comments on proposed uthread_write.c changes

Daniel Eischen eischen at
Tue Sep 9 17:46:12 PDT 2003

On Tue, 9 Sep 2003, Garrett Wollman wrote:

> <<On Tue, 9 Sep 2003 19:46:12 -0400 (EDT), Daniel Eischen <eischen at> said:
> >   Libc_r's write treats a return of 0 from __sys_write() as a
> >   partial write and continues looping.
> This is a bug.  The Standard is quite clear that a write of zero bytes
> is not possible unless the supplied buffer length is zero.  In the
> specific case of non-blocking files, if data might be written but
> doing so would cause the calling thread to block, write() must return
> -1 with errno set to [EAGAIN]; it may not return zero.  Therefore, a
> zero return from write() always indicates a permanent condition.


Dan (Langille), go ahead and commit the fix to -current if
you'd like.

Dan Eischen

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