---
name: "_Exit"
section: "3"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/_exit/3"
---

# \_Exit(3)

terminate the calling process

Part of [\_exit(3)](/_exit/3.md).

## NAME

\_exit, \_Exit - terminate the calling process

## LIBRARY

Standard C library (*libc*, *-lc*)

## SYNOPSIS

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

**\[\[noreturn\]\] void \_exit(int** *status***);**

**#include \<stdlib.h\>**

**\[\[noreturn\]\] void \_Exit(int** *status***);**

Feature Test Macro Requirements for glibc (see [**feature\_test\_macros**(7)](/feature_test_macros/7.md)):

**\_Exit**():

```
    _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
```

## DESCRIPTION

**\_exit**() terminates the calling process "immediately". Any open file descriptors belonging to the process are closed. Any children of the process are inherited by [**init**(1)](/init/1.md) (or by the nearest "subreaper" process as defined through the use of the [**prctl**(2)](/prctl/2.md) **PR\_SET\_CHILD\_SUBREAPER** operation). The process's parent is sent a **SIGCHLD** signal.

The value *status & 0xFF* is returned to the parent process as the process's exit status, and can be collected by the parent using one of the [**wait**(2)](/wait/2.md) family of calls.

The function **\_Exit**() is equivalent to **\_exit**().

## RETURN VALUE

These functions do not return.

## STANDARDS

- **\_exit**()

  POSIX.1-2024.

- **\_Exit**()

  C11, POSIX.1-2024.

## HISTORY

- **\_exit**()

  4\.3BSD, SVr4, POSIX.1-1988.

- **\_Exit**()

  C99, POSIX.1-2001.

Up to glibc 2.3, these functions invoked [**exit**(2)](/exit/2.md). Since glibc 2.3, they invoke [**exit\_group**(2)](/exit_group/2.md), in order to terminate all of the threads in a process.

## NOTES

For a discussion on the effects of an exit, the transmission of exit status, zombie processes, signals sent, and so on, see [**exit**(3)](/exit/3.md).

The function **\_exit**() is like [**exit**(3)](/exit/3.md), but does not call any functions registered with [**atexit**(3)](/atexit/3.md) or [**on\_exit**(3)](/on_exit/3.md). Open [**stdio**(3)](/stdio/3.md) streams are not flushed. On the other hand, **\_exit**() does close open file descriptors, and this may cause an unknown delay, waiting for pending output to finish. If the delay is undesired, it may be useful to call functions like [**tcflush**(3)](/tcflush/3.md) before calling **\_exit**(). Whether any pending I/O is canceled, and which pending I/O may be canceled upon **\_exit**(), is implementation-dependent.

## SEE ALSO

[**execve**(2)](/execve/2.md), [**exit**(2)](/exit/2.md), [**exit\_group**(2)](/exit_group/2.md), [**fork**(2)](/fork/2.md), [**kill**(2)](/kill/2.md), [**wait**(2)](/wait/2.md), [**wait4**(2)](/wait4/2.md), [**waitpid**(2)](/waitpid/2.md), [**atexit**(3)](/atexit/3.md), [**exit**(3)](/exit/3.md), [**on\_exit**(3)](/on_exit/3.md), [**termios**(7)](/termios/7.md)