The logical unit specifier identifies the logical unit to be
accessed. The logical unit specifier takes either of the following
forms:
{ [UNIT=]u }
{ [UNIT=]* }
- u
- Is an integer expression with a value that refers to a specific
file or I/O device. On VAX processors, the integer is in the range
of 0 through 119; on Alpha processors, the integer is in the range
of 0 through 2**31-1.
If necessary, the value is converted to integer data type before
use.
- *
- Specifies that the default input or output unit is to be
accessed.
The keyword UNIT is optional if the logical unit specifier is the
first parameter in the control list.
A logical unit number is assigned to a file, device, or Tru64 UNIX
pipe in one of two ways:
- Explicitly through an OPEN statement
- Implicitly by the system
If you use READ to implicitly open a file, the file is opened
as STATUS='OLD'. If you use WRITE to
implicitly open a file, the file is opened as follows:
- On OpenVMS systems: STATUS='NEW'
- On Tru64 UNIX systems: STATUS='UNKNOWN'
For More Information:
- On the OPEN statement: on OpenVMS systems, see Section 9.6; on Tru64 UNIX systems,
see Section 10.6.
- On implicit logical assignments, see your user manual.
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