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RE: [Boost-Users] Re: [BGL] Best way to abort an algorithm from w ithi n a visitor?
by Garriss, Michael 19 Sep '02

19 Sep '02

I agree. I hate to see the return -1 (for example) on some "exceptional" case in a function when an exception makes more sense. It's not necessarily an "oops" case, it's an "exception." Either way the caller has to check the special case. There is a good reason that exceptions are named exceptions and not errors. Mike Garriss -----Original Message----- From: Peter Dimov [mailto:pdimov@mmltd.net] Sent: Thursday, September 19, 2002 10:20 AM To: Boost-Users(a)yahoogroups.com Subject: Re: [Boost-Users] Re: [BGL] Best way to abort an algorithm from withi n a visitor? From: "Mark Storer" <mstorer(a)cardiff.com> > Using exceptions in this way just bugs me. Religious reasons I guess. As > the Esteemed Mr. Hylsop ;) mentioned earlier, exceptions are for "oops". > This seems alot like the whole "do{}while(0)" with various 'break' > statements sprinkled in to avoid multiple returns/nested ifs. Useful, but > Just Not Right. A common misconception. Many people try to project their own ideas/expectations on language features, rather than simply using them as tools where appropriate. There is nothing "oops"-y about exceptions. They are a control flow mechanism; one that has interesting properties, but a control flow mechanism nonetheless. If it works and leads to a better code, it's foolish to avoid it without a technical reason. A similar example is when people don't use "struct" for C++ classes because it "doesn't feel right", or when trying to choose between "typename" and "class" for template parameters. The language features simply do not carry this kind of religious/emotional payload. It's all in your mind. Yahoo! Groups Sponsor ADVERTISEMENT <http://rd.yahoo.com/M=234081.2377872.3808768.2225242/D=egroupweb/S=17050067 88:HM/A=1225247/R=0/*http://ad.doubleclick.net/clk;4547223;7007303;y?http:// www.ameriquestmortgage.com/welcome.html?ad=Yahoo01> <http://us.adserver.yahoo.com/l?M=234081.2377872.3808768.2225242/D=egroupmai l/S=:HM/A=1225247/rand=147617524> Info: < http://www.boost.org <http://www.boost.org> > Wiki: < http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl <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 the Yahoo! Terms of Service <http://docs.yahoo.com/info/terms/> . [Non-text portions of this message have been removed]

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lambda lib & mingw gcc 2.95.2?
by Mynhard Rudolph 19 Sep '02

19 Sep '02

Hi all Does the lambda library compile under mingw with gcc 2.95.2? I'm a newbie and I can't figure out what's wrong with the following test example: #include <boost/lambda/bind.hpp> #include <boost/lambda/lambda.hpp> using namespace boost; using namespace boost::lambda; struct A { int d; }; int main (int argc, int argv[]) { A* a = new A(); int b = (a ->* &A::d); int c = (_1 ->* &A::d)(a); return c - b; } g++ test.cpp -Wall -Ix:/boost_1_28_0/ -D__PROCESSOR_X86__ -D__WIN32__ -D__GCC__ -o test.o test.cpp: In function `int main(int, int *)': test.cpp:12: no match for `const boost::lambda::lambda_functor<boost::lambda::pl aceholder<1> > & ->* int A::*' make: *** [test.exe] Error 1 Would appreciate any clues. ;-) Mynhard

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RE: [Boost-Users] [BGL] Best way to abort an algorithm from withi n a visitor?
by Mark Storer 18 Sep '02

18 Sep '02

If efficiency is your goal, exceptions are not the answer. Just enabling exceptions at compile time makes a noticable performance hit. Actually throwing an exception can gobble up a 1000 cycles, give or take. That's per throw. If you catch and throw again, you'll pay again. Now if you've got more than a hundred or so entries left to go, exceptions really are the greener grass. What's wrong with 'return', perhaps along-side some sort of 'done' status variable? I'm only vaguely familiar with the vistor pattern, but these would seem to be the obvious choice. --Mark Storer Software Engineer Cardiff Software #include <disclaimer> typedef std::disclaimer<Cardiff> Discard;

