Re: [9fans] non-truncating create

[Joel “chesky” Salomon <JoelCSalomon@Gmail.com>]

> Rc just tries the open, and if that fails, tries the create.
> It doesn't even bother looking at the error code.
> If the open failed due to permissions, so will the create.

Drawterm barfed on me and I lost the bit of code this suggested; when
I tried to recreate it I ended up checking for OTRUNC a few times.
Not pretty.

> Or use create with OEXCL if you really care.

Sort of the way create(2) calls create(5) first, then open(5) if that
failed?  My code now looks like:
	o = create(oname, omode|OEXCL, ~0);	/* fails if file exists */
	if(o < 0)
		o = open(oname, omode);
	if(o < 0){
		complain("can’t open %s for writing: %r", oname);
		return;
	}
which has no special-case code depending on OTRUNC being set or no.

I suppose I ought to look at /sys/src/cmd/rc to see how it’s really
done.  Mañana.

Thanks for the assist.

--Joel