Re: exec 0</dev/null vs. nohup?

[Ralf Wildenhues]

Hello Jay,

* Jay K wrote on Wed, May 26, 2010 at 03:17:39PM CEST:
> I don't have the full background any longer, but I made
> this change to a configure script:
> 
> before:
> 
> exec 7<&0 </dev/null 6>&1
> 
> after:
> 
> exec 6>&1
> 
> my comment at the time (2008-06-03) was:
> take minor change to older boilerplate from other nearby
>  configure files, in order to let it work under "nohup", on OpenBSD
>  otherwise there is an error about an invalid file handle
>  
>  Make sense?

Not really, to me at least.

> Clearly you are doing this on purpose though.

Yes, we are.  If you need the original standard input during the
configure script, you can get at it with the AS_ORIGINAL_STDIN_FD
macro; see `info Autoconf "File Descriptor Macros"'.

> Maybe it just prints an error but there's no error?
> 
> I just did a quick experiment with just
> 
> exec 0</dev/null
> 
> and nohup but couldn't get an error.
> 
> I've surely upgraded OpenBSD in the meantime.

Well, if you cannot reproduce an error any more, I'll go and claim
we shouldn't need to worry until you hit it again.  ;-)

Cheers,
Ralf