lkml.org 
[lkml]   [2002]   [Nov]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [rfc] epoll interface change and glibc bits ...
On Thu, Nov 21, 2002 at 12:28:16AM +0000, Jamie Lokier wrote:
> Davide Libenzi wrote:
> > 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.
> That makes more sense to me, because it will be fine to use `ptr' even
> on 128-bit pointer machines when they arrive, yet preserves the
> property that 64<->32 bit conversion functions don't need to reformat
> the buffer when running 32-bit applications on a 64-bit CPU... even if
> the 32-bit application uses the `ptr' field.
> Did I just write that? :)

The problem with sizeof(void *) being >= sizeof(__uint64_t) is that the
data structure is the wrong length. Binary compatibility would not be
maintained.

Still... I believe that the days of 128-bit pointers are comfortably
far enough away that it does not cause any concerns at all for me. (I
suspect the kernel will need quite a few more changes than just this
to support 128-bit poitners...)

mark

--
mark@mielke.cc/markm@ncf.ca/markm@nortelnetworks.com __________________________
. . _ ._ . . .__ . . ._. .__ . . . .__ | Neighbourhood Coder
|\/| |_| |_| |/ |_ |\/| | |_ | |/ |_ |
| | | | | \ | \ |__ . | | .|. |__ |__ | \ |__ | Ottawa, Ontario, Canada

One ring to rule them all, one ring to find them, one ring to bring them all
and in the darkness bind them...

http://mark.mielke.cc/

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:31    [W:0.088 / U:0.184 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site