[patch, libfortran] PR33985 access="stream",form="unformatted" doesn't buffer

[Angelo Graziosi]

I have applied the patch added here
http://gcc.gnu.org/ml/fortran/2007-11/msg00011.html to GFC-4.2.2 under
Cygwin and have not observed any progesses in reading a binary file
of about 36MB. The file is written with these statements (nr = nz = 1499):

   ...
   open(30,file=fMap,status='unknown',access='stream')

   write(30) nr,nz
   write(30) dr,dz
   r = 0.D0*dr
   do j = 0,nr
      z = 0.D0*dz
      do k = 0,nz
         call bcalc(r,z,br,bz)
         write(30) br,bz
         z = z+dz
      enddo
      r = r+dr
   enddo
   close(30)


and it is read with

   open(MAPUNT,file='cobra.map',status='OLD',access='STREAM')
   read(MAPUNT) nr,nz
   read(MAPUNT) dr,dz
   call alloc_mem()
   ! ===============================================
   !  Setting MAXR and MAXZ for GUFLD interpolation
   ! ===============================================
   maxR = real(nr*dr)
   maxZ = real(nz*dz)
   write(*,*)
   write(*,'(A)',advance='NO') 'Loading B field...'
   do i = 0,nr
      do j = 0,nz
         read(MAPUNT) br(i,j),bz(i,j)
      enddo
   enddo
   close(MAPUNT)


WITH or WITHOUT the patch it takes about 2 minutes to read it (1m54.578)!

G77 takes 53 seconds to read a similar file of 50MB (the unformatted files
for G77 have the record marker, so the size increases); G95 takes less
than 6 seconds (but I suspect that g95 on Cygwin uses pure Windows libs).

So, have I misinterpreted the meaning of the patch or is it specific for
GFC-4.3 and not for 4.2.2?

Am I missing something else?


TIA,

   Angelo.