Return the name of any buffer that might be attached to a Tcl channel.
This can be any Tcl output channel, e.g. stderr or stdout.
INPUT
None
OUTPUT
The buffer name.
STATUS
The getchannelbuffer command will return an error in the following cases:
No Tcl channel matching channelId is found.
No buffer is attached to channelId.
PARAMETERS
channelId
Identifies the channel for which the query is being applied.