title: Can I access Windows Kernel system calls directly?
body: <p>I have been doing research into Windows internals, and have just recently learned about system calls and I am wondering if it is possible to use these system calls like functions? I understand they aren't really meant to be accessed externally.</p>
  
  <p>For instance: <code>NtUserEmptyClipboard</code> is a system call in Win32k.sys, and it's address is <code>0x117f</code></p>
  
  <p>If I wanted to use this call like a function, how could I do so?</p>