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Step 2 - Opening a file

Once the file is available (allocated) it has to be opened before any further processing can occur.

EXECIO will perform an implicit open when the first read or write command is issued if the file or data set is not already open, but sometimes an explicit open may be required.

Opposite is the basic syntax for an explicit open. The examples on the following pages will have additional operands as required.

z/OS EXECIO data set explicit open syntax

z/VM EXECIO data set explicit open syntax

In both cases above, a closing parenthesis ) is optional and hence is often omitted.

Choose only one of DISKR, DISKW and DISKRU as appropriate.