Re: Unexpected soft update inconsistency

[Cedric Berger <cedric@xxxxxxxxx>]

Matthew Dillon wrote:

> :    (2) new system call entry points for non-blocking read and write, then
> :	libc_r can completely ignore FNONBLOCK and just use the new entry
> :	points.
> :
> :    Otherwise this little problem is going to bite us over and over again
> :    as time passes.
> :
> :    I'm thinking (2) might be the only real solution.
>
>     Something like this:
>
>     nbpread(int d, void *buf, size_t nbytes, off_t offset)
>     nbpread(int d, const void *buf, size_t nbytes, off_t offset)
>
>     (same arguments as pread/pwrite).  offset can be -1, indicating that the
>     current offset should be used and updated.  The function would perform
>     the operation non-blocking regardless of the non blocking setting on the
>     file pointer.
>
>     libc_r would then use the new entry points and would not mess with
>     the non-blocking flag on the FP at all.

That would be fantastic.

I've banged my head with this problem often enough.

And I'm not the only one, of course:

http://cr.yp.to/unix/nonblock.html

Cedric