SELECT ..... FOR UPDATE? How to check it?

[dutch]

Dear All,

I would like to know how to check the SELECT .... FOR UPDATE (Record Lock).
1. Program will freeze until the first lock is :end()
2. Lock Column (flag) is not certain correct. Because, if the user which for FOR UPDATE quit. The column flag still "lock" status.

What is the solution like Rlock()?

Regards,
Dutch