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[BGL] Best way to abort an algorithm from within a visitor?
by Chris Russell 18 Sep '02

18 Sep '02

Is there a way to abort an algorithm while it's processing? Can I throw an exception out of a visitor method? I have a case where I need the algorithm to crunch on a large graph until some condition dependent on property data is reached. If and when the condition is met, I would like to skip the processing of the remaining vertices/edges and save the cycles. Does using exceptions sound like a reasonable approach? - Thanks Chris P.S. Thanks for the help with properties and property maps the other day. I cleaned up my code and eventually tracked the source of my considerable confusion to a bug in an operator= defined on the object that I'm using as an internal property. This bug manifested itself by re-initializing previously set data seemingly at random >8|-~ Arg... My bad.

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RE: [Boost-Users] [BGL] Best way to abort an algorithm from withi n a visitor?
by Jim.Hyslop 18 Sep '02

18 Sep '02

Steve M. Robbins [mailto:steven.robbins@videotron.ca] wrote: > I use that technique to abort the Dijkstra shortest path > search when I find my > goal node. It works fine, as far as I can tell, but I'd be > interested to > learn if there is a better way. It seems anti-idiomatic to me. Exceptions are intended to signify exceptional circumstances that you would not normally expect to encounter (at least according to one school of thought). An exception tells me "Oops, something went wrong here" not "we succeeded, here's the answer". Many of the exceptions I catch are called "oops": try { /* ... */ } catch (std::exception &oops) { /* ... */ } One possible snag might be if your code interacts with someone else's code, which will catch the exception and not pass it on to you. In the context we're talking about, though, I don't see that as a significant problem. An exception is certainly an easy way to abort the search, and since I don't have an alternative to offer, I'll shut up now ;=) -- Jim

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Levenshtein Distance algorithm
by Philippe Lalande 18 Sep '02

18 Sep '02

Hi, I was wondering if anyone could tell me if Boost contains a function that could perform a 'Levenshtein distance' calculation on a sequence. The Levenshtein distance is a measure of the similarity between two strings calculated as the number of deletions, insertions, or substitutions required to transforms the source string to the target string. IMO, it is an interesting algorithm that could apply to any kind of sequence. I'd be happy to discuss interface and implementation on the dev list if such algorithm does not exist yet. Thank you Philippe

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RE: [Boost-Users] Re: Newbie needs help w/VC6 & filesystem (take 2)
by Jim.Hyslop 18 Sep '02

18 Sep '02

John B. Williston [mailto:yg-boost-users@gmane.org] wrote: > On Tue, 17 Sep 2002 12:40:53 -0400, Douglas Gregor <gregod(a)cs.rpi.edu> > wrote: > > >Could you copy 'n' paste some of the link errors you are > getting? It seems > >like you did the right thing (at least, I don't know of a > better way), but > >perhaps knowing what symbols are being redefined would help > isolate the > >problem. > > I sure can. The following is the compile output: > > --------------------Configuration: TestFs - Win32 > Debug-------------------- > Compiling... > Main.cpp > Linking... > LINK : warning LNK4075: ignoring /INCREMENTAL due to /FORCE > specification > msvcprtd.lib(MSVCP60D.dll) : warning LNK4006: "public: __thiscall > [...] already > defined in Main.obj; second definition ignored I've typically found these errors when you have mixed the run-time library usage, or MFC usage. One part of your project wants to link in the C run-time library as a DLL, but another part of your project wants to link it in as a static library. Make sure that all the projects, including the ones that build any libraries you're linking with, use the same "Use runtime library" option (Project | Settings, "C/C++" tab, "Code Generation" category), and also that all projects use the same "Microsoft Foundation Class" option (on the General tab). -- Jim

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checked_delete with pointer template parameter
by Craig Henderson 18 Sep '02

