June 2002 - Boost-users - lists.boost.org

Trouble with tuple
by marshjray 24 Jun '02

24 Jun '02

Using 1.28.0, in source file "boost/tuple/detail/tuple_basic_no_partial_spec.hpp" (line 651), notice the transposition of <T5> and <T6>: return make_tuple(detail::assign_to_pointee<T1>(&t1), detail::assign_to_pointee<T2>(&t2), detail::assign_to_pointee<T3>(&t3), detail::assign_to_pointee<T4>(&t4), detail::assign_to_pointee<T6>(&t5), <---- detail::assign_to_pointee<T5>(&t6)); <---- Looks like a typo? Thanks, - Marsh

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Boost::Signal ?
by srivatsan raghavan 21 Jun '02

21 Jun '02

hi all, i was looking thru the boost cvs recently, and i saw a signals & slots implementation in the cvs, but as far as i can tell, it's not a part of the standard boost libs.. anyone know it's fate, and if there are plans to include it in the next boost release? __________________________________________________ Do You Yahoo!? Yahoo! - Official partner of 2002 FIFA World Cup http://fifaworldcup.yahoo.com

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Thread Priority
by Tobias McNulty 19 Jun '02

19 Jun '02

Is getting/setting thread priority implemented in boost threads? I didn't see any mention of it on the web site, other than the behavior of mutexes under Priority Driven scheduling. Thanks, Toby -- Tobias McNulty Data Description, Inc. 840 Hanshaw Road, Suite 9 Ithaca, NY 14850 Phone: (607) 257-1000 E-mail: tmcnulty(a)datadesk.com Web: www.datadesk.com

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scoped_lock
by tmcnulty1982 19 Jun '02

19 Jun '02

boost::recursive_mutex::scoped_lock is crashing with some unknown exception in its destructor, no matter whether the lock is locked or not. Has anyone else experienced this problem and possibly have a solution? Thanks, Toby

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MS VS 6: passing boost::shared_ptr<T> to a dll function
by lognez 19 Jun '02

19 Jun '02

Hi all, I am trying to pass a smart pointer (boost::shared_ptr<T>) as an argument to a function that is implemented by a dll and called by an executable, but whenever I execute the application, it goes into a loop, no matter what the type of T is. When the function is implemented in the exe or when the function is called from inside the dll it works fine. Does anybody have a clue what could be happening? BTW, I'm not implicating a bug in boost, I know that it could as well be a MS VC++ bug but I would just like to know how this comes and how I can solve it. Corno PS I've tried to post this message directly to the newsgroup but that did not work. Is that news group perhaps read only?

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boost::threads - a few more questions....
by Peter 18 Jun '02

18 Jun '02

I have a few more questions regarding boost::threads: 1) Is is at all possible to get a return value from a function which was passed into a thread - for example after calling thread.join() ?? 2) Assuming that I create a thread from within another thread ( for exaple: from within the "main" thread - main()); is there a mechanism for that newly created thread to notify my "main" thread that it has finished execution?? Is there some sort of library (I am looking for something platform independent) which would allow me to do that?? 3) I would lie to run two threads in a client application. One would be responsible for receiving and the other for sending data. The threads would basically run in infinite loops. Both sending and receiving would be done to/from the SAME socket. My question is: Do i still have to lock the mutex during each opperation?? I have been doing a LOT of testing WITHOUT locking it and have not had my program crash (yet). Is that because the kernel (running win2000 and using the winsock API) is somehow dealing with all the overhead of locking/unlocking the socket, or have I just been lucky?? Thanks in advance for any suggestions. Best to you all Peter

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RE: [Boost-Users] boost::threads queation
by Mark Storer 18 Jun '02

