goroutine, but in C

a simple example is the sleep_sort algorithm showing in test.c. It utlizes nested function extension from gcc, so it may not compile if you are on clang or other compiler, but the idea is the same.

• goroutine
• channel
• waitGroup

goroutine uses a M:N design, where in each kernel thread itself, it performs user space context switch.

But in C, although it is doable with ucontext.h or manually save program counter, registers, etc., it is difficult to have a stable and crossplatform way to do that. I could've use ucontext.h and implement a posix only coroutine, but it turns out to be almost impossible to perform work stealing, since it is not possible to change uc_link after calling makecontext.

So that croutine just spawn a new kernel thread when all threads in the thread pool is busy working. And it is not really a coroutine, it is just a thread pool that grow automatically.