18 Sep '02

I need to free memory from a container with elements of pointers, where the container value_type is a pointer type. I cannot use the checked_delete template as it is, as the template parameter is defined without the '*' pointer. For example, the following fails (obviously): typedef std::vector<char *> X; X x; ... std::for_each(x.begin(), x.end(), boost::checked_delete<X::value_type>); I'm using VC7, so have no partial specialization available, so using the type traits library remove_pointer<> does not work: typedef boost::remove_pointer<typename X::value_type>::type type; std::for_each(x.begin(), x.end(), boost::checked_delete<type>); My existing solution uses a unary functor, as below, but this met with critism on the Boost Developers' list. What would be the 'boost' solution to this problem? template<typename T> class free_heap_ptr : public std::unary_function<T, void> { public: free_heap_ptr() { } ~free_heap_ptr() { } void operator() (T p) { delete p; } }; ... std::for_each(changes_.begin(), changes_.end(), free_heap_ptr<typename change_list::value_type>()); TIA -- Craig

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Is there a Type2Type in boost ?
by Baptiste Lepilleur 17 Sep '02

17 Sep '02

Hi everyone, I've looked around and failed to find the Type2Type template, detailed by Andrei Alexandrescu in a CUJ article (http://cuj.com/experts/1810/alexandr.htm?topic=experts) in boost. While the implementation is trivial: template<typename Type> struct Type2Type { typedef Type original_type; }; I'd rather have it in a well known library. Has it been replaced by something else ? Baptiste.

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Newbie needs help with VC6 & filesystem library
by John B. Williston 17 Sep '02

17 Sep '02

Greetings, Though I'm an "old hand" at C++, I'm a complete newbie when it comes to Boost. The piece that really caught my eye, in light of my current project, is the directory iterator. To date, however, I haven't had any success getting it to compile and function under Win32 with MSVC6, so I thought I would post here. I first have a couple of general questions about using Boost, and then one specific question about the problems with my project at hand. (1) Is there a "right" way to include Boost stuff with VC6? Adding the Boost base directory to my list of include directories seems to work for the official stuff, but it clearly doesn't work for the filesystem stuff because Directory.h is not in the base\boost directory. I can put it there myself, of course, but I'm wondering if there is some intended way to use the beta libraries before they become a part of the whole. (2) Is there a "right" way to link Boost stuff with VC6? The filesystem stuff, like the regex stuff and some other pieces, requires actual compilation and cannot simply be included as header files. I have already built all the official libraries using the bjam utility, but I cannot help noticing they're each stored in hideously long paths beneath the boost base directory. Is there a "right" directory under the Boost hierarchy into which the resulting libs should be copied for ease of inclusion in VC6? Or should I copy them into my project directories as needed? Or should I simply come up with my own system? To get to the more specific question, let me explain how I've addressed (1) and (2) for the time being. Regarding (1), I've copied Directory.h and Boost.h into the base\boost directory so that they may be included without changing the existing source code. That was simple enough. Regarding (2), I've decided to add Directory.cpp to my project and compile it as a module, rather than try to get the linking to work externally. Having said that, consider the following code: #include <windows.h> #include "boost/directory.h" int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) { using namespace boost::filesystem; std::string strFilename; for (dir_it it("./"); it != dir_it(); ++it) if (!get<is_hidden>(it)) strFilename = *it; return 0; } This is an extremely minimal test case of integrating the filesystem stuff into a Win32 application. When compiling the application, I get the following lengthy and inscrutable (to me, at least) error message: WinMain.obj : error LNK2001: unresolved external symbol "__declspec(dllimport) public: __thiscall boost::filesystem::get<struct boost::filesystem::is_hidden>::get<struct boost::filesystem::is_hidden>(class boost::filesystem::dir_it const &)" (__imp_ ??0?$get@Uis_hidden@filesystem@boost@@@filesystem@boost@@QAE@ABVdir_it@12@@Z) The error message seems to suggest that the filesystem stuff isn't available in my project. I find that confusing because the Directory.cpp module compiles without any errors, and I am thus inclined to think that, in fact, all of the filesystem stuff is in my project. Thus, I must also ask the third question: (3) Can anyone explain to me what I might be doing wrong and, more importantly, how I might correct it? Thanks much to all the Boost authors for an interesting set of tools. And thanks in advance to any who respond for all the help with my specific issue. John

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Newbie needs help w/VC6 & filesystem (take 2)
by John B. Williston 17 Sep '02

