Re: [Boost-users] [multi_index] passing 'cons t TYPE' as 'this' argument discards qualifiers

From: damny_at_[hidden]
Date: 2007-12-28 03:30:10

hi joaquín,

now it works. thank you.

> > are there possibilities to avoid the 'std::string' for the 'name' 
> > key? 
> 
> I'm not getting this question. Could you please elaborate?

i would like to know if it is possible to use char[] or char* as an alphanumeric key value and not std::string.
improper tests didn't work.

daniel

> ----- Mensaje original -----
> De: damny_at_[hidden]
> Fecha: Martes, Diciembre 25, 2007 5:17 pm
> Asunto: [Boost-users] [multi_index] passing 'cons t TYPE' as 'this' 
> argument discards qualifiers
> Para: boost-users_at_[hidden]
> 
> > merry xmas everyone,
> 
> Merry Xmas :)
> 
> [...]
> > class cClass {
> >  private:
> >    int att1;
> >  public:
> >    std::string  nme;  // name
> >    int               idf;    // identifier
> >    cClass();
> >    cClass(std::string nme, int idf);
> >    int get_attribute();
> > };
> > 
> [...]
> >  mMapByNme::iterator itrNme = locMsg.get<0>().find("name1");
> >  mMapByIdf::iterator itrIdf = locMsg.get<1>().find(456);
> >  printf( "att1 = %d\n", itrNme->get_attribute() );
> [...]
> > main.cpp: In function `int main()':
> > main.cpp:33: error: passing 'const cClass' as 'this' argument of 
> > 'int cClass::get_attribute()' discards qualifiers
> > Process terminated with status 1 (0 minutes, 20 seconds)
> > 
> > any hints how to solve the problem?
> 
> The problem here is that elements of a multi_index_container
> are immutable, and the iterators ony grant const access
> to them. In this regard, the behavior is the same as that
> of a regular std::set. To solve your particular problem you can
> const-qualify the offending member function:
> 
>   int get_attribute() const;
> 
> > how to encapsulate this special multi_index into a class, that 
> > fits the above description of the needed 'map'.
> 
> You should probably consider whether Boost.Bimap could
> be a better approach, but I see you're already discussing
> this issue with Matías.
> 
> > are there possibilities to avoid the 'std::string' for the 'name' 
> > key? 
> 
> I'm not getting this question. Could you please elaborate?
> 
> > where are the more easier examples for C++-templates/boost
> > newbies like me :o) ?
> 
> HTH,
> 
> Joaquín M López Muñoz
> Telefónica, Investiación y Desarrollo
> _______________________________________________
> Boost-users mailing list
> Boost-users_at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/boost-users
> 

__________________________________________________________________________
Erweitern Sie FreeMail zu einem noch leistungsstärkeren E-Mail-Postfach!		
Mehr Infos unter http://produkte.web.de/club/?mc=021131