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DCL:MATH1:SYSLIB : Internal Variable Management and Message Output: Explanation of Functions

2.5.2 IUFOPN

1.

Function

Returns the minimum number of  I/O device that exists and is not connected (therefore can be used).

2.

Call

IUFOPN()

3.

Explanation of Parameters

IUFOPN

(I)

Integer value that returns a device number.

4.

Notes

(a)

This value inquires the condition of the I/O device corresponding to the device numbers 1 to 99, in ascending order, and returns the device number for the first I/O device which exists and is not connected (not open). If no I/O devices is available, it will return 0.