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Unit testing Questions
by Thomas Thorp 25 Sep '07

25 Sep '07

I'm a newbie with boost and have some questions about unit testing- 1 - In looking for documentation, I see that most of the sample links on the boost.org site for unit testing examples are dead. Is there another place I can see them. 2 - Is there a good tutorial on all of the features of boost testing? It looks really good, but it seems to be really hard to follow. 3 - Is there a way to test for 1.#QNAN in a floating point value? This is part of my initialization sequence. "BOOST_CHECK_EQUAL" results a failure. Thanks in advance. Thomas Thorp Senior Software C++ Engineer Advanced Composite Software - Production

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Re: [Boost-users] Question about pool.
by 蹬三轮的 25 Sep '07

25 Sep '07

> We use boost pool in our project and we found boost's pool may occupy > too much memory. Say, if we need a block of memory which size is > 1317B, boost's pool will allocate a truck of memory 5268B on a 32bits > platform, leave 3951 bytes unused (it get worse on 64bits platform). I > don't think it is necessary to allocate 5268B, for the sake of > performance, only 1320B is enough for align. It should be resovled > because pool is so important to many large application. pool allocates several blocks of memory at once, then divvies them out. Nothing is wasted. Or did you have something else in mind? -- Cory Nelson Hi Nelson, thanks for your reply. According to the description of pool, it should be working like you said. But actually it is not the same. Hereby, there are two cases provided. I think you will find two totally different results between them. 1. blocksize = 1316 Everything is ok. . 2. blocksize =1317 Disaster! You can notice the waste allocated memory. I just want case 2 to run like case 1. Following is the code, you can check it. 1. i: 0 need: 41(KB) alloc: 41(KB) waste: 8(B) i: 32 need: 82(KB) alloc: 82(KB) waste: 8(B) i: 96 need: 164(KB) alloc: 164(KB) waste: 8(B) i: 224 need: 329(KB) alloc: 329(KB) waste: 8(B) i: 480 need: 658(KB) alloc: 658(KB) waste: 8(B) i: 992 need: 1(MB) alloc: 1(MB) waste: 8(B) i:2016 need: 2(MB) alloc: 2(MB) waste: 8(B) i:4064 need: 5(MB) alloc: 5(MB) waste: 8(B) i:8160 need: 10(MB) alloc: 10(MB) waste: 8(B) 2. i: 0 need: 41(KB) alloc: 164(KB) waste: 123(KB) i: 32 need: 82(KB) alloc: 329(KB) waste: 246(KB) i: 96 need: 164(KB) alloc: 658(KB) waste: 493(KB) i: 224 need: 329(KB) alloc: 1(MB) waste: 987(KB) i: 480 need: 658(KB) alloc: 2(MB) waste: 1(MB) i: 992 need: 1(MB) alloc: 5(MB) waste: 3(MB) i:2016 need: 2(MB) alloc: 10(MB) waste: 7(MB) i:4064 need: 5(MB) alloc: 20(MB) waste: 15(MB) i:8160 need: 10(MB) alloc: 41(MB) waste: 30(MB) here is the sample code: #include <iostream> #include <boost/pool/pool.hpp> #include <iomanip> #include <boost/lexical_cast.hpp> using namespace std; int i = 0; int nextSize = 0; int blockSize = 1317; string sizeFormat(int n) { if (n < 1024) { return boost::lexical_cast <string> (n) + "(B)"; } else if (n < 1048576) { return boost::lexical_cast <string> (n / 1024) + "(KB)"; } else { return boost::lexical_cast <string> (n / 1048576) + "(MB)"; } } struct MyAllocator { typedef std::size_t size_type; typedef std::ptrdiff_t difference_type; static char * malloc(const size_type bytes) { int need = nextSize * blockSize; int waste = bytes - need; cout << "i:" << setw(4) << i << " need:" << setw(10) << sizeFormat(nextSize * blockSize) << " alloc:" << setw(10) << sizeFormat(bytes) << " waste:" << setw(10) << sizeFormat(waste) << endl; return new (std::nothrow) char[bytes]; } static void free(char * const block) { delete [] block; } }; int main() { //typedef std::vector <int, MA <int> > MYVector; boost::pool <MyAllocator> intPool(blockSize); for (i = 0; i < 10000; ++i) { nextSize = intPool.get_next_size(); intPool.malloc(); } }

