---
name: "idle"
section: "2"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/idle/2"
---

# idle(2)

make process 0 idle

## NAME

idle - make process 0 idle

## SYNOPSIS

```
#include <unistd.h>
```

**\[\[deprecated\]\] int idle(void);**

## DESCRIPTION

**idle**() 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.

Only process 0 may call **idle**(). Any user process, even a process with superuser permission, will receive **EPERM**.

## RETURN VALUE

**idle**() never returns for process 0, and always returns -1 for a user process.

## ERRORS

- **EPERM**

  Always, for a user process.

## STANDARDS

Linux.

## HISTORY

Removed in Linux 2.3.13.