_exit(3) — Linux manual page

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | STANDARDS | HISTORY | NOTES | SEE ALSO | COLOPHON

_exit(3)                 Library Functions Manual                _exit(3)

NAME         top

       _exit, _Exit - terminate the calling process

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

       #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)):

       _Exit():
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L

DESCRIPTION         top

       _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) (or by the
       nearest "subreaper" process as defined through the use of the
       prctl(2) 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) family of calls.

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

RETURN VALUE         top

       These functions do not return.

STANDARDS         top

       _exit()
              POSIX.1-2024.

       _Exit()
              C11, POSIX.1-2024.

HISTORY         top

       _exit()
              4.3BSD, SVr4, POSIX.1-1988.

       _Exit()
              C99, POSIX.1-2001.

       Up to glibc 2.3, these functions invoked exit(2).  Since glibc
       2.3, they invoke exit_group(2), in order to terminate all of the
       threads in a process.

NOTES         top

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

       The function _exit() is like exit(3), but does not call any
       functions registered with atexit(3) or on_exit(3).  Open stdio(3)
       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) 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         top

       execve(2), exit(2), exit_group(2), fork(2), kill(2), wait(2),
       wait4(2), waitpid(2), atexit(3), exit(3), on_exit(3), termios(7)

COLOPHON         top

       This page is part of the man-pages (Linux kernel and C library
       user-space interface documentation) project.  Information about
       the project can be found at 
       ⟨https://www.kernel.org/doc/man-pages/⟩.  If you have a bug report
       for this manual page, see
       ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
       This page was obtained from the tarball man-pages-6.19.tar.gz
       fetched from
       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
       2026-09-09.  If you discover any rendering problems in this HTML
       version of the page, or you believe there is a better or more up-
       to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not
       part of the original manual page), send a mail to
       man-pages@man7.org

Linux man-pages 6.19            2026-07-02                       _exit(3)

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