Calling external DLL function with Qt

[yaba]

Hi all,
I bet this is an old question, and I did some research at StackOverflow and Google, however, I ended up more confused.
How do I simply call a dll function? without linking the dll or other mumbojumbo
something like:

rundll32 USER32.DLL,LockWorkStation

rundll32 USER32.DLL,LockWorkStation

To copy to clipboard, switch view to plain text mode 

Thank you.