March 2004 - Boost-users - lists.stage.boost.cppalliance.org

boost::shared_ptr and stl algorithms
by Bill Eidson 15 Apr '05

15 Apr '05

std::vector< boost::shared_ptr<T> > TVec; I want to write a function object to run std::for_each. to do somework against members of T and accumulate results in functor. My attempts have failed in VC7 with memory errors in my operator() method. struct fo { bool operator()( boost::shared_ptr<T>& t ) { return true; } }; Thanks in advance bille

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Will libraries built on WinNT run on Win98? (MinGW)
by Reed Hedges 31 Mar '05

31 Mar '05

I know that Win98 is not really supported, but is there any chance that libraries (specifically thread and regex) that were build on WinNT using MinGW work on Win98 (in MinGW)? My guess is no, but has anyone tried it? thanks reed

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RE: [Boost-users] Re: about license
by Darryl Green 04 Apr '04

04 Apr '04

> -----Original Message----- > From: David Abrahams [mailto:dave@boost-consulting.com] > Sent: Tuesday, 2 March 2004 12:43 AM > > "Darryl Green" <Darryl.Green(a)unitab.com.au> writes: > > > I'm happy to provide a patch once I'm reasonably sure I > understand the > > license. I'm assuming an email discussion will be more > productive than > > patches in the meantime. I have one more question that I > have a proposed > > FAQ answer for, but my "answer" is based purely on what I think it > > should be, not an understanding of the law. I've been trying to educate myself about the law in this area, with some help from Alexander Terekhov. I'm not at all convinced now that there is any derivative work produced by the compilation step, however this seems to make no difference to the result. It seems the compiled code is a translation of both works, agregated (a compilation) in some way then. I think whoever produces the compilation can license it however they like, subject to permission being granted by the authors of the original works to include their work in the compilation. I don't know if this is sufficiently clearly allowed by the wording of the boost license, though I think "use" must surely allow this for software source libs as there is no other way to "use" them. So the final answer is the same - but some of the questions and answers in between may be wrong. Have you received any feedback from lawyers about this? Regards Darryl Green. ########################################################################## This e-mail is for the use of the intended recipient(s) only. If you have received this e-mail in error, please notify the sender immediately and then delete it. If you are not the intended recipient, you must not use, disclose or distribute this e-mail without the author's prior permission. We have taken precautions to minimise the risk of transmitting software viruses, but we advise you to carry out your own virus checks on any attachment to this message. We cannot accept liability for any loss or damage caused by software viruses. ##########################################################################

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Re: [boost] [BGL] forced client complexity
by Jeremy Siek 02 Apr '04

02 Apr '04

Hi, I too am dissatisfied with the complexity of many parts of the BGL... On Mar 31, 2004, at 4:48 AM, Provisional Dissonance wrote: > Is there any particular reason that a > simplified interface is not made available? Just a lack of time. The priority was placed on providing flexibility and efficiency so that the BGL components could handle any situation... that flexibility came at the price of complexity. I think a good next step would be to provide more special purpose components that are easier to use. > Perhaps a > container adapter could be packaged with the library > allowing a compromise of functionality and flexibility > for simplicity? Could you explain this "container adaptor" idea more. > #include <less_than_10_graph_headers> > ... > digraph<some_node_type,some_edge_context_type> g; > g << "vertex" << make_pair("vertex", > "implicit_vertex"); > g.add_edge("brother", "sister", "sibling"); > if(g.find(make_pair("brother", "sister"))) > related = true; Perhaps this is a good place to start. Could you explain each of the above lines of code. Then we can compare to an implementation in the current BGL and pinpoint problem areas. Cheers, Jeremy _______________________________________________ Jeremy Siek <jsiek(a)osl.iu.edu> http://www.osl.iu.edu/~jsiek Ph.D. Student, Indiana University Bloomington Graduating in August 2004 and looking for work C++ Booster (http://www.boost.org) _______________________________________________

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linker error creating simple unit_test (boost 1.31.0 + win32 + vc 71)
by Langston, Matthew David 02 Apr '04