18 Jun '02

This has little to do with boost (which, again, is why I can answer; at least in part) A member function cannot be addressed like a regular function. Ask yourself this question: With just a function pointer to go by, what will the compiler use for 'this'? The Good News: STL contains a template functor to take care of this for you: "std::mem_fun". I haven't messed with it personally, but the docs sure make it sound like it would do the trick. The Bad News: I'm not so sure the thread class will let you use it. I'm not familiar with the function0<> template, so I don't know whether or not std::mem_fun will work with boost::thread. Anybody care to chime in here? --Mark Storer Software Engineer Cardiff Software #include <disclaimer> typedef std::disclaimer<Cardiff> Discard; -----Original Message----- From: Peter [mailto:yg-boost-users@m.gmane.org] Sent: Monday, June 17, 2002 9:09 PM To: boost-users(a)yahoogroups.com Subject: [Boost-Users] boost::threads queation Is it possible to pass a pointer of a class member function into a thread ?? I have no problems passing functions (or pointers to functions rather) which are not members of any classes. However when I try to pass member functions, I get compile errors. I am using MSVS 6.0 on win 2000. The following is a simplified model of my situation. I am trying to create a thread inside a function of one class and pass into it, a pointer of a member function of another class: // all necessary includes; class testClass1 { public: // constructor testClass1() { // init code} ~testClass1() {} void fun1() { // some code} }; class testClass2 { testClass2() { // init code} ~testClass2() {} // SEE HERE PLEASE void fun2() { // some code.. boost::thread myThread(&object1.fun1) ; // PROBLEM HERE // more code... } testClass1 object1; }; int main(int argc, char **argv) { testClass2 class2; // some code... class2.fun2(); // more code.... return 0; } Any help would be greatly appreciated. Thanks in advance. Peter Info: <http://www.boost.org> Wiki: <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl> Unsubscribe: <mailto:boost-users-unsubscribe@yahoogroups.com> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

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Re: [Boost-Users] MS VS 6: passing boost::shared_ptr<T> to a dll function
by Peter Dimov 18 Jun '02

18 Jun '02

Your problem was that the EXE was using the single-threaded runtime, but the DLL has been set to multithreaded. The mutex lock in the DLL was spinning forever. When I set both to multi-threaded, it works, even with different heaps. Interesting issue. It can be made to work even in this case but this will cost performance. ----- Original Message ----- From: <corno(a)dds.nl> To: "Peter Dimov" <pdimov(a)mmltd.net> Sent: Tuesday, June 18, 2002 13:52 Subject: Re: [Boost-Users] MS VS 6: passing boost::shared_ptr<T> to a dll function > hmmmm.... > 2nd try :) > > > Did you forget the attachment? ;-) > > > > ----- Original Message ----- > > From: <corno(a)dds.nl> > > To: <pdimov(a)mmltd.net> > > Sent: Tuesday, June 18, 2002 0:39 > > Subject: Re: [Boost-Users] MS VS 6: passing boost::shared_ptr<T> to a dll > > function > > > > > > > > > > > > Thanx Craig, that turned out to be the problem for VC++ as well. > > > > > > > > Yep, but shared_ptr is supposed to work in this case, in theory. ;-) > > I'll > > > > look into this. Any more information that can help me find the problem? > > > > > > > > > > Peter, > > > > > > I made 2 small projects that illustrate the problem. (change the path to > > the > > > boost lib ofcourse) > > > It can very likely be that I am doing something terribly stupid :) but > > anyways, > > > here's what I see; > > > > > > If I build and run it with a single memory manager I see output for all 4 > > steps. > > > If I build and run it with separated memory managers I see output for > > step > > 1 > > > and 2 only and then it hangs. > > > > > > Corno > > > > > > > > > > >

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boost::threads queation
by Peter 18 Jun '02

18 Jun '02

Is it possible to pass a pointer of a class member function into a thread ?? I have no problems passing functions (or pointers to functions rather) which are not members of any classes. However when I try to pass member functions, I get compile errors. I am using MSVS 6.0 on win 2000. The following is a simplified model of my situation. I am trying to create a thread inside a function of one class and pass into it, a pointer of a member function of another class: // all necessary includes; class testClass1 { public: // constructor testClass1() { // init code} ~testClass1() {} void fun1() { // some code} }; class testClass2 { testClass2() { // init code} ~testClass2() {} // SEE HERE PLEASE void fun2() { // some code.. boost::thread myThread(&object1.fun1) ; // PROBLEM HERE // more code... } testClass1 object1; }; int main(int argc, char **argv) { testClass2 class2; // some code... class2.fun2(); // more code.... return 0; } Any help would be greatly appreciated. Thanks in advance. Peter

