Severe problem with formatted write

[Paul Thomas]

Francois-Xavier

> Hi,
>
>>
>> I'd like to help (for example, reverting the patches you quote one by
>> one until we find the right one), but I can't see the failure you
>> mention on x86_64-linux (which is the only fast computer I have access
>> too right now).
>
I finally got some time to do just that:

Working up from 16th March, I hit the right one with:

2005-04-09  Bud Davis  <bdavis@gfortran.org>
        Steven G. Kargl <kargls@comcast.net>

    PR fortran/19872
    * io/transfer.c (data_transfer_init): truncate an existing
    file on the first write.

transfer.c:1170
  /* Overwriting an existing sequential file ?
     it is always safe to truncate the file on the first write */
  if (g.mode == WRITING
      && current_unit->flags.access == ACCESS_SEQUENTIAL
      && current_unit->current_record == 0)
    struncate(current_unit->s);

If I comment out the code, the problem (documented below) goes away. 
 Expanding the macro by hand does not help, so the (s)->truncate 
function must be broken, for RH9 at least.

Will investigate further.

Paul T

Documenation of problem:

      integer, parameter   :: nloops =1
      open (9, file = "foo.out")
      write (9, *) "The foobar test"
      write(9,*) 42, 42, 42, 40
      do i = 1, nloops
         write (9,*) "step=", i
      end do
      write(9,*)' The end of the foobar test'
      close (9)
      STOP
      END

produces

<86 NULLS> The foobar test
          42          42          42          40
 step=           1
  The end of the foobar test

Upping the parameter to nloops, results in, at least 1400 NULLS on the 
first line,  followed by
 step=         429
 step=         430
 step=         431
 step=         432
....
to a correct conclusion.

removing the above patch results in the correct output.