[Python-Dev] Threading idea -- exposing a global thread lock

[Phillip J. Eby]

At 02:21 PM 3/14/2006 -0500, Tim Peters wrote:
>There _is_ some variation in what "critical section" means, exactly,
>to different thread programming cultures, but in none does it mean:
>
>     a section of code such that, once a thread enters it, all other
>     threads are blocked from doing anything for the duration

Well, I'm showing my age here, but in the good ol' days of the 8086 
processor, I recall it frequently being used to describe a block of 
assembly code which ran with interrupts disabled - ensuring that no task 
switching would occur.

Obviously I haven't been doing a lot of threaded programming *since* those 
days, except in Python.  :)


>The common meaning is:
>
>     a section of code such that, once a thread enters it, all other
>     threads are blocked from entering the section for the duration

That doesn't seem like a very useful definition, since it describes any 
piece of code that's protected by a statically-determined mutex.  But you 
clearly have more experience in this than I.