In fact, this sort of conversion is explicitly mentioned in the C++ standard
in section 4.4:
[Note: if a program could assign a pointer of type T** to a pointer of type
const T** (that is, if line //1 below was allowed), a program could
inadvertently modify a const object (as it is done on line //2). For
example,
int main() {
const char c = 'c';
char* pc;
const char** pcc = &pc; //1: not allowed
*pcc = &c;
*pc = 'C'; //2: modifies a const object
}
-- end note]
Brad Town
> Donald,
> First, a cv-qualifier is a "const", "volatile", or
> "const volatile"
> qualifier on a type. (If you have access to the C++ standard, it's in
> section 3.9.3.)
> Second, your trouble is because gcc is being a little
> more strict
> than the other compiler. You need to add a "const" between
> the two *'s in
> the return definition of the function. Or, add "typedef
> Foo** PPFoo" or the
> like and use that whenever you need to use the
> pointer-to-pointer-to-Foo.
>
> Brad Town
>
>
> > -----Original Message-----
> > From: Donald Brinkman [mailto:[EMAIL PROTECTED]]
> > Sent: Thursday, December 7, 2000 4:21 PM
> > To: [EMAIL PROTECTED]
> > Subject: cv-quals lack an intervening 'const'
> >
> >
> > Hello all . . .
> >
> > I have been given the task of porting a small project from an IRIX
> > environment into a visual c++ compatible library. To
> > accomplish this I
> > decided to use Cygwin, since it has such nice utilities for
> > creating DLLs.
> > Everything has been going fine, with only a few changes here
> > and there,
> > until I stopped dead on this problem. Given the member function:
> >
> > const Foo** FooBar::getA() const
> > {
> > return ( A )
> > }
> >
> > where A is a const Foo**
> >
> > I get the following message:
> >
> > Return to const Foo** from Foo **const adds cv-quals without
> > intervening
> > 'const'.
> >
> >
> > Now, please, can someone tell me just what a cv-qual is and
> > why the compiler
> > complains about this on Cygwin with gcc but not on IRIX with
> > cc? Any help
> > would be greatly appreciated.
> >
> > Donald Brinkman
> >
> >
> > --
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> >
>
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