March 2008 - Boost-users - lists.preview.boost.org

boost::filesystem::path and Windows CreateFile()
by pashapal＠aol.com 27 Mar '08

27 Mar '08

Hi, I was hoping someone could help, cause I am stumped. I have a library that opens disk images (img, dd, raw) via a string representing the file of the disk image. I supply the string as the lead argument in the constructor of boost::filesystem::path p(pImagePath, boost::filesystem::no_check) ; It works on?all?platforms tested. However, now I want to open a physical drive directly, rather than an image file in Windows. I have looked up the string representation of drives in Win 32 and apparently //./X: , however, it does not work with the path constructor. I have tried variations with the backslash etc. Windows allows access to a drive through the CreateFile() function, can I use this somehow and convert it into a boost::path? Any idea what I am doing wrong? In essences I want to access a windows drive as a boost::filesystem::path, that I can then later use for memory mapping. Thanks , Pasha boost::filesystem::path p(pImagePath, boost::filesystem::no_check) ; It works on?all?platforms tested. However, now I want to open a physical drive directly, rather than an image file in Windows. I have looked up the string representation of drives in Win 32 and apparently //./X: , however, it does not work with the path constructor. I have tried variations with the backslash etc. Windows allows access to a drive through the CreateFile() function, can I use this somehow and convert it into a boost::path? Any idea what I am doing wrong? In essences I want to access a windows drive as a boost::filesystem::path, that I can then later use for memory mapping. Thanks , Pasha

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Containers question
by James Sutherland 26 Mar '08

26 Mar '08

Fellow boost enthusiasts, I want to be able to store a set of information that contains types. For example: > template<typename T> > void register_field( const FieldID id ) > { > // need to keep a record of (T,id) > } Later on, I need to recover the type and id (T,id) for use. Any thoughts on a way to accomplish this? Thanks for any advice, James

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generic data assign
by Olaf Peter 26 Mar '08

26 Mar '08

Hello, how can I make the snipped more generic in that way, that I can use it with different data members, e.g. as template argument the &actions::m_data::text data address. Then I could write e.g. set_generic<&actions::m_data::text, std::string> set_text; Thanks, Olaf ---8<--- #include <iostream> #include <string> struct data { std::string text; }; struct actions { explicit actions(data& d) : set_text( *this ), m_data( d ) { } template<typename T> struct set_generic { explicit set_generic( actions& actions ) : self( actions ) { } void operator()(const T& data) const { self.m_data.text = data; } private: actions& self; }; set_generic<std::string> set_text; set... data& m_data; }; using namespace std; int main() { data d; actions a( d ); a.set_text( "Hello" ); cout << d.text << endl; } --->8---

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Re: [Boost-users] serialization and ::copyFrom
by Andrei Popa 26 Mar '08

26 Mar '08

Robert Ramey wrote: > Oh, that should be easy: > > D1 *d1p; > > ar << d1; > ar >> *d1p; > > Robert Ramey Hi,At> ar << d1;> ar >> bp; // but "bp" points already to an object of type D1I meant : "bp" is "Base* bp"So, if I call ar >> *bp; the Base::load will be called, not the derived D1:load.Actually more precisely, I intend to do solass Base { ... virtual .. } class D1 : public Base { } Base* bp1 = new D1(..some thing..); Base* bp2 = new D1(..some thing else..); ar << *bp1; ar >> *bp2; This means for all my serializable classes I have a kind of "=" operator defined. regards, Andrei _________________________________________________________________ Invite your mail contacts to join your friends list with Windows Live Spaces. It's easy! http://spaces.live.com/spacesapi.aspx?wx_action=create&wx_url=/friends.aspx…

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Re: [Boost-users] serialization and ::copyFrom
by Andrei Popa 26 Mar '08

26 Mar '08

Hi, First of all, thanks for that "NEW" remark, this is an important information for me. It is not about the D2, I do not intend to copy data from an object of a type into an object of an other type. ar << d1; ar >> bp;// but "bp" points already to an object of type D1 I'm trying to read in data from archive into the object pointed by bp. Is this possible? If not. What other possibilities do I have? Any workaround? Thanks, Andrei _________________________________________________________________ Connect to the next generation of MSN Messenger http://imagine-msn.com/messenger/launch80/default.aspx?locale=en-us&source=…

