comedi_lock - subdevice reservation
int comedi_lock (comedi_t * device, unsigned int subdevice);
The function comedi_lock() reserves a subdevice for use by the current
process. While the lock is held, no other process is allowed to read,
write, or configure that subdevice, although other processes can read
information about the subdevice. The lock is released when
comedi_unlock() is called, or the device is closed.
If sucessful, 0 is returned. If there is an error, -1 is returned.
28 October 2007