Deallocating Memory to MS-DOS

ID: Q48636

5.00 5.10 1.00 1.00a MS-DOS kbprg

The information in this article applies to:

Microsoft FORTRAN for MS-DOS, versions 5.0 and 5.1
Microsoft FORTRAN PowerStation for MS-DOS, versions 1.0 and 1.0a

SUMMARY

When using the DEALLOCATE command the storage space reserved by ALLOCATE is not returned to the system. Yet, the space is free for use inside of the FORTRAN program.

MORE INFORMATION

To clarify the documentation, the memory allocated by the ALLOCATE instruction is held by the program until the program terminates. The DEALLOCATE instruction frees the memory for use inside the main program. The space is not returned to MS-DOS.

If you must have the memory deallocate back to MS-DOS, you can spawn to a child process where you ALLOCATE and DEALLOCATE. When the child process terminates, the memory that was claimed by the FORTRAN child process will be returned to MS-DOS.

The following code demonstrates this process:

Sample Code

C C Main file. C

      interface to integer*2 function spawnlp
     + [C,VARYING] (mode)
      integer*2 mode
      end

      integer*2 spawnlp

      I=spawnlp(0,loc('child.exe'C),loc('child.exe'C),
     Xint4(0))
      end

C----------------------------------------------------------

C---------------------------------------------------------- C Child process (separate file), called by spawnlp in C parent. C

      integer size
      character*1 arr1[allocatable] ()
      parameter (size=20000)

      allocate (arr1(size))
      DEALLOCATE (arr1)
      end

C----------------------------------------------------------

Additional reference words: kbinf 5.00 5.10 1.00 KBCategory: kbprg KBSubcategory: FORTLngIss

Last Reviewed: April 30, 1998