man2/_exit.2

   1 .\" Hey Emacs! This file is -*- nroff -*- source.
   2 .\"
   3 .\" This manpage is Copyright (C) 1992 Drew Eckhardt;
   4 .\"                               1993 Michael Haardt, Ian Jackson.
   5 .\"
   6 .\" Permission is granted to make and distribute verbatim copies of this
   7 .\" manual provided the copyright notice and this permission notice are
   8 .\" preserved on all copies.
   9 .\"
  10 .\" Permission is granted to copy and distribute modified versions of this
  11 .\" manual under the conditions for verbatim copying, provided that the
  12 .\" entire resulting derived work is distributed under the terms of a
  13 .\" permission notice identical to this one.
  14 .\"
  15 .\" Since the Linux kernel and libraries are constantly changing, this
  16 .\" manual page may be incorrect or out-of-date.  The author(s) assume no
  17 .\" responsibility for errors or omissions, or for damages resulting from
  18 .\" the use of the information contained herein.  The author(s) may not
  19 .\" have taken the same level of care in the production of this manual,
  20 .\" which is licensed free of charge, as they might when working
  21 .\" professionally.
  22 .\"
  23 .\" Formatted or processed versions of this manual, if unaccompanied by
  24 .\" the source, must acknowledge the copyright and authors of this work.
  25 .\"
  26 .\" Modified Wed Jul 21 23:02:38 1993 by Rik Faith <faith@cs.unc.edu>
  27 .\" Modified 2001-11-17, aeb
  28 .\"
  29 .TH _EXIT 2 2001-11-17 "Linux" "Linux Programmer's Manual"
  30 .SH NAME
  31 _exit, _Exit \- terminate the current process
  32 .SH SYNOPSIS
  33 .B #include <unistd.h>
  34 .sp
  35 .BI "void _exit(int " status );
  36 .sp
  37 .B #include <stdlib.h>
  38 .sp
  39 .BI "void _Exit(int " status );
  40 .SH DESCRIPTION
  41 The function
  42 .BR _exit ()
  43 terminates the calling process "immediately".
  44 Any open file descriptors
  45 belonging to the process are closed; any children of the process are
  46 inherited by process 1,
  47 .IR init ,
  48 and the process's parent is sent a
  49 .B SIGCHLD
  50 signal.
  51 .LP
  52 The value
  53 .I status
  54 is returned to the parent process as the process's exit status, and
  55 can be collected using one of the
  56 .BR wait (2)
  57 family of calls.
  58 .LP
  59 The function
  60 .BR _Exit ()
  61 is equivalent to
  62 .BR _exit ().
  63 .SH "RETURN VALUE"
  64 These functions do not return.
  65 .SH "CONFORMING TO"
  66 SVr4, POSIX.1-2001, 4.3BSD.
  67 The function
  68 .BR _Exit ()
  69 was introduced by C99.
  70 .SH NOTES
  71 For a discussion on the effects of an exit, the transmission of
  72 exit status, zombie processes, signals sent, etc., see
  73 .BR exit (3).
  74 .LP
  75 The function
  76 .BR _exit ()
  77 is like
  78 .BR exit (3),
  79 but does not call any
  80 functions registered with
  81 .BR atexit (3)
  82 or
  83 .BR on_exit (3).
  84 Whether it flushes
  85 standard I/O buffers and removes temporary files created with
  86 .BR tmpfile (3)
  87 is implementation dependent.
  88 On the other hand,
  89 .BR _exit ()
  90 does close open file descriptors, and this may cause an unknown delay,
  91 waiting for pending output to finish.
  92 If the delay is undesired,
  93 it may be useful to call functions like
  94 .BR tcflush (3)
  95 before calling
  96 .BR _exit ().
  97 Whether any pending I/O is cancelled, and which pending I/O may be
  98 cancelled upon
  99 .BR _exit (),
 100 is implementation-dependent.
 101 .SH "SEE ALSO"
 102 .BR execve (2),
 103 .BR exit_group (2),
 104 .BR fork (2),
 105 .BR kill (2),
 106 .BR wait (2),
 107 .BR wait4 (2),
 108 .BR waitpid (2),
 109 .BR atexit (3),
 110 .BR exit (3),
 111 .BR on_exit (3),
 112 .BR termios (3)