- Boost-users - lists.boost.org

Re: [string_algo] Split and Predicates
by David Brownell 28 Jan '05

28 Jan '05

Thanks for your quick response, Pavol, this did the trick and cleared up my misunderstanding. Might I suggest an overloaded version of split that takes a string/character string as a delimiter. Althought the implementation details are different, I still think it fits well into the intent of the split algorithm and may clear up issue for others have the same problem as I did. Thanks again for your help! David Brownell "Pavol Droba" <droba(a)topmail.sk> wrote in message news:<20050128071103.GC31065(a)lenin.felcer.sk>... > Hi, > > > It is possible to achieve what you want quite easily. However, split algorithm > is not the right tool for this. > Split is a high level wrapper over the split_iterator and it is quite specialized. > > So this is the code, that should work for you: > > #include <boost/algorithm/string/find_iterator.hpp> > #include <boost/algorithm/string/finder.hpp> > > static char const STRING[] = "this\r\nis\r\n\r\na test!"; > > typedef boost::split_iterator<const char*> char_split_iterator; > > for(char_split_iterator It=char_split_iterator(STRING, boost::first_finder("\r\n"); > It!=char_split_iterator(); > ++It) > { > cout << *It << endl; > } >

1 0

Date-Time gregorian::date construction question
by Wolfgang Fertsak 28 Jan '05

28 Jan '05

If a date object is constructed from an invalid date(e.g. Feb 29th, 2005) and the values are specified in the constructor, an exception is thrown. If the object is constructed from a string representation with from_string(), no exception is thrown and the object has the next valid date (in this case Mar 1st, 2005). Is this a bug or a feature? Best regards, Wolfgang #include <iostream> #include <boost/date_time/gregorian/gregorian.hpp> using namespace boost::gregorian; using namespace std; int main() { try { // throws exception date Date1(2005,2,29); string strDate("2005-02-29"); // throws no exception date Date2 = from_string(strDate); // output is 2005-03-01 cout << to_iso_extended_string(Date2) << endl; } catch(std::exception&e) { cout << e.what() << endl; } return 0; }

5 7

Warnings in date_time
by John Eddy 28 Jan '05

28 Jan '05

Hello, I just started using the date-time library and it is a great library. There are a few warnings that I have noticed so far that could be avoided with some explicit casts. I am using VC .NET 2003. Here are the ones I've noticed so far: in microsec_time_clock.hpp on line 102 which reads: boost::uint32_t sub_sec = (filetime % 10000000) / 10; // microseconds same file, line 118 which reads: int adjust = resolution_traits_type::res_adjust()/1000000; in time_system_counted.hpp on line 57 which reads: typename calendar_type::date_int_type dc = day_count(); in date_parsing.hpp on line 211 which reads: ss << ss.narrow(*beg++, 'X'); // 'X' will cause exception to be thrown Thanks, John

2 1

Error Compiling Boost Graph example/graphviz.cpp
by Welson Sun 28 Jan '05

28 Jan '05

Hi, I would like to parse the graphviz dot file using your read_graphviz in the boost graph library. However, when I compiling the example/graphviz.cpp file, I got the following error: $ g++ graphviz.cpp /cygdrive/c/DOCUME~1/welson/LOCALS~1/Temp/cctY52MA.o(.text+0x602):graphviz.c pp: undefined reference to `boost::read_graphviz(std::basic_string<char, std::char_ raits<char>, std::allocator<char> > const&, boost::subgraph<boost::adjacency_li t<boost::vecS, boost::vecS, boost::directedS, boost::property<boost::vertex_att ibute_t, std::map<std::basic_string<char, std::char_traits<char>, std::allocato <char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> , std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, td::allocator<char> > const, std::basic_string<char, std::char_traits<char>, st ::allocator<char> > > > >, boost::no_property>, boost::property<boost::edge_att ibute_t, std::map<std::basic_string<char, std::char_traits<char>, std::allocato <char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> , std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, td::allocator<char> > const, std::basic_string<char, std::char_traits<char>, st ::allocator<char> > > > >, boost::property<boost::edge_index_t, int, boost::no_ roperty> >, boost::property<boost::graph_graph_attribute_t, std::map<std::basic string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string< har, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_strin <char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pa r<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, b ost::property<boost::graph_vertex_attribute_t, std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::ch r_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std:: har_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic string<char, std::char_traits<char>, std::allocator<char> > const, std::basic_s ring<char, std::char_traits<char>, std::allocator<char> > > > >, boost::propert <boost::graph_edge_attribute_t, std::map<std::basic_string<char, std::char_trai s<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char> std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<cha >, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, s d::char_traits<char>, std::allocator<char> > const, std::basic_string<char, std :char_traits<char>, std::allocator<char> > > > >, boost::property<boost::graph_ ame_t, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, oost::no_property> > > >, boost::listS> >&)' collect2: ld returned 1 exit status However, I can use the write_graphviz to generate the .dot file from a graph, which means I have compiled the library correctly. Do you have any idea what is going on here? Best Regards, Welson Sun ------------------------------------- Electrical and Computer Engineering Brigham Young Unversity 461 CB, Provo, Utah 84602 Office: (801) 422-7206 Email: welson(a)et.byu.edu -------------------------------------

