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Re: RFC: Update Intel386, x86-64 and IA MCU psABIs for passing/returning empty struct

On Mon, Feb 8, 2016 at 8:15 AM, Jonathan Wakely <> wrote:
> On 8 February 2016 at 16:05, H.J. Lu wrote:
>> My understanding is
>> A type that is standard-layout means that it orders and packs its
>> members in a way that is compatible with C.
>> What is the corresponding compatible type in C?
> An empty structure, such as struct A.
> One of the requirements for standard-layout classes is "has all
> non-static data members and bit-fields in the class and its base
> classes first declared in the same class" so standard layout classes
> are allowed to have base classes, as long as either the base class is
> empty (so doesn't alter layout) or the derived class doesn't add
> members (so has the same layout as the base). If neither the base
> class is an empty record, and the derived class doesn't add any
> non-static data members or bit-fields, then the base class should be
> an empty record too.

if it is the case

struct A { };
struct B { };
struct C : A, B { };

is an empty record.


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