Detect that a child is waiting for input

[unDEFER via Digitalmars-d]

On Wednesday, 23 November 2016 at 07:18:27 UTC, Shachar Shemesh 
wrote:
> The shell does that for background processes. I think it takes 
> away the TTY from its children, and this way, when they try to 
> read from stdin, they get SIGSTOP from the system.
>
> I'm not sure what the precise mechanism is.
>
> There are flags passed to wait which will cause it to report 
> when a child gets SIGSTOP.
>
> Hope this helps,
> Shachar

Really interesting information, thank you, I will try to dig in 
this direction.