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problem with boost::any, boost::lambda
by Fei Liu 25 Sep '07

25 Sep '07

The following small code snippet does not compile with boost 1.33.1. What did I do wrong or the library is limited in what it can do? g++ -fstrict-aliasing -fomit-frame-pointer -Wall -pedantic -ansi -g -O2 anytest.cpp -o anytest anytest.cpp: In function ‘int main()’: anytest.cpp:22: error: ‘const struct boost::lambda::lambda_functor<boost::lambda::placeholder<1> >’ has no member named ‘type’ gcc version 4.1.1 20060525 (Red Hat 4.1.1-1) #include <iostream> #include <string> #include <vector> #include <algorithm> #include <boost/any.hpp> #include <boost/lambda/lambda.hpp> #include <boost/lambda/if.hpp> using namespace std; using namespace boost::lambda; using namespace boost; using boost::any_cast; int main(){ vector<any> a; any val = 3; a.push_back(val); val = string("456"); a.push_back(val); std::for_each(a.begin, a.end(), if_then(_1.type() == typeid(int))[cout << _1 << ' ']); }

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boost lambda document example does not compile
by Fei Liu 25 Sep '07

25 Sep '07

Hello, group I am trying out the code snippet in http://www.boost.org/doc/html/lambda/le_in_details.html 'Naming delayed constants and variables'. I got some compile errors complaining about synthesized method error with the following code: #include <iostream> #include <boost/lambda/lambda.hpp> #include <boost/ref.hpp> #include <vector> #include <iterator> #include <algorithm> using namespace std; using namespace boost::lambda; using namespace boost; int main(){ int i = 1; (_1 += 2)(i); // i is now 3 (++_1, cout << _1 << '\n')(i); // i is now 4, outputs 4 int j = 40; _1 = j; var(i) = _1 = j; cout << i << '\n'; vector<int> a; a.reserve(10); a.resize(10); //for_each(a.begin(), a.end(), istream_iterator<int>(cin)); // for_each(a.begin(), a.end(), cin >> _1); i = 0; for_each(a.begin(), a.end(), (_1 = var(i)++)); // delayed evaluation through 'var' for_each(a.begin(), a.end(), cout << _1 << ' '); cout << '\n'; for_each(a.begin(), a.end(), cout << ' ' << _1); cout << '\n'; for_each(a.begin(), a.end(), (var(j) = _1, _1 = var(i), var(i) = var(j))); //<------------ Error for_each(a.begin(), a.end(), cout << _1 << ' '); cout << '\n'; }

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[multi_index] modify problem with composite_key
by Jeffrey Holle 24 Sep '07

