(j3.2006) Connecting more than one unit to a file

[Van Snyder]

9.5.4p4 says it is processor dependent whether more than unit can be
connected to a file.

9.5.6.1p8 prohibits it.

Since the permission in 9.5.4p4 is new, and is newly remarked in A2, we
can assume that not changing the prohibition in 9.5.6.1p8 to a processor
dependency was an oversight.

Assuming we wish to allow multiple units to be connected to a file, do
we need further explanation of how nonadvancing and asynchronous output
work if they are done simultaneously on more than one unit connected to
the same file?