Example

       #include <stdlib.h>
       #include <stdio.h>
       #include <unistd.h>     /* write, close */
       #include <fcntl.h>      /* Creat */

       main()
       {
           int status,
               fd;

           /* Creat a file we are sure is there        */

           fd = creat("system.test", 0);
           write(fd, "this is an example of using system", 34);
           close(fd);

           if (system(NULL)) {
               status = system("DIR/NOHEAD/NOTRAIL/SIZE SYSTEM.TEST");
               printf("system status = %d\n", status);
           }
           else
               printf("system() not supported.\n");
       }

   Running this example program produces the following result:

   DISK3$:[JONES.CRTL.2059.SRC]SYSTEM.TEST;1
                              1
   system status = 1