Re: [9fans] i/o on a hangup channel asymmetry

[erik quanstrom <quanstro@quanstro.net>]

On Sat Jul 18 14:41:02 EDT 2009, rvs@sun.com wrote:
> In the "mom, why sky is blue" department, here's a silly question:
> is there any good reason that read(2) on a hangup channel returns
> an error, while write(2) on a hangup channel terminates an application
> (by generating a note, of course, which can be ignored, but still)?

hmm.  from a quick read of port/sysfile.c, i think the precise behavior
might depend on the underlying device.  if devtab[m->c->type]->bread/bwrite
are (ultimately) based on qbread and qbwrite, i read qio as saying that neither should
generate a note.

perhaps i've been asleep at the swtch, but i don't recall seing writes
on closed channels terminate programs with a note.

- erik