Constant kernel::error::code::ENOSYS

pub const ENOSYS: Error;

Invalid system call number.

This error code is special: arch syscall entry code will return ENOSYS if users try to call a syscall that doesn’t exist. To keep failures of syscalls that really do exist distinguishable from failures due to attempts to use a nonexistent syscall, syscall implementations should refrain from returning ENOSYS.