| Input Parameter | Significance |
| DtvLong idn | ident-number of the record |
| char *tab | name of the table |
| char *col | name of the BLOB-table column |
| Output Parameter | Significance |
| int *siz | length of the data segment |
| char **dat | pointer to the data segment |
| Return Code | Significance |
| 0 | all ok |
| 1 | no record for ident-number found |
| -1 | database error at reading BLOB-field |