2 1

exception safety of boost graph library
by Ovidiu Deac 28 Jan '05

28 Jan '05

Hello everybody, We are going to use boost graph library within our application and I would like to know if there are any known issues regarding the exception safety. Is the basic guarantee satisfied? Is the strong guarantee satisfied? (see Herb Sutter's definition of basic/strong guarantee in Exceptional C++) "Basic guarantee: Even in the presence of exceptions thrown by T or other exceptions, Stack objects don't leak resources. Note that this also implies that the container will be destructible and usable even if an exception is thrown while performing some container operation. However, if an exception is thrown, the container will be in a consistent, but not necessarily predictable, state. Containers that support the basic guarantee can work safely in some settings. Strong guarantee: If an operation terminates because of an exception, program state will remain unchanged. This always implies commit-or-rollback semantics, including that no references or iterators into the container be invalidated if an operation fails. For example, if a Stack client calls Top and then attempts a Push that fails because of an exception, then the state of the Stack object must be unchanged and the reference returned from the prior call to Top must still be valid." (Herb Sutter, Exceptional C++) Thank you, vidu

2 1

[string_algo] Split and Predicates
by David Brownell 28 Jan '05

28 Jan '05

I am attempting to split a string with the string_algo library, using the code below. It appears that the split algorithm is designed to split on instances of individual characters rather than sequences of characters. Is there something I can do to split on a substring? The code below illustrates the problem, where I am forces to use the is_any_of predicate rather than something that implies equality. It seems like this is a trivial use of the algorithm, so there could easily be something that I am missing. typedef std::vector<boost::iterator_range<char const *> > ResultsType; ResultsType results; static char const STRING[] = "this\r\nis\r\n\r\na test!"; boost::split(results, boost::iterator_range<char const *>(STRING, STRING + sizeof(STRING)), boost::is_any_of("\r\n")); // The problem is here. I would like to be able // to use something like equals, but split requires // a predicate that takes a single argument rather than // a range. for(ResultsType::const_iterator rptr = results.begin(); rptr != results.end(); ++rptr) std::cout << "'" << std::string(rptr->begin(), rptr->end()) << "'\n"; Thanks! David Brownell

2 1

Graphs (boost1.32.0) Trouble with dijkstra visitor and VC 7.1
by Tony Juricic 28 Jan '05

28 Jan '05

Has anybody created custom dijkstra_shortest_paths algorithm visitor for discover_vertex event? I am having all sorts of compilation errors using MSVC 7.1 and defining my visitor using example code. Reshuffling the code (but at this point I hardly know what am I really doing) I got the following to compile: // define visitor for discover_vertex event template <class Vertex, class Tag> struct target_visitor : public default_dijkstra_visitor { target_visitor(Vertex u) : v(u) { } template <class Vertex, class Graph> void discover_vertex(Vertex u, Graph& g) { if ( u==v ) assert(0); } private: Vertex v; }; template <class Vertex, class Tag> target_visitor<Vertex, Tag> target_visit(Vertex u, Tag) { return target_visitor<Vertex, Tag>(u); } ... // call dijkstra_shortest_paths with custom visitor // parameters below are defined as in dijkstra-example.cpp dijkstra_shortest_paths(g, s, predecessor_map(&p[0]).distance_map(&d[0]).visitor(target_visit(D, on_discover_vertex()))); Tony Confused

2 1

error in boost/graph/fruchterman_reingold.hpp
by Jamie Wilkinson 28 Jan '05

28 Jan '05

The doc at http://boost-consulting.com/boost/libs/grpah/doc/fruchterman_reingold.html suggests that there is a 4 argument version of the function, taking only the graph, a position map, width and height; but attempts to compile such a function against the headers from the latest CVS results in a compile error: error: no matching function for call to ` fruchterman_reingold_force_directed_layout(Umbrella::Document&, Umbrella::View::load_from_document()::PositionMap&, double&, double&)' Removing the typenames Param, Tag, and Rest from lines 371-372 of the header allows the compile to continue. Index: boost/graph/fruchterman_reingold.hpp =================================================================== RCS file: /cvsroot/boost/boost/boost/graph/fruchterman_reingold.hpp,v retrieving revision 1.5 diff -u -c -r1.5 fruchterman_reingold.hpp cvs diff: conflicting specifications of output style *** boost/graph/fruchterman_reingold.hpp 29 Dec 2004 16:53:05 -0000 1.5 --- boost/graph/fruchterman_reingold.hpp 12 Jan 2005 09:18:16 -0000 *************** *** 368,375 **** params); } ! template<typename Graph, typename PositionMap, typename Dim, typename Param, ! typename Tag, typename Rest> void fruchterman_reingold_force_directed_layout(const Graph& g, PositionMap position, --- 368,374 ---- params); } ! template<typename Graph, typename PositionMap, typename Dim> void fruchterman_reingold_force_directed_layout(const Graph& g, PositionMap position,

4 4

Bind Overload Workaround?
by Duane Murphy 28 Jan '05

28 Jan '05

How do I work around this problem with bind? #include <boost/bind.hpp> namespace { class functions { public: int func( int ); int func( int, int ); }; void test() { functions a_func; boost::bind( functions::func, a_func, 1, _1 ); } } Bind can't determine which function to call because it is overloaded and it doesn't know the context in which it will be called. With CodeWarrior 8 on Mac OS X I get "illegal use of template argument dependent type 'T::result_type' It references an "unspecified" template deep in the bowels of bind. As I recall there was some way of helping bind to pick one of the overloaded functions using a typedef or something similar. (Maybe that was function?). Thanks for any tips, ...Duane

2 2

boost serialization
by Daniel Goller 28 Jan '05

28 Jan '05

are there any problems with boost serialization including linker errors or does this indicate a broken install i have heard of problems with boost serialization but do not know which they might be before running off in the wrong direction i figured i would gather information here to solve this: http://bugs.gentoo.org/show_bug.cgi?id=78043 problem any help on this will be appreciated Daniel

4 6