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Simple iterator adaptor example
by Duane Murphy 17 Dec '01

17 Dec '01

I have taken a quick look at iterator adaptor and it seems quite powerful. It seems that iterator_adaptor has two uses. First to adapt one iterator to another. It also seems like it should be able to be used as an interface to other information that has container like qualities that needs an iterator. For example files in directory. Does anyone have an example of how to build one of the later? Not specifically an iterator over files, but the general ability to build an iterator from something that's not an iterator? Thanks for the pointers, ..Duane

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RE: [Boost-Users] MSVC6 and tuple
by Tom Matelich 17 Dec '01

17 Dec '01

Yeah, I also avoid any using in any header, but what are you going to do if you can't compile otherwise? > -----Original Message----- > From: Darin Adler [mailto:darin@bentspoon.com] > Sent: Monday, December 17, 2001 2:15 PM > To: Boost-Users(a)yahoogroups.com > Subject: Re: [Boost-Users] MSVC6 and tuple > > > On 12/17/01 12:36 PM, "Tom Matelich" <tmatelich(a)zetec.com> wrote: > > > Any suggestions? > > This may not be what you have in mind, but in my own code I prohibit: > > using namespace boost; > > But in code outside header files, I always use: > > using boost::tuple; > > And the like, except in cases where there are name conflicts. > So I have > includes at the top of my source files, followed by using statements, > followed by code. > > -- Darin > > > ------------------------ Yahoo! Groups Sponsor > ---------------------~--> > Need new boots for winter? Looking for a perfect gift for > your shoe loving friends? > Zappos.com is the perfect fit for all your shoe needs! > http://us.click.yahoo.com/ltdUpD/QrSDAA/ySSFAA/EbFolB/TM > -------------------------------------------------------------- > -------~-> > > 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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MSVC6 and tuple
by Tom Matelich 17 Dec '01

17 Dec '01

I have a tuple as a member of one of my classes, and it appears, that MSVC 6 requires me to do a using boost::tuple, rather than declaring it with the boost namespace at the var. For this declaration in my header: boost::tuple<int, double> willis; I get the following error: file.h(161) : error C2059: syntax error : '<' file.h(161) : error C2238: unexpected token(s) preceding ';' If I add the using (which I would prefer not to do), the declaration: tuple<int, double> willis; works fine. Any suggestions?

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transitive_closure_test.cpp
by Janos Murvai 17 Dec '01

17 Dec '01

Hi, I compiled this program: transitive_closure_test.cpp with: g++ -ftemplate-depth-30 -I /net/cooler/vol/export/proteome/murvai/CC/BOOST/boost_1_26_0/ transitive_closure_test.cpp then I run: Created graph with 13 vertices. transitive_closure Segmentation fault (core dumped) Exit 139 What can I do in this case? Thank you, Janos

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Why not "if (px != rpx) " ?
by Louis Lavery 17 Dec '01

17 Dec '01

Hello, The following is use by the boost shared_ptr assignment operators (see boost\smart_ptr.hpp)... void share(T* rpx, long* rpn) { if (pn != rpn) { // Q: why not px != rpx? A: fails when both == 0 ++*rpn; // done before dispose() in case rpn transitively // dependent on *this (bug reported by Ken Johnson) dispose(); px = rpx; pn = rpn; } } // share ...I curious to know what it means by "fails when both == 0". I mean, I can't see as the sky would fall in if the test was "if (px != rpx)". Am I missing something? Thanks, Louis.

