Re: Austin group ruling on ungetc vs. fflush

[Bruno Haible]

Eric Blake wrote:
> > If you remove this special-casing, one of the tests in the testsuite fails.
> > Namely when the first fseek after fflush attempts to position beyond end of
> > file. That's something that lseek() does not support, but we are forced to
> > used lseek() in this situation, by POSIX. You can try to undo these two
> > hunks and fix the resulting test failure differently...
> 
> Huh?  "The lseek() function shall allow the file offset to be set beyond
> the end of the existing data in the file.  If data is later written at
> this point, subsequent reads of data in the gap shall return bytes with
> the value 0 until data is actually written into the gap."
> http://www.opengroup.org/onlinepubs/9699919799/functions/lseek.html

Probably true. Then it must be something instead the streams that gets messed
up by this situation.

If I remove this special-casing, I get these test failures (on a glibc system):

test-ftell.c:97: assertion failed
./test-ftell.sh: line 3: 22277 Abgebrochen             ./test-ftell${EXEEXT} 1 
< "$srcdir/test-ftell.sh"
FAIL: test-ftell.sh
test-ftello.c:107: assertion failed
./test-ftello.sh: line 3: 22283 Abgebrochen             ./test-ftello${EXEEXT} 
1 < "$srcdir/test-ftello.sh"
FAIL: test-ftello.sh

Bruno