#include <stdio.h>	/* printf, etc */
#include <sys/types.h>  /* almost always need this with system programming */
#include <unistd.h>	/* fork, getpid, getppid */
#include <stdlib.h>	/* free, malloc, etc */
#include <readline/readline.h>
#include <sys/wait.h>  

/* Another fork test program - this has the parent wait for the child to 
   die. The child reads a string from standard input (using readline)
   and then exits.

   The parent looks at the status code from the child and prints
   out some stuff...
 */


/* this function is only called by the child */

void child() {
  char *s;
  pid_t me = getpid();

  printf("%u: Child is running\n",me);
  printf("%u: Parent pid is %u\n",me,getppid());

  s = readline("Child is waiting for a line of text: ");
  free(s);
}


/* this function is only called in the parent */
void parent(pid_t childpid) {
  pid_t me = getpid();
  int cstat;

  printf("%u: Parent is running\n",me);
  printf("%u: Child  pid is %u, waiting ...\n",me,childpid);

  wait(&cstat);

  printf("%u: wait returned.\n",childpid);

  /* print out some status information */

  if (WIFEXITED(cstat)) 
    printf("Child exited with status code %d\n",WEXITSTATUS(cstat));
  if (WIFSIGNALED(cstat))
    printf("Child was killed by signal %d\n",WTERMSIG(cstat));
  if (WIFSTOPPED(cstat))
    printf("Child is stopped, signal was %d\n",WSTOPSIG(cstat));

}


int main(int argc, char **argv) {
  pid_t childpid;

  if (childpid = fork()) {
    /* fork returns child's pid in the parent - this is parent only code */
    parent(childpid);
  } else {
    /* fork returned 0 - this is child only code */
    child();
  }
  return(0);
}