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In article <41gq8b$1jm@tango.cs.wustl.edu>, schmidt@cs.wustl.edu (Douglas C. Schmidt) writes:
|> Hi,
|> 
|> 	I've got a question about the behavior of operator->(), in
|> particular, can it return a pointer to a builtin type?
|> 
|> 	For example, consider the following:
|> 	
|> ----------------------------------------
|> #include <stdio.h>
|> 
|> class Foo
|> {
|> public:
|>   Foo (int i): i_ (i) {}
|> 
|>   int *operator->()
|>   {
|>     return &this->i_;
|>   }
|> 
|> private:
|>   int i_;
|> };
|> 
|> int main ()
|> {
|>   Foo foo (10);
|>   printf ("%d, ", ++*(int *) foo.operator->());
|>   printf ("%d\n", ++*(int *) foo.operator->());
|>   // prints "11, 12"
|>   return 0;
|> }
|> ----------------------------------------
|> 
|> 	When I compile this with gcc it compiles and runs fine.
|> However, when I use SunC++ 4.0.1 I get the following error:
|> 
|> ----------------------------------------
|> % CC foo.C
|> "foo.C", line 9: Error: Cannot have a return type of int* for Foo::operator->().
|> 1 Error(s) detected.
|> ----------------------------------------
|> 
|> 	I tried to find a discussion of this in the ARM, but couldn't
|> find it discussed there.  Can someone please tell me if this is legal
|> in the draft ANSI/ISO C++ standard?

    Sun compiler seem to be doing right thing here.
    Consider this
    
    Foo *x = new Foo(10);
    x->f();  // f() is one of the public interface/function for Foo class.

    Now if *x.operator->() returned a pointer to int, the statements will be
    equivelent of:
    int *i = new i(10);
    i->f();
    
    Which of course should not work. That is operator->() should return 
    pointer to a User defiend type(struct/class).

Ajay

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