17 Sep '02

Greetings, I'm sorry for my earlier post. I didn't realize that the dir_it beta stuff was not what was being referred to as the "filesystem". I now know better, and I'm trying to make the filesystem stuff work instead. Unfortunately, I'm having no better luck. Consider the following code: #include "boost/filesystem/operations.hpp" // includes boost/filesystem/path.hpp #include "boost/filesystem/fstream.hpp" // ditto #include <iostream> // for cout int main(int iArgc, char** pArgv) { namespace fs = boost::filesystem; int iNumNodes = 0; fs::directory_iterator end_itr; // default construction yields past-the-end for (fs::directory_iterator itr("debug"); itr != end_itr; ++itr) { if (fs::is_directory(*itr)) std::cout << (*itr).file_path() << " (dir)" << std::endl; else std::cout << (*itr).file_path() << std::endl; iNumNodes++; } std::cout << iNumNodes << " total." << std::endl; return 0; } That's a relatively brain-dead use, I should think, to enumerate the contents of the debug folder to the console. Unfortunately, when I try compiling this, the linker complains horribly about all kinds of symbols already being defined in the filesystem object modules. To ditch the linker errors, I've temporarily used the /force switch, but that's hardly illuminating. First, can anyone tell me how to avoid getting a plethora of multiply-defined symbol errors? Or is /force my only real option? Second, if I use the /force switch, I get all kinds of unhandled exception errors when the directory iterator is constructing. Changing the string I pass to it at construction just changes which exception it emits. With the code above as written, the culprit is: template<typename Y> void reset(Y * p) // Y must be complete { BOOST_ASSERT(p == 0 || p != px); // catch self-reset errors this_type(p).swap(*this); } That's lines 181-185 of boost/shared_ptr.hpp, and I haven't a clue why it's freaking out. Tracing through all the code shows that the exception is occurring AFTER the swap seems to succeed. I'm stumped as to what the problem might be. But I sure would appreciate any advice y'all can offer. So far I have to say that I'm impressed with the Boost library features, but it seems a cast-iron bitch to make it actually compile and link in any real-world programs. John

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Advantage to STLport w VC7?
by dick.bridges＠tais.com 17 Sep '02

17 Sep '02

I'm preparing an upgrade from VC6 SP5 to VC7. I'm told the VC7 STL was improved but specifics are hard to come by. Can anyone tell me if there's still an advantage, <emphasis> with respect to the Boost libraries</emphasis>, to using STLport with VC7? TIA for any suggestions.

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regex 1.28.0 build (question - and problem report)
by acarsac 17 Sep '02

17 Sep '02

Hi, 2 things while upgrading from 1.25 to 1.28 : -I was trying to build the regex library (1.28.0) with msvc-stlport configuration. vc6.bat set STLPORT_PATH="c:\Mes Documents\STLport-4.5.3" nmake -fvc6-stlport.mak will fail. i had to erase some lines in vc6-stlport.mak because i guess it does not support space in path. i do the install by hand too. unless that, it work fine for me. -I was just wondering why the boost build system (jam) makes the regex library if i need to rebuild them with nmake whereas i specify the good target os for both ? Alex.

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question about edge_property_type
by wei guo 16 Sep '02

16 Sep '02

Hi, group: I have a problem of using edge_property_type. in the example file: undirected.cpp, I added several lines like: template < typename DirectedGraph > void directed_graph_demo() { const int V = 2; DirectedGraph digraph(V); typename graph_traits < DirectedGraph >::vertex_descriptor u, v; typedef typename DirectedGraph::edge_property_type Weight; typename property_map < DirectedGraph, edge_weight_t >::type weight = get(edge_weight, digraph); typename graph_traits < DirectedGraph >::edge_descriptor e1, e2; bool found; ......... Weight w1 = get(weight, e1); // <<----------- added line Weight w2 = get(weight, e2); // put( weight, e1, w1*w2/(w1+w2) ); // <<----------- added line std::cout << "weight[(u,v)] = " << get(weight, e1) << std::endl; std::cout << "weight[(v,u)] = " << get(weight, e2) << std::endl; } I got following compiling errors with KAI compiler: "undirected.cpp", line 83: error: no operator "*" matches these operands operand types are: Weight * Weight put( weight, e1, w1*w2/(w1+w2) ); ^ detected during instantiation of "void directed_graph_demo<DirectedGraph>() [with DirectedGraph=DirectedGraph]" "undirected.cpp", line 83: error: no operator "+" matches these operands operand types are: Weight + Weight put( weight, e1, w1*w2/(w1+w2) ); ^ detected during instantiation of "void directed_graph_demo<DirectedGraph>() [with DirectedGraph=DirectedGraph]" 2 errors detected in the compilation of "undirected.cpp". however, if I change the put statement in the example code to be: put( weight, e1, get(weight, e1)*get(weight, e2)/(get(weight, e1)+get(weight, e2)) ); it compiled successfully. So, what do I missing here, and what is the return type of get(weight, e2) ? and how it connected with DirectedGraph::edge_property_type ? thanks in advance! weiqing --------------------------------- Do you Yahoo!? Yahoo! News - Today's headlines [Non-text portions of this message have been removed]

