April 2009 - Boost-users - lists.boost.org

bind: what am I doing wrong here?
by Noah Roberts 15 Apr '09

15 Apr '09

Simply want to grab the keys from a map and assign them to a vector: #include <iostream> #include <boost/bind.hpp> #include <map> #include <vector> #include <string> #include <algorithm> // some dumb object struct Test { int x; int y; Test(int a, int b) : x(a), y(b) {} Test() : x(), y() {}}; int main() { std::pair<std::string, Test> p = std::make_pair("Test", Test(1,2)); // works as I expect std::cout << boost::bind(&std::pair<std::string, Test>::first, _1)(p) << std::endl; std::map<std::string,Test> m; m["Test"] = Test(3,4); std::vector<std::string> keys(m.size()); // won't compile: std::transform(m.begin(), m.end(), keys.begin(), boost::bind(&std::pair<std::string,Test>::first, _1)); } It seems to barf on the transform call because of inability to call get_pointer on std::pair<>?? From what I understand of transform though it should be behaving more like the former call (output to stream) that compiles and works: *out_it = op(*in_it) - in fact a test function works. Why is it even attempting to call get_pointer()? Boost version is 1.37.0, compiler is MSVC 8.0 Error output follows: 1>e:\boostvs3\include\boost\mem_fn.hpp(333) : error C2784: 'T *boost::get_pointer(const std::auto_ptr<_Ty> &)' : could not deduce template argument for 'const std::auto_ptr<_Ty> &' from 'const std::pair<_Ty1,_Ty2>' 1> with 1> [ 1> _Ty1=const std::string, 1> _Ty2=Test 1> ] 1> e:\boostvs3\include\boost\get_pointer.hpp(21) : see declaration of 'boost::get_pointer' 1> e:\boostvs3\include\boost\mem_fn.hpp(352) : see reference to function template instantiation 'const R &boost::_mfi::dm<R,T>::call<const U>(U &,const void *) const' being compiled 1> with 1> [ 1> R=std::string, 1> T=std::pair<std::string,Test>, 1> U=std::pair<const std::string,Test> 1> ] 1> e:\boostvs3\include\boost\bind.hpp(222) : see reference to function template instantiation 'const R &boost::_mfi::dm<R,T>::operator ()<A1>(const U &) const' being compiled 1> with 1> [ 1> R=std::string, 1> T=std::pair<std::string,Test>, 1> A1=std::pair<const std::string,Test>, 1> U=std::pair<const std::string,Test> 1> ] 1> e:\boostvs3\include\boost\bind\bind_template.hpp(32) : see reference to function template instantiation 'R boost::_bi::list1<A1>::operator ()<const std::basic_string<_Elem,_Traits,_Ax>&,F,boost::_bi::list1<std::pair<_Ty1,_Ty2> &>>(boost::_bi::type<T>,F &,A &,long)' being compiled 1> with 1> [ 1> R=const std::basic_string<char,std::char_traits<char>,std::allocator<char>> &, 1> A1=boost::arg<1>, 1> _Elem=char, 1> _Traits=std::char_traits<char>, 1> _Ax=std::allocator<char>, 1> F=boost::_mfi::dm<std::string,std::pair<std::string,Test>>, 1> _Ty1=const std::string, 1> _Ty2=Test, 1> T=const std::basic_string<char,std::char_traits<char>,std::allocator<char>> &, 1> A=boost::_bi::list1<std::pair<const std::string,Test> &> 1> ] 1> c:\program files\microsoft visual studio 8\vc\include\algorithm(650) : see reference to function template instantiation 'const std::basic_string<_Elem,_Traits,_Ax> &boost::_bi::bind_t<R,F,L>::operator ()<std::pair<_Ty1,_Ty2>>(A1 &)' being compiled 1> with 1> [ 1> _Elem=char, 1> _Traits=std::char_traits<char>, 1> _Ax=std::allocator<char>, 1> R=const std::basic_string<char,std::char_traits<char>,std::allocator<char>> &, 