02 Apr '04

I'm trying to create a simple unit test (using the Unit Test Framework) using boost 1.31.0 + win32 + vc71, but I get the following linker error due to the undefined symbol __imp___CrtSetReportHook: tests error LNK2019: unresolved external symbol __imp___CrtSetReportHook referenced in function "public: int __thiscall boost::execution_monitor::execute(bool,int)" (?execute@execution_monitor@boost@@QAEH_NH@Z) There was mention of this undefined symbol (__imp___CrtSetReportHook) in this thread: http://lists.boost.org/MailArchives/boost/msg43787.php. However, that post was concerning the Metrowerks compiler, but I am using Microsoft's vc71 compiler. Can someone help me resolve this undefined symbol (__imp___CrtSetReportHook) problem? Here is my simple "unit test suite" that I am trying to build: #include <boost/test/unit_test.hpp> #include <boost/test/included/unit_test_framework.hpp> using boost::unit_test_framework::test_suite; void test_GleamData() { BOOST_CHECK(2 == 1); // non-critical test => continue after failure } test_suite* init_unit_test_suite( int, char* [] ) { test_suite* test = BOOST_TEST_SUITE( "GleamAnalysis Test Suite" ); test -> add( BOOST_TEST_CASE( &test_GleamData ), 1 /* expected one error */ ); return test; } Warmest regards, Matt

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about license
by Marleny Rafferty 01 Apr '04

01 Apr '04

Hi- I am considering using boost in my applications, but I have a question about the boost license at http://www.boost.org/LICENSE_1_0.txt . It says (edited) "Permission is hereby granted, free of charge, to ... use [and] reproduce ... the Software". It also says that any derivative works must also have the same license grant. If my application uses boost libraries unchanged, is it considered a derivative work? If so, does that mean that if I distribute my compiled software, I must allow free of charge use and distribution? Thanks. -- Marleny

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removing parallel edges in the Boost Graph Library?
by Nicholas Burlett 01 Apr '04

01 Apr '04

I am trying to use BGL to model a directed multigraph, but every time I try to remove just one of the edges (u,v), it removes all of the edges from u to v. My graph definition is: typedef adjacency_list<listS, listS, bidirectionalS, VertexProperty, EdgeProperty> graphdata; where VertexProperty and EdgeProperty are properties I've defined. Everything else seems to work: I have can add parallel edges, find the edge I want to remove based on the EdgeProperty, filter the graph for topological sorting, check for existing edges, etc. In the following, e is of type graph_traits<graphdata>::edge_descriptor, and g is the graph of type graphdata (defined above): std::cout << "about to remove edge\n"; DumpInfo(); remove_edge(e, g); std::cout << "removed edge\n"; DumpInfo(); Here is some sample output: about to remove edge vertex: 0 out-edges: in-edges: (1,0) (1,0) adjacent vertices: vertex: 1 out-edges: (1,0) (1,0) in-edges: adjacent vertices: 0 0 removed edge vertex: 0 out-edges: in-edges: adjacent vertices: vertex: 1 out-edges: in-edges: adjacent vertices: Note that there were two edges present before the call to remove_edge, but only one after. What am I doing wrong? I'm using version 1.31, if that helps. Thanks, Nicholas Burlett nrb23(a)cornell.edu

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Re: [boost] [BGL] forced client complexity
by Cromwell Enage 31 Mar '04

