Native File Untie {R}←⎕NUNTIE Y

This closes one or more native files. Y is a scalar or vector of negative integer tie numbers. The files associated with elements of Y are closed. Native file untie with a zero length argument (⎕NUNTIE ⍬) flushes all file buffers to disk - see File Untie for more explanation.

The shy result of ⎕NUNTIE is a vector of tie numbers of the files actually untied.