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[BGL] setting a breakpoint in an algorithm visitor
by Chris Russell 16 Sep '02

16 Sep '02

p.156 of the BGL book: "... visitors are passed by value..." I was attempting to set a breakpoint in a visitor event handler (that I know is executing) but the breakpoint is seemingly ignored by my debugger. This is because the visitor I construct and subsequently pass to the algorithm is not the object that is actually dispatched by the algorithm. Correct? Using the Intel compiler under MS DevStudio 6 on Windows, I inserted a ::DebugBreak() (asm int 3) into the visitor and *do* hit that but only have assembly language and not source to step through at that point. Why are visitors passed to algorithms by value? Any suggestions for debugging visitor code at the C++ source level and not in assembly? - Regards Chris

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[BGL] Property map question
by Chris Russell 16 Sep '02

16 Sep '02

What determines when boost::get(Graph, vertex_myproperty_t) returns a boost::property_map<graph_t, vertex_myproperty>::type vs. a ::const_type? Suppose: enum vertex_myproperty_t { vertex_myproperty = 12345}; BOOST_INSTALL_PROPERTY(vertex,myproperty); typedef property<vertex_myproperty_t, MyPropertyObject, ....> vertex_properties_t; typedef adjacency_list<vecS,vecS,bidirectionalS, vertex_properties_t> graph_t; typedef property_map<graph_t, vertex_myproperty_t>::type vertex_myproperty_map_t; graph_t Graph;

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Re: Thanks for the help...
by Peter Dimov 16 Sep '02

16 Sep '02

From: "someuserat" <marktutt(a)excite.com> > > If I can impose, I've got another question that I think is in the same > area... > > I couldn't think of a way to call Widget::operator()(const WidgetPtr > w) through the smart pointer, so I wrote an equivalent method called > equals to try to imlement the following function. > > void WidgetMgr::dropWidget(const WidgetPtr w){ > > col.erase(remove_if(col.begin(),col.end(),boost::b > ind2nd(boost::mem_fn(&Widget::equals),c))); > } ... where Widget::equals takes a WidgetPtr? Based on this information, I think that you need boost::bind(&Widget::equals, _1, w) (Please use the boost-users list.) > Is there any reference to the boost libraries that goes into more > detail? I've got several books on STL that never seem to address the > issues I'm running into with smart pointers, I'm afraid what I may run > into once I really get into the meat of this project.

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RE: [Boost-Users] lexical_cast question
by Björn Karlsson 16 Sep '02

16 Sep '02

> From: Mark Snelling [mailto:mark@bakedbeans.com] > > Ok, I guess I'll just make my own temporary one based on the > original in > the meantime :) > > Mark. > Or, you could use the version with proposed changes - it's in the Files section at YahooGroups. Bjorn

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RE: [Boost-Users] lexical_cast question
by Björn Karlsson 16 Sep '02

16 Sep '02

> From: Mark Snelling [mailto:mark@bakedbeans.com] > > Hi, > Does the boost::lexical_cast library support wide character sets for > example: > > #include <boost/lexical_cast.hpp> > > using namespace boost; > using namespace std; > > void main () > { > wstring wtext(L"1234"); > int val = lexical_cast<int>(wtext); > } > Not the current version of lexical_cast - the implementation uses stringstream to perform the conversion. A proposed change to lexical_cast does handle wide characters correctly. I'm not sure about the status of that proposal, though. Bjorn Karlsson