31 Mar '04

prs, On reflection, I've decided to cross-list my reply. > If one accepts the axiom that "a picture is worth a > thousand words," then it naturally follows that > discussion of graphs is always overly prolix. I recently had a chat with a fellow programmer and attempted to summarize, in semi-layman terms, how the core algorithms of my multi-state-mazes library work. They're pretty simple, but I couldn't do it without paper and pencil. > Sadly, the same reasoning is also applicable to > the code of graph libraries. If a "code-visualizing compiler IDE" existed that would give us "code pictures" (plus conform to the new C++ standard, not ICE, and so on), I'm pretty sure more of us would be using it for all programming projects, not just graph applications. :) But seriously, with graph theory containing several different problem domains (search, network, AI, etc.), a graph library attempting to be generic enough for use in all of them is necessarily complex. > Boost.Graph seems to expose and require an > unnecessarily large amount of complexity, > though. If by "exposure" you mean lots of source code, I'll take that complexity any day of the week and twice on Sundays. :) The library does have a rather steep learning curve, especially if you're somewhat unfamiliar with graph theory and/or template programming. > Whereas libraries like Spirit go to great lengths > to make hard things easy, BGL seems to try only to > make hard things possible. I haven't looked at the Spirit library yet, so I can't tell you how easy it may be to use it. Perhaps getting your hands on a copy of the Boost Graph Library book will help (I don't have one, so I'm not certain). > The amount of scaffolding required > to use BGL for even the simplest of projects > often dwarfs the code size of a naive, > yet functional, special-purpose implementation. Special-purpose implementation of a graph library? Or the project? BGL aims to be as generic as the STL, but whereas each STL container deals with essentially one type of element, a graph needs to contain two types: a vertex type and an edge type. Furthermore, while most STL algorithms confine themselves to handling just those STL container elements, most graph algorithms also need the properties of vertices and/or edges as input. BGL delegates some of the responsibility of property storage to the Boost Property Map Library. I'm just glad the developers kept the complexity down to its current level. > While I understand that the BGL is deeply entrenched > in boost culture, certain academic circles, and even > publications, I nonetheless suggest that BGL lacks > the ease of use necessary for widespread adoption. Having dwelt in the academic circle known as the University of Central Florida, and thus familiar with the theoretical uses of a graph library (plus I've studied some game development apps on the side), I'd like to learn more about how the Real World would want to use BGL. > Even knowing that ease-of-use is not a criterion > for acceptance into boost, looking at what is > required of the client to use the BGL always leaves > me feeling perplexed. Is there any particular reason > that a simplified interface is not made available? Again, I don't know a simple graph problem that requires a simplified graph interface. > Perhaps a container adapter could be packaged with > the library allowing a compromise of functionality > and flexibility for simplicity? I thought the boost::vector_as_graph class template served that purpose. Wrap it around a std::vector<EdgeList>, with EdgeList = std::list<unsigned int> (or an edge list container of your choice, so long as the value type is usable as an index in the vector), and you should be good to go. > If a graphing problem is trivial, shouldn't BGL > provide a trivial solution? Why are the simplest > useful examples several hundred lines of code? The examples don't seem that big and hard to understand. Of course, quite a few of them have #ifdefs that I could do without since I don't use the compilers in question, but I can live with them. > I apologize for all of my vague criticisms - my > intention is not to flame but rather to test the > waters. Your criticisms seem healthy, and I hope my responses are helpful. > It is difficult for me to assess whether the > simplicity I yearn for isn't present for stylistic > reasons or whether it would rather necessitate a > sacrifice of flexibility, functionality or > implementation clarity. Nor is it clear to me to > what extent these criteria can be compromised to > promote clarity of client code. For what it is > worth, the kind of ease-of-use I'm imagining might > look like: #include <less_than_10_graph_headers> ... digraph<some_node_type,some_edge_context_type> g; g << "vertex" << make_pair("vertex", "implicit_vertex"); g.add_edge("brother", "sister", "sibling"); if(g.find(make_pair("brother", "sister"))) related = true; > Could someone please elucidate on why it is > impossible/impractical/unnecessary/whatever for a > graph library to have such an interface? I believe the potential for ambiguity would hinder this syntax the most. In this case, you'd have to overload operator<< to input both edges and vertices, and what if some_node_type turned out to be std::pair? You couldn't pass in make_pair(vertex,vertex) as an edge then. The same goes for g.find(); is it supposed to find a vertex, an edge, or both? Also, it seems you want to be able to use non-built-in or custom types as vertex IDs. You'll have to build your own custom-type-to-vertex map and bind it to the graph; BGL won't do it for you, to retain its genericity. Incidentally, BGL favors free functions over member functions. The rationale for that can be found in the FAQ <http://www.boost.org/libs/graph/doc/faq.html>. > Should I accept that the BGL is not the magic bullet > graph library and move on, or can this kind of > simplicity be somehow found within? Yeah, no magic bullets here. It depends on the problem you are trying to solve. Cromwell Enage __________________________________ Do you Yahoo!? Yahoo! Finance Tax Center - File online. File on time. http://taxes.yahoo.com/filing.html

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Re: [BGL] forced client complexity
by Christopher D. Russell 31 Mar '04

