2017-12-12 Jerry DeLisle <jvdelisle@gcc.gnu.org>
PR libgfortran/78549
* io/inquire.c (inquire_via_unit): Adjust test for existence for
pre-connected internal units.
* io/transfer.c (finalize_transfer): When done with a transfer
to internal units, free the format buffer and close the stream.
(st_read_done): Delete freeing the stream, now handled using
sclose in finalize_transfer. (st_write_done): Likewise.
* io/unit.c (get_unit): Return NULL for special reserved unit
numbers, signifying not accessible to the user.
(init_units): Insert the two special internal units into the
unit treap. This makes these unit structures available without
further allocations for later use by internal unit I/O. These
units are automatically deleted by normal program termination.
* io/unix.c (mem_close): Add a guard check to protect from double free.
From-SVN: r255621
606778c6f5