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lexical_cast question
by Mark Snelling 16 Sep '02

16 Sep '02

Hi, Does the boost::lexical_cast library support wide character sets for example: #include <boost/lexical_cast.hpp> using namespace boost; using namespace std; void main () { wstring wtext(L"1234"); int val = lexical_cast<int>(wtext); }

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How to build boost threads library on AIX 4.3.3 with VisualAge 5
by robertpsather 16 Sep '02

16 Sep '02

Building Boost on AIX is difficult. Here's a recipe that worked for me, for building on the following platform: Boost source download version 28 AIX 4.3.3 on RS/6000 VisualAge 5.0 Jam: downloaded binary of Boost.Jam Version 3.1.0. OS=AIX. bash shell Building Boost Setup: Downloaded version 28 tar.gz file to ~/boost. Un-gzipped and untarred. Set export BOOST_ROOT=/home/satherb/boost/boost_1_28_0 Attempt: jam "-sTOOLS=vacpp" Result: Many compilation errors, in building of regexp library. For example: Error: "libs/regex/build/../src/cpp_regex_traits.cpp", line 196.39: 1540-0257 (S) An object or reference of type "std::messages_base::catalog" cannot be initialized with an expression of type "int". Attempt: in cpp_regex_traits.cpp", line 196, changed "-1" to "(size_t) 1" Result: compiler says "cannot be initialised with type unsigned long." for the same line. Attempt: Noted that www.boost.org says that threads lib does not depend on regex or python. Edited Jamfile to comment out unnecessary targets python and regex. Result: Most errors are "Thread support is unavailable". Looking at source indicates this is because BOOST_HAS_THREADS macro is undefined. Attempt: export BOOST_HAS_THREADS=1 Result: same errors. Attempt: run ./configure Result: configure gives error message that says "compiler does not produce output" (or something like that) However, running configure again worked! Here were the recent settings of environmental variables: export BOOST_ROOT=/home/satherb/boost/boost_1_28_0 export _MT=1 export CC=xlC_r export CXX=xlC export _POSIX_THREADS=1 export LIBS=-lpthread (I don't know which of these was the key. If you discover the answer, please let me know.) Attempt: Did as configure suggested: "Adjustments to boost configuration have been written to user.hpp, copy this to boost/config/user.hpp to use "as is" " Result: jam still gives "Thread support is unavailable" errors. Attempt: added a line to boost/config/user.hpp: #define BOOST_HAS_THREADS Result: builds! (Don't know yet if it works properly, of course. The examples don't build.) Bob Sather bob.sather(a)lloydstsb.delete_this_part.co.uk

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graph vertices / IRIX / GCC
by yg-boost-users＠m.gmane.org 16 Sep '02

16 Sep '02

Hello, Q: one can construct a graph using adjacency_list<> and then immediately iterate over the vertices, right? The program below writes out the numbers 0 to 9 when compiled using gcc 3.2 on linux. Ditto on my IRIX system, *unless* I try to optimize. I expect this is a GCC optimizer bug, but I just want to be sure I haven't overlooked something in the boost docs. Thanks, -S #include <iostream> #include <boost/graph/graph_traits.hpp> #include <boost/graph/adjacency_list.hpp> typedef boost::adjacency_list< boost::vecS, boost::vecS, boost::undirectedS, boost::no_property, boost::property<boost::edge_weight_t,float> > Graph; typedef boost::graph_traits<Graph>::vertex_descriptor vertex_descriptor; typedef boost::graph_traits<Graph>::edge_descriptor edge_descriptor; int main() { Graph g( 10 ); boost::graph_traits<Graph>::vertex_iterator ui, ui_end; for (boost::tie(ui, ui_end) = boost::vertices(g); ui != ui_end; ++ui) { std::cout << "*ui = " << *ui << std::endl; } return 0; }

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graph vertices / IRIX / GCC
by Steve M. Robbins 16 Sep '02

