Jack Scheible wrote:

> 
> That is why we programmers don't have to worry about fragmenting
> memory, until we reach the 4 gig limit.  The OS writers have already
> solved the problem.
> 

I can see it's diffucilt to convince you... :-)
Just test the small attached F90 program, which recursively
reallocate a 1D tab (sizes are the Fibonacci serie),
and tell me what are the result and your conclusions.

Here is the output I have on a RS6000:

hugonnet% a.out
 
 total allocated = 1024
 
 total allocated = 2048
 
 total allocated = 3072
 
 total allocated = 5120
 
 total allocated = 8192
 
 total allocated = 13312
 
 total allocated = 21504
 
 total allocated = 34816
 
 total allocated = 56320
 
 total allocated = 91136
 
 total allocated = 147456
 
 total allocated = 238592
 
 total allocated = 386048
 
 total allocated = 624640
 
 total allocated = 1010688
 
 total allocated = 1635328
 
 total allocated = 2646016
 
 total allocated = 4281344
 
 total allocated = 6927360
 
 total allocated = 11208704
 realloc of  18136064  failed
 dealloc of a --> total allocated = 0
 alloc of  29344768 (= 11208704 + 18136064 ) possible!





-- 
Pierre Hugonnet                             Seismic Data Processing R&D
COMPAGNIE GENERALE DE GEOPHYSIQUE
mail: 1 rue Leon Migaux                     phone.....(33) 164 47 45 59
      91302 MASSY                           fax.......(33) 164 47 32 49
      FRANCE                                [log in to unmask]
      
My opinions are not necessarily those of CGG (nor those of JPII)



PROGRAM toto
IMPLICIT NONE

INTEGER :: fibo(3) = (/1,1,0/)*1024
INTEGER :: ierr, l
REAL, POINTER :: a(:)

allocate( a(fibo(1)) )
CALL reallocate(a, fibo(2), STAT=ierr) ; IF (ierr /= 0) STOP


DO
   
   write(*,*)
   fibo(3) = fibo(1)+fibo(2) ; fibo(1) = fibo(2) ; fibo(2) = fibo(3)
   
   l = size(a)
   write(*,*)"total allocated =",l
   CALL reallocate( a, fibo(3), STAT=ierr)
   IF (ierr /= 0) THEN
      write(*,*)"realloc of ",fibo(3)," failed"
      deallocate(a)
      write(*,*)"dealloc of a --> total allocated = 0"
      allocate( a(fibo(3)+l), STAT=ierr)
      IF (ierr == 0) THEN
         write(*,*)"alloc of ",l+fibo(3),"(=",l,"+",fibo(3),") possible!"
      ELSE
         write(*,*)"alloc of ",l+fibo(3),"(=",l,"+",fibo(3),") failed"
      END IF
      STOP 
   ELSE
      CYCLE
   END IF

END DO


          
       
CONTAINS

SUBROUTINE reallocate(a,new_size,stat)
REAL, POINTER :: a(:), temp(:)
INTEGER, INTENT(IN) :: new_size
INTEGER, INTENT(OUT) :: stat
INTEGER :: ncopy

allocate(temp(new_size), STAT=stat)
IF (stat == 0) THEN
   ncopy = min(size(a),new_size)
   ! temp(1:ncopy) = a(1:ncopy)
   deallocate(a)
   a => temp
END IF

END SUBROUTINE

END