Simple fork example – Without checking return value

#include <unistd.h>

int main() {
  printf("welcome..pid=%d\n", getpid());
  fork();  //intentionally not capturing return value, in this example
  printf("Thank You\n");
  //printf("thank you,pid=%d,ppid=%d\n", getpid(), getppid());
  return 0;
}


Observations & Understanding

• How many times printf gets executed in above code
• Can you distinguish between parent and child in above code
• Mapping child’s ppid with parent’s pid
• What is parent’s ppid, to which process it belongs to?
• Check the pid, ppid values from the output of ps, pstree commands (Ensure program won’t terminate by using sleep/getchar)
• What if fork is called multiple times, unconditionally without checking return values