## 9.3.118 PRESENT (A)

Description: | Returns whether or not an optional dummy argument is present (has an associated actual argument).
Class: | Inquiry function; Generic
Arguments: | A must be an optional argument of the current procedure.
Results: | The result is a scalar of type default logical. The result is .TRUE. if A is present; otherwise, the result is .FALSE..

Examples

Consider the following:

    SUBROUTINE CHECK (X, Y)
      REAL X, Z
      REAL, OPTIONAL :: Y
      ...
      IF (PRESENT (Y)) THEN
        Z = Y
      ELSE
         Z = X * 2
      END IF
    END
    ...
    CALL CHECK (15.0, 12.0)      ! Causes B to be set to 12.0
    CALL CHECK (15.0)            ! Causes B to be set to 30.0

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