lockfree.fifo provides the info if the queue is empty or not.
it is mainly done as debugging help, but it is not supposed to be used in concurrent code ...
Because this function is available I thought it is safe to used it.
well, there is a warning in the docs, noting, that this function is not thread-safe :)
I didn't look at your library, but I think that this decision is dangerous. I think that this debug functionalities should be enabled only if explicitly required by the user, who is assumed to know what is doing.
well, the user of the library has to make sure, that this function is not used in places, where a concurrent access to the queue is possible ... but, well, even _if_ it would be possible to atomically check, whether a stack/queue is empty, the result is not valid any more, at the time, when you use the result: fifo f; thread a: bool is_empty = f.empty(); // true thread b: f.enqueue(); thread a: if (is_empty) do_something(); // fifo is not empty any more so querying the state of lockfree data structures is always dangerous ... cheers, tim -- tim@klingt.org http://tim.klingt.org art is short - life is long Jack Kerouac