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preprocessor/min and MSVC
by Rodney.Schuler＠ing-dm.com 14 Dec '01

14 Dec '01

I saw the boost preprocessor library and I thought that BOOST_PREPROCESSOR_MIN might help solve a problem in some code that I am maintaining. This code has the naive implementation of MIN and MAX: #define MIN(a,b) ((a)<(b)?(a):(b)) This code also has many (tens of thousands!) of places where a function calls are used as arguments to MIN and MAX like this: foo=MIN(func(args1),func(args2)) The function called is a very long running function. The performance hit taken by three evaluations of the function is a problem I am working to fix. I know the best solution is to add some local variables, and store the results of the functions in them, then use MIN on the local vars. But I'd like to get some Idea of how much performance increase I am likely to get by crawling through the code and fixing all the occurrences of MIN(func(args1),func(args2)) Wondering if BOOST_PREPROCESSOR_MIN had a way to make only two evaluations of func I wrote: #include <iostream> #include <boost/preprocessor/min.hpp> using std::cout; using std::endl; int func(int i) { cout << " func called " << i << endl; return i; } int main () { cout << "result " << BOOST_PREPROCESSOR_MIN(func(1),func(2)) << "\n" << endl; cout << "result " << BOOST_PREPROCESSOR_MIN(func(4),func(3)) << "\n" << endl; return 0; } And my compilers (MSVC 5 sp3 and MSVC 6 sp5) responded thusly: C:\temp\boostminvc5\main.cpp(15) : error C2065: 'BOOST_PREPROCESSOR_IF_BOOLBOOST_PREPROCESSOR_BOOLBOOST_PREPROCESSOR_IF_BOOLBOOST_PREPROCESSOR_BOOLBOOST_PREPROCESSOR_NOR_BOOLBOOST_PREPROCESSOR_BOOLBOOST_PREPROCESSOR_ADDBOOST_PREPROCESSOR_SUBfunc' : undeclared identifier C:\temp\boostminvc5\main.cpp(15) : error C2065: 'BOOST_PREPROCESSOR_SUBfunc' : undeclared identifier C:\temp\boostminvc5\main.cpp(15) : error C2146: syntax error : missing ';' before identifier 'BOOST_PREPROCESSOR_BOOLBOOST_PREPROCESSOR_ADDBOOST_PREPROCESSOR_SUBfunc' C:\temp\boostminvc5\main.cpp(15) : error C2065: 'BOOST_PREPROCESSOR_BOOLBOOST_PREPROCESSOR_ADDBOOST_PREPROCESSOR_SUBfunc' : undeclared identifier C:\temp\boostminvc5\main.cpp(15) : error C2065: 'BOOST_PREPROCESSOR_NOR_BOOLBOOST_PREPROCESSOR_BOOLBOOST_PREPROCESSOR_SUBfunc' : undeclared identifier C:\temp\boostminvc5\main.cpp(15) : error C2146: syntax error : missing ')' before identifier 'BOOST_PREPROCESSOR_BOOLBOOST_PREPROCESSOR_SUBfunc' C:\temp\boostminvc5\main.cpp(16) : error C2146: syntax error : missing ';' before identifier 'BOOST_PREPROCESSOR_BOOLBOOST_PREPROCESSOR_ADDBOOST_PREPROCESSOR_SUBfunc' C:\temp\boostminvc5\main.cpp(16) : error C2146: syntax error : missing ')' before identifier 'BOOST_PREPROCESSOR_BOOLBOOST_PREPROCESSOR_SUBfunc' First, this is a bug report. Second, can anybody answer my question does BOOST_PREPROCESSOR_MIN get around the unnecessary evaluations problem? Thanks -Rodney Rodney.Schuler(a)ing-dm.com

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run test programs...
by Janos Murvai 13 Dec '01

