Hi,

I am trying to figure out which portion of the N2691 explicitly
mentions that the return type of a function can be a pointer or
reference to an incomplete type. $8.3.5/9 of course states that "The
type of a parameter or the return type for a function definition shall
not be an incomplete class type....", but I could not figure out
anything with respect to pointer or reference to incomplete type for
return type.

Please let me know.

struct A;

struct B{
A& f(); // function returning reference to an incomplete type
};

struct A{};

A& B::f(){static A a; return a;}
int main(){
B object;
}

Regards,
Dabs.

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On Aug 9, 8:59 am, rkld...@gmail.com wrote:
> I am trying to figure out which portion of the N2691 explicitly
> mentions that the return type of a function can be a pointer or
> reference to an incomplete type. $8.3.5/9 of course states that "The
> type of a parameter or the return type for a function definition shall
> not be an incomplete class type....", but I could not figure out
> anything with respect to pointer or reference to incomplete type for
> return type.

class T;
T foo();
T * bar();
T & baz();

foo returns an incomplete type. bar returns a pointer to an incomplete
type, and baz returns a reference to an incomplete type. T is an
incomplete type. A pointer to T is a pointer to an incomplete type. A
pointer to an incomplete type is a complete type.

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rkldabs@gmail.com wrote:
> Hi,
>
> I am trying to figure out which portion of the N2691 explicitly
> mentions that the return type of a function can be a pointer or
> reference to an incomplete type. $8.3.5/9 of course states that "The
> type of a parameter or the return type for a function definition shall
> not be an incomplete class type....", but I could not figure out
> anything with respect to pointer or reference to incomplete type for
> return type.
>
> Please let me know.
>
> struct A;
>
> struct B{
> A& f(); // function returning reference to an incomplete type
> };
>
> struct A{};
>
> A& B::f(){static A a; return a;}
> int main(){
> B object;
> }
>
> Regards,
> Dabs.
>

As far as I know, returning a reference or a pointer to an incomplete
type has been legal since C++98. In fact, returning a pointer to an
incomplete type has been legal in C since C90.

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rkldabs@gmail.com ha scritto:
> Hi,
>
> I am trying to figure out which portion of the N2691 explicitly
> mentions that the return type of a function can be a pointer or
> reference to an incomplete type. $8.3.5/9 of course states that "The
> type of a parameter or the return type for a function definition shall
> not be an incomplete class type....", but I could not figure out
> anything with respect to pointer or reference to incomplete type for
> return type.

A pointer or reference type is always a complete type, regardless of the
fact the pointed/referred type is incomplete. So you don't need an
explicit statement to allow them nor there's a reason to disallow them.
Their case is thus covered by the general statement you already mentioned.

HTH,

Ganesh

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