c++ - Can I access Windows Kernel system calls directly? -

i have been doing research windows internals, , have learned system calls , wondering if possible use these system calls functions? understand aren't meant accessed externally.

for instance: ntuseremptyclipboard system call in win32k.sys, , it's address 0x117f

if wanted use call function, how so?

emptyclipboard 1 of so-called "win32 api" , ntuseremptyclipboard corresponding "native api".

• http://en.wikipedia.org/wiki/native_api

unlike linux syscall(2), supposed directly call "native api". heard in ntdll.dll rather win32k.sys. should able invoke them normal functions defined in normal dll.

• is there way call windows native api functions user mode?