Comment by dragontamer

> utilizing System V IPC

Hmm, that's a bit more complex than what I'd put at #1. I'd probably put System V IPC closer to #2 ("use a mutex") levels of complications.

System V Shared memory + Semaphores is definitely "as complicated" as pthread mutexes and semaphores.

But messages, signals, pipes, and other process-level IPC is much simpler. I guess SystemV IPC exists for that shady region "between" the high level stuff, and the complex low-level mutexes / semaphores.

Maybe "1.75", if I were to put it in my list above somewhere. Closer to Mutexes in complexity, but still simpler in some respects. Depends on what bits of System V IPC you use, some bits are easier than others.

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The main benefit of processes is that startup and shutdown behavior is very well defined. So something like a pipe, mmap, and other I/O has a defined beginning and end. All sockets are closed() properly, and so forth.

SystemV throws a monkey wrench into that, because the semaphore or shared memory is "owned by Linux", so to speak. So a sem_post() is not necessarily going to be sem_wait(), especially if a process dies in a critical region.