Describing field use for logical files

 

You can specify that the fields in a logical file be input-only, both (input/output), or neither fields.

To describe field use for a logical file, specify one of the following items in position 38:

Entry

Meaning

Blank

For simple or multiple format logical files, defaults to B (both) For join logical files, defaults to I (input only).

B

Both input and output allowed; not valid for join logical files.

I

Input only (read only).

N

Neither input nor output; valid only for join logical files.

The usage value (in position 38) is not used on a reference function. When another file refers to a field (using a REF or REFFLD keyword) in a logical file, the usage value is not copied into that file.

• Describing field use for logical files: Both
  A both field can be used for both input and output operations. Your program can read data from the field and write data to the field.

• Describing field use for logical files: Input only
  An input-only field can be used for read operations only. Your program can read data from the field, but cannot update the field.

• Describing field use for logical files: Neither
  A neither field is used neither for input nor for output.

 

Parent topic:

Describing logical file record formats