<Example Program>

Program logical_fun_example
  Logical(1) :: a ! Single-byte logical.
  a = .False.
  Call s(Logical(a))
  Call s(.Not.Logical(a))
Contains
  Subroutine s(b)
    Logical b ! Default logical.
    Print *, 'b is', b
  End Subroutine
End Program

Execution Results

 b is F
 b is T