seq_open — initialize sequential file
int seq_open ( | struct file * file, |
const struct seq_operations * op); |
struct file * filefile we initialize
const struct seq_operations * opmethod table describing the sequence
seq_open sets file, associating it with a sequence described
by op. op->start sets the iterator up and returns the first
element of sequence. op->stop shuts it down. op->next
returns the next element of sequence. op->show prints element
into the buffer. In case of error ->start and ->next return
ERR_PTR(error). In the end of sequence they return NULL. ->show
returns 0 in case of success and negative number in case of error.
Returning SEQ_SKIP means “discard this element and move on”.
seq_open will allocate a struct seq_file and store its
pointer in file->private_data. This pointer should not be modified.