Re: [rfc] epoll interface change and glibc bits ...

[Davide Libenzi]

On Wed, 20 Nov 2002, Mark Mielke wrote:

> On Wed, Nov 20, 2002 at 03:19:30PM -0800, Davide Libenzi wrote:
> > On Wed, 20 Nov 2002, Mark Mielke wrote:
> > > >     struct epoll_event {
> > > >         unsigned short events;
> > > >         unsigned short revents;
> > > >         __uint64_t obj;
> > > >     };
> > > Forget any argument I had against removing 'fd'. This sounds good.
> > > Perhaps 'obj' should be named 'userdata'?
> > >      struct epoll_event {
> > >          unsigned short   events;
> > >          unsigned short   revents;
> > >          __uint64_t       userdata;
> > >      };
> > Do we want to have a union instead of a direct 64bit int ?
>
> I was going to suggest this, except I couldn't figure out what to
> suggest that it look like... I finally figured that the value could be
> cast, or wrapped in a union by userspace (although theoretically, this
> might mean more words than absolutely necessary to initialize on a
> 32-bit CPU...)
>
> What were you thinking? 1X64 bit or 2X32 bit?

Something like :

typedef union epoll_obj {
	void *ptr;
	__uint32_t u32[2];
	__uint64_t u64;
} epoll_obj_t;

I'm open to suggestions though. The "ptr" enable me to avoid wierd casts
to avoid gcc screaming.

- Davide