[SFML 2] Linux not needing "openal32.dll"?

[Symphonym]

So I recently tried playing a few test sounds with SFML on Linux and one thing boggles
my mind. That (unlike SFML on Windows 7) it dosen't throw an error message in the style of
"openal32.dll is missing from your computer". Which could then be found in the "extlibs" folder
in the directory where I've built my SFML files. But here on Linux I have the "extlibs" folder as well,
but I don't have need of "libsndfile-1.dll" nor "openal32.dll", why?

I would assume that they're already installed on my computer somewhere, and it then finds those
files when running. However, isn't ".dll" a "Windows only thing"? As far as I know Linux uses .a and .so
as library extensions. And Windows is using .lib files to import the libraries during compile time, and then on
run-time it needs the .dll files in the same directory as the .exe (And the .lib files are at this point not needed?)?

[Laurent]

Yes, .dll files are only for Windows.

On Linux, since shared libraries are very well managed and easy to install, it's up to the user to have all the dependencies installed (most of them are standard and most likely already installed).