title: fork and exec with respect to locking shared memory - C
body: <p>So I'm just wondering if I had a simple task to do in concurrency, how would I do this with multiple processes using fork() and exec() from a parent process, while locking some aspects of the parent process' memory (so that they don't overwrite each other), but making it available to those processes later?</p>
  
  <p>I know I can do this with POSIX threads with their mutex locks, but what's the process equivalent to that? Is there a way to "lock" shared memory amongst threads? And then would I have to "wait()" for the other threads to finish those locked areas of memory before the other threads could access it?</p>