From: musiphil@bawi.org   
      
   On 2011-06-28 12:12, Seungbeom Kim wrote:   
   > On 2011-06-27 11:02, A. McKenney wrote:   
   >>   
   >>    By far the most common usage of   
   >>    reinterpret_cast<> in the code I   
   >>    work on is between (char *) and   
   >>    (unsigned char *) (or their const   
   >>    equivalents.)   
   >>   
   >>    I consider this "practically portable",   
   >>    because I am not aware of any   
   >>    implementation where it would make   
   >>    sense for the pointer representation to   
   >>    differ between the signed and unsigned   
   >>    versions.   
   >>   
   >>    Can anyone conceive of an architecture where   
   >>    a standard-conforming C++ implementation would   
   >>    have any reason to use different representations   
   >>    for  signed char * and unsigned char *?   
   >   
   > I can't, especially when the standard guarantees that the three   
   > character types have the same object representation, including   
   > the same alignment requirements [3.9.1/1], and even that char*   
   > have the same representation and alignment requirements as void*   
   > [3.9.2/4].   
   >   
   > Why should char* be more closely related to void* than to signed char*   
   > or unsigned char*? Why doesn't the standard simply guarantee that the   
   > three character pointer types also have the same object representation,   
   > and that they can be converted by static_cast among one another?   
   >   
   > Assuming the status quo, is it correct that we have to go through void*   
   > to convert among the three character types, e.g.   
   >   
   >    signed char* scp = /* ... */;   
   >    unsigned char* ucp =   
   >        static_cast(static_cast(scp));   
   >   
   > or   
   >   
   >    signed char* scp = /* ... */;   
   >    void* vp = scp;   
   >    unsigned char* ucp = static_cast(vp);   
   >   
   > to be strictly conforming?   
   >   
   > In addition, what about conversion from any object pointer to a   
   > character pointer: I guess we should go through void* here as well.   
   > Am I correct?   
      
   I'm sad to find out that none of these questions have been answered.   
   Can anyone shed some light on them, please? :-)   
      
   --   
   Seungbeom Kim   
      
      
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