fortran2003新特性：可分配数组用于外部过程的参数

Module testMod
    implicit none
contains
    
    subroutine test_alloc( array )  !.. 如果外部调用，并且要返回array，则在此过程结束的地方不可以释放，必须在外部进行释放
        implicit none
        real, allocatable :: array(:)
        
        !.. local variables
        integer :: i 
        integer :: istat
        
        if ( allocated(array) ) then
            write( *,'(1x,a)' ) 'sub: array is allocated!'
        else
            write( *,'(1x,a)' ) 'the array is not allocated!'
        end if
        
        !.. deallocate the array
        if ( allocated( array ) ) then
            deallocate( array )
        end if
        
        !.. reallocate array
        allocate( array(5), stat = istat )
        
        !.. save data
        forall ( i = 1: size(array) )
            array(i) = 6 - i 
        end forall
        
        !.. write out data
        write( *,'(*(g0,3x))' ) array
        
    end subroutine test_alloc
    
end module testMod
    
    
Program main
    use testMod
    implicit none 
    real, allocatable :: a(:)
    integer :: istat
    
    allocate( a(6), stat= istat )
    a = [1,2,3,4,5,6]
    write( *,'(*(g0,3x))' ) a
    
    !.. call sub
    call test_alloc( a )
    write( *,'(*(g0,3x))' ) a
    deallocate( a )
    
End program main

执行结果如下：
1.000000   2.000000   3.000000   4.000000   5.000000   6.000000
 sub: array is allocated!
5.000000   4.000000   3.000000   2.000000   1.000000
5.000000   4.000000   3.000000   2.000000   1.000000