Re: coproc problem when input closed but output open

[Rory Mulvaney <rory1@xxxxxxxx>]

Thanks.

On Wed, 16 Mar 2011, Bart Schaefer wrote:

> You still have "cat <&6 &" running in the background.  That has a copy of
> the coproc's stdin (fd5) open, because it inherited all the descriptors
> of the parent shell and fd5 is not specially closed the way the "p"
> descriptor is.  You can use
> 
>   cat <&6 5>&- &
> 
> to be sure cat doesn't inherit fd5.
> 
> It might be clearer if you restructure the code to be:
> 
>   coproc wcFunc
>   wcf=$!
> 
>   # copy output of coproc to stdout
>   cat <&p &
> 
>   # copy the write and read fd's for the coproc
>   exec 5>&p 6<&p
>   exec 6<&-
> 
>   # start another null coproc to get a new target for the p fd
>   coproc exit
> 
> Then you don't need to fiddle with fd5 when starting the cat.
>