Retrieve a whole list of values from the this data model.
This function calls gda_data_proxy_get_value for each column index specified in cols_index, and generates a
SList on the way.
| this |
a DataProxy object |
| proxy_row |
a proxy row |
| cols_index |
array containing the columns for which the values are requested |
| n_cols |
size of |
|
a new list of values (the list must be freed, not the values), or null if an error occurred |