In IBM DOS/VS compatibility mode, when compiling for object versions 8.1 and greater, the compiler accepts the ACTUAL KEY feature for relative files opened in RANDOM access mode. For such files, the relative key numbers will be zero-based, rather than one-based, as with RELATIVE KEY. For example, if you have a relative file with a fixed record length of 3 bytes and a relative file with the following contents:
The record keys for the different modes are:
RELATIVE ACTUAL AAA: 1 0 BBB: 2 1 CCC: 3 2
ACUCOBOL-GT does not support SEEK and reports an Unsupported Operation error if it is present.