unimplemented(2) -- Linux man page
NAMEafs_syscall, break, ftime, getpmsg, gtty, lock, mpx, prof, profil, putpmsg, security, stty, ulimit - unimplemented system calls
SYNOPSISUnimplemented system calls.
DESCRIPTIONThese system calls are not implemented in the Linux 2.4 kernel.
RETURN VALUEThese system calls always return -1 and set errno to ENOSYS.
NOTESNote that ftime(3), profil(3) and ulimit(3) are implemented as library functions.