[Typo3] How to get PID of current page

[Jogvan Olsen]

How can I get the PID of current  page and assign it to a variable?

What I like to do is something like this:

In CONSTANS:
Pid_of_current_page = TSFE:id  /  I know 'TSFE:id' is wrong - the problem is 
that I don't know what to use instead.


And then use 'Pid_of_current_page' in my SETUP like this:
Xxx = {$Pid_of_current_page}

My problem is that I can't find out how to assign 'Pid_of_current_page' to 
current PID.

Hope you can help.

Thanks in advance
Jogvan Olsen