short l_type;       /* 2 bytes */
  short l_whence;     /* 2 bytes*/
  long four_byte_foo; /* what's this? */
  long long l_start;  /* 8 bytes */
  long long l_len;    /* 8 bytes */
  unsigned int l_pid; /* 4 bytes */
  long four_byte_bar; /* what is this? */