bug#13299: 24.3.50; Tramp adb and device not found

[Eli Zaretskii]

> From: Michael Albinus <michael.albinus@gmx.de>
> Cc: nyc4bos@aol.com,  13299@debbugs.gnu.org
> Date: Mon, 18 Mar 2013 08:33:19 +0100
> 
> > What do you mean by "timer" here?  Even in Emacs this has multiple
> > meanings, to say nothing of the rest of the world ;-)
> 
> There is the following code:
> 
>   (with-timeout (10)
>     (with-temp-buffer
>       (when (zerop (call-process tramp-adb-program nil t nil "devices"))
>       ...
> 
> No problem under GNU/Linux. Under MS Windows, the timeout does not
> interrupt the `call-process' form, when it is overdued. That's why I
> have replaced it with a `start-process' implementation.

Hmm... can you describe how this works on Posix platforms?  Once
call-process forks the child process, it is AFAICS blocked inside
waitpid, so how do Emacs timers (which are the basis for with-timeout)
succeed to run at all?  What am I missing?