Use a file declaration with the following attributes to define a sequential regional data set:
DCL filename FILE RECORD
INPUT | OUTPUT | UPDATE
SEQUENTIAL
BUFFERED
[KEYED]
ENVIRONMENT(options);
Since BUFFERED and UNBUFFERED will be treated the same for REGIONAL(1) data sets, either option can be specified in the ENV option. For example, the FROM option is not required on a REWRITE for a SEQUENTIAL UNBUFFERED file and the LOCATE statement is allowed for OUTPUT SEQUENTIAL data sets even if UNBUFFERED is specified.
To define a direct regional data set, use a file declaration with the following attributes:
DCL filename FILE RECORD
INPUT | OUTPUT | UPDATE
DIRECT
ENVIRONMENT(options);Default file attributes are shown in Table 13. The file attributes are described in the PL/I Language Reference. Options of the ENVIRONMENT attribute are discussed below.