[Bug fortran/38291] New: Rejects I/O with POS= if FMT=*

[Bug fortran/38291] New: Rejects I/O with POS= if FMT=*

[burnus at gcc dot gnu dot org]

Found at
http://de.wikibooks.org/wiki/Fortran:_Fortran_2003:_Ein-_und_Ausgabe

The following is valid and the error message is bogus:

read( 50, *, pos = 1 )
                     1
Error: FMT=* is not allowed with a REC= specifier at (1).

open(50,access='stream')
read( 50, *, pos = 1 )
end


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           Summary: Rejects I/O with POS= if FMT=*
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Keywords: rejects-valid
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: burnus at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38291

[Bug fortran/38291] Rejects I/O with POS= if FMT=*

[jvdelisle at gcc dot gnu dot org]

------- Comment #1 from jvdelisle at gcc dot gnu dot org  2008-11-27 14:20 -------
I am on it.


-- 

jvdelisle at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |jvdelisle at gcc dot gnu dot
                   |dot org                     |org
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2008-11-27 14:20:54
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38291

[Bug fortran/38291] Rejects I/O with POS= if FMT=*

[jvdelisle at gcc dot gnu dot org]

------- Comment #2 from jvdelisle at gcc dot gnu dot org  2008-12-01 03:55 -------
read( 50, *, pos = 1 )

is valid only if the unit has been connected for STREAM access. F2003

"9.5.1.10    POS= specifier in a data transfer statement

The POS= specifier specifies the file position in file storage units. This
specifier may appear in a data transfer statement only if the statement
specifies a unit connected for stream access. A child data transfer statement
shall not specify this specifier."

So the read statement by itself is invalid.  However, we should generate better
error message for this case. I have a patch on the way.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38291

[Bug fortran/38291] Rejects I/O with POS= if FMT=*

[burnus at gcc dot gnu dot org]

------- Comment #3 from burnus at gcc dot gnu dot org  2008-12-01 06:44 -------
> read( 50, *, pos = 1 )
> is valid only if the unit has been connected for STREAM access.

Well, (a) I don't see how this can be tested at compile time and (b) I thought
that
  open(50,access='stream')
is doing so.

> So the read statement by itself is invalid.
???


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38291

[Bug fortran/38291] Rejects I/O with POS= if FMT=*

[jvdelisle at gcc dot gnu dot org]

------- Comment #4 from jvdelisle at gcc dot gnu dot org  2008-12-01 16:32 -------
> So the read statement by itself is invalid.
???

I was testing with and without the open statement in the test case and saw that
we were not catching that error either.  Regardless, the problem is that I was
using dt->rec instead of dt->pos and our runtime just defaulted to using the
dt-rec for stream I/O.  This fix is that we have to use dt->pos in the matchers
and actually test conditions for pos= instead of rec= .

I will post the patch tonight. 


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38291

[Bug fortran/38291] Rejects I/O with POS= if FMT=*

[burnus at gcc dot gnu dot org]

------- Comment #5 from burnus at gcc dot gnu dot org  2008-12-01 16:40 -------
(In reply to comment #4)
> > > So the read statement by itself is invalid.
> > ???
> 
> I was testing with and without the open statement in the test case and saw
> that we were not catching that error either.

Ah, you are also talking about the run-time check in the library and not only
about the compile-time check in f951.

> I will post the patch tonight.
Thanks a ton!


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38291

[Bug fortran/38291] Rejects I/O with POS= if FMT=*

[jvdelisle at gcc dot gnu dot org]

------- Comment #6 from jvdelisle at gcc dot gnu dot org  2008-12-02 05:35 -------
Patch submitted.  There is ABI breakage with 4.3 in that patch I noticed after
I submitted, so I am now testing some tweaks.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38291

[Bug fortran/38291] Rejects I/O with POS= if FMT=*

[jvdelisle at gcc dot gnu dot org]

------- Comment #7 from jvdelisle at gcc dot gnu dot org  2008-12-04 05:32 -------
I am holding off on committing the patch.