24 Sep '07

I am having problems using the modify method with my composite_key. Here is my multi_index container definition: typedef multi_index_container< entry, indexed_by< ordered_unique<member<entry,DataVertex,&entry::m_vertex> >, ordered_non_unique< composite_key< entry, member<entry,int,&entry::m_y>, member<entry,int,&entry::m_x> > > > > C; C m_c; namespace ll=boost::lambda; typedef nth_index<C,1>::type XYINDEX; I have a XYINDEX::iterator that is defined using the equal_range method of an XYINDEX order. Now I wish to modify the m_x attribute that this iterator points to so I attempt to write: inline void Positioner::updateX(XYIterator iter,int x) { m_c.modify(iter,(&ll::_1)->*&Positioner::entry::m_x=x); } I get this compiler error: positioner.h:77: error: no matching function for call to 'boost::multi_index::multi_index_container<Positioner::entry, boost::multi_index::indexed_by<boost::multi_index::ordered_unique<boost::multi_index::member<Positioner::entry, unsigned int, &Positioner::entry::m_vertex>, mpl_::na, mpl_::na>, boost::multi_index::ordered_non_unique<boost::multi_index::composite_key<Positioner::entry, boost::multi_index::member<Positioner::entry, int, &Positioner::entry::m_y>, boost::multi_index::member<Positioner::entry, int, &Positioner::entry::m_x>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>, mpl_::na, mpl_::na>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, std::allocator<Positioner::entry> >::modify(boost::multi_index::detail::bidir_node_iterator<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::index_node_base<Positioner::entry> >, mpl_::na>&, const boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::other_action<boost::lambda::assignment_action>, boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::action<2, boost::lambda::other_action<boost::lambda::member_pointer_action> >, boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::other_action<boost::lambda::addressof_action>, boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> > >, int Positioner::entry::* const, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> > >, const int, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> > >)' I have also tried: m_c.modify_key(iter,ll::_1=x); But this gives me this error: positioner.h:78: error: no matching function for call to 'boost::multi_index::multi_index_container<Positioner::entry, boost::multi_index::indexed_by<boost::multi_index::ordered_unique<boost::multi_index::member<Positioner::entry, unsigned int, &Positioner::entry::m_vertex>, mpl_::na, mpl_::na>, boost::multi_index::ordered_non_unique<boost::multi_index::composite_key<Positioner::entry, boost::multi_index::member<Positioner::entry, int, &Positioner::entry::m_y>, boost::multi_index::member<Positioner::entry, int, &Positioner::entry::m_x>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>, mpl_::na, mpl_::na>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, std::allocator<Positioner::entry> >::modify_key(boost::multi_index::detail::bidir_node_iterator<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::index_node_base<Positioner::entry> >, mpl_::na>&, const boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::other_action<boost::lambda::assignment_action>, boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, const int, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> > >)' While a method like this compiles and works, I would like to be more efficent: inline void Positioner::updateX(DataVertex vertex,int x) { C::iterator iter=m_c.find(vertex); assert(iter!=m_c.end()); m_c.modify(iter,(&ll::_1)->*&Positioner::entry::m_x=x); } Can somebody tell me if what I'm trying to do is possible? If so, how?

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[continued][boost::fusion v2 and xpressive] versioning conflicts...
by Ovanes Markarian 24 Sep '07

24 Sep '07

Eric, sorry for the delay. I only now found some time to work on that issue: http://lists.boost.org/boost-users/2007/08/30120.php After analysing your post and investigation what's going on, I would like to write my opinion: changing xpressive_fwd.hpp or proto_fwd.will not help. I grepped where fusion includes are used and need to enclose these in some conditional statements: #ifdef BOOST_XPRESSIVE_FUSION_V2 # include ... //fusion 2 headers #else # include ... // fusion 1 headers #endif Actually this can be done using some kind of a macro function like: #include BOOST_XPRESSIVE_FUSION_ROOT(sequence/cons.hpp) ... The macro function will deliver the root dependent on the predefined macros like: 1. if !defined XPRESSIVE_FUSION_ROOT and use V2 => choose the root for V2 else => choose the root for V1 As I found out the following files need to be changed: linker.hpp alternate_matcher.hpp alt_compilers.hpp any.hpp cons.hpp arg_traits.hpp op_base.hpp proto_fwd.hpp If you give me your green light I will do it and submit a patch. With Kind Regards, Ovanes

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boost lambda document example does not compile
by Fei Liu 24 Sep '07

24 Sep '07

Hello, group I am trying out the code snippet in http://www.boost.org/doc/html/lambda/le_in_details.html 'Naming delayed constants and variables'. I got some compile errors complaining about synthesized method error with the following code: #include <iostream> #include <boost/lambda/lambda.hpp> #include <boost/ref.hpp> #include <vector> #include <iterator> #include <algorithm> using namespace std; using namespace boost::lambda; using namespace boost; int main(){ int i = 1; (_1 += 2)(i); // i is now 3 (++_1, cout << _1 << '\n')(i); // i is now 4, outputs 4 int j = 40; _1 = j; var(i) = _1 = j; cout << i << '\n'; vector<int> a; a.reserve(10); a.resize(10); //for_each(a.begin(), a.end(), istream_iterator<int>(cin)); // for_each(a.begin(), a.end(), cin >> _1); i = 0; for_each(a.begin(), a.end(), (_1 = var(i)++)); // delayed evaluation through 'var' for_each(a.begin(), a.end(), cout << _1 << ' '); cout << '\n'; for_each(a.begin(), a.end(), cout << ' ' << _1); cout << '\n'; for_each(a.begin(), a.end(), (var(j) = _1, _1 = var(i), var(i) = var(j))); <------------ Error for_each(a.begin(), a.end(), cout << _1 << ' '); cout << '\n'; }

