Compile error including asm/uaccess.h

<snip>
====== Errors (C++) ==========

In file included from /usr/include/linux/sched.h:14,
from /usr/include/asm/uaccess.h:8,
from test.cpp:1:
/usr/include/linux/timex.h:173: field `time' has incomplete type In file included from /usr/include/linux/sched.h:17,
from /usr/include/asm/uaccess.h:8,
from test.cpp:1:
/usr/include/asm/system.h:238: parse error before new' /usr/include/asm/system.h: In function long unsigned int __cmpxchg(...)':
/usr/include/asm/system.h:241: `size' undeclared (first use this function)
/usr/include/asm/system.h:241: (Each undeclared identifier is reported only

</snip>

Well rule of thumb says "Do not include kernel headers in userspace" second rule of thumb says "if you have to do so take care of variables that is need to be defined..."