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Re: [Boost-users] [variant] not copy-constructable
by Bjorn.Karlsson＠readsoft.com 17 Jul '05

17 Jul '05

> From: Felipe Magno de Almeida [mailto:felipe.m.almeida@gmail.com] > > What I wanted is a vector of variant<object1, object2> and I dont want > object1 and object2 to be copied because it is expensive. But Im not > figuring out how to do this... tried boost::ref either with no > success... :/ Boost.Smart_ptr (http://www.boost.org/libs/smart_ptr/smart_ptr.htm) can help: use boost::shared_ptr, which is a reference-counted smart pointer. typedef boost::variant<object1,object2> variant_type; std::vector<boost::shared_ptr<variant_type> > vec; boost::shared_ptr<variant_type> v(new variant_type(object1())); vec.push_back(v); // No copying of the variant Bjorn Karlsson

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filesystem.dll built with BOOST_ALL_DYN_LINK
by Larry E. Ramey 16 Jul '05

16 Jul '05

Hello all, I just pulled boost from the CVS repository and built the filesystem library. bjam -d2 --with-filesystem This works and links great on my linux system. When I go over to windows with MSVC 7.1 and try to link I get stuck trying to autolink to the static lib. So It looks to me like the proper solution is to uncomment #define BOOST_ALL_DYN_LINK in the boost/config/user.hpp file. So I do that. Now we are trying to link to the .dll. Good. Only problem is I have two undefined symbols. (demangled) boost::filesystem::path::iterator::increment boost::filesytem::path::iterator::decrement So what did I do wrong? I can't believe I'm the first person to have this problem, but I couldn't find anything in the FAQ or mailing list archives. -- This e-mail and any attachments may contain confidential and privileged information. If you are not the intended recipient, please notify the sender immediately by return e-mail, delete this e-mail and destroy any copies. Any dissemination or use of this information by a person other than the intended recipient is unauthorized and may be illegal. Unless otherwise stated, opinions expressed in this e-mail are those of the author and are not endorsed by the author's employer.

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gcc 4.0 and none_t
by Vincent Torri 16 Jul '05

16 Jul '05

Hello, I have installed boost 1.33, compiled with gcc 4.0. In a program, I use none_t like that: third(subContextBlock.localCtxt) = val( boost::detail::none_t() ) and gcc reports this error: ../../src/parser/grammar/statement.cpp:143: error: 'none_t' is not a member of 'boost::detail' I don't understand at all... Does someone see any problem ? Also, I don't understand the '*' in the definition of none_t. Could someone explain this Thank you Vincent Torri

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Regex Compile Problem
by Chris Coleman 16 Jul '05

16 Jul '05

Hi, While working on a project of ours I have come accross this problem using boost-1.32 on Mac OS X 10.4: It appears to be related to the regex library. <snip> Making all in mantrad source='mantra_request_admin.cpp' object='mantra_request_admin.o' libtool=no \ depfile='.deps/mantra_request_admin.Po' tmpdepfile='.deps/mantra_request_admin.TPo' \ depmode=gcc3 /bin/sh ../../depcomp \ g++ -DHAVE_CONFIG_H -I. -I. -I../.. -I.. -I../libs/sockets -I../libs/sigaware -I../libs/threadpool -Wall -g -D_THREAD_SAFE -c -o mantra_request_admin.o `test -f 'mantra_request_admin.cpp' || echo './'`mantra_request_admin.cpp /opt/local/include/boost/regex/v4/char_regex_traits.hpp: In member function 'uint_fast32_t boost::deprecated::char_regex_traits_i<wchar_t>::lookup_classname(const wchar_t*, const wchar_t*) const': /opt/local/include/boost/regex/v4/char_regex_traits.hpp:68: error: 'boost::re_detail::c_traits_base::<anonymous enum>' is/uses anonymous type /opt/local/include/boost/regex/v4/char_regex_traits.hpp:68: error: trying to instantiate 'template<class T> struct boost::is_integral' make[3]: *** [mantra_request_admin.o] Error 1 make[2]: *** [all-recursive] Error 1 make[1]: *** [all-recursive] Error 1 make: *** [all] Error 2 </snip> The thing is I have not had this problem on any other platform, or indeed 2 other Mac's running an (as far as I'm aware) identical setup. Does anyone have any ideas as to the possible cause of this? Many Thanks Chris This message has been checked for viruses but the contents of an attachment may still contain software viruses, which could damage your computer system: you are advised to perform your own checks. Email communications with the University of Nottingham may be monitored as permitted by UK legislation.

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Re: [Boost-users] Container/Algorithm question
by JOAQUIN LOPEZ MU?Z 16 Jul '05

16 Jul '05

----- Mensaje original ----- De: Elisha Berns <e.berns(a)computer.org> Fecha: Viernes, Julio 15, 2005 7:40 pm Asunto: Re: [Boost-users] Container/Algorithm question > Thanks Joaquin, > > Your code worked perfectly and probably sped up the application by a > factor of 3. Such a large speedup hints at an improvement on algorithmic complexity. My proposal has O(log n) insertion and O(log n) lookup. > One thing though, out of curiosity, what kind of > containerdoes Boose.MultiIndex use internally? Strictly speaking, Boost.MultiIndex does not rely on any external container. A multi_index_container, though, is composed of several indices, each of which is roughly modelled after some std:: container. Ordered indices, which are the ones used in this case, behave like std::set, so the proposal is equivalent to a hand made container using two std::sets --actually, it should be more efficient than the hand made option. > And is there any > way to further > optimize Boost.MultiIndex by specifying what type of container is used > internally? > Yes. Starting with Boost 1.33. Boost.MultiIndex provides hashed indices, which, if properly used, can yield better performance both at insertion and lookup wrt ordered indices. I'm compiler-disabled during weekends, so let me come back to you next Monday with alternatives to my first proposal taking advantage of hashed indices. Have a nice weekend, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo PS: I'm curious, in which context do you need this kind of rather odd container?

