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Kevin McIsaac (KevinM@lamsys.com) wrote:
> 
>   typedef char* Pc;
>   void f(const Pc);       // void f(char* const)  (not const char*)
>   void g(const int Pc);   // void g(const int)
> 
> May questions are: why the f(const Pc) resolves to char* const? Is the 
> associativity changed? And is it possible to format f(), using Pc, such that 
> it resolves to const char*? TIA.

Because Pc is a pointer to char so const Pc should be a constant pointer to
a char. This is written char* const.
const char* is a pointer to a constant char which is something different.

-- 
[=======================================================================]
[ Kevin Lentin                   |      The Mighty Carlton Blues      | ]
[ K.Lentin@cs.monash.edu.au      |          1995 AFL Premiers         | ]
[ Macintrash: 'Just say NO!'     |CARLTON 21-15-141 d geelong 11-14-80| ]
[=======================================================================]

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> ==========Kevin McIsaac, 11/30/95==========
 
>   typedef char* Pc;
>   void f(const Pc);       // void f(char* const)  (not const char*)
>   void g(const int Pc);   // void g(const int)
 
> May questions are: why the f(const Pc) resolves to char* const? Is the 
> associativity changed?

I look at it this way:
The normal interpretation of const char * is as if
you wrote (const char)* instead.
But when you said:
typedef char* Pc;
you, in effect, put in parantheses as: (char *)
for any use of Pc.
A typedef is indivisible as it is now a type and
char * is just the meaning of the type.
It is like asking how you break an int into two parts.
So const can only apply to it as an indivisible unit.
As a result, const PC is the same as Pc const.

This is actually the feature a typedef provides
in setting up complicated meanings correctly.
If you nibble at it in small enough pieces,
order is less important and it is harder to mess
up the parentheses (once you understand).
Some examples involve pointers to functions that
return messy pointers to functions.  A sequence
of typedefs is a good way to get it right, and later
to determine what it is you got right.  You might
even avoid a headache from it.

> And is it possible to format f(), using
> Pc, such that it resolves to const char*? TIA.

There is no way.

Good Day
Dick
Dick.Menninger@DaytonOH.ATTGIS.COM



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