The SAFEARRAY is a standard way to pass arrays or collections between COM objects. The Genstat data structure names and types are passed in a SAFEARRAY containing two dimensions. The first dimension of the array contains the type BSTR and is used to store the names of the data structures. The second dimension contains the data type (e.g. scalar, variate etc…) in an integer (VT_I4). The data types have a numerical coding which is shown below.
Data types
| Number | Data structure |
| 1 | Scalar |
| 2 | Factor |
| 3 | Text |
| 4 | Variate |
| 5 | Matrix |
| 6 | Diagonal matrix |
| 7 | Symmetric matrix |
| 8 | Table |
| 9 | Anova save structure |
| 10 | Time series save structure |
| 11 | Expression |
| 12 | Formula |
| 13 | Dummy |
| 14 | Pointer |
| 15 | LRV – latent roots and vectors |
| 16 | SSP – sums of squares and products |
| 17 | TSM – model for Box-Jenkins modelling of time series |
| 18 | Regression save structure |
| 22 | Tree |