On 27/03/2013 5:47pm, Charles-François Natali wrote:
>> multiprocessing currently only allows sharing of such shared arrays
>> using inheritance.
>
> You mean through fork() COW?

Through fork, yes, but "shared" rather than "copy-on-write".

>>   Perhaps we need a picklable mmap type which can be sent over pipes
>> and queues.  (On Unix this would probably require fd passing.)
>
> If you use POSIX semaphores, you could pass the semaphore path and use
> sem_open in the other process (but that would mean you can't unlink it
> right after open).

I assume you mean "shared memory" and shm_open(), not "semaphores" and 
sem_open().  I don't think shm_open() really has any advantages over 
using mmaps backed by "proper" files (since posix shared memeory uses up 
space in /dev/shm which is limited).

By using fd passing you can get the operating system to do ref counting 
on the mmaps and not worry about when to unlink.