With this test case I have found a nasty problem:

! { dg-do run }
! PR38291 Rejects I/O with POS= if FMT=*
character(15) :: sAccess
character(1) :: instr
open(50, access="stream", form="formatted")
write(50, *, pos=1) "Just something"
read( 50, *,pos=7)
inquire(50, access=sAccess)
if (sAccess.ne."STREAM") call abort
close(50,status="delete")
end

With the patch submitted to list, I get unstable execution. Sometimes errors
with -m32, sometimes with -m64, Sometimes one execution to the next.  I do not
know if this is a latent bug or one introduced by the patch.  I suspect latent
because this is the first time we actually are using dtp->pos even though it
has been in the dtp structure.  Here is a sample output:

$ gfc streamio_16.f90 
$ ./a.out 
At line 7 of file streamio_16.f90 (unit = 50, file = 'fort.50')
Fortran runtime error: End of file
$ ./a.out 
$ ./a.out 
At line 7 of file streamio_16.f90 (unit = 50, file = 'fort.50')
Fortran runtime error: End of file
$ ./a.out 
$ ./a.out 
At line 7 of file streamio_16.f90 (unit = 50, file = 'fort.50')
Fortran runtime error: End of file


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38291

[Bug fortran/38291] Rejects I/O with POS= if FMT=*

[jvdelisle at gcc dot gnu dot org]

------- Comment #8 from jvdelisle at gcc dot gnu dot org  2008-12-05 05:39 -------
The alternating error was an artefact of the test case and not part of the bug.
 I have submitted a fixed patch that eliminates the incorrect EOF error.  I
will commit soon.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38291

[Bug fortran/38291] Rejects I/O with POS= if FMT=*

[jvdelisle at gcc dot gnu dot org]

------- Comment #9 from jvdelisle at gcc dot gnu dot org  2008-12-06 04:15 -------
Subject: Bug 38291

Author: jvdelisle
Date: Sat Dec  6 04:13:34 2008
New Revision: 142515

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=142515
Log:
2008-12-05  Jerry DeLisle  <jvdelisle@gcc.gnu.org>

        PR fortran/38291
        * io.c (match_dt_element): Use dt->pos in matcher.
        (gfc_free_dt): Free dt->pos after use.
        (gfc_resolve_dt): Use dt->pos in resolution of stream position tag.

2008-12-05  Jerry DeLisle  <jvdelisle@gcc.gnu.org>

        PR libfortran/38291
        * io/transfer.c (data_transfer_init): Add checks for POS= valid range.
        Add check for unit opened with ACCESS="stream". Flush and seek if
        current stream position does not match. Check ENDFILE on read.

Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/io.c
    trunk/libgfortran/ChangeLog
    trunk/libgfortran/io/transfer.c


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38291

[Bug fortran/38291] Rejects I/O with POS= if FMT=*

[jvdelisle at gcc dot gnu dot org]

------- Comment #10 from jvdelisle at gcc dot gnu dot org  2008-12-06 04:19 -------
Subject: Bug 38291

Author: jvdelisle
Date: Sat Dec  6 04:17:31 2008
New Revision: 142516

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=142516
Log:
2008-12-05  Jerry DeLisle  <jvdelisle@gcc.gnu.org>

        PR fortran/38291
        * gfortran.dg/streamio_16.f90: New test.

Added:
    trunk/gcc/testsuite/gfortran.dg/streamio_16.f90
Modified:
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38291

[Bug fortran/38291] Rejects I/O with POS= if FMT=*

[jvdelisle at gcc dot gnu dot org]

------- Comment #11 from jvdelisle at gcc dot gnu dot org  2008-12-06 04:19 -------
Fixed on trunk.


-- 

jvdelisle at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.4.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38291

[Bug fortran/38291] Rejects I/O with POS= if FMT=*

[jvdelisle at gcc dot gnu dot org]

------- Comment #12 from jvdelisle at gcc dot gnu dot org  2008-12-06 21:54 -------
Subject: Bug 38291

Author: jvdelisle
Date: Sat Dec  6 21:53:11 2008
New Revision: 142528

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=142528
Log:
2008-12-06  Jerry DeLisle  <jvdelisle@gcc.gnu.org>

        PR libfortran/38291
        * io/transfer.c (data_transfer_init): Add fbuf_flush inadvertently
        ommitted.  Add check for invalid use of REC= with ACCESS="stream".  Fix
        comment.

Modified:
    trunk/libgfortran/ChangeLog
    trunk/libgfortran/io/transfer.c


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38291