ABAP Keyword Documentation → ABAP − Reference → Processing External Data → ABAP File Interface
Locking Files
The file interface does not contain an integrated locking mechanism that ensures that only one ABAP program at a time can access a file. If multiple programs are writing to a file at the same time, the results are unpredictable.
To avoid this situation, use SAP locks or an unambiguous file name, such as UUIDs.
Other versions: 7.31 | 7.40 | 7.54
Note
When multiple AS Instancess in AS ABAP try to access a file at the same time, conflicts can still occur despite SAP locks. This is the case, for example, when the operating system buffers data before writing it to a file.