On Wed, Jan 16, 2013 at 07:39:53PM +0100, Michal Privoznik wrote: > On 16.01.2013 19:31, Daniel P. Berrange wrote: > > On Wed, Jan 16, 2013 at 07:27:46PM +0100, Michal Privoznik wrote: > >> Currently, whenever somebody calls saferead() on nonblocking FD > >> (safewrite() is totally interchangeable for purpose of this > >> message) he might get wrong return value. For instance, in the > >> first iteration some data is read. The number of bytes read is > >> stored into local variable 'nread'. However, in next iterations > >> we can get -1 from read() with errno == EAGAIN, in which case the > >> -1 is returned despite fact some data has already been read. So > >> the caller gets confused. > >> > >> Moreover, the comment just above the functions says, they act > >> like regular read() with nicer handling of EINTR. Well, they > >> don't now. > > > > I think that it is correct that these APIs return -1 on EAGAIN. > > These APIs should *not* be used on non-blocking FDs. > > > In that case I think we have to note it explicitly in the comments. BTW, what code did you encounter that was using this with non-blocking fds ? Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list