16 Sep '02

Hello, Q: one can construct a graph using adjacency_list<>(N) and then immediately iterate over the vertices, right? The program below writes out the numbers 0 to 9 when compiled using gcc 3.2 on linux. Ditto on my IRIX system, *unless* I try to optimize. I expect this is a GCC optimizer bug, but I just want to be sure I haven't overlooked something in the boost docs. Thanks, -S #include <iostream> #include <boost/graph/graph_traits.hpp> #include <boost/graph/adjacency_list.hpp> typedef boost::adjacency_list< boost::vecS, boost::vecS, boost::undirectedS, boost::no_property, boost::property<boost::edge_weight_t,float> > Graph; int main() { Graph g( 10 ); boost::graph_traits<Graph>::vertex_iterator ui, ui_end; for (boost::tie(ui, ui_end) = boost::vertices(g); ui != ui_end; ++ui) { std::cout << "*ui = " << *ui << std::endl; } return 0; }

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ASCII Code Problem.. Please Help me.
by Sean Lee 15 Sep '02

15 Sep '02

I am currently trying to use Regex++ and I almost got there. However, I try to use Regex++ with XML parser and I got some problem. Here is the xml expression. <subtree name="itinerary" regex="(<\\s*TR\\s*VALIGN=TOP>\\s*<TD\\s*WIDTH=250>\\s*<\\s*B \\s*>[^>]+AM</B>?)"> Since "<" and ">" are not valid in XML Syntax, I have to use "<" and ">". I have loaded the xml file in my program and did following thing. char* regex=NULL; _bstr_t strRegex; strRegex=pIXMLDOMNode->text; // regex="(<\\s*TR\\s*VALIGN=TOP>\\s*<TD\\s*WIDTH=250>\\s*<\\s*B \\s*> //[^>]+AM</B>?)"> regex = (char*)malloc(_bstr_t(strRegex).length()); lstrcpy(regex,strRegex); AfxMessageBox(regex); // got the same string. But when I compared with following string and I got "FALSE". char* temp="(<\\s*TR\\s*VALIGN=TOP>\\s*<TD\\s*WIDTH=250>\\s*<\\s*B\\s*>[^>]+AM</B> ?)"; if(lstrcmp(temp,regex)==0) Please help me. Thank you very much. Sean Lee slee(a)qixo.com

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tokenizer bug? core dump
by wugui 14 Sep '02

14 Sep '02

\\n ok, \\r\\n core dump what happend? { const string test_string = "\"message ; \\r\\n message\" \"quote \\\"\" 'escape \\\\'"; typedef tokenizer<escaped_list_separator<char> > Tok; escaped_list_separator<char> sep("\\"," ;","\"\'"); Tok tok(test_string, sep); for(Tok::iterator beg=tok.begin(); beg!=tok.end();++beg) cout << "[" << *beg << "]" << endl; } (gdb) bt #0 0x281047b4 in kill () from /usr/lib/libc.so.4 #1 0x28144b26 in abort () from /usr/lib/libc.so.4 #2 0x28097444 in __terminate () from /usr/lib/libstdc++.so.3 #3 0x28097461 in __terminate () from /usr/lib/libstdc++.so.3 #4 0x280977fb in __sjthrow () from /usr/lib/libstdc++.so.3 #5 0x804c5ea in boost::iterator_adaptor<boost::detail::token_iterator_base<char const *>, boost::detail::tokenizer_policy<basic_string<char, string_char_traits<char>, __default_alloc_template<false, 0> >, boost::escaped_list_separator<char, string_char_traits<char> > >, basic_string<char, string_char_traits<char>, __default_alloc_template<false, 0> >, basic_string<char, string_char_traits<char>, __default_alloc_template<false, 0> > const &, basic_string<char, string_char_traits<char>, __default_alloc_template<false, 0> > const *, forward_iterator_tag, int>::iterator_adaptor () #6 0x804bdd9 in boost::tokenizer<boost::escaped_list_separator<char, string_char_traits<char> >, char const *, basic_string<char, string_char_traits<char>, __default_alloc_template<false, 0> > >::begin () #7 0x804a64f in main () #8 0x804a4b5 in _start ()

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