Re: Why does close_stdout close stdout and stderr?

[Eric Blake]

On 4/29/19 2:45 PM, Florian Weimer wrote:
> I get that error checking is important.  But why not just use ferror and
> fflush?  Closing the streams is excessive and tends to introduce
> use-after-free issues, as evidenced by the sanitizer workarounds.

If I recall the explanation, at least some versions of NFS do not
actually flush on fflush(), but wait until close(). If you want to avoid
data loss and ensure that things written made it to the remote storage
while detecting every possible indication when an error may have
prevented that from working, then you have to go all the way through
close().

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org

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