# ISATTY

Portability Function: Checks whether a logical unit number is a terminal.

## Module

USE IFPORT

result = ISATTY (lunit)

iunit | (Input) INTEGER(4). An integer expression corresponding to a Fortran logical unit number. Must be in the range 0 to 100 and must be connected.

## Results

The result type is LOGICAL(4). The result is .TRUE. if the specified logical unit is connected to a terminal device; otherwise, .FALSE..

If lunit is out of range or is not connected, zero is returned.

Parent topic: H to I