1> F=boost::_mfi::dm<std::string,std::pair<std::string,Test>>, 1> L=boost::_bi::list1<boost::arg<1>>, 1> _Ty1=const std::string, 1> _Ty2=Test, 1> A1=std::pair<const std::string,Test> 1> ] 1> c:\program files\microsoft visual studio 8\vc\include\algorithm(685) : see reference to function template instantiation '_OutIt std::_Transform<std::_Tree<_Traits>::iterator,_OutIt,_Fn1,std::_Iter_random_helper<_Cat1,_Cat2>::_Iter_random_cat>(_InIt,_InIt,_OutIt,_Fn1,_InOutItCat,std::_Range_checked_iterator_tag)' being compiled 1> with 1> [ 1> _OutIt=std::_Vector_iterator<std::string,std::allocator<std::basic_string<char,std::char_traits<char>,std::allocator<char>>>>, 1> _Traits=std::_Tmap_traits<std::string,Test,std::less<std::string>,std::allocator<std::pair<const std::string,Test>>,false>, 1> _Fn1=boost::_bi::bind_t<const std::basic_string<char,std::char_traits<char>,std::allocator<char>> &,boost::_mfi::dm<std::string,std::pair<std::string,Test>>,boost::_bi::list1<boost::arg<1>>>, 1> _Cat1=std::_Tree<std::_Tmap_traits<std::string,Test,std::less<std::string>,std::allocator<std::pair<const std::string,Test>>,false>>::iterator::iterator_category, 1> _Cat2=std::_Vector_iterator<std::string,std::allocator<std::basic_string<char,std::char_traits<char>,std::allocator<char>>>>::iterator_category, 1> _InIt=std::_Tree<std::_Tmap_traits<std::string,Test,std::less<std::string>,std::allocator<std::pair<const std::string,Test>>,false>>::iterator, 1> _InOutItCat=std::_Iter_random_helper<std::_Tree<std::_Tmap_traits<std::string,Test,std::less<std::string>,std::allocator<std::pair<const std::string,Test>>,false>>::iterator::iterator_category,std::_Vector_iterator<std::string,std::allocator<std::basic_string<char,std::char_traits<char>,std::allocator<char>>>>::iterator_category>::_Iter_random_cat 1> ] 1> e:\dev_workspace\experimental\scratch\scratch\main.cpp(21) : see reference to function template instantiation '_OutIt std::transform<std::_Tree<_Traits>::iterator,std::_Vector_iterator<_Ty,_Alloc>,boost::_bi::bind_t<R,F,L>>(_InIt,_InIt,_OutIt,_Fn1)' being compiled 1> with 1> [ 1> _OutIt=std::_Vector_iterator<std::string,std::allocator<std::basic_string<char,std::char_traits<char>,std::allocator<char>>>>, 1> _Traits=std::_Tmap_traits<std::string,Test,std::less<std::string>,std::allocator<std::pair<const std::string,Test>>,false>, 1> _Ty=std::string, 1> _Alloc=std::allocator<std::basic_string<char,std::char_traits<char>,std::allocator<char>>>, 1> R=const std::basic_string<char,std::char_traits<char>,std::allocator<char>> &, 1> F=boost::_mfi::dm<std::string,std::pair<std::string,Test>>, 1> L=boost::_bi::list1<boost::arg<1>>, 1> _InIt=std::_Tree<std::_Tmap_traits<std::string,Test,std::less<std::string>,std::allocator<std::pair<const std::string,Test>>,false>>::iterator, 1> _Fn1=boost::_bi::bind_t<const std::basic_string<char,std::char_traits<char>,std::allocator<char>> &,boost::_mfi::dm<std::string,std::pair<std::string,Test>>,boost::_bi::list1<boost::arg<1>>> 1> ] 1>e:\boostvs3\include\boost\mem_fn.hpp(333) : error C2784: 'T *boost::get_pointer(T *)' : could not deduce template argument for 'T *' from 'const std::pair<_Ty1,_Ty2>' 1> with 1> [ 1> _Ty1=const std::string, 1> _Ty2=Test 1> ] 1> e:\boostvs3\include\boost\get_pointer.hpp(14) : see declaration of 'boost::get_pointer'

