'''funlock fileId ?start? ?length? ?origin?'''

Remove a locked from a file that was previously placed with  the flock command.  The arguments are the same as for the flock command, see that command for more details.

The funlock command is not  available  on  Windows  95.   It  is available on Windows NT.

There is no funlock in Tcl...

... but there is in [TclX].

... and there [tclx file commands for core]