https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95104
--- Comment #4 from kargl at gcc dot gnu.org ---
(In reply to Bill Long from comment #3)
> A comment from the original user: gfortran 8.3.0 appears to do the right
> thing. So perhaps a regression somewhere in the 9.x line?
A note of the gfortran wiki says full asynchronous support became
available in 9.1. SO, likely a bug introduced in 9. This fixes
the segfault as it is never correct to dereference a NULL pointer.
Index: libgfortran/io/transfer.c
===================================================================
--- libgfortran/io/transfer.c (revision 280157)
+++ libgfortran/io/transfer.c (working copy)
@@ -4492,7 +4492,7 @@ void
st_wait_async (st_parameter_wait *wtp)
{
gfc_unit *u = find_unit (wtp->common.unit);
- if (ASYNC_IO && u->au)
+ if (ASYNC_IO && u && u->au)
{
if (wtp->common.flags & IOPARM_WAIT_HAS_ID)
async_wait_id (&(wtp->common), u->au, *wtp->id);
With this patch, your program prints '0'. Don't know if this
is the only thing that needs fixing. Thanks for the bug report.
