// Question 1

// in fork2.c
#include <stdio.h>
#include <unistd.h>

int main() {
  int pid1 = fork();
  int pid2 = fork();
  printf("The pids are: %d %d\n", pid1, pid2);
}


$ gcc fork2.c -o fork2
$ ./fork2

What prints?




















How many lines print? 0, 1, 2, 3, 4, more? 4 lines!

Line 8 starts a new process

Original process                                    Child 1 Process
pid1 = <id of child 1>                              pid1 = 0
int pid2 = fork();                                  int pid2 = fork();
printf(...)                                         printf(...)

Original                  Child 2                   Child 1                   Child 3
pid1 = <id of child 1>    pid1 = <id of child 1>    pid1 = 0                  pid1 = 0
pid2 = <id of child 2>    pid2 = 0                  pid2 = <id of child 3>    pid2 = 0
printf(...)               printf(...)               printf(...)               printf(...)

two positive integers     pos int and then 0        0 and then pos int        0 and then 0