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new to boost::threads - question
by Peter 18 Jun '02

18 Jun '02

Is it possible to pass a pointer of a class member function into a thread ?? I have no problems passing functions (or pointers to functions rather) which are not members of any classes. However when I try to pass member functions, I get compile errors. I am using MSVS 6.0 on win 2000. The following is a simplified model of my situation. I am trying to create a thread inside a function of one class and pass into it, a pointer of a member function of another class: // all necessary includes; class testClass1 { public: // constructor testClass1() { // init code} ~testClass1() {} void fun1() { // some code} }; class testClass2 { testClass2() { // init code} ~testClass2() {} // SEE HERE PLEASE void fun2() { // some code.. boost::thread myThread(&object1.fun1) ; // PROBLEM HERE // more code... } testClass1 object1; }; int main(int argc, char **argv) { testClass2 class2; // some code... class2.fun2(); // more code.... return 0; } Any help would be greatly appreciated. Thanks in advance. Peter

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RE: [Boost-Users] tolower not in std::
by bjorn.karlsson＠readsoft.com 17 Jun '02

17 Jun '02

> From: ccullum [mailto:yg-boost-users@m.gmane.org] > I am getting a message stating that tolower is not found in > the std::, but > transform can be found. Has anyone seen this before? > In future posts, please state the Boost library that is causing trouble. There is already one reply to this seemingly-close-to-being-off-topic note; another possibility is that you've simply failed to #include the header where tolower resides, which is <cctype>. Bjorn [Non-text portions of this message have been removed]

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tolower not in std::
by ccullum 17 Jun '02

17 Jun '02

I am getting a message stating that tolower is not found in the std::, but transform can be found. Has anyone seen this before? Thanks, Christopher cullum ccullum(a)uprizer.com

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[BGL] using Borland C++Builder 5
by Alex Henderson 17 Jun '02

17 Jun '02

Hi, I had a problem compiling both the test file (libs/graph/test/graph.cpp) and the first example (libs/graph/example/file_dependencies.cpp) of the BGL and traced the problem to the support for tuples. The offending line is line 40 of boost/tuple/tuple.hpp which incorporates tuples::get into the boost namespace. Commenting out this line allows the files above to compile and run OK. Leaving it in invokes an internal compiler error. The test file for tuples works OK with Builder 5 and so I guess there's a dependency somewhere. The question is - if I comment out this line am I going to get hit with problems elsewhere in the BGL? I'm new to the BGL and don't know whether the whole thing is built on the abilities of tuples. [Using boost_1_28_0, BCC5 sp1, Win2000 sp2] Thanks for any thoughts. Alex

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RE: [Boost-Users] MS VS 6: passing boost::shared_ptr<T> to a dll function
by Smith, Eric V. 16 Jun '02

16 Jun '02

How about some sample code? It's hard to help if we don't know exactly what you're trying to do. > -----Original Message----- > From: lognez [mailto:corno@dds.nl] > I am trying to pass a smart pointer (boost::shared_ptr<T>) as an > argument to > a function that is implemented by a dll and called by an executable, > but > whenever I execute the application, it goes into a loop, no matter > what the > type of T is. When the function is implemented in the exe or > when the function is called from inside the dll it works > fine. Does anybody have a clue what could be happening? BTW, > I'm not implicating a bug in boost, I know that it could as well > be a > MS VC++ bug but I would just like to know how this comes and how I > can solve > it.

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Re: Static power() function, to add in common_factor
by Daryle Walker 14 Jun '02

14 Jun '02

on 6/12/02 12:11 AM, ravioli(a)softhome.net wrote: > Is there an interest into having a power() template calculating the N-th power > of any number, when N is known at compile-time ?t uses the algorithm of the > STL power function(), and runs between two or three times faster, and maybe > could be of interest in the " <boost/math/common_factor.hpp> which provides > run-time and compile-time evaluation of the greatest common divisor (GCD) or > least common multiple (LCM) Proposals for new libraries usually go to the regular Boost list, not this one. Besides that: What would this have to do with the common-factor library? I've never heard of a function called "power". Is it a STL function that didn't get into the standard? Are there any docs for it? How do you know what algorithm it uses? > It simply works this way, for example to have PI at exponent three : > double a = power_const<3>( 3.14159) > > As the single include file is very short, please apologize if I give it > straight on, just to save your time and to have an idea how badly you judge my > poor code ;) [TRUNCATE code] I don't think your implementation will work for negative exponents. -- Daryle Walker Mac, Internet, and Video Game Junkie darylew AT mac DOT com

