March 2005 - Boost-users - lists.preview.boost.org

[Boost-users] Re:[Foreach]TroubleiteratingoverBoost.MultiIndexcontainers
by Arkadiy Vertleyb 09 Mar '05

09 Mar '05

Thorsten, I admit that my understanding of the problem was too simplistic, and apologize for being judgmental. (although I still think ADL-based solutions should be avoided, if only because of the GCC issue. Or, the GCC support should not be claimed) Regards, Arkadiy

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indirect_iterator of reverse_iterator
by Thomas Matelich 08 Mar '05

08 Mar '05

Hello, I'm a little behind the times and am trying to port my old iterator_adapters code to use the new library (1.32). We have a class which is little more than a wrapper around a vector<shared_ptr<T> >, and I am having a heck of a time with setting its typedef for reverse_iterator and const_reverse_iterator. I just can't get const_reverse_iterator to do assignment and comparison with reverse_iterator. I've tried to make indirect_iterators out of the native reverse iterators, using boost::reverse_iterators of indirect_iterators, and a number of more complicated combinations of the 3. No matter which I try I get errors about the const_reverse_iterator not playing nicely with the reverse_iterator. I think I've read everything on the list archives about indirect_iterator, but perhaps I missed something. I'm going to try my code on g++ (currently using VC 7.1) and then work on a complete example, but I thought I'd throw this out and see if someone can quickly answer it. Thanks, Tom

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Trouble converting johnson_all_pairs to use file IO.
by David E. Konerding DSD staff 08 Mar '05

08 Mar '05

Hi folks, I'm trying to convert the Boost Graph Library example from a graph built in the code, to one that usses the adjacency_list_io supporto load the graph from a file. I was able to convert the dijkstra example this way, and had no problems. I'm getting a weird error when I disable GRAPH_CODE (this example is very close to the true example in the boost source distribution): test.cpp: In function `int main(int, char**)': test.cpp:44: no matching function for call to `johnson_all_pairs_shortest_paths (main(int, char**)::Graph&, int[V][V], boost::bgl_named_params<int*, boost::vertex_distance_t, boost::no_property>)' Here's the actual code;l anybody have suggestions? #include <boost/config.hpp> #include <fstream> #include <iostream> #include <iomanip> #include <vector> #include <boost/property_map.hpp> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/adjacency_list_io.hpp> #include <boost/graph/johnson_all_pairs_shortest.hpp> int main(int argc, char **argv) { using namespace boost; typedef adjacency_list<vecS, vecS, directedS, no_property, property< edge_weight_t, int, property< edge_weight2_t, int > > > Graph; typedef std::pair < int, int >Edge; #if defined GRAPH_CODE const int V = 5; Edge edge_array[] = { Edge(0, 1), Edge(0, 4), Edge(0, 2), Edge(1, 3), Edge(1, 4), Edge(2, 1), Edge(3, 2), Edge(3, 0), Edge(4, 3) }; const std::size_t E = sizeof(edge_array) / sizeof(Edge); Graph g(edge_array, edge_array + E, V); property_map < Graph, edge_weight_t >::type w = get(edge_weight, g); int weights[] = { 3, -4, 8, 1, 7, 4, -5, 2, 6 }; int *wp = weights; graph_traits < Graph >::edge_iterator e, e_end; for (boost::tie(e, e_end) = edges(g); e != e_end; ++e) w[*e] = *wp++; #else std::ifstream graph_in(argv[1]); Graph g; graph_in >> read( g ); const int V = num_vertices(g); #endif std::vector < int >d(V, (std::numeric_limits < int >::max)()); int D[V][V]; johnson_all_pairs_shortest_paths(g, D, distance_map(&d[0])); return 0; }

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regex: JavaScript RegEx to boost::regex conversion
by pps 08 Mar '05

