Re: Some questions

["Kurt D. Zeilenga" <Kurt@OpenLDAP.org>]

At 09:56 AM 1/3/01 +0530, srihari  parimi wrote:

>Hi
>
>I have some queries
>
>1. When we define an objectclass as per the RFC2252 we must specify
>   whether it is ABSTRACT / STRUCTURAL/ AUXILLARY. My question is 
>   what is the significance of these 'keywords' with respect to the
>   object class definition ??

See  http://www.salford.ac.uk/its024/Version.Web/Contents.htm

It provide decent descriptions of the X.500 data model.  Also
of interest is:

 http://www.redbooks.ibm.com/abstracts/sg244986.html



>2. What is the significance of the attributetype 'objectClass' ??

>If
>   I am defining a new objectclass then can I include 'objectClass'
>   with MUST clause and if so what would it mean ??

In general, no.  Structural object classes pick up a MUST
from 'top' (all structural objects inherit from 'top') and
since every object is structurally some class, all objects
must have an objectClass attribute.

>3. Is OpenLDAP thread-safe ?? That is, can I develop a multithreaded
>   program calling LDAP APIs without having to create and acquire
>   locks unless, it is absolutely essential.

In general, the LDAP C (client) API is not thread safe.  Even when -lldap_r
is used, some synchronization is required.  

> I am asking this because
>   there is a question in the FAQ-O-MATIC which says that OpenLDAP
>   1.x is designed for non-preemptive multi-threaded environments 
>   ( eg. POSIX threads ). Is it true of version 2.x ??

This refers to the server, not the LDAP C (client) API.
1.2 slapd is designed for non-preemptive threading environments.
2.0 slapd is designed for both preemptive and non-preemptive
threading environments.

>In fact there
>   is an explicit mention that 'it is not safe for pre-emptive threads
>   environment' ??
>
>Thanks
>Srihari