IPC

Inter Process Communication

However, when you start fork()'ing processes, you immediately start to think of the neat multi-user things you could do if the processes could talk to each other easily. So you try making a global array and then fork()'ing to see if it is shared. (That is, see if both the child and parent process use the same array.) Soon, of course, you find that the child process has its own copy of the array and the parent is oblivious to whatever changes the child makes to it.

How do you get these guys to talk to one another, share data structures, and be generally amicable?

The Interprocess Communication (IPC) can accomplish this task.