tree ce0e0893db789935471c976d053c62c0eaaa30a0
parent 1929b8a907a1cbc6f6caeb9366e96b5b4f19750f
author Andy Lutomirski <luto@amacapital.net> 1408724843 -0700
committer Andy Lutomirski <luto@kernel.org> 1428706445 -0700

errno.h: Improve ENOSYS's comment

ENOSYS is the mechanism used by user code to detect whether the
running kernel implements a given system call.  It should not be
returned by anything except an unimplemented system call.

Unfortunately, it is rather frequently used in the kernel to
indicate that various new functions of existing system calls are not
implemented.  This should be discouraged.

Improve the comment in errno.h to help clarify ENOSYS's purpose.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>