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boost::archive::iterators::base64_from_binary
by Dmitry Timoshenko 15 Apr '09

15 Apr '09

Hello. I encountered a problem when tried to use base64_from_binary and binary_from_base64. * **typedef* vector<unsigned char> RawData_t; ** *typedef* base64_from_binary<transform_width<RawData_t::const_iterator, 6, 8> > to_base64_transformer; ** *typedef* transform_width<binary_from_base64<RawData_t::const_iterator>, 8, 6 > to_binary_transformer; RawData_t unicomm::files::base64encode(*const* RawData_t& src) { *return* RawData_t(to_base64_transformer(src.begin()), to_base64_transformer(src.end())); } The problem is in that source sequence should be multiple of 3. When I try to use sequence with different size I get assertion failure in std::vector class which tells: iterator is not dereferencable. It seems those dataflow iterators try to look for data after the input sequence end(). The problem is already discussed here: http://lists.boost.org/boost-users/2008/08/39790.php But, there is (above) no any valuable information about the problem. Is it bug or feature? How can I resove the problem? It is an abiltity to complete the input collection to make it multiple of 3 and on other side remove that dummy information added before. But, it is wanted that it would be more correctly resolved. Did anybody have any solution? Thank you.

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Iteratro List corruputed Boost::regex in VS2008
by Lee sophia 15 Apr '09

15 Apr '09

Hi, I'm new with Boost libraries. I was able to run the Boost:: regex in VS2005. However, when I converted the same project into VS2008. It always prompt with "Iterator List Corrupted" error at Xutility.cpp, when it reach the declaration of Boost::regex, for elg boost::regex Str(CONST_STR). It is calling the function/declaration from a c++ API dll. Does anyone meet this kind of problem? Is it the settings of the VS2008 incorrect? Thank you.

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How to obtain shared_ptr<Derived> from shared_ptr<Base>?
by Dominique Devienne 15 Apr '09

15 Apr '09

I have a class diagram with the following base classes: class Object; class Ident { ... private: ... friend class Object; void set_object(Object* obj) { object_ = obj; } private: ... Object* object_; }; class Object { ... public: Ident* ident() { return ident_.get(); } const Ident* ident() const { return ident_.get(); } shared_ptr<Ident> ident_ptr() { return ident_; } protected: Object(shared_ptr<Ident> ident) : ident_(ident) { ident_->set_object(this); } virtual ~Object() { ident_->set_object(0); } private: shared_ptr<Ident> ident_; }; An Object in memory always has an Ident, which it shares with client code, but the Ident of an Object can be loaded before the object itself, and will also remain after the Object is gone, as long as client code references it. Ident has a "back" pointer to its Object, which is maintained by Object directly via friendship. (yes, the design is tightly coupled). In effect Ident is almost like a "weak" proxy to its Object. Then there are derived class pairs from Ident+Object: class VehiculeIdent : public Ident { /* Vehicule-specific ident members */ } class Vehicule : public Object { protected: Vehicule() : Object(shared_ptr<VehiculeIdent>(new VehiculeIdent)) {} public: // covariant return type VehiculeIdent* ident() { return polymorphic_downcast<VehiculeIdent*>(Object::ident()); } const VehiculeIdent* ident() const { /* same as above */ } }; Vehicule is itself the base of a base hierarchy (Car, Bike, etc...), and I have other such "roots" (which all derive from Object). There's a manager class per root which composes a Boost.MultiIndex container specific to each root identity, which a simple interface like so: typedef multi_index_container< shared_ptr<VehiculeIdent>, indexed_by< ... > > > VehiculeIndex; class VehiculeMgr { public: ... bool bind_vehicule(Vehicule* v); void unbind_vehicule(Vehicule* v); private: VehiculeIndex index_; }; The problem I have is that I need a shared_ptr<VehiculeIdent> to insert to the B.MI index which I obtain from the Vehicule*, but given the API above I can only obtain a VehiculeIdent* or a shared_ptr<Ident>, both of which are inadequate to interact with the B.MI. I worked around this issue so far by changing VehiculeIdent like so: class VehiculeIdent : public Ident, public enable_shared_from_this<VehiculeIdent> { ... shared_ptr<VehiculeIdent> as_shared_ptr() { return shared_from_this(); } }; at which point I can now write for example: bool VehiculeMgr::bind_vehicule(Vehicule* v) { return index_.insert(v->ident()->as_shared_ptr()).second; } But this solution seems unsatisfactory to me, because it forces the derivation and additional as_shared_ptr member in the public API of all Ident-deriving "root ident" classes, which I only need it inside VehiculeMgr (whose B.MI index is private). So long story short, is there a clean way to obtain a shared_ptr<VehiculeIdent> from a shared_ptr<Ident> which one "knows" is a VehiculeIdent, to avoid my as_shared_ptr hack above? Thanks for any help, --DD PS: I'm happy to get advice on the design overall as well, separate from this main subject of this post.

