Hello Sebastian!
You wrote:
 SN>  I have the following modules (files, they call 'em):        
 SN>  CATALOG.CPP
 SN>         #include"fecha.hpp"
 SN>  FECHA.HPP
 SN>         struct fecha{
 SN>                 int operator==(fecha& item);
 SN>                 int operator>(fecha& item);
 SN>                 int operator<(fecha& item);
 SN>         };
 SN>         .
 SN>  FECHA.CPP
 SN>         #include"fecha.hpp"
 SN>         int operator==(fecha& item){}
 SN>         int operator>(fecha& item){}
 SN>         int operator<(fecha& item){}
 SN>  When I compile everything in a single proyect ( ahm using
 SN> Borland C++ 4.02)
 SN>  the linker tells that the operators in fecha are not definded in the
 SN>  module CATALOG.CPP. How come?
Because they aren't.  You have declared three operators in the header as 
member functions of the structure "fecha", so the code compiled in 
CATALOG.CPP naturally looks for functions that are defined in that scope.  
The three functions that you've defined in FECHA.CPP *are*not* members of the 
structure!  They are global functions.  So the linker won't accept them as 
the member functions that it is looking for.
Change the three function definitions in FECHA.CPP to
     int fecha::operator==(fecha& item){}
     int fecha::operator>(fecha& item){}
     int fecha::operator<(fecha& item){}
and all will be well.
OBTW, your compiler should have issued an error (or at least a warning) when 
you tried to compile FECHA.CPP, since the three global functions you'd 
defined were never declared.  This may be acceptable C, but it's a no-no in 
C++.
    -Ron  (ron-bass@ti.com)
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