass Test; // Run the test Test.RunTest(); getch(); return 0; } Thanks again for the help! Daniel ********************************************************************************************** Disclaimer - This email and any files transmitted with it are proprietary and may contain privileged or copyright information. You must not present this message to another party without gaining permission from the sender. If you are not the intended recipient you must not copy, distribute or use this email or the information contained in it for any purpose other than to notify us. If you have received this message in error, please notify the sender immediately, and delete this email from your system. We do not guarantee that this material is free from viruses or any other defects although due care has been taken to minimize the risk. eSafe scanned this email for viruses, vandals and malicious contentAny views expressed in this message are those of the individual sender, except where the sender specifically states them to be the views of LSI. **********************************************************************************************

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