[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Comment #26 from fxcoudert at gcc dot gnu dot org 2005-10-30 13:49 --- Finally fixed by the last two commits (on both 4.0 and 4.1). -- fxcoudert at gcc dot gnu dot org changed: What|Removed |Added URL|http://gcc.gnu.org/ml/fortra| |n/2005-10/msg00682.html | Status|ASSIGNED|RESOLVED Keywords|patch | Resolution||FIXED Target Milestone|--- |4.0.3 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Comment #25 from fxcoudert at gcc dot gnu dot org 2005-10-30 13:25 --- Subject: Bug 20179 Author: fxcoudert Date: Sun Oct 30 13:25:25 2005 New Revision: 106018 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=106018 Log: PR libfortran/20179 * io/unix.c (flush_if_preconnected): New function. * io/io.h: Add prototype for flush_if_preconnected. * io/transfer.c (data_transfer_init): Use flush_if_preconnected to workaround buggy mixed C-Fortran code. * gfortran.dg/mixed_io_1.f90: New test. * gfortran.dg/mixed_io_1.c: New file. Added: branches/gcc-4_0-branch/gcc/testsuite/gfortran.dg/mixed_io_1.c - copied unchanged from r106017, trunk/gcc/testsuite/gfortran.dg/mixed_io_1.c branches/gcc-4_0-branch/gcc/testsuite/gfortran.dg/mixed_io_1.f90 - copied unchanged from r106017, trunk/gcc/testsuite/gfortran.dg/mixed_io_1.f90 Modified: branches/gcc-4_0-branch/gcc/testsuite/ChangeLog branches/gcc-4_0-branch/libgfortran/ChangeLog branches/gcc-4_0-branch/libgfortran/io/io.h branches/gcc-4_0-branch/libgfortran/io/transfer.c branches/gcc-4_0-branch/libgfortran/io/unix.c -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Comment #24 from fxcoudert at gcc dot gnu dot org 2005-10-30 12:48 --- Subject: Bug 20179 Author: fxcoudert Date: Sun Oct 30 12:48:52 2005 New Revision: 106017 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=106017 Log: PR libfortran/20179 * io/unix.c (flush_if_preconnected): New function. * io/io.h: Add prototype for flush_if_preconnected. * io/transfer.c (data_transfer_init): Use flush_if_preconnected to workaround buggy mixed C-Fortran code. * gfortran.dg/mixed_io_1.f90: New test. * gfortran.dg/mixed_io_1.c: New file. Added: trunk/gcc/testsuite/gfortran.dg/mixed_io_1.c trunk/gcc/testsuite/gfortran.dg/mixed_io_1.f90 Modified: trunk/gcc/testsuite/ChangeLog trunk/libgfortran/ChangeLog trunk/libgfortran/io/io.h trunk/libgfortran/io/transfer.c trunk/libgfortran/io/unix.c -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Comment #23 from fxcoudert at gcc dot gnu dot org 2005-10-29 12:44 --- Patch for that PR submitted (http://gcc.gnu.org/ml/fortran/2005-10/msg00682.html). -- fxcoudert at gcc dot gnu dot org changed: What|Removed |Added URL||http://gcc.gnu.org/ml/fortra ||n/2005-10/msg00682.html Keywords||patch http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From fxcoudert at gcc dot gnu dot org 2005-09-12 11:18 --- (In reply to comment #21) > It must have been some kind of regression (at least for libfortran) because > it > worked in the 4.0.0 release when we first tried it. This bug was introduced while fixing another bug. This will now work on both branches, including 4.0.2 (to be released soon). -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From T dot Farago at lumc dot nl 2005-09-12 10:13 --- Ah great for fixing this, will try out as soon as the latest snapshot comes. I had the problem that was present in comment #17, just Fortran, no C-Fortran mix. It must have been some kind of regression (at least for libfortran) because it worked in the 4.0.0 release when we first tried it. