i *realize* how the offset value might/will increase across subsequent
calls. what i was asking about was this routine from p. 87 of LDD3:
static void *scull_seq_start(struct seq_file *s, loff_t *pos)
{
if (*pos >= scull_nr_devs)
return NULL; /* No more to read */
return scull_devices + *pos;
}
why would the *start* routine be checking if the offset was already
out of range if it should begin at zero?
It does not begin at zero :) 'Start' does not mean start reading from the 'first position'. It means start reading from the position where we left last time (previous calls to read
i.e. 1 start call/multiple next calls).
So, it begins at the current 'pos'. This 'pos' might have been be updated in previous calls to start/next.
Regards,
- Ratnadeep
i can see how you want to do that kind of checking with the *next*
routine.
rday