13 Dec '01

Hi, I'm one new user. I tried to run test programs in the : ..../boost_1_26_0/libs/graph/test When I try to compile: g++ -I /net/cooler/vol/export/proteome/murvai/CC/BOOST/boost_1_26_0/ adj_matrix_cc.cpp I got many error message (some example from the error messages): What can I do in this case? /net/cooler/vol/export/proteome/murvai/CC/BOOST/boost_1_26_0/boost/iterator_adaptors.hpp:817: instantiated from `boost::iterator_adaptor<boost::iterator_adaptor<char *,boost::detail::dir_adj_matrix_out_edge_iter_policies<unsigned int,char *,unsigned int>,boost::detail::matrix_edge_desc_impl<boost::directed_tag,unsigned int>,boost::detail::matrix_edge_desc_impl<boost::directed_tag,unsigned int>,boost::detail::matrix_edge_desc_impl<boost::directed_tag,unsigned int> *,boost::multi_pass_input_iterator_tag,int>,boost::filter_iterator_policies<boost::detail::does_edge_exist,boost::iterator_adaptor<char *,boost::detail::dir_adj_matrix_out_edge_iter_policies<unsigned int,char *,unsigned int>,boost::detail::matrix_edge_desc_impl<boost::directed_tag,unsigned int>,boost::detail::matrix_edge_desc_impl<boost::directed_tag,unsigned int>,boost::detail::matrix_edge_desc_impl<boost::directed_tag,unsigned int> *,boost::multi_pass_input_iterator_tag,int> >,boost::detail::matrix_edge_desc_impl<boost::directed_tag,unsigned int>,boost::detail::matrix_edge_desc_impl<boost::directed_tag,unsigned int>,boost::detail::matrix_edge_desc_impl<boost::directed_tag,unsigned int> *,boost::multi_pass_input_iterator_tag,int>' /net/cooler/vol/export/proteome/murvai/CC/BOOST/boost_1_26_0/boost/graph/adjacency_matrix.hpp:326: instantiated from `boost::adjacency_matrix<boost::directedS,boost::no_property,boost::no_property,boost::no_property,allocator<bool> >' /net/cooler/vol/export/proteome/murvai/CC/BOOST/boost_1_26_0/boost/graph/graph_traits.hpp:38: instantiated from `boost::graph_traits<boost::adjacency_matrix<boost::directedS,boost::no_property,boost::no_property,boost::no_property,allocator<bool> > >' /net/cooler/vol/export/proteome/murvai/CC/BOOST/boost_1_26_0/boost/graph/graph_concepts.hpp:177: instantiated from `boost::VertexListGraphConcept<boost::adjacency_matrix<boost::directedS,boost::no_property,boost::no_property,boost::no_property,allocator<bool> > >' /net/cooler/vol/export/proteome/murvai/CC/BOOST/boost_1_26_0/boost/concept_check.hpp:41: instantiated from `boost::function_requires<boost::VertexListGraphConcept<boost::adjacency_matrix<boost::directedS,boost::no_property,boost::no_property,boost::no_property,allocator<bool> > > >()' adj_matrix_cc.cpp:35: instantiated from here /net/cooler/vol/export/proteome/murvai/CC/BOOST/boost_1_26_0/boost/type_traits/composite_traits.hpp:204: incomplete type `boost::is_member_pointer<char *>' does not have member `value' Thank you, Janos

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run test programs..
by Janos Murvai 13 Dec '01

