Go-flavored concurrency in C

Go's concurrency is one of the main reasons people like the language. You write go f(), send values through channels, and the runtime scheduler runs thousands of goroutines on just a few OS threads. It feels effortless. None of that machinery exists in C. Which made me wonder: how close can you get to Go's concurrency model using only POSIX threads? Obviously, native OS threads can't match the efficiency of lightweight goroutines, but what is the actual cost, when does it become a problem, and is there any way to at least partially avoid it? I ran into these questions while adding concurrency to Solod (So), a strict subset of Go that translates to plain C, with no runtime and no garbage collector. In the end, I came to the conclusion that you can do quite a lot with pthreads — as long as you're honest about the tradeoffs. This post is about the POSIX threads-based concurrency model I chose, the benefits it offers, and its limitations. Mutex/Cond • Atomics • Pool • Channel •…