milisseconds in C

/*** Program teste_ftime.c**** Illustrates the use of ftime function to perform a task for a period** of time.  Prints dots for 5000 msecs.**** H. Paul Roach, MSU, 5 August, '96*/#include <stdio.h>                                            /* 1 */            #include <sys/timeb.h>                                         /* 2 */                                                              /* 4 */int main(void)                                               /* 5 */{                                                             /* 6 */   struct timeb t_start, t_current;                           /* 7 */   int t_diff;                                                /* 8 */   ftime(&t_start);                                           /* 9 */   do                                                         /* 10 */   {                                                          /* 11 */      printf(".");                                            /* 12 */      ftime(&t_current);                                      /* 13 */      t_diff = (int) (1000.0 * (t_current.time - t_start.time)/* 14 */        + (t_current.millitm - t_start.millitm));             /* 15 */   }                                                          /* 16 */   while(t_diff < 5000);                                      /* 17 */   return 0;}    //gcc -Wall teste_ftime.c -o teste_ftime