test if a file is locked?

[Benjamin Han]

On Mon, 22 Dec 2003, Carl Banks wrote:
> Fortepianissimo wrote:
> >
> >
> > I can lock a file using the following snippet:
> >
> > ---
> > import fcntl
> >
> > f=open('flock.txt','w')
> > fcntl.lockf(f.fileno(),fcntl.LOCK_EX)
> > ---
> >
> > If some other script tries to open 'flock.txt', it'll wait until the
> > file is unlocked/closed.
> >
> > My question is, I'd like to tell a script to quit *immediately* if it
> > cannot open the file, or, if it knows the file is locked.
> >
> > The reason I need this is I want to serialize parallel processes using
> > a lock file. Any suggestion is welcome!
>
>
> Try this:
>
> fcntl.lockf(f.fileno(),fcntl.LOCK_EX|fcntl.LOCK_NB)

Ok looks like I'm still missing something: so how do you get 'f' without
using open() or file()? Either of these will put the script on hold...

Thanks!