User`s guide

Method 1
If there is a known reasonable upper-bound on the array dimensions, define (by assigning an
arbitrary value to it) the highest element of the array. For multi-dimensional arrays, assign
the highest element of each possible sub-array. This assignment prevents the arrays from
extending.
Method 2
Use the TAS function to interlock access to the array. In this case, access to the array is
handled exclusively from one or two subroutines that include the TAS to control access to the
array. For details, see the TAS program instruction in the V+Language Reference Guide.
Arrays
V+Language User's Guide, v17.0
Page 106