On Jan 26, 2007, at 11:25 AM, George Georgalis wrote:
> I'm developing a makefile target that does some
> administrative tasks.  Some targets modify /etc
> files. I'd like to generate a unique id when I make
> the target, so on it's completion, we can check for
> any files that have changed.
>
> If this was shell, I'd use something like
>
>  	lock=/tmp/${0}-$$ ; [ -e "$lock"] || touch $lock

You almost certainly don't actually want to generate a lockfile where  
the name changes based on the PID of the make process, because this  
does nothing to guard against two or more people running this  
makefile at the same time, and blowing away each others changes.   
Instead, create a lockfile using a known path, and put the PID of the  
make process into it, so that you can detect stale locks (see whether  
that PID exists, and is a make process if you want to get fancy)....

-- 
-Chuck