Buffered/unbuffered I/O issues

[Harald Anlauf]

Hi,

I am a little bit confused about the handling of buffering
of I/O with gfortran, especially when piping stddout to
another program.  Instead of opening a bug report, I would
like to ask here about opinions.
(I am working on an older Suse 9.0 Linux system (x86)).

Consider the program:

print *, "foo"
call sleep (2)
write(*,*) "bar"
call sleep (2)
print *, "Done."
end

I have set:

% echo $GFORTRAN_UNBUFFERED_6 
1
% echo $GFORTRAN_UNBUFFERED_ALL

Running the program without stdout redirection, it prints
 foo
 bar
 Done.
with the desired delay of two seconds between the prints.
But when starting as:
% ./a.out | tee foobar
it appears to buffer the standard output.
Am I doing something plain wrong?

Funnily, setting GFORTRAN_UNBUFFERED_ALL=1 makes the above
example work, but will unbuffer everything.

Now I tried:
% unbuffer ./a.out | tee foobar |cat -e
 foo^M$
 bar^M$
 Done.^M$

This now works almost as expected, but exhibits a !"§$% bug
in "unbuffer".
(unbuffer is also broken because it redirects stderr to stdout)

Did I miss something obvious?

Cheers,
-ha

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