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Dynamic Bitset formal review - half way point
by Mat Marcus 14 Jun '02

14 Jun '02

Reminder - We have just past the half way point for the formal review of dynamic bitset. So far we have: 1 formal yes vote 1 formal no vote Discussion regarding iterators for dynamic bitset and comparison to vector<bool>. Some minor corrections and updates. I would like to see more formal reviews (including a yes or no vote) before the review period ends on the 17th. Thanks, Mat ##### > The formal review of Dynamic Bitset by Chuck Alison and > Jeremy Siek will commence today Saturday June 8th and run > through Monday, June 17th. > > The library is currently available at > <http://groups.yahoo.com/group/boost/files/dyn_bitset.tar.gz> > > > Below is an excerpt from the library's documentation: > > The dyn_bitset class represents a set of bits. It provides > accesses to the value of individual bits via an operator[] > and provides all of the bitwise operators that one can > apply to builtin integers, such as operator&& and > operator<<. The number of bits in the set is specified at > runtime via a parameter to the constructor of the > dyn_bitset. > > Each bit represents either the Boolean value true (set) or > false (reset). To toggle a bit is to change the value to > true if it is false and to false if it is true. Each bit > has a non-negative position pos. The position pos == 0 > corresponds to the least significant bit and pos == size() > - 1 is the most significant bit. When converting an > instance of dyn_bitset to or from an unsigned long, the > bit position pos corresponds to the bit value 1 << pos. > > The dyn_bitset class is nearly identical to the > std::bitset class. The difference is that the size of the > dyn_bitset (the number of bits) is specified at run-time > during the construction of a dyn_bitset object, whereas > the size of a std::bitset is specified at compile-time > through an integer template parameter. > > > For information about submitting a Formal Review, see > http://www.boost.org/more/formal_review_process.htm > > Please try out the library and comment during the review > period. Be sure to say whether or not you think the library > should be accepted by Boost. > > Compiler notes: This library has been tested using the > following compiler platforms: > > Gcc 2.95 and 3.01 > Kai C++ > Metrowerks Codewarrior 8 (beta, Mac) > Visual C++ 7.0 > Comeau > > The library presently requires template friend support and is > known not to compile with CodeWarrior 7.2 or Visual C++ 6.0. > > The library has not been tested with Borland. > > > The Formal Review manager is Mat Marcus. > > > > > > _______________________________________________ > Unsubscribe & other changes: > http://lists.boost.org/mailman/listinfo.cgi/boost-announce

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RE: [Boost-Users] shared_ptr in Borland C++ Builder
by scleary＠jerviswebb.com 12 Jun '02

12 Jun '02

> From: Craigus [mailto:yg-boost-users@m.gmane.org] > > Hi > > I'm new to using the Boost library. Welcome! :) > I have Codeguard turned on (detects memory leaks, accessing freed memory, > overwriting memory illegally and the like). When the shared_ptr object > count goes to zero operator() in checked_deleter eventually gets called. > Codeguard is reporting (in poor English): > > Method called on illegally casted object If you want to fix the problem: uncheck Project Options -> C++ -> Zero length empty class members. Then rebuild (not remake). The rest of this e-mail is just explaining what the error is and why this fixes it. Here's the problem: CodeGuard is complaining that the 'this' pointer for the checked_deleter object is invalid when its operator() is called. (The error is not reported if you uncheck the "Validate the 'this' pointer on member function entry" and rebuild). Many function objects contain no data or base classes, but operator() cannot be static, so for these function objects (including checked_deleter), a sort of unspoken convention has arisen: never use the 'this' pointer. But CodeGuard validates the 'this' pointer anyway... In common implementations of Standard C++, CG's validation would work: in the case where a function object is used as a most-derived class, it has non-zero size (according to the Standard), so 'this' would reference a "placeholder" memory location for that object. in the case where a function object is used as a base class, then the most-derived class has non-zero size, and 'this' would reference a member in some derived class. C++ Builder, however, has a non-Standard-conforming option that is on by default: Project Options -> C++ -> Zero length empty class members. This creates a "loophole" in the first case described above: in the case where a function object is used as a most-derived class *as a member of another class*, it has zero-size(!) -- and therefore if it is the last member of that class, 'this' would reference memory *after* the most-derived class. Unchecking this option allows CG's validations to work in the way described above, closing the "loophole". Happy coding! :) -Steve