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[ptr_container] Does ptr_map delete objects if inserting fails?
by Boris 24 Sep '07

24 Sep '07

struct foo { }; boost::ptr_map<int, foo> bar; bar.insert(1, new foo()); bar.insert(1, new foo()); Does this code leak? Or does bar delete the second instance of foo? Boris

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Thread, communicate data from main program to thread(s) and back
by Torsten Mohr 24 Sep '07

24 Sep '07

Hi, i've set up an example of a main program that starts two threads and then sends some data to those thread(s). When the thread(s) have processed the data they should notify the main program/thread and wait for new data. I'd like to make sure that what i write is also portable and does not just by chance work on the platform i use. boost::condition seems to be the right thing to look at, is that right? Is there some example for data communication between threads available? Best regards, Torsten.

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[ptr_container] Why is the key passed to ptr_map by non-const reference?
by Boris 24 Sep '07

24 Sep '07

Before anyone refers me to the FAQ at http://www.boost.org/libs/ptr_container/doc/faq.html#why-does-ptr-map-t-ins… - I read it. While it's clear why a reference is used I don't understand why it is a *non-const* reference. Any reason why it's not const? Boris

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scheming with spirit
by jono 24 Sep '07

24 Sep '07

hello all, i'm building a scheme interpreter with spirit and boost. it needs to be simple and robust enuf for a demanding production environment. i've looked for evidence of somebody else having built a scheme or lisp with spirit and boost, and have been surprised to find nothing. it seems like something that almost falls out of the existing classes (variant, shared_ptr, spirit..). it amazes me how few people understand the simplicity of power of lisp and the interpreter pattern in general. the first paper on lisp was published in 1958, and you only have to look at xml to see how relevant list processing is today. an optimal lisp implementation built with spirit & boost could be extremely concise and elegant, but i'm pretty new to spirit and i'm not sure i have the time to find it. my efforts so far are pure kludgery. i think a lisp interpreter included in the boost example code, or even a full boost class, would be very useful. with traits specialization it could be very flexible, and it would introduce an interesting tool for prototyping and testing other boostified code. does anybody know of an existing spirit/lisp implimentation, and is there any interest in developing such a project in open source? cheers jono poff Day One Digital Media Ltd. Auckland, NZ

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[type_traits] Interesting problem with is_base_of.
by Seweryn Habdank-Wojewódzki 23 Sep '07

23 Sep '07

Dears There are two codes. The first is workig as it is specified in the documentation, but the second not. Why there are problems with the second code? Regards. // This code works perfectly #include <boost/type_traits.hpp> #include <boost/static_assert.hpp> #include <boost/utility.hpp> template <typename B, typename R> class test { public: test () { BOOST_STATIC_ASSERT((boost::is_base_of<B, R>::value)); } }; int main() { test <int, int> t (); } // The code belo is not working #include <boost/type_traits.hpp> #include <boost/static_assert.hpp> #include <boost/utility.hpp> template <typename B> class test { public: template <typename R> test (R const &) { BOOST_STATIC_ASSERT((boost::is_base_of<B, R>::value)); } }; int main() { test <int> t (static_cast<int>(0)); } -- |\/\/| Seweryn Habdank-Wojewódzki \/\/

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[serialization]Is it ok to use the trunk version?
by Sean Huang 23 Sep '07

23 Sep '07

We really want to get the improvements (header order and threading issue) made on the trunk over 1.34.1 but the regression results make us very nervous. We only intend to use it with Intel 10 and MSVC8 and do not generate any dlls so I assume majority of the test failures do not really matter to us. Still many tests fail on Intel C++ v10. Could somebody explain to me what these errors mean and their impact on product code? I noticed there are still a branch created for the next release so I assume some work is being done. Regards, Sean

