This routine replaces an existing record in the file. It has four parameters: file_handle, record, length, and keyval.
| file_handle | must be a valid file handle returned by R-OPEN-FUNCTION. |
| record | is the record data to write to the file. |
| length | is the number of bytes to write (for variable-length files). |
| keyval | is the record number to write. A keyval of -1 means to write at the end of the file. |
The R-REWRITE-FUNCTION routine does not change the current file position.