unix-0104

#include <sys/types.h>
#include <fcntl.h>
#include <stdio.h>
void main(void)
{
    int pid2, pid3, st; /* process 1 */
    printf("Process 1, pid = %d:\n", getpid());
    pid2 = fork();
    if (pid2 == 0) /* process 2 */
    {
        printf("Process 2, pid = %d:\n", getpid());
        pid3 = fork();
        if (pid3 == 0) /* process 3 */
        {
            printf("Process 3, pid = %d:\n", getpid());
            sleep(2);
            printf("Process 3: end\n");
        } /* process 2 */
        if (pid3 < 0) printf("Cann't create process 3: error %d\n", pid3);
        wait(&st);
        printf("Process 2: end\n");
    }
    else /* process 1 */
    {   if (pid2 < 0) printf("Cann't create process 2: error %d\n", pid2);
    wait(&st);
    printf("Process 1: end\n");
    }
    exit(0);
}