#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/wait.h>

int main(int argc, char *argv[])
{

    pid_t cpid, w;
    int status;
    cpid = fork();

    if (cpid == -1)
    {
        perror("fork");
        exit(EXIT_FAILURE);
    }

    if (cpid == 0)
    {
        printf("Child PID is %ld\n", (long)getpid());
        if (argc == 1)
            pause();
        _exit(atoi(argv[1]));
    }
    else
    {
        do
        {
            w = waitpid(cpid, &status, WUNTRACED | WCONTINUED);
            if (w == -1)
            {
                perror("waitpid");
                exit(EXIT_FAILURE);
            }
            if (WIFEXITED(status))
            {
                printf("exited, status=%d\n", WEXITSTATUS(status));
            }
            else if (WIFSIGNALED(status))
            {
                printf("killed by signal %d\n", WTERMSIG(status));
            }
            else if (WIFSTOPPED(status))
            {
                printf("stopped by signal %d\n", WSTOPSIG(status));
            }
            else if (WIFCONTINUED(status))
            {
                printf("continued\n");
            }
        } while (!WIFEXITED(status) && !WIFSIGNALED(status));
        exit(EXIT_SUCCESS);
    }
}