[Python-Dev] Raw I/O writelines() broken

[R. David Murray]

On Mon, 20 Aug 2012 23:42:56 +0200, Antoine Pitrou <solipsis at pitrou.net> wrote:
> On Mon, 20 Aug 2012 23:17:10 +0200
> Antoine Pitrou <solipsis at pitrou.net> wrote:
> > 
> > Hello,
> > 
> > I was considering a FileIO.writelines() implementation based on
> > writev() and I noticed that the current RawIO.writelines()
> > implementation is broken: RawIO.write() can return a partial write but
> > writelines() ignores the result and happily proceeds to the next
> > iterator item (and None is returned at the end).
> > 
> > (it's probably broken with non-blocking streams too, for the same
> > reason)
> > 
> > In the spirit of RawIO.write(), I think RawIO.writelines() could return
> > the number of bytes written (allowing for partial writes).
> 
> Another possibility would be a separate RawIO.writev() that would allow
> partial writes, and to fix RawIO.writelines() to always do complete
> writes.

I think writelines doing a partial write is counter-intuitive in the
Python context (as well as being contrary to the existing
documentation), so I think I'd favor this.

--David