[Bug libfortran/107031] endfile truncates file at wrong position

["kargl at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107031

--- Comment #6 from kargl at gcc dot gnu.org ---
(In reply to anlauf from comment #3)
> (In reply to kargl from comment #2)
> > gfortran's current behavior is correct.
> > 
> > 
> >    12.3.4.4 File position after data transfer
> > 
> >    In all other cases, the file is positioned after the record just
> >    read or written and that record becomes the preceding record.
> > 
> >    12.8.3 ENDFILE statement
> > 
> >    Execution of an ENDFILE statement for a file connected for sequential
> >    access writes an endfile record as the next record of the file.
> > 
> > After reading '5', the file is position at the record that contains '6'.
> > So, ENDIFLE writes the endfile record after the record with '6'.
> 
> Hmm, interpretation of text?
> 
 Yes, it is interpretation.

Let <R> denote the start of record and </R> the end of the record.
One has 

<R>5</R><R>6</R><R>7</R>

After reading '5', the file is positioned to after that record.  If * denotes
the current file, then one can have

<R>5</R>*<R>6</R> or <R>5</R><R>*6</R>

Both meet the requirement of 12.3.4.4. Now by 12.8.3, the endfile will give

<R>5</R>EOF

while the latter would give

<R>5</R><R>*6</R>EOF.