On 8 July 2014 13:07, Christoph Hellwig [off-list ref] wrote:

There's two different AT_* namespaces.  The flags that most *at syscalls
has, and the the one for the dfd argument, which currently only contains
AT_FDCWD, although a new constant has recently been proposed to it.

Having an AT_BENEATH magic value for the dfd argument certainly feels
elegant to me

How would that work? The directory beneath which openat is looking is
conveyed in the dfd argument itself. If I'm understanding this right,
you'd have to pass a different value for "open relative to fd#5" and
"open relative to fd#5, but beneath it only", which doesn't sound
hugely elegant to me.

Meredydd