[boost.png"] Boost Conversion Library

   The Conversion Library improves program safety and clarity by = performing
   otherwise messy conversions.  It includes cast-style function = templates 
   designed to complement the C++ Standard's built-in casts.

   To reduce coupling, particularly to standard library IOStreams, the = Boost
   Conversion Library is supplied by several headers:
     * The   [1]boost/cast   header  provides   polymorphic_cast<>  and
       polymorphic_downcast<> to perform safe casting = between polymorphic
       types.
     * The [2]boost/lexical_cast header = provides  lexical_cast<> general
       literal text conversions, such as an int = represented as a string, or
       vice-versa.
     * The [3]boost/implicit_cast header  provides implicit_cast<> which is
       used when the source type = is  implicitly convertible to the target
       type, to force the implicit = conversion.  It's less liberal than
       static_cast, which will convert in the opposite  direction..
     _________________________________________________________________

   Revised Jan 25, 2006

References

   1. file://localhost/tmp/3D"cast.htm"
   2. file://localhost/tmp/3D"lexical_cast.htm"
   3. file://localhost/tmp/boost/implicit_cast.hpp"