Detect that a child is waiting for input

[unDEFER via Digitalmars-d]

Hello!
I'm using pipeProcess() to create a process:

pipes = pipeProcess(["bash", "-c", BASH_COMMAND], Redirect.stdin 
| Redirect.stdout | Redirect.stderr);

Is it possible detect that the child is waiting for input on 
stdin?
I can't find decision even for C. I think it is impossible if the 
child uses unblocking reading. But I want to detect blocking 
reading.