[Bug fortran/29053] New: Consecutive STREAM I/O file positions mixed up

jvdelisle at gcc dot gnu dot org gcc-bugzilla@gcc.gnu.org
Wed Sep 13 02:33:00 GMT 2006


With the following test case and no optimization, the dtp pointer is duplicated
resulting in the dtp-rec values getting mixed up during consecutive writes:

program avl
   implicit none
   real dt, t, a(10)
   integer i, place
   dt = 1.e-6
   a = real( (/ (i, i=1, 10) /) )
   open(unit=11, file='a.dat', access='stream')
   open(unit=12, file='b.dat', access='stream')
   do i = 1, 10
      t = i * dt
      write(11) t
      write(12) a
   end do
   close(11)
   close(12)
end program avl

Test case from Steve Kargl.  The end result should be a.dat file of length 40
and b.dat file of length 400.  The result is:

-rw-rw-r-- 1 jerry jerry  396 Sep 12 19:32 a.dat
-rw-rw-r-- 1 jerry jerry  436 Sep 12 19:32 b.dat

With -O1 this program works fine.

With gdb you can see the transfer calls given the same dtp pointer for both
files.


-- 
           Summary: Consecutive STREAM I/O file positions mixed up
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jvdelisle at gcc dot gnu dot org
  GCC host triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29053



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