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dijkstra_shortest_paths usage problem
by Juho Eskeli 23 Sep '07

23 Sep '07

Hi, I've got a following problem: is it possible to add extra cost to edge weight if changing direction? What I mean is I have created a map of vertexes with weights and each vertex has edges to general cardinal points (n,ne,e,se,s,sw,w,nw). Now that the algorithm has found a shortest distance from origin to, let's say southeast. Now all the other edges than the one going southeast are penalized. Figure of the situation: | -o- <- starting point | Least distance > o-o <- Penalized | o <- Not penalized, moving to south o denotes a vertex, - and | are edges I presume dijkstra visitor should be used for this, but I'm too much of a newbie. Any help appreciated.

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math_toolkit bindings/rr.hpp
by Jordan Kyriakidis 23 Sep '07

23 Sep '07

The function template <class V> void assign_large_int(V a) inside boost::math::ntl::RR contains the lines t = static_cast<double>(a & 0xffff); m_value += ldexp(RR(t), exp).value(); My compiler (powerpc-apple-darwin8-g++-4.0.1) complains about the second line: error: cannot convert 'boost::math::ntl::RR' to 'double' for argument '1' to 'double ldexp(double, int)' I assume this is because it cannot see the function definition for RR ldexp(RR r, int exp) defined further down in RR.hpp. This trivial patch fixes the error for me: math_toolkit/boost/math/bindings$ svn diff rr.hpp Index: rr.hpp =================================================================== --- rr.hpp (revision 39435) +++ rr.hpp (working copy) @@ -25,6 +25,9 @@ namespace ntl { +class RR; +RR ldexp(RR r, int exp); + class RR { public: math_toolkit/boost/math/bindings$ but there may (probably?) be similar errors for the other functions. Cheers, Jordan

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A need for a COOKBOOK
by dhruva 23 Sep '07

23 Sep '07

Hi, I am trying to get more into BOOST than what I am using currently (which is quite minimal compared to what BOOST has to offer these days) and which does not include a whole lot of new things that have got into BOOST. Are there any BOOST professionals willing to come up with a COOKBOOK for using BOOST libraries? The book "Beyond the C++ Standard Library: An Introduction to Boost" has a decent coverage but is quite dated compared to the leap BOOST library suite has seen in the recent days. As a user of BOOST, I request someone with good knowledge to come up with a COOKBOOK (like the PERL/PYTHON cookbook) for the benefit for BOOST users. It could be modeled along the PYTHON COOKBOOK. Activestate has a site to submit recipes and those are taken up, polished and edited into a nice book. with best regards, dhruva -- Dhruva Krishnamurthy Contents reflect my personal views only!

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[iterator_facade] problem with dereference method
by Jeffrey Holle 23 Sep '07

23 Sep '07

I'm attempting to write a simple iterator, but am having problems with it. The following code snippet shows the datum that is used to feed the iterator, the beginning of the iterator class, the method that is producing a compiler error, and the error. typedef std::vector<DataEdge> Edges; struct NeighboringEdgeInfo { NeighboringEdgeInfo() : size(0),current_pos(0) {} NeighboringEdgeInfo(size_t size_,size_t current_pos_) : size(size_),current_pos(current_pos_) {} Edges::const_iterator start; size_t size; size_t current_pos; }; class AdjacentEdgeIter : public boost::iterator_facade<AdjacentEdgeIter,DataEdge,boost::forward_traversal_tag> { .... inline const DataEdge& AdjacentEdgeIter::dereference() const { return *(node.start+node.current_pos); <<< produces the error } The error: iterator_facade.hpp:517: error: invalid initialization of reference of type 'boost::detail::edge_desc_impl<boost::bidirectional_tag, unsigned int>&' from expression of type 'const boost::detail::edge_desc_impl<boost::bidirectional_tag, unsigned int>' Note that I have tried to make the NeighboringEdgeInfo::start iterator mutable to avoid this error, but it didn't help. Can somebody explain what is going on??