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bit_iterator
by Jan Langer 12 Jun '02

12 Jun '02

hello, i do use iterator adaptor to build a bit_iterator, which return single bits of the elements of an underlying iterator. the base_type of my iterator_adaptor is std::pair <BaseIterator, unsigned int> representing the iterator and the bit position. now my iterator does not work if i adapt istreambuf_iterator because self operator++(int) { self tmp(*this); ++*this; return tmp; } of iterator_adaptor is not able to use the proxy returned by the postfix increment of the input iterator. now i searched the archive and found in: Subject: Re: [boost] (infinite) sequences using recurrence relations From: Corwin Joy < cjoy@xxxx > Date: Fri, 10 Aug 2001 01:21:28 -0500 the following sentence: >In table 72, p. 511 of the standard you will notice something weird about >the postfix increment operator: >Namely, it is specified as (void)r++. >In other words, unlike all other standard iterator types, an input iterator >is not required to return a copy of its old value! but this would mean that the expression *i++ is wrong in most cases. is there a trick to make iterator_adaptor also handle this case or shall i hope that nobody types *i++ with my bit_iterator based on such an input iterator, or did i understand something incorrectly? regards -- jan langer ... jan(a)langernetz.de "pi ist genau drei"

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shared_ptr in Borland C++ Builder
by Craigus 12 Jun '02

12 Jun '02

Hi I'm new to using the Boost library. I'm using the shared_ptr because I can't do what I want to do with the std::auto_ptr (which is to have them stored in other STL containers). I ran into the following problem in C++ Builder 5, patch 1- I have Codeguard turned on (detects memory leaks, accessing freed memory, overwriting memory illegally and the like). When the shared_ptr object count goes to zero operator() in checked_deleter eventually gets called. Codeguard is reporting (in poor English): Method called on illegally casted object It doesn't matter what type the shared_ptr holds. I even tried a console program that contains only the following line (apart from return 0; of course :-): boost::shared_ptr< int > tmp( new int ); As soon as that object goes out of scope it is destroyed and operator() is called as I indicated above and Codeguard reports the error. Has anyone else seen this behaviour ? I was originally using Boost 1.27, which gave me the same error when I used the reset method. I downloaded 1.28 and that went away so that now it's only happening when the actual shared_ptr object is destroyed. I don't have much idea of what's going on inside the shared_ptr, so I don't even know where to start looking. Any help will be much appreciated. Thanks Craigus

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Re: Re: How to use Iterator Adaptors?
by David Abrahams 12 Jun '02

12 Jun '02

"Duane Murphy" <duanemurphy(a)mac.com> wrote in message news:20020610181043.12388@mail.murphyslogic.com... > --- At Tue, 4 Jun 2002 13:02:08 +0100, Keith MacDonald wrote: > > >> So, what is the "normal" way of creating an iterator out of thin air as > >> it were? > > > >That was the question in my mind, which the first sentence of the Iterator > >Adaptors documentation led me to hope it would answer: "The Iterator Adaptor > >library allows you transform an arbitrary ``base'' type into a > >standard-conforming iterator". If the base type is a container, how do you > >do it? > > Keith, > Your email was delayed in my queue for some reason. Were you able to > figure out how to do an iterator from a container from the discussion > between Dave Abrahms and myself? Well, of course you have to think about what data the iterator will need in order to do the iteration. The Base type can't be just a container if you want the iterator to traverse the container's elements -- you need to store some indication of the position within the container -- e.g. a node pointer, and index, or an interator -- as (part of) the Base type. -Dave

