>Thanks Sergey.
>So, let me see if I understood it correctly:
>1. When the table header is locked other users cannot
>add records but they can write to the records already
>in the table.

Yes unless a command requires a table lock, like REPLACE FOR

>2. When the whole table is locked with flock() users
>can't write at all. Only reading.


Other users cannot write but can read. The user that placed table lock can write to the table.