1 1

Iteration with cycling and clamping.
by Michael Marcin 22 Sep '07

22 Sep '07

I have some code which cycles through items in a list as the user presses buttons. I need to be able to move forward and backwards through this list and apply a filtering predicate. For lists that cycle through the available items when operator++ is called on the last iterator before end that satisfies the predicate it the iterator should point to the first element that satisfies the predicate. When operator-- is called on that iterator it should point to the last iterator before end again. For lists that traverse the available items without cycling when operator++ is called on the last iterator before end that satisfies the predicate the iterator should point to the same element. When operator-- is called on the first iterator that satisfies the predicate the iterator should point to the same element. The logic isn't very hard but I'd rather not duplicate it. Are there any available iterator adaptors that perform these operations at the range limits? Thanks, Michael Marcin

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container performance on 64 bit systems
by Bruce Adams 22 Sep '07

22 Sep '07

Hi, This may seem slightly off topic initially but bear with me. I have recently been having fun with the ordinary STL containers on a 64bit linux system. In particular the sorted associative containers set and map bloat the memory usage to an unacceptable level. Part of this is down to 64 bit pointers versus 32 bit pointers. In a standard Red-Black tree implementation each node has 3 pointers, these double in size as do any pointers in the containers themselves. There are also issues with allocating on 8byte and 16byte boundaries. I measured and discovered that an otherwise highly efficient structure took *10* times as much memory on a 64bit machine vs. the 32bit one. I can half the memory usage for a std::set by replacing it with a std::vector and sorting it manually. Nothing too out of the ordinary there. To solve my problem I have replaced a large number of 64bit pointers with indices and manipulate std::vector's of these instead of using associative containers. Are there any 'better' implementations of std::set etc. (preferably open source GNU/Linux compatible) out there? Are any planned? Does boost contain any suitable replacements? Does boost itself suffer from or tackle this 64bit bloat problem? Regards, Bruce. ____________________________________________________________________________________ Boardwalk for $500? In 2007? Ha! Play Monopoly Here and Now (it's updated for today's economy) at Yahoo! Games. http://get.games.yahoo.com/proddesc?gamekey=monopolyherenow

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Re: [Boost-users] [multi-index] possible extension
by Ovanes Markarian 21 Sep '07

21 Sep '07

Joaquin, to be honest I did it also the way deriving from the boost::noncopyable and multi_index_container class. The only problem is the need of initializing constructors, which are either not available or must be explicitly overridden in the derived class. If standard containers are lacking this functionality it is not a reason to avoid it in a lib which stands for technology or ideas after standard containers. On the other hand I would like to point out that it is possible to specify a default policy of being copyable for a container. Only if someone wishes the container to be noncopyable she/he can/should specify it. There would be no change in the external interface for usage if the user is not aware of this feature. Best Regards, Ovanes. > On 9/21/07, Joaquin M Lopez Munoz <joaquin(a)tid.es> wrote: > > > > Hello Ovanes, > > > > Ovanes Markarian <om_boost <at> keywallet.com> writes: > > > > > > > > Hello Joaquín,I would like to make a proposal for additional feature > > of > > > optionaly making multi-index container non-copyable (via copying > > policy > > > class). The same way as a user can decide which indicies to use she/he > > > could specify whether the new data-structure should be copyable or > > not. > > > In my case I was assuming to pass container by reference, but it was > > > copied by some function object. Which produced despite the performane > > > issue wrong results. Using the non-copyable policy I would simply get > > a > > > compiler error. > > > > With all due respect, I don't think this is a feature > > worth including into the lib because: > > > > 1. All standard containers are copyable, I don't see > > any compelling reason to deviate from that. > > 2. The overlook you mention could have happened with almost > > any other kind of object, having this particular type patched > > makes little difference In the grand scheme of things. > > > > Anyway, you can have your own noncopyable_multi_index_container > > by simply deriving from multi_index_container and providing > > the necessary forwading constructors (save copy, of course). > > Maybe this is sufficient for your needs. > > > > Best, > > > > Joaquín M López Muñoz > > Telefónica, Investigación y Desarrollo > > > > _______________________________________________ > > Boost-users mailing list > > Boost-users(a)lists.boost.org > > http://lists.boost.org/mailman/listinfo.cgi/boost-users > > >

