Insert a new record with the given key and data into a key file,
Insert a new record with the given key and data into a key file,Multiple records with the same key are allowed, if there are already records with the same key the new record will be inserted behind all records with the same key.
The current record of the file will be set to the new record
RESTRICTIONS:
- the file must be open for update,
- key must point to the key to be inserted,
- keylen must be bigger than 0 and smaller than 256,
- data must point to the data be inserted,
- datalen must not be negative,
- if datalen == 0, the pointer data is not evaluated at all