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

type_traits::is_POD<> problem
by s9801758 06 Jun '02

06 Jun '02

Hello, I'm using MSVC6.0 with service-pack 6.0 installed. But I'm getting some weird problems. Consider the following simple program: ---------------------------------------------------- struct q { int x; }; int main() { int t; t = boost::is_POD< int >::value; // Ok, t = true; t = boost::is_POD< void >::value; // Ok?, t = true (is 'void' considered a POD?); t = boost::is_POD< q >::value; // Error, t = false } ---------------------------------------------------- Unless my definition of a POD type is incorrect, I think that q is considered POD, right? Am I doing something wrong here, or is the combination boost and msvc fatal once again? Just to be complete, I have the following defines in my main header: #define BOOST_NO_FUNCTION_PTR_TEMPLATE_PARAMETERS #define BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION Thanks in advance, Jaap Suter

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Boost regex and MacOS X.
by Mystical Catty Tananeka 06 Jun '02

06 Jun '02

I've been trying to make MacOS X compile the example snippets from boost_1_28_0/libs/regex/example/snippets/ and I keep getting these messy link errors. It looks like /usr/bin/c++ is having trouble linking to libboost_regex.a here's an example: localhost% c++ -o regex_grep_example_1 regex_grep_example_1.cpp -lboost_regex /usr/bin/ld: Undefined symbols: __._Q25boostt14reg_expression3ZcZQ25boostt12regex_traits1ZcZt9allocator1Zc ___Q25boostt14reg_expression3ZcZQ25boostt12regex_traits1ZcZt9allocator1ZcPCc UiRCB2 ___Q35boost9re_detailt18match_results_base2ZPCcZt9allocator1ZcRCB1 _allocator__CQ25boostt14reg_expression3ZcZQ25boostt12regex_traits1ZcZt9alloc ator1Zc _allocator__CQ35boost9re_detailt18match_results_base2ZPCcZt9allocator1Zc _cow__Q35boost9re_detailt18match_results_base2ZPCcZt9allocator1Zc _m_free__Q35boost9re_detailt18match_results_base2ZPCcZt9allocator1Zc _set_first__Q35boost9re_detailt18match_results_base2ZPCcZt9allocator1ZcPCc _set_first__Q35boost9re_detailt18match_results_base2ZPCcZt9allocator1ZcPCcUl _set_size__Q35boost9re_detailt18match_results_base2ZPCcZt9allocator1ZcUlPCcn 1 localhost% I haven't enough experience with boost to know how to fix this, or even what it means, exactly. If its informative, c++ -v returns: Apple Computer, Inc. version gcc-934.3, based on gcc version 2.95.2 19991024 (release)

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BGL: subgraph<..> Problems
by Matthias Kronenberger 06 Jun '02

06 Jun '02

1. How to create a subgraph from a given simple boost graph type? 2. Why are modell subgraph not the same concept as the underlying graph type? Why are not all non-member function defined for the only graph modell adjacence_list<> also available for subgraph? 3. I've defined something like class NG { public: typedef boost::property<boost::vertex_all_t, SomeIterator, Vertex_Property > vertex_SPIterator_Prop; // GridSP_type::iterator typedef Default::Graph<vertex_SPIterator_Prop, Edge_Property>::Subgraph::Undirected Graph; ... }; where struct Default { ..... template<class VertexProperties=boost::no_property, class EdgeProperties=boost::no_property, class GraphProperties=boost::no_property, class EdgeList=boost::hash_setS, class VertexList=boost::listS > struct Graph { ........ struct Subgraph { typedef typename boost::subgraph < boost::adjacency_list<EdgeList, VertexList, boost::undirectedS, boost::property<boost::vertex_index_t,int, VertexProperties>, boost::property<boost::edge_index_t, int, EdgeProperties > ,GraphProperties> > Undirected; }; .... }; and then i'm doing somewhere else { vertex_descriptor v=boost::add_vertex( theGraph); IteratorMap[Prop ] =v; boost::put( boost::vertex_all_t() , theGraph, v, Prop); return v; } I get a nice error with MSVC 6.5 d:\matthias\programmieren\boost\boost\graph\subgraph.hpp(751): error C2679: Binaerer Operator '=': Kein Operator definiert, der einen rechtsseitigen Operator vom Typ 'const _Ht_iter<pair<int const,surrect::PNSurfel<vectorD<float,3>>>,_Nonconst_trait............ (no operator= defined for the type conversion used in put pmap[k] = val;) But using a simple adjacence_list<..> instead of the subgraph< adjacence_list<...> this mess compiles fine. What am i doing wrong? Are there better ways to create a property map containing (const) iterators, that don't modell STL::RandomAccesIterator? Matthias

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RE: [Boost-Users] Re: boost::noncopyable usage question
by Michael Davis 06 Jun '02

06 Jun '02

According to the C++ Standard, 12.8/10, the assignment operator cannot be inherited because if it is not provided, the compiler will provide one implicitly. Or at least, that is my understanding of it. Given this, how can boost::noncopyable work?