08 Mar '05

Hello, I have problem creating case less, global match and multi line regexes in boost and I'd like to ask for a few examples of equivalent (Javascript's RegEx <-> boost::regex) regex test js: string.match( /^abc/ ) string.match( /^abc/i) string.match( /^abc/g) string.match( /^abc/m) c++ regex_match(string, regex("^abc"), match_default) regex_match(string, regex("^abc"), match_default | icase) // <- is it correct? regex_match(string, regex("^abc"), ?? ) //global match? regex_match(string, regex("^abc"), ?? ) //multi line? also I'd like to ask what are the proper namespaces/typedefs/enums I have to use for match flags (for example, there's boost::regex_constants::icase and boost::regex::icase etc...) Thank you

2 2

bjam: rule SubInclude unknown in module Jamfile
by Andre Stechert 08 Mar '05

08 Mar '05

Hi, I'm trying to make pmade software's netxx package available via darwinports, but I'm running into some trouble from bjam. In particular, while doing the build, bjam fails like this: ... DEBUG: Assembled command: 'cd "/Users/andrestechert/darwinports/dports-local/devel/netxx/work/netxx -0.4.2" && NETXX_JAM=bjam MACOSX_DEPLOYMENT_TARGET=10.3 bjam --prefix=/opt/local -sTOOLS=darwin -sBOOST_BUILD_PATH=/opt/local/share/boost-build/' Jamfile:4: in modules.load rule SubInclude unknown in module Jamfile</Users/andrestechert/darwinports/dports-local/devel/netxx/work/ netxx-0.4.2>. /opt/local/share/boost-build/build/project.jam:255: in load-jamfile /opt/local/share/boost-build/build/project.jam:67: in project.load /opt/local/share/boost-build/build-system.jam:75: in load /opt/local/share/boost-build//kernel/modules.jam:259: in import /opt/local/share/boost-build//kernel/bootstrap.jam:120: in boost-build /opt/local/share/boost-build//boost-build.jam:1: in module scope ... I can't find any related bugs in the archive and strings `which bjam` | grep SubInclude yields: rule SubInclude which indicates to me that jambase.c is properly including SubInclude into the bjam binary. Anyone have a hint as to why bjam wouldn't be able to find the SubInclude rule? Apologies if this is a newbie question, this is my first adventure with boost.jam... Thanks in advance, Andre

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segfault in boost program options when using gcc 4.0
by Stephen Torri 07 Mar '05

07 Mar '05

I am testing out gcc 4.0 with an application that I am building. I found that there is a segfault in the command line parser for boost program options. While I understand that boost has yet to officially support gcc 4.0 I want to alert the developers to a potential problem. Ofcourse this needs to be investigated to ensure that the compiler is not the cause of the error. If it is then I can forward the test program attached along with the boost developer's response to the gcc developers. --------- G++ compiler ------------ bash-2.05b$ /usr/local/bin/g++ -v Using built-in specs. Target: i686-pc-linux-gnu Configured with: ../gcc/configure : (reconfigured) ../gcc/configure Thread model: posix gcc version 4.0.0 20050226 (prerelease) ---------- Boost version ------------- boost 1.32-r1 (Gentoo 2004.3 profile) --------- Program backtrace --------- Program received signal SIGSEGV, Segmentation fault. __gnu_cxx::__pool<true>::_M_reclaim_block (this=0x80518c0, __p=0x80555d8 "", __bytes=0) at mt_allocator.cc:222 222 const size_t __which = _M_binmap[__bytes]; Current language: auto; currently c++ (gdb) bt #0 __gnu_cxx::__pool<true>::_M_reclaim_block (this=0x80518c0, __p=0x80555d8 "", __bytes=0) at mt_allocator.cc:222 #1 0x0804bf97 in __gnu_cxx::__mt_alloc<std::string, __gnu_cxx::__common_pool_policy<__gnu_cxx::__pool, true> >::deallocate () #2 0x0804bfc1 in std::_Vector_base<std::string, std::allocator<std::string> >::_M_deallocate () #3 0x0804bff9 in std::_Vector_base<std::string, std::allocator<std::string> >::~_Vector_base () #4 0x0804c0a6 in std::vector<std::string, std::allocator<std::string> >::~vector () #5 0x0804c0e5 in boost::program_options::common_command_line_parser::~common_command_line_parser () #6 0x0804c13b in boost::program_options::basic_command_line_parser<char>::~basic_command_line_parser () #7 0x0804e0a3 in boost::program_options::parse_command_line<char> () #8 0x0804a5c2 in main () (gdb) quit Stephen

