Unformatted, indexed WRITE statements transfer binary data (without translation) between the entities specified in the I/O list and the current record.
No key parameters are required in the list of control parameters, because all necessary key information is contained in the output record.
If the values specified by the I/O list do not fill a fixed-length record being written, the unused portion of the record is filled with zeros. If the values specified do not fit in the record, an error occurs.
Since derived data types of sequence type usually have a fixed record format, you can write to indexed files by using a sequence derived-type structure that models the file's record format. This lets you perform the I/O operation with a single derived-type variable instead of a potentially long I/O list. Nonsequence derived types should not be used for this purpose.
If the file is connected for formatted I/O, unformatted data transfer is prohibited.
The following example shows an unformatted, indexed WRITE statement:
WRITE (UNIT=8, IOSTAT=IO_STATUS) A, B, C