13 Dec '01

Hi, I'm one new user. I tried to run test programs in the : ..../boost_1_26_0/libs/graph/test When I try to compile: g++ -I /net/cooler/vol/export/proteome/murvai/CC/BOOST/boost_1_26_0/ adj_matrix_cc.cpp I got many error message (some example from the error messages): What can I do in this case? /net/cooler/vol/export/proteome/murvai/CC/BOOST/boost_1_26_0/boost/iterator_adaptors.hpp:817: instantiated from `boost::iterator_adaptor<boost::iterator_adaptor<char *,boost::detail::dir_adj_matrix_out_edge_iter_policies<unsigned int,char *,unsigned int>,boost::detail::matrix_edge_desc_impl<boost::directed_tag,unsigned int>,boost::detail::matrix_edge_desc_impl<boost::directed_tag,unsigned int>,boost::detail::matrix_edge_desc_impl<boost::directed_tag,unsigned int> *,boost::multi_pass_input_iterator_tag,int>,boost::filter_iterator_policies<boost::detail::does_edge_exist,boost::iterator_adaptor<char *,boost::detail::dir_adj_matrix_out_edge_iter_policies<unsigned int,char *,unsigned int>,boost::detail::matrix_edge_desc_impl<boost::directed_tag,unsigned int>,boost::detail::matrix_edge_desc_impl<boost::directed_tag,unsigned int>,boost::detail::matrix_edge_desc_impl<boost::directed_tag,unsigned int> *,boost::multi_pass_input_iterator_tag,int> >,boost::detail::matrix_edge_desc_impl<boost::directed_tag,unsigned int>,boost::detail::matrix_edge_desc_impl<boost::directed_tag,unsigned int>,boost::detail::matrix_edge_desc_impl<boost::directed_tag,unsigned int> *,boost::multi_pass_input_iterator_tag,int>' /net/cooler/vol/export/proteome/murvai/CC/BOOST/boost_1_26_0/boost/graph/adjacency_matrix.hpp:326: instantiated from `boost::adjacency_matrix<boost::directedS,boost::no_property,boost::no_property,boost::no_property,allocator<bool> >' /net/cooler/vol/export/proteome/murvai/CC/BOOST/boost_1_26_0/boost/graph/graph_traits.hpp:38: instantiated from `boost::graph_traits<boost::adjacency_matrix<boost::directedS,boost::no_property,boost::no_property,boost::no_property,allocator<bool> > >' /net/cooler/vol/export/proteome/murvai/CC/BOOST/boost_1_26_0/boost/graph/graph_concepts.hpp:177: instantiated from `boost::VertexListGraphConcept<boost::adjacency_matrix<boost::directedS,boost::no_property,boost::no_property,boost::no_property,allocator<bool> > >' /net/cooler/vol/export/proteome/murvai/CC/BOOST/boost_1_26_0/boost/concept_check.hpp:41: instantiated from `boost::function_requires<boost::VertexListGraphConcept<boost::adjacency_matrix<boost::directedS,boost::no_property,boost::no_property,boost::no_property,allocator<bool> > > >()' adj_matrix_cc.cpp:35: instantiated from here /net/cooler/vol/export/proteome/murvai/CC/BOOST/boost_1_26_0/boost/type_traits/composite_traits.hpp:204: incomplete type `boost::is_member_pointer<char *>' does not have member `value' Thank you, Janos

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boost.regex and submatches
by John Maddock 13 Dec '01

13 Dec '01

>I'm trying to match strings of the form "a&b&c&d" with the following >expression: "(?:([^&]+)&)*([^&]+)". This nicely matches the whole >string but instead of giving me the submatches "a", "b", "c" and "d" >I just get "c" and "d". Could anyone tell me what I'm doing wrong? Look more closely at your expression: it has only *two* marked sub-expressions, $1 gets "overwritten" each time it matches. - John Maddock http://ourworld.compuserve.com/homepages/john_maddock/

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boost.regex and submatches
by markus_schoepflin 13 Dec '01

13 Dec '01

Hi all, I'm trying to match strings of the form "a&b&c&d" with the following expression: "(?:([^&]+)&)*([^&]+)". This nicely matches the whole string but instead of giving me the submatches "a", "b", "c" and "d" I just get "c" and "d". Could anyone tell me what I'm doing wrong? Sample code, tested with MSVC6SP5 and Boost 1.26.0: #include <boost/regex.hpp> #include <string> #include <iostream> void main(void) { const char *input ="a&b&c&d"; const boost::regex syntax("(?:([^&]+)&)*([^&]+)"); boost::cmatch matches; if(boost::regex_match(input, matches, syntax)) { for (boost::cmatch::size_type i = 0; i < matches.size(); ++i) std::cout << static_cast<std::string>(matches[i]) << '\n'; } } Tia, Markus

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