[TYPO3-english] Reference api from other php program

[Francesc Juliana]

 Hello everybody:

I have an intranet working on my business under typo3 4.0 (old version).
I have developed a php program that I want to  use under typo3. I would
like to get the identified user (in typo3) and their roles inside the
plataform.
Which includes do I need in order to access api Typo3?
Which is the procedure to get this kind of access?

Thanks in advance,

xescjp