Re: Multithreading, callbacks from unknown threads [OT]

[Ross Bencina <rossb-lists@...>]

On 17/03/2012 7:11 PM, Gaspard Bucher wrote:
> [1]
> https://github.com/lubyk/lubyk/blob/master/modules/lk/include/lubyk/Fifo.h

With the exception of Visual C++2005 (and maybe later) where "volatile" 
also implies implicit memory barriers, the above linked code is not 
guaranteed to be safe.

Atomicity of the read and write pointers is not sufficient.

It is necessary to add processor memory barriers to ensure that the 
written data in the queue buffer is visible to the reader at the point 
that the reader sees the write pointer change.

Required memory barriers and barrier pairing will depend on the 
architecture.

Ross.