OK, I see. Your implementation sounds a little like how "make -j" is actually implemented (in C). This basically sounds like implementing a semaphore with a pi

OK, I see. Your implementation sounds a little like how "make -j" is actually implemented (in C). This basically sounds like implementing a semaphore with a pipe. http://make.mad-scientist.net/papers/jobserver-implementation/ http://make.mad-scientist.net/papers/jobserver-implementatio... """ Rather than using complex schemes such as a central server, shared memory, sockets, etc. for synchronizing the various instances of make, he suggested we use the simplest, most basic UNIX construct: a pipe. Not only is this easy, but it’s also a relatively portable concept. Most operating systems these days implement some sort of pipe feature, because that paradigm is so useful. The idea is ingeniously simple: the initial, top-level make creates a pipe and writes N one-byte tokens into the pipe. That pipe is shared between that make and all submakes, and any time any make wants to run a job it first has to read a token from the pipe. Once the job is complete, it writes the token back to the pipe. Since there are only N tokens, you know that you will never invoke more than N jobs. """