Detect the O.S.

Hi all.
I Know that there are some system variables that allow you to know what O.S. is running on your computer (Win98/win95/WinNT),
and I want to know whose are them and How can I use them. I work with some API's and those are different deppending on which O.S.
is running and is for that reason that I want to know on which O.S. is running my project.

Thanks for all.

Persi

[Lothar Haensler]

the GetVersionEx API tells you your os version.