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VC6 error_code.hpp compile errors
by Daniele Barzotti 15 Apr '09

15 Apr '09

Hi, I'm developing an ATL library to wrap another LIB with VC6. The includes comprehends: #include <boost/asio.hpp> #include <boost/asio/serial_port.hpp> #include <boost/thread.hpp> #include <boost/signals2/signal.hpp> #include <boost/scoped_ptr.hpp> #include <boost/enable_shared_from_this.hpp> When I compile I get these errors: --------------------------------------------------------------- g:\lib\boost_1_38_0\boost\system\error_code.hpp(45) : error C2252: 'value' : pure specifier can only be specified for functions g:\lib\boost_1_38_0\boost\system\error_code.hpp(45) : see reference to class template instantiation 'boost::system::is_error_code_enum<T>' being compiled g:\lib\boost_1_38_0\boost\system\error_code.hpp(48) : error C2252: 'value' : pure specifier can only be specified for functions g:\lib\boost_1_38_0\boost\system\error_code.hpp(48) : see reference to class template instantiation 'boost::system::is_error_condition_enum<T>' being compiled g:\lib\boost_1_38_0\boost\system\error_code.hpp(145) : error C2258: illegal pure syntax, must be '= 0' g:\lib\boost_1_38_0\boost\system\error_code.hpp(145) : error C2252: 'value' : pure specifier can only be specified for functions g:\lib\boost_1_38_0\boost\system\error_code.hpp(230) : error C2039: 'type' : is not a member of 'enable_if<struct boost::system::is_error_condition_enum<Cond>,void>' g:\lib\boost_1_38_0\boost\system\error_code.hpp(244) : error C2039: 'type' : is not a member of 'enable_if<struct boost::system::is_error_condition_enum<Cond>,class boost::system::error_condition>' g:\lib\boost_1_38_0\boost\system\error_code.hpp(297) : error C2784: 'struct boost::type &__thiscall boost::system::error_condition::operator =(ErrorConditionEnum)' : could not deduce template argument for 'struct boost::type &' from 'class boost::sy stem::error_condition &' g:\lib\boost_1_38_0\boost\system\error_code.hpp(297) : error C2785: 'struct boost::type &__thiscall boost::system::error_condition::operator =(ErrorConditionEnum)' and 'class boost::system::error_condition &__thiscall boost::system::error_condition: :operator =(const class boost::system::error_condition &)' have different return types g:\lib\boost_1_38_0\boost\system\error_code.hpp(245) : see declaration of '=' g:\lib\boost_1_38_0\boost\system\error_code.hpp(317) : error C2039: 'type' : is not a member of 'enable_if<struct boost::system::is_error_code_enum<Cond>,void>' g:\lib\boost_1_38_0\boost\system\error_code.hpp(330) : error C2039: 'type' : is not a member of 'enable_if<struct boost::system::is_error_code_enum<Cond>,class boost::system::error_code>' g:\lib\boost_1_38_0\boost\system\error_code.hpp(384) : error C2784: 'struct boost::type &__thiscall boost::system::error_code::operator =(ErrorCodeEnum)' : could not deduce template argument for 'struct boost::type &' from 'class boost::system::erro r_code &' g:\lib\boost_1_38_0\boost\system\error_code.hpp(384) : error C2785: 'struct boost::type &__thiscall boost::system::error_code::operator =(ErrorCodeEnum)' and 'class boost::system::error_code &__thiscall boost::system::error_code::operator =(const cl ass boost::system::error_code &)' have different return types g:\lib\boost_1_38_0\boost\system\error_code.hpp(331) : see declaration of '=' g:\lib\boost_1_38_0\boost\system\error_code.hpp(395) : error C2143: syntax error : missing ';' before '}' g:\lib\boost_1_38_0\boost\system\error_code.hpp(401) : error C2143: syntax error : missing ';' before '}' g:\lib\boost_1_38_0\boost\system\error_code.hpp(451) : fatal error C1903: unable to recover from previous error(s); stopping compilation --------------------------------------------------------------- Could someone give me some feedback? I need VC6 because its the only environment I can use to develop an ATL project! Thanks in advance! Daniele.