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Linking problem with Borland C++ 5.6
by Sergey.Tsyrulnikov＠t-systems.com 26 Mar '08

26 Mar '08

I try to compile a simple thread_group-example with Borland C++ 5.6 for Win32. I get the following link error: Error: Unresolved external 'boost::thread_group::create_thread(const boost::function0<void, std::allocator<boost::function_base> >&)' referenced from C:\BACPP\SERVICEADAPTER\SRC\SERG.OBJ I have built the boost_thread-bcb-mt-1_34_1.lib with Bjam and Borland. The examples can be created with the library. The MSVC-Variant works without errors. Link-Call: C:\Programme\Borland\CBuilder6\BIN\ILINK32 -Tpe -r -ap -Gn C:\Programme\Borland\CBuilder6\lib\C0X32.OBJ /v -L..\..\Extern\BCB582\BDP\lib -L..\ ..\Xerces\lib\BCB582 -L..\..\Boost\lib\BCB582 -L..\..\LogEngineBA\lib\BCB582 -LC:\Programme\Borland\CBuilder6\lib serg.obj /LIBPATH:..\..\Extern\BC B582\BDP\lib orb_br.lib vdlog_br.lib vport_br.lib /LIBPATH:..\..\Xerces\lib\BCB582 xerces-bor_2_7_0.lib /LIBPATH:..\..\Boost\lib\BCB582 boost_thread-b cb-mt-1_34_1.lib /LIBPATH:..\..\LogEngineBA\lib\BCB582 LogEngine.lib C:\Programme\Borland\CBuilder6\lib\import32.lib C:\Programme\Borland\CBuilder6\li b\cw32mti.lib , serg.exe Turbo Incremental Link 5.60 Copyright (c) 1997-2002 Borland Error: Unresolved external 'boost::thread_group::create_thread(const boost::function0<void, std::allocator<boost::function_base> >&)' referenced from C:\BACPP\SERVICEADAPTER\SRC\SERG.OBJ RLINK32 Version 6.00 (c) Copyright 1992-2002 Borland Software Corporation. Source: #include <iostream> #include <stdio> #include <boost/thread/thread.hpp> #include <boost/bind.hpp> #include <boost/smart_ptr.hpp> #include <vector> using namespace std ; void doCallThreads(std::string text){ printf("Start Thread .......%s\n", text); } void doCallThreadsXXX(){ printf("Start Thread .......\n"); } void doCallsWithThreads(const int countThreads){ // std::vector<boost::thread *> threads; boost::thread_group threads; for(int i = 0; i<countThreads; i++){ //threads.create_thread(boost::bind(doCallThreads, "hhh")); threads.create_thread(&doCallThreadsXXX); // threads.create_thread(&doCallThreadsXXX); printf("Thread %d gestartet\n", (i+1)); } printf("All threads started\n"); // Warten bis alle thread fertig sind threads.join_all(); printf("All threads stopped\n"); } int main(int argc, char* const* argv) { try { doCallsWithThreads(5); cout << "ENDE" << endl ; } catch(std::exception ex) { cout << "Error: " << ex.what() << endl ; throw; } catch(...) { cout << "Error" ; throw; } return 0 ; } Any idea?????

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[boost] [Graph] need help on remove_vertex ....
by Bernhard Lippmann 26 Mar '08

