Build

clang -lpthread prod_cons.c

Run

1. ./a.out can show you the consumer starts before the producer finishes and continues until the end.
2. ./a.out | grep cC can show you when the consumer starts to decrement.
3. ./a.out | grep fin can show you the highest counter reached by the producer, the consumer finishes consuming at this point.

Test

1. for i in {1..1000}; do ./a.out; done | sort | uniq -c