[erlang-questions] Port process exits with status einval while external program still runs

[Michael Truog]

  On 2017/5/27 23:31, Khitai Pang wrote:
>> I have observed a situation where the port process exits with reason
>> 'einval' but the external program still runs.  The connected process of
>> the port receives {EXIT,#Port<0.3069817>,einval}.  What makes a port
>> process exit with 'einval' while the external program still runs?

Normally that is due to the port source code not handling a HUP on the output file descriptor, from poll (POLLHUP) or the equivalent using a different function.

Best Regards,
Michael