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From cvs-commit at gcc dot gnu dot org 2005-09-11 18:55 --- Subject: Bug 20179 CVSROOT:/cvs/gcc Module name:gcc Branch: gcc-4_0-branch Changes by: [EMAIL PROTECTED] 2005-09-11 18:55:16 Modified files: gcc/testsuite : ChangeLog libgfortran: ChangeLog libgfortran/io : io.h transfer.c unix.c Added files: gcc/testsuite/gfortran.dg: overwrite_1.f Log message: PR libfortran/19872 * gfortran.dg/overwrite_1.f: New test. PR libfortran/19872 PR libfortran/20179 * io/unix.c (is_preconnected): Add function to test if a stream corresponds to a preconnected unit. * io/io.h: Add prototype for is_preconnected. * io/transfer.c (data_transfer_init): Truncate overwritten files on first write, but not preconnected units. Patches: http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.5084.2.397&r2=1.5084.2.398 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/overwrite_1.f.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=NONE&r2=1.1.2.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.163.2.90&r2=1.163.2.91 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/io/io.h.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.16.10.7&r2=1.16.10.8 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/io/transfer.c.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.32.2.16&r2=1.32.2.17 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/io/unix.c.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.21.10.14&r2=1.21.10.15 -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From cvs-commit at gcc dot gnu dot org 2005-09-11 13:35 --- Subject: Bug 20179 CVSROOT:/cvs/gcc Module name:gcc Changes by: [EMAIL PROTECTED] 2005-09-11 13:34:57 Modified files: libgfortran: ChangeLog libgfortran/io : io.h transfer.c unix.c Log message: PR libfortran/20179 * io/unix.c (is_preconnected): Add function to test if a stream corresponds to a preconnected unit. * io/io.h: Add prototype for is_preconnected. * io/transfer.c (data_transfer_init): Do not truncate preconnected units. Patches: http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/ChangeLog.diff?cvsroot=gcc&r1=1.301&r2=1.302 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/io/io.h.diff?cvsroot=gcc&r1=1.29&r2=1.30 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/io/transfer.c.diff?cvsroot=gcc&r1=1.57&r2=1.58 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/io/unix.c.diff?cvsroot=gcc&r1=1.38&r2=1.39 -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From fxcoudert at gcc dot gnu dot org 2005-09-10 16:16 --- I should add that the code concerned is in io/transfer.c, line 1174: /* 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->last_record == 0) struncate(current_unit->s); Well, my opinion is that this comment is wrong! :) -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From fxcoudert at gcc dot gnu dot org 2005-09-10
16:06 ---
Looking at that again, it is clear that there is a bug in the way libgfortran
handles pre-connected units. In short, the fd-based I/O library behaves like it
is the first program to access the file; this is not right for pre-connected
units. First example:
$ cat b.c
extern void foo_(void);
int main ()
{
write (1, "Hello world\n", 13);
foo_ ();
return 0;
}
$ cat b.f
subroutine foo
write (*,"(A)") "Ciao world!"
end
$ ./b.out
Hello world
Fortran runtime error: End of record
$ cat a.sh
#!/bin/sh
${*} a.f
echo Before
./a.out
echo After
$ cat a.f
print *, "foo"
end
$ ./a.sh ./debug/irun/bin/gfortran -static > foo && cat foo
foo
After
$ ./a.sh ./debug/irun/bin/gfortran -static
Before
foo
After
>From the strace, the problem is quite clear: fd_truncate is called on the fd #1
(stdout), when the unit is opened.
