[Bug fortran/19451] New: Some read and write confusion with a read-only file

[Thomas dot Koenig at online dot de]

$ cat open+write.f90
program main
  character(len=10) a
  call system("rm -f asdf.dat; touch asdf.dat; chmod u-w asdf.dat")
  open(file="asdf.dat",unit=10,err=999,action="read")
  write(10,*,err=20) "Hello, world"
  print *,"write to read-only file succeeded"
  call abort
20 continue
  ! rewind(10)
  read(10,'(A)',end=30,err=999) a
  print *,"read from empty file succeeded"
  call abort
999 continue
  print *,"error reading from read-only file"
  call abort
30 continue
  print *,"Success!"
end
$ gfortran open+write.f90
$ ./a.out
 error reading from read-only file
Aborted

Uncommenting the rewind statement leads to

$ ./a.out
 read from empty file succeeded
Aborted
$ gfortran -v ; gfortran -dumpmachine
Using built-in specs.
Configured with: ../gcc-4.0-20050109/configure --prefix=/home/zfkts
--enable-languages=c,c++,f95
Thread model: posix
gcc version 4.0.0 20050109 (experimental)
ia64-unknown-linux-gnu

-- 
           Summary: Some read and write confusion with a read-only file
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: Thomas dot Koenig at online dot de
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19451