idle(2) -- Linux man page
NAMEidle - make process 0 idle
DESCRIPTIONidle is an internal system call used during bootstrap. It marks the process's pages as swappable, lowers its priority, and enters the main scheduling loop. idle never returns.
RETURN VALUEidle never returns for process 0, and always returns -1 for a user process.
- Always, for a user process.
CONFORMING TOThis function is Linux-specific, and should not be used in programs intended to be portable.
NOTESSince 2.3.13 this system call does not exist anymore.