| Input Parameters | Significance |
| DtvLong idm | mask Id |
| DtvLong idf | field Id |
| Output Parameters | Significance |
| no | - |
| Return Code | Significance |
| 0 | field exists in mask |
| 1 | field does not exist in mask |
Use this function to check the existence of a field whenever you want to apply complex program functions to the field but are not sure whether the object still exists in local memory.
Attention!
Applying a program function to a non-existent object can result in a system crash.