--
What|Removed |Added
Priority|P3 |P2
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From fxcoudert at gcc dot gnu dot org 2005-09-08 20:59 --- *** Bug 23778 has been marked as a duplicate of this bug. *** -- What|Removed |Added CC||T dot Farago at lumc dot nl http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From pinskia at gcc dot gnu dot org 2005-06-17 18:12 --- *** Bug 22106 has been marked as a duplicate of this bug. *** -- What|Removed |Added CC||svrci at tbi dot univie dot ||ac dot at http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From fxcoudert at gcc dot gnu dot org 2005-05-30 07:45 --- Patch for first part of the problem applied. Keeping open according to comments #8 to #11. -- What|Removed |Added URL|http://gcc.gnu.org/ml/fortra| |n/2005-05/msg00267.html | GCC build triplet|i686-pc-linux-gnu | GCC host triplet|i686-pc-linux-gnu | GCC target triplet|i686-pc-linux-gnu | http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From cvs-commit at gcc dot gnu dot org 2005-05-30 07:42 --- Subject: Bug 20179 CVSROOT:/cvs/gcc Module name:gcc Branch: gcc-4_0-branch Changes by: [EMAIL PROTECTED] 2005-05-30 07:42:38 Modified files: libgfortran: ChangeLog libgfortran/io : unix.c Log message: PR libfortran/20179 * io/unix.c (fd_close): Add test so that we don't close() stdout and stderr. Patches: http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.163.2.45&r2=1.163.2.46 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/io/unix.c.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.21.10.4&r2=1.21.10.5 -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From cvs-commit at gcc dot gnu dot org 2005-05-30 07:38 --- Subject: Bug 20179 CVSROOT:/cvs/gcc Module name:gcc Changes by: [EMAIL PROTECTED] 2005-05-30 07:38:36 Modified files: libgfortran: ChangeLog libgfortran/io : unix.c Log message: PR libfortran/20179 * io/unix.c (fd_close): Add test so that we don't close() stdout and stderr. Patches: http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/ChangeLog.diff?cvsroot=gcc&r1=1.231&r2=1.232 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/io/unix.c.diff?cvsroot=gcc&r1=1.26&r2=1.27 -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From fxcoudert at gcc dot gnu dot org 2005-05-25 18:37 --- In my view, interoperation implies that every part of code leaves the system in a clean state (I/O streams flushed, FPE flags in correct state) when execution switches to another part of code. That is what the patch I mentionned is doing: making sure gfortran doesn't stdout when some other code might still need it. Now, it might be necessary to have special workarounds for the most common problems (such as this one with stdout) that we can fix, even if we shouldn't have to take care of. As always, the problem is: adding lots of ad hoc tricks with "negligible" performance loss can result in big performance losses for nothing in the most usual cases. Anyway, I'll work on something. If you have some spare time (dreams, dreams), a bit of performance-profiling could be useful. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From stevenj at alum dot mit dot edu 2005-05-25 16:47 --- It was already noted above that adding fflush to the user's code would fix the output. As a quality-of-implementation issue, however, I would suggest that libgfortran should do it. 1) Interoperating well with code in other languages, and especially with C (the de facto lingua franca) is increasingly important nowadays. 2) libc is the most common way to write to stdio. Arguably, the onus is on code using other libraries to interoperate well with it, rather than vice versa. (We're not talking about C code with some random home-brewed I/O library here.) 3) Fortran 2000 has a standard way to call C functions in libraries that may not have been designed to be called from non-C languages, and it won't always be practical to modify the C code to call fflush (e.g. the source may not even be available). Nor can the Fortran user herself easily call fflush(stdout), because that call is not available (?) in Fortran. Hence, if it is to be done at all in such cases, it has to be done in libgfortran. 