Static analysis says:
src\pipe.cpp(193): error V547: Expression is always false. Probably the '||' operator should be used here.

If flush() is called on a pipe whose state was
"terminated" or "double_terminated", the programmer's
intent was to return immediately. But in fact the
two conditions can never be true simultaneously, so
the early return never happens, and we may try to flush
a terminated pipe anyway.