https://gcc.gnu.org/bugzilla/show_bug.cgi?id=30617
--- Comment #47 from anlauf at gcc dot gnu.org --- (In reply to Thomas Koenig from comment #46) > It might be possible to generate warning when a function that > is called from the argument list of an external I/O statement > does external I/O. This would also generate false positives, for > example for code like > > write (10,*) my_func(10.) > > ... > > integer function my_func(a) > real, intent(in) :: a > write (20,*) 'In my_func: argument is: ', a > > ... ... and there is no real restriction to only consider functions: any procedure that can be called from my_func could do I/O on the same unit. I am afraid we need to track the state of external units whether they are already in use or not.
