On Thu, Jan 18, 2007 at 08:46:54PM +0100, Bert Freudenberg wrote:
> 
> Am Jan 18, 2007 um 20:01  schrieb Giovanni Corriga:
> 
> >Il giorno gio, 18/01/2007 alle 00.27 +0000, Keith Hodges ha scritto:
> >>Giovanni Corriga wrote:
> >>>Il giorno mer, 17/01/2007 alle 22.41 +0000, Keith Hodges ha scritto:
> >>>
> >>>>Hello,
> >>>>
> >>>>just a quick question, are any of the VM's particularly the unixish
> >>>>ones, wired to produce output on stdout or stderr. Are there  
> >>>>primitives
> >>>>for doing so without any plugins?
> >>>>
> >>>
> >>>If you need output only, you can try opening /dev/stdout and /dev/ 
> >>>stderr
> >>>as simple files.
> >>>
> >>>This should work on Linux; not sure if it'll work on other Unix  
> >>>systems.
> >>>
> >>>	Giovanni
> >>>
> >>Yes that worked!
> >
> >Just for the record, this works for reading from  stdin too, but
> >unfortunately it's a synchronous (blocking) read.
> 
> Actually, when you use AsyncFile for reading, this works fine :)
> 
> In the OLPC image I use this to read commands from a pipe issued by  
> an external process.

Yup, and you can also directly set a file stream for nonblocking
reads with #primitiveSQFileSetNonBlocking (OSPP comes with the
unix VM).  This permits direct reads from standard input as in
OSProcess class>>readFromStdIn.

Either way you can safely read from stdin without hanging the image.

Dave