Does this count as single consumer?

[svenoaks]

I have an operation which involves a single producer thread, and guaranteed only a single consumer thread accessing the queue concurrently. The rub is that the consumer could theoretically change pid numbers, ie be a different thread. Does this still count as SPSC or do I have to use the multiple thread version.

[cameron314]

That's a perfectly valid use of the queue, it still counts as single-consumer. However, you need to be careful to ensure that the memory effects from the first thread are fully seen by the second thread when the hand-off is made (i.e. make use of memory barriers (acquire-release) or a higher-level synchronization primitive like a mutex).