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

[Khitai Pang]

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?


Thanks
Khitai