1 0

boost::unary_traits
by Matthias Kaeppler 07 Mar '05

07 Mar '05

Hello, I have written an adaptor for functions and function objects which allows to invoke operations on the pointees when working on a collection of pointers. For example, it allows to sort a list of pointers by a predicate applying to the pointees. To make it work with normal functions and functors, I utilized boost::unary_traits and boost::binary_traits. This is the class template for the unary version: template< typename Operation > class indirecter_unary : public std::unary_function< typename boost::unary_traits<Operation>::argument_type, typename boost::unary_traits<Operation>::result_type > { typedef typename boost::unary_traits<Operation>::argument_type arg_type; typedef typename boost::unary_traits<Operation>::param_type param_type; typedef typename boost::unary_traits<Operation>::result_type result_type; typedef typename boost::unary_traits<Operation>::function_type function_type; function_type op_; public: explicit indirecter_unary( param_type op ): op_(op) {} result_type operator() (arg_type *arg) const { return op_(*arg); } }; Now, the problem arises when I pass a function which takes references. Like this: bool pred( int& a ) { //... } indirecter_unary< bool ()(int&) > fctor(pred); ext::indirecter_unary<bool ()(int&)>': code/FileBrowser.cpp:90: instantiated from here code/ext/indirect.hpp:80: error: forming pointer to reference type `int&' Line 80 is the line where operator() is defined. The error message indicates that argument_type is obviously not correct in this context. I thought the boost traits would take care of the right argument types? Am I missing something? -- Matthias Kaeppler

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Safe downcast of a shared_ptr?
by steve ahlgren 07 Mar '05

07 Mar '05

Hello : Is there safe/easy way to downcast shared pointers? ie boost::shared_ptr< Derived_Type > dPtr = [appropriate_method_here] ( base_ptr ); Thanks in advance; Steve a.

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[regex] Is there any function to know where the input fails to match a regex?
by jordi 07 Mar '05

07 Mar '05

Hello, Maybe my question is a silly question but I have a recurrent problem and maybe there is an easy solution: I need to create a lot of regex expressions to match several Unix command outputs. Usually, my firsts regex definitions are wrong and they don't match, so when the match fails I would like to know where the "problem" is (more or less) in order to change the regular expression. For example: Input text: "123 hello abc" My first wrong Regex: "(\d)+\s+(\w)+\s+(\d)+" If I try to match this input against the regex using regex_search with the boost::match_continuous flag I only have the false value returned by the function but it doesn't help me to know that the "123 hello" matched the regex because the problem starts at "abc" trying to match "(\d)+". I can simulate what I need checking subexpressions adding every iteration a new "sub-regex" and stopping when the match fails (I do it manually, changing the regex). With my undefined funtion I would obtain: - Input text:"123 hello abc" - Latest rigth Regular expression: "(\d)+\s+(\w)+\s+" Matches: "123 hello " - First wrong regex: "(\d)+\s+(\w)+\s+(\d)+" does not match. -> So, "(\d)+" does not match "abc" I understand that usually this is not as easy as I write in my simple example because of the power of regular expressions but I think a function like that would improve a lot the error reporting capabilities. Is there any way to do what I need or I must to write my own check function? Best regards, Jordi

4 7

Borland compiler error E2437
by Roman Morokutti 07 Mar '05

07 Mar '05

Hi, I am not able to compile function_base.hpp at lines 595(55), 607(55), 616(55), 625(55). Error E2437 D:\boost\boost_1_32_0\boost/function/function_base.hpp 598(55): 'typename' should be followed by a qualified, dependent type name Does anyone know a workaround for this? Greetings Roman

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