substr(buff1,n1,n2,buff2)      /* Ó¼ÞÚ ÌÞݶ */
     char buff1[];
     int n1;
     int n2;
     char buff2[];
    { int i;
      int j = 0;
      for ( i = n1; j < n2; i++ )
          {  *(buff2 + j) = *(buff1 + i);
             j++;
          }
      *(buff2 + j) = 0x00;
    return(0);
    }