Hands-On System Programming with Linux

The rules of fork – a summary

For your convenience, this table summarizes the fork rules we have encoded in this chapter:

Rule	The rule of fork
1	After a successful fork, execution in both the parent and child process continues at the instruction following the fork
2	To determine whether you are running in the parent or child process, use the fork return value: it's always 0 in the child, and the PID of the child in the parent
3	After a successful fork, both the parent and child process execute code in parallel
4	Data is copied across the fork, not shared
5	After the fork, the order of execution between the parent and child process is indeterminate
6	Open files are (loosely) shared across the fork
7	The parent process must ...