The arrays passed by IDispatch::Invoke within VARIANTARGs are called safe arrays. Safe arrays contain information about the number of dimensions and bounds within them. When an array is an argument or the return value of a function, the parray field of VARIANTARG points to an array descriptor. Do not access this array descriptor directly, unless you are creating arrays containing elements with nonvariant data types. Instead, use the functions SafeArrayAccessData and SafeArrayUnaccessData to access the data.
The base type of the array is indicated by VT_ tag | VT_ARRAY. The data referenced by an array descriptor is stored in column-major order, which is the same ordering scheme used by Visual Basic and FORTRAN, but different from C and Pascal. Column-major order is when the left-most dimension (as specified in a programming language syntax) changes first.
The following sections define the safe array descriptor, along with the functions you use when accessing the data in the descriptor and the array.