The producer-consumer problem

A producer puts items into a shared buffer and consumers take them out. Each side has to wait when the buffer is wrong for it: full for the producer, empty for the consumer. The tabs follow the four implementations in OSTEP Chapter 30 in order: two that are broken in different ways, then two that work. The line labels p1 to p6 and c1 to c6 are the ones the book uses in its traces.