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[boost-users] boost-python linker error problem.
by chun ping wang 21 Sep '07

21 Sep '07

building a simple Dfa library, i get some linker problem. Its trying to open a file that does not exist. I attach two files.. what is inside my boost_msvc\lib folder. and the diagonsis of errors and warnings. Mainly the problem is that its trying to find "boost_python-vc80-mt-1_34_1.lib" which does not exist since i build boost with layout=system

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[multi-index] possible extension
by Ovanes Markarian 21 Sep '07

21 Sep '07

Hello Joaquín, I would like to make a proposal for additional feature of optionaly making multi-index container non-copyable (via copying policy class). The same way as a user can decide which indicies to use she/he could specify whether the new data-structure should be copyable or not. In my case I was assuming to pass container by reference, but it was copied by some function object. Which produced despite the performane issue wrong results. Using the non-copyable policy I would simply get a compiler error. With Kind Regards, Ovanes

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[python]
by Gennadiy Rozental 21 Sep '07

21 Sep '07

Hi, In my new company we are using Boost.Python. Boost version is 1.33.1. It's my first steps with the library, so please bare with me if this is something trivial. I've got this noncopyable class Foo class Foo : boost::noncopyable { /*...*/ }; and shift operator defined: Foo& operator<<( Foo& foo, int ) { ... return foo; } Here is my export statement (FooSP is smart pointer on Foo using namespace boost::python; class_<Foo, FooSP, bases<FooBase>, boost::noncopyable>( "Foo", no_init ) .def( self << int() ) ; Here is my Python script extract that is being executed from C++ "foo << 2 << 4" I never got to the second shift call. Instead I an getting exception from Boost.Python: TypeError: No to_python (by-value) converter found for C++ type: class A I kinda found couple ways to deal with it: 1. define operator<< to return FooSP, which I do not like for assymetry and other reasons 2. avoid using self << int() and define explicit function: Foo& shift_op( Foo& foo, int ) { ... return foo; } ... .def( "__lshift__", &shift_op, return_internal_reference<1>() ) What is the proper way to deal with it? And why original error is reported? Gennadiy

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[mpl] Instantiating a vector of factory functions
by Dan Posluns 21 Sep '07

21 Sep '07

Okay, I'm a lot closer to my goal of having an automated factory of objects that are dynamically polymorphic but have their inheritance set up through static means. What I have now is something like this: // My factory template template<class Base, class Derived> struct Factory { Base *create() { return new Derived(); } }; // My vector of factories for the different Derived types typedef mpl::vector< Factory<Base, Derived1>, Factory<Base, Derived2>, Factory<Base, Derived3> > MyFactories; (I actually use MPL to automatically cross and combine different classes, which is pretty cool.) Now I could create a vector of the same length with every type as a pointer to a Factory function, and with Fusion I could probably instantiate it (although I haven't got that working yet). But that still wouldn't get me what I want, which is a table of those factory functions that I can index into at run-time. Can anyone suggest a technique for doing this? Thanks, Dan. -- Dan Posluns, B. Eng. & Scty. (Software Engineering and Society) dan(a)danposluns.com - ICQ: 35758902 http://www.danposluns.com "The great thing about being the only species on the planet that makes a distinction between right and wrong is that we get to make the rules up for ourselves as we go." - Douglas Adams, Last Chance to See

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[date_time/general] license question
by Olaf Krzikalla 21 Sep '07

21 Sep '07

Hi all, In the date_time library there is the libs\date_time\xmldoc\license.xml covering the date_time library. It states that the copyright notice of the date_time library has to "appear in supporting documentation". Does this includes manuals for commercial binaries? I m'wondering because IMHO this wouldn't comply with point 4 of the boost license requirments as written at www.boost.org/more/license_info.html#requirements OTOH I'm neither a lawyer nor a native english speaker so I'm sure I misinterpret something. Can anyone shed some light on this? Thanks Olaf Krzikalla

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