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RE: [Boost-Users] boost::noncopyable usage question
by Mark Storer 05 Jun '02

05 Jun '02

This is more of a C++ question than a boost one (which is why I can answer it;). Your deletes are fine. The only way this would cause a problem is to delete through a boost::noncopyable pointer (in which case everything derived from it would leak). I'm guessing the author, Dave Abrahams, didn't think anyone was going to declare a noncopyable*, so decided to pass on that little bit of extra overhead involved in declaring a destructor virtual. Or it could be a mistake. Dave has posted to this list at least once... So tell us, did you mean to leave it non-virtual? --Mark Storer Software Engineer Cardiff Software #include <disclaimer> typedef std::disclaimer<Cardiff> Discard; -----Original Message----- From: Bobby Thomale [mailto:bthomale@mac.com] Sent: Wednesday, June 05, 2002 9:30 AM To: Boost Users List Subject: [Boost-Users] boost::noncopyable usage question I have a simple question about the usage of boost::noncopyable. I think I know the answer, but I am not sure. The noncopyable class defines a non-virtual destructor. Generally speaking, overriding a non-virtual destructor is considered a "bad thing" but in certain cases (like, I am guessing, this one) it is okay and works like you'd expect. Here's what I am worried about: Let's say I have a base class of an inheritance tree that I want to be non-copyable. So I do this: class MyBase : private boost::noncopyable { public: MyBase (); virtual ~MyBase (); ... }; Then I derive from it class A: class A : public MyBase { public: A (); virtual ~A(); }; and define a destructor for class A, too. Does this do what I would expect, ie whether I delete a MyBase* or an A*, it calls the destructors for both A and MyBase like it is supposed to? I suppose the trivial, empty noncopyable destructor never gets called (which is okay) whether I delete a MyBase* or an A*, correct? (Just curious...) -- Bobby --------------------------------------------------------------------- Bobby Thomale Senior Software Developer Inoveon Corporation http://www.inoveon.com/ --------------------------------------------------------------------- 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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boost::noncopyable usage question
by Bobby Thomale 05 Jun '02

05 Jun '02

I have a simple question about the usage of boost::noncopyable. I think I know the answer, but I am not sure. The noncopyable class defines a non-virtual destructor. Generally speaking, overriding a non-virtual destructor is considered a "bad thing" but in certain cases (like, I am guessing, this one) it is okay and works like you'd expect. Here's what I am worried about: Let's say I have a base class of an inheritance tree that I want to be non-copyable. So I do this: class MyBase : private boost::noncopyable { public: MyBase (); virtual ~MyBase (); ... }; Then I derive from it class A: class A : public MyBase { public: A (); virtual ~A(); }; and define a destructor for class A, too. Does this do what I would expect, ie whether I delete a MyBase* or an A*, it calls the destructors for both A and MyBase like it is supposed to? I suppose the trivial, empty noncopyable destructor never gets called (which is okay) whether I delete a MyBase* or an A*, correct? (Just curious...) -- Bobby --------------------------------------------------------------------- Bobby Thomale Senior Software Developer Inoveon Corporation http://www.inoveon.com/ ---------------------------------------------------------------------

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Tupls browsing...
by Igor Korzinek 04 Jun '02

04 Jun '02

Hi, I did not take a look at the tuple internals, but it seems that there is some head-tail connection probably built in compile time. So can someone from template gurus answer if it makes sense and if it is possible to add some method that will make sequential access possible. Some function that will getNext() or some kind of search within a tuple ? Is it too stupid or just impossible ? Igor

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Is it worth using if I use MSVC
by Igor Korzinek 04 Jun '02

04 Jun '02

Hi, I'm new to boost. The doc I've browsed seems fine and something what I need. I'm focusing on TUPLEs part. So, besides mentioned cref and ref stuff, is there any other issue I can expect with awful (but a must for me) MS VC 6 ? And are there any sample for using this part of boost ? THX, Igor

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Newbie Thread Installation Problem
by gclee46 03 Jun '02

03 Jun '02

(Please excuse me it this is a duplicate post - I tried to send it yesterday and it didn't seem to arrive) I have Boost 1_28_0 and installed the prebuilt version of Jam for Windows. After installing threads with C:\boost_1_28_0>bjam "-sTOOLS=borland" I get, after skipping the pyton stuff, and all the install messages: ...found 390 targets... However when I try to use the thread I get the following: Borland C++ 5.5.1 for Win32 Copyright (c) 1993, 2000 Borland testthread1.cpp: Fatal F1003 \boost_1_28_0\boost/thread/thread.hpp 17: Error directive: Thread support is unavailable! *** 1 errors in Compile *** I believe that I followed all the directions...I'm using Windows XP Home. Any help would be greatly appreciated. Greg

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BGL and MS compilers (VC++ and Wince)
by a_schweitzer 03 Jun '02

03 Jun '02

I am having difficulting getting BGL to compiler with VC++ 6.0 and Windows CE 3.0, platform builder. In both cases I get internal compiler errors, although at different lines in the compiler. VC++ worked when I had all my code in one cpp file. When I broke it out into multiple files I couldn't get it to compile even when I put it back in one file. I have tried the Zm and Z7 switches to no avail. Perhaps I need the service pack? Wince dies much more quickly, I think when it sees adjacency_list.hpp or depth_first_search.hpp. Does anyone have some perspective on how BGL projects with MS work out? Is there any hope for Wince?

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