4) If the performance loss of calling fflush before outputting to stdio in libgfortran is negligible (I have no data, just a guess), why is this even a question? -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From fxcoudert at gcc dot gnu dot org 2005-05-25 11:10 --- In the modified program, calls to fflush are missing, but they are missing from the C routine. The library does not use FILE* streams and, as far as I know, it does its own flushing right. The problem you mention could be avoided by a preemptive fflush(stdout), but this is only working around the user's code problems: when you use two different systems of I/O, you should take care that each cleans up its internal mess before switching to the other one. gfortran did not do this properly, hence the patch I submitted. Now, my opinion is that in the case of the code from comment #8, it's up to the user to write his code more carefully. As an addition to this opinion (I'll be glad to hear any other point of view), here is a small "state-of-the-art" on this point: Intel, IBM compilers do as I suggest here, while Portland, MIPSpro and Sun compilers do as you expect. -- What|Removed |Added AssignedTo|unassigned at gcc dot gnu |fxcoudert at gcc dot gnu dot |dot org |org Status|NEW |ASSIGNED Last reconfirmed|2005-05-23 17:12:29 |2005-05-25 11:10:59 date|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From stevenj at alum dot mit dot edu 2005-05-24 23:51 --- I doubt that merely omitting close() from the end of the library will entirely fix the problem. You really need to add an fflush before every output to stdio. For example, modify ciotst.f to: program ciotst call cio write(*,*) 'Hello world.' call cio end The g77 output is: foo bar baz Hello world. foo bar baz as you would expect, but the gfortran output is in the wrong order (as well as missing the final "baz" in my unpatched gfortran) because of missing flushes: foo bar Hello world. bazfoo bar (If you look in libf2c you'll see that it uses fflush in a number of places.) -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From fxcoudert at gcc dot gnu dot org 2005-05-23 17:12 --- Good news for this PR. I located the root of the problem, which is that when the library ends, we close() the stdout file descriptor, while the last line of output (without newline trailing character) is not written yet. So, the right thing to do might be not have a special test for stdout and stderr, so that we don't close() those. Patch submitted for review. -- What|Removed |Added URL||http://gcc.gnu.org/ml/fortra ||n/2005-05/msg00267.html Last reconfirmed|2005-05-22 22:09:34 |2005-05-23 17:12:29 date|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From fxcoudert at gcc dot gnu dot org 2005-05-22 22:09 --- As a reply to comment 2: this is indeed a problem of mixing unix-style and C-style I/O, but not mmap ones (this was a different PR, fixed some time ago now: mmap is not used on standard input, output and error). Consider the following (program given in bug-report compiled as indicated): $ ./a.out foo bar $ ./a.out | cat $ GFORTRAN_STDOUT_UNIT=-1 ./a.out | cat foo bar $ echo `./a.out` $ echo `GFORTRAN_STDOUT_UNIT=-1 ./a.out` foo bar baz -- What|Removed |Added CC||fxcoudert at gcc dot gnu dot ||org Last reconfirmed|2005-02-27 18:18:51 |2005-05-22 22:09:34 date|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From tobi at gcc dot gnu dot org 2005-02-27 18:18 --- We should probably call fflush() in the following places: - at the beginning of a Fortran I/O operation - at termination of the program anywhere else? -- What|Removed |Added Status|UNCONFIRMED |NEW Ever Confirmed||1 Last reconfirmed|-00-00 00:00:00 |2005-02-27 18:18:51 date|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From stevenj at fftw dot org 2005-02-23 23:17 --- Subject: Re: cannot mix C and Fortran I/O On Wed, 23 Feb 2005, Thomas dot Koenig at online dot de wrote: > Add "fflush(stdout);" at the end of cio.c, and things work > as expected. This is a workaround, but it would be nice to be able to mix C and Fortran code with I/O more seamlessly. Is putting an fflush into a few strategic places in libgfortran that expensive that it overwhelms the benefit of seamless integration with stdio? -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From Thomas dot Koenig at online dot de 2005-02-23 22:54 --- Add "fflush(stdout);" at the end of cio.c, and things work as expected. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From pinskia at gcc dot gnu dot org 2005-02-23 20:18 --- Actually this looks more like mixing stdio functions and unix style functions (well mmap ones). -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
[Bug libfortran/20179] cannot mix C and Fortran I/O
--- Additional Comments From pinskia at gcc dot gnu dot org 2005-02-23 20:08 --- Werid. -- What|Removed |Added Component|fortran |libfortran http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20179
