I don't think there's a data race, given that the whole thing is single-threaded. Multiple processes should be used for parallelism (see step 7 of the tutorial)

I don't think there's a data race, given that the whole thing is single-threaded. Multiple processes should be used for parallelism (see step 7 of the tutorial). As for the default stack size, it's hard (but doable) to work with smaller stack size in C. For example, humble printf() can allocate a buffer several kB long on stack.