26 Mar '08

Hi, I need some help on the remove_edge, remove_vertex functions. What is wrong with my two functions, removing edges or vertex from a graph with a given name in the coressponding property map. pls. see code snippet after calling my function a second time I get a run time error. I did the code as shown under http://www.boost.org/libs/graph/doc/adjacency_list.html but I feel the rebuild of the vectors did not work, any input is welcome Best Bernhard this is the code in the main program: // ok MyElementList.RemoveVertexByName("vss!",g, VertexNamesMap); // now the run time error ... MyElementList.RemoveVertexByName("vss!s",g, VertexNamesMap); this is the called sub routine: /*$ **************************************************************************** ** Method Name RemoveVertexByName ()... Parameters std::string AE_Name Return long , Index in Map Description remove vertex with a given name see http://www.boost.org/libs/graph/doc/adjacency_list.html for troubles **************************************************************************** ****** */ void TElementList::RemoveVertexByName(std::string elementname, TGraph &g, TVertexNameMap &VertexNamesMap) { Tvertex_iter vi, vi_end, next; tie(vi, vi_end) = vertices(g); for (next = vi; vi != vi_end; vi = next) { ++next; if (VertexNamesMap[*vi] == elementname) { remove_vertex(*vi, g); } } } /*$ **************************************************************************** ** Method Name RemoveEdgeByName () Parameters std::string AE_Name Return long , Index in Map Description Removes the edge (u,v) from the graph. void remove_edge(vertex_descriptor u, vertex_descriptor v, adjacency_list& g) void remove_edge(edge_descriptor e, adjacency_list& g) **************************************************************************** ****** */ void TElementList::RemoveEdgeByName(std::string elementname, TGraph &g, TEdgeNameMap &EdgeNamesMap) { Tedge_iter xei, xei_end; for (tie(xei, xei_end) = edges(g); xei != xei_end; ++xei) { Tedge_descriptor e = *xei; if (EdgeNamesMap[e] == elementname) { remove_edge (e,g); } // Tvertex_descriptor u = source(e, g), v = target(e, g); // if .... (option 29 } } No virus found in this outgoing message. Checked by AVG. Version: 7.5.519 / Virus Database: 269.21.8/1339 - Release Date: 22.03.2008 16:43

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vertex_descriptor NULL check
by Hardik Kheskani 26 Mar '08

26 Mar '08

I am using adjacent lists and using vertex_descriptors. Is there a way to check if the vertex_descriptor is NULL or 'not assigned' yet? graph_traits < adjacent_list_graph >::vertex_descriptor vd ; can I assign this to NULL ? and can I use vd == NULL or vd != NULL ? Any help/info is greatly appreciated. Hardik True religion is real living; living with all one's soul, with all one's goodness and righteousness. -Albert Einstein I got a simple rule about everybody. If you don't treat me right shame on you! -Louis Armstrong ____________________________________________________________________________________ Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ

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[mpl] Sorting types by index
by Scott Meyers 26 Mar '08

26 Mar '08

I have an mpl::vector of all possible types I care about. It's called AllTypes. Given a sequence containing some subset of types in AllTypes, I want to order the sequence so that the types occur in the same relative order as in AllTypes. So if AllTypes is A, B, C, D, E and I'm given B, E, A I want to produce A, B, E Fundamentally, I'm sorting things based on their index in AllTypes. Well, that's what I want to be doing. What I'm really doing is getting compilation errors referring to a missing tag in my metafunction, which is called IndexOf. The code I'm using is below. I'd appreciate it if people would take a look and help me figure out why it's not working. Thanks, Scott #include <boost/mpl/sort.hpp> #include <boost/mpl/distance.hpp> #include <boost/mpl/find.hpp> using namespace boost; // return the index of type T in sequence S template<typename S, typename T> struct IndexOf { enum { value = mpl::distance<typename mpl::begin<S>::type, typename mpl::find<S, T>::type >::value }; }; int main() { using mpl::_1; using mpl::_2; typedef mpl::vector<char, short, int, long, float, double> AllTypes; typedef mpl::vector<long, char, short> Unsorted; typedef mpl::sort<Unsorted, // this call to mpl::less<IndexOf<AllTypes,_1>, // sort doesn't IndexOf<AllTypes,_2> > // compile >::type Sorted; }

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Is boost a library or a framework?
by Robert Dailey 26 Mar '08

26 Mar '08

Hi, My head has been spinning lately on trying to nail down the difference between a library and a framework. One of my co-workers calls Boost a framework because it is a collaboration of components, and the fact that boost is so large makes it a framework. However, boost boasts itself as a library and I'm just wondering why it is such. One definition I read for a framework is that it has no requirement to be minimal, and boost is a fairly un-minimal library. Read the link below on an interesting conversation between the differences in a library and a framework: http://www.artima.com/forums/flat.jsp?forum=106&thread=152104

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