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How to use Boost Regex Partial Match
by Gundala Viswanath 15 Apr '09

15 Apr '09

Dear all, Given this code. I expect to get this output from the corresponding input: Input: FOO Output: Match Input: FOOBAR, Output: Match Input: BAR, Output: No Match But why it gives "No Match" for input FOOBAR? __BEGIN__ #include <iostream> #include <vector> #include <fstream> #include <sstream> #include <boost/regex.hpp> using namespace std; using namespace boost; int main ( int arg_count, char *arg_vec[] ) { if (arg_count !=2 ) { cerr << "expected one argument" << endl; return EXIT_FAILURE; } string InputString = arg_vec[1]; string toMatch = "FOO"; const regex e(toMatch); if (regex_match(InputString, e,match_partial)) { cout << "Match" << endl; } else { cout << "No Match" << endl; } return 0; }

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convert ptime to FILETIME?
by Hansi 15 Apr '09

15 Apr '09

Hi, I have searched now a lot in the documentation of ptime... Is there any function available which converts ptime to FILETIME? I can find only FILETIME to ptime.. Thanks Hansjörg

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Corrupted boost::regex::smatch results (on MSVS 2003)
by david.weber＠l-3com.com 15 Apr '09

15 Apr '09

All, I'm using Boost.Regex from v1.35.0. We're seeing the smatch matchresults object getting corrupted when being returned by value from a function. The smatch variable is good within the function (it is an object defined locally on the stack), but when returned it is corrupted with bad data. We're seeing this only in Visual Studio 2003, and no other platform. I'm still trying to figure out a workaround, but I do not have source access at the moment, to try and debug it that way. Just wondering if there are any known issues. A google search didn't return much by way of discussion of this sort of issue. Thanks --dw

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[Bind] how can a make the equivalent to the , operator
by Robert Ramey 15 Apr '09

15 Apr '09

I would like to compose two function objects into one. Bind describse this using || or && but my function objects return void. How can i package them into a new one that invokes both the components. Robert Ramey

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Unknown number of multitoken lists?
by David Doria 15 Apr '09

15 Apr '09

I want to do something like this: --NumLists 2 --List0 a.txt b.txt --List1 c.txt d.txt vector<vector<string> > Lists(2); po::options_description desc("Allowed options"); desc.add_options() ("help", "produce help message") ("List0", po::value<vector<string> >(&Lists[0])->multitoken(), "List0.") ("List1", po::value<vector<string> >(&Lists[1])->multitoken(), "List1.") ; But if I wanted to handle --NumLists 10, I would have to manually add List0, List1, ... List10 as parameters. That seems a bit silly, but maybe this is a very odd usage? Please let me know if you can think of a better way to handle this. Thanks, David

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