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[BGL]
by Angelique Michaut 12 Jun '02

12 Jun '02

Hello, I use the BGL to read a graphviz file and I do a depth_first_search on the graph. I would like to determine the fontname (times-roman for example) the fontcolor (black for example) and the position of each node when the depth_first_search is done. Could you help me? Thinks

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How to use Iterator Adaptors?
by keithmac66 11 Jun '02

11 Jun '02

Hi, I'm struggling to understand how to use Iterator Adaptors, due to a lack of simple examples. This is disappointing, given that supposedly "Using iterator_adaptor, you can easily implement an iterator class" (www.boost.org/libs/utility/iterator_adaptors.htm) Can anyone help, by explaining how to implement a random access iterator for a custom collection class? e.g.: template <class T> class DumbCollection { public: DumbCollection(T data[10]) { for (int i = 0; i < 10; i++) m_data[i] = data[i]; } iterator begin(); iterator end(); private: T m_data[10]; }; Thanks, Keith

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how to compile the boost/regex without comand line
by Aza Lsaja 11 Jun '02

11 Jun '02

Hi, I'm new on this list as well as on C++ world. I try to install boost library but failed. This is what I did: [Win98, MSVC 6.0 without service pack] 1. Download and extract the zip file to root directory. I have C:\boost_1_27_0 now. (success) 2. Download Boost.Build for windows from sourceforge, unpack and installing, reboot (success) 3. go to c:\boost_1_27_0 directory, then execute this in command prompt: jam -sBOOST_ROOT=. -sTOOLS="msvc" (fail) the dos prompt yield many lines but I cant read it. It's too fast. I think it's error messages. Or maybe I missing some procedure? please let me know. I guess my compiler is broken and I need MSVC service pack. But, I can't download it at this time. Acctually, I just want to use the boost's regex library. Can I compile the regex manually (by the IDE) so I can use it with include ( #include <boost/regex.hpp> ) in my codes? If yes, how? Sorry for my english, I hope you understand me. Thanks. Aza ------------------- Kemudahan Hosting PlasaCom ---------------------------------- Hosting menjadi lebih mudah dan murah dengan keringanan 50% biaya registrasi mail hosting dan webhosting selama bulan Juni 2002. Klik http://idc.plasa.com untuk pendaftaran ---------------------------------------------------------------------------------

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[BGL] How can my visitors visit?
by �ڱ�� 11 Jun '02

11 Jun '02

Compiling below, It's OK. but executing, visitors do nothing. What's the problem? Is this slicing problem? why? thank you in advance. ---------------------- below ------------------------ // bfs visitor 1. just printing every vertex in breath first order. struct graph_printer1 : public default_bfs_visitor { template<typename Vertex, typename Graph> void discover_vertex(Vertex u, Graph& g) { cout << " graph printer 1" << u <<"\n"; } }; // bfs visitor 2. same as visitor 1 except message. struct graph_printer2 : public default_bfs_visitor { template<typename Vertex, typename Graph> void discover_vertex(Vertex u, Graph& g) { cout << " graph printer 2" << u <<"\n"; } }; // graph wrapper class graph_wrapper { protected: adjacency_list<vecS, vecS, bidirectionalS, VertexProperty, EdgeProperty> m_graph; public: // HERE. this Visit function does nothing.!! void Visit(default_bfs_visitor* vis, int vertexID ) { breadth_first_search(m_graph, vertex(vertexID, m_graph), visitor(*vis)); } }; int main() { graph_wrapper holder; graph_printer1 vis1; graph_printer2 vis2; holder.Visit(&vis1); holder.Visit(&vis2); return 0; } ---------------------------------------- Ki-Soo, Park e-mail: park(a)erhouse.co.kr wfms123(a)hotmail.com

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Hi!
by rajanik3 11 Jun '02

11 Jun '02

Hi! Could some body tell me how to use boost libraries in Unix. I am using tcsh shell. After downloading, what should I change in order for the compiler to locate the boost library headers. Thanks, Raj.

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