typedef struct flock
{
  WORD l_type;   /* Type of lock:
                      0 = Read-only lock
                      1 = Write-only lock
                      2 = Read/Write lock */
  WORD l_whence; /* 0 = offset from beginning of file
                    1 = offset from current position
                    2 = offset from end of file */
  LONG l_start;  /* Offset to start of lock */
  LONG l_len;    /* Length of lock (0 for rest of file) */
  WORD l_pid;    /* Process ID maybe filled in by call */
} FLOCK;