31 Mar '04

A well written critique. I had to go look up the word "prolix" (i.e. verbose). In defense of BGL: I am no BGL expert despite having read the book several times and writing a complex client application that uses dozens of different graph types. I admit, it was some hard work getting going with BGL. However, this is because I didn't know C++ templates nearly as well as I thought I did. Certainly there's nothing in the library that would preclude anyone from writing simpler BGL-derived classes that offer solutions that are packaged to solve specific problems. Post specific problems and people will help. > It is difficult for me to assess whether the > simplicity I yearn for isn't present for stylistic > reasons or whether it would rather necessitate a > sacrifice of flexibility, functionality or > implementation clarity. Having become baseline proficient with BGL, I would disagree that it's overly complex. To me BGL is an elegant solution to a class of very complex problems that strikes a reasonable balance between complexity and flexibility. In my opinion, if you frequently use graphs BGL is well worth the investment required to learn how to use it. - Chris "Provisional Dissonance" <prosonance(a)yahoo.com> wrote in message news:20040331094800.93338.qmail@web60105.mail.yahoo.com... > If one accepts the axiom that "a picture is worth a > thousand words," then it naturally follows that > discussion of graphs is always overly prolix. Sadly, > the same reasoning is also applicable to the code of > graph libraries. Boost.Graph seems to expose and > require an unnecessarily large amount of complexity, > though. Whereas libraries like Spirit go to great > lengths to make hard things easy, BGL seems to try > only to make hard things possible. The amount of > scaffolding required to use BGL for even the simplest > of projects often dwarfs the code size of a naive, yet > functional, special-purpose implementation. > > While I understand that the BGL is deeply entrenched > in boost culture, certain academic circles, and even > publications, I nonetheless suggest that BGL lacks the > ease of use necessary for widespread adoption. Even > knowing that ease-of-use is not a criterion for > acceptance into boost, looking at what is required of > the client to use the BGL always leaves me feeling > perplexed. Is there any particular reason that a > simplified interface is not made available? Perhaps a > container adapter could be packaged with the library > allowing a compromise of functionality and flexibility > for simplicity? If a graphing problem is trivial, > shouldn't BGL provide a trivial solution? Why are the > simplest useful examples several hundred lines of > code? > > I apologize for all of my vague criticisms - my > intention is not to flame but rather to test the > waters. It is difficult for me to assess whether the > simplicity I yearn for isn't present for stylistic > reasons or whether it would rather necessitate a > sacrifice of flexibility, functionality or > implementation clarity. Nor is it clear to me to what > extent these criteria can be compromised to promote > clarity of client code. For what it is worth, the > kind of ease-of-use I'm imagining might look like: > > #include <less_than_10_graph_headers> > ... > digraph<some_node_type,some_edge_context_type> g; > g << "vertex" << make_pair("vertex", > "implicit_vertex"); > g.add_edge("brother", "sister", "sibling"); > if(g.find(make_pair("brother", "sister"))) > related = true; > > Could someone please elucidate on why it is > impossible/impractical/unnecessary/whatever for a > graph library to have such an interface? Should I > accept that the BGL is not the magic bullet graph > library and move on, or can this kind of simplicity be > somehow found within? > > Thanks in advance, > prs > > > __________________________________ > Do you Yahoo!? > Yahoo! Finance Tax Center - File online. File on time. > http://taxes.yahoo.com/filing.html > _______________________________________________ > Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost >

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Re: boost::variant's and > 10 supported types
by Aleksey Gurtovoy 31 Mar '04

31 Mar '04

Eric Friedman writes: > Preston A. Elder wrote: > > How do I support > 10 types in a variant without having support for > > make_variant_over (since I wish to still support Borland and MSVC 6/.NET > > (aka. 7, not 7.1), as well as gcc). > > To solve your problem under the current implementation, you need a > greater value for BOOST_MPL_LIMIT_LIST_SIZE. I'm unfortunately not > attuned enough to the MPL implementation to know what is involved in > attaining this; I've CCed this to Aleksey Gurtovoy (the MPL maintainer), > who may be able to help you. Just #define-ing BOOST_MPL_LIMIT_LIST_SIZE to something that is a multiple of 10 (e.g. 20) before including Boost headers should work. -- Aleksey Gurtovoy MetaCommunications Engineering

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