OPEN-FUNCTION (op-code 1)

This routine opens an existing indexed file. If it is successful, the value in RETURN-CODE should be moved to a data item that is USAGE POINTER. This data item is passed as the open file handle to the other file handling routines. If it fails, RETURN-CODE is set to a NULL value. After the file is opened, the primary key is set as the current key of reference and is positioned at the beginning of the file.

The OPEN routine has three parameters, name, mode and l_parms.