How to lock files (the easiest/best way)?

[Elmo Mäntynen]

On Sat, 15 Jul 2006 23:52:10 +0200, Sybren Stuvel wrote:

> Elmo Mäntynen enlightened us with:
>> Only locally. I want to be able to read/write to a single file from
>> multiple possibly parallel processes. Would 'touch lock' (or
>> something like that) work reliably (this just occured to me)?
> 
> I use a lock directory for that, os.mkdir('/var/lock/somedir').
> If you use a file, you need two steps:
>     1) Check whether the lock-file exists
>     2) Create the lock-file
> 
> This is not atomic. With a directory, creating it will fail if it
> already exists. This means you can atomically check for the lock, and
> if it doesn't exist already, you've immediately created it too.
> 
> Sybren

Thanks. Is that what atomic basically means?