What's the differences between slapadd and ldapadd?

[Wang Penghui <wangpenghui@realss.com>]

Hi all.

Each of the commands "ldapadd" and "slapadd" could add entries to a 
slapd server.
But i could not make clear that what's the differences between them.
When should use "ldapadd" and when should use "slapadd"?
Could someone pick me up a doc about it?

THank you for your response!

Wang Penghui