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Boost.Spirit bug report [Was: Bug report on Boost 1.32 lib]
by Aleksey Gurtovoy 15 Jul '05

15 Jul '05

Ulzii Luvsanbat <batul(a)microsoft.com> writes: > Hi Aleksey, Hi Ulzii, > > I got this email address from boost.org, if you're not the right person > please forward this to the appropriate folks. The most appropriate place for bug reports would be either of our two main mailing lists (http://www.boost.org/more/mailing_lists.htm) to one of which I'm cc-ing. Please see http://www.boost.org/more/bugs.htm for the more details on the Boost bug reporting policy. > We believe we ran into a > bug in Boost 1.32 library. Here are the details: > > Basically boost_1_32_0\libs\spirit\test\bug_fixes.cpp test is failing > for us with Visual C++ Compiler. > > In range_run.ipp file: > > template <typename CharT> > inline bool > range_run<CharT>::test(CharT v) const > { > if (!run.empty()) > { > const_iterator iter = > std::lower_bound( > run.begin(), run.end(), v, > range_char_compare<CharT>() > ); > > if (iter != run.end() && iter->includes(v)) > return true; > > if (iter != run.begin()) > return (--iter)->includes(v); > } > > return false; > > } > > but range_char_compare::operator() in > boost\spirit\utility\impl\chset\range_run.hpp does not accept the same > types as arguments: > > template <typename CharT> > struct range_char_compare { > > bool operator()(range<CharT> const& x, const CharT y) const > { return x.first < y; } > > bool operator()(const CharT x, range<CharT> const& y) const > { return x < y.first; } > }; > > Now, in our lower_bound implementation (in Debug) we > assume/enforce that Predicate is a valid ordering on the (First, Last) > interval. > > The C++ Standard says: > > 25.3.3 Binary search [lib.alg.binary.search] > > 1 All of the algorithms in this section are versions of > binary search and assume that the sequence being searched is in > order according to the implied or explicit comparison function. > > The explicit comparison function provided to lower_bound in the > repro case cannot be applied on the sequence being searched. Thus, we > cannot check the assumption of 25.3.3.1. > > The test passes if we add one more overload in range_char_compare, > something like: > > template <typename CharT> > struct range_char_compare { > bool operator()(range<CharT> const& x, const CharT y) const > { return x.first < y; } > > bool operator()(const CharT x, range<CharT> const& y) const > { return x < y.first; } > > bool operator()(range<CharT> const& x, range<CharT> const& y) const > { return x.first < y.first; } > > }; > > Can you please confirm this? I believe http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2001/n1313.html covers this exact issue in detail. HTH, -- Aleksey Gurtovoy MetaCommunications Engineering

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very basic boost::filesystem::path question
by Peter Koch Larsen 15 Jul '05

15 Jul '05

Hi boosters I have a very basic question. Why does path("s:/dbgdata/testdata.2") throw the exception boost::filesystem::filesystem_error with the errormessage "boost::filesystem::path: invalid name "s:" in path: "s:/dbgdata/testdata.2"? It certainly looks as if I've overlooked something quite fundamental. I'm using MSVC 8-0 Beta 2 and boost version 1.32.0. Kind regards Peter Koch Larsen

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Container/Algorithm question
by Elisha Berns 15 Jul '05

15 Jul '05

Hi, I have some confusion regarding which type of container/algorithm to use to optimize the lookup (not necessarily the insertion) of unique pairs where the definition of unique is: Either member of the pair can occur an infinite/unbounded number of times provided the other member of the pair never occurs more than once: (3,4), (3,5), (3,6), (6,6), (5,6), (4,6)... etc. So what am I looking at? Some container that allows multiple keys of the same value provided the value is always unique. And also multiple values of the same value provided the key is always unique. Is there such a thing, or something better suited? Thanks, Elisha Berns e.berns(a)computer.org tel. (310) 556 - 8332 fax (310) 556 - 2839

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tuple
by Jim Pritts 15 Jul '05

15 Jul '05

Hello, Is it possible to do something like the following: typedef boost::tuple<double, int, int> element; std::vector<element> d; std::vector<element>::iterator i = std::max_element(d.begin(), d.end(), bind(std::max<double>,bind(get<0>,_2),_1)); In other words, I would like the functionality of select1st with std::pair. Thanks, Jimmy.

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partial specialization: mpl?
by Cory Nelson 15 Jul '05

15 Jul '05

I have a function like: template<typename CharT> void foo() { std::basic_string<CharT> str; ... if(str=="bar") ... } I'd like to check at compile time if CharT is a char or wchar_t to specialize the string used to compare- MPL seems like the thing I would use for this but documentation on doing this seems scarce. Could someone give me an example? -- Cory Nelson http://www.int64.org

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