Counter concurrency access

[Pascal Jakobi]

Hi there

I am creating a program that needs to increment a counter. Typically a 
serial number has to be incremented every time I create a certificate.

The problem is to handle concurrent access. Fundamentally I need to 1/ 
read the counter 2/ increment it. Therefore no one must be provided 
access to the counter during these two operations.

Therefore I need to set a lock before the read operation and release it 
after the update. Is there a way to do this with OL ? I am conscious of 
the ldapmodify features thanks to Clement, however, this will not lock 
the read.

Thks in adv.

P