| .\" This manpage is Copyright (C) 1992 Drew Eckhardt; |
| .\" and Copyright (C) 1993 Michael Haardt, Ian Jackson. |
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| .\" Modified Wed Jul 21 23:02:38 1993 by Rik Faith <faith@cs.unc.edu> |
| .\" Modified 2001-11-17, aeb |
| .\" |
| .TH _EXIT 2 2016-03-15 "Linux" "Linux Programmer's Manual" |
| .SH NAME |
| _exit, _Exit \- terminate the calling process |
| .SH SYNOPSIS |
| .B #include <unistd.h> |
| .sp |
| .BI "void _exit(int " status ); |
| .sp |
| .B #include <stdlib.h> |
| .sp |
| .BI "void _Exit(int " status ); |
| .sp |
| .in -4n |
| Feature Test Macro Requirements for glibc (see |
| .BR feature_test_macros (7)): |
| .in |
| .sp |
| .ad l |
| .BR _Exit (): |
| .RS 4 |
| _ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L |
| .RE |
| .ad |
| .SH DESCRIPTION |
| The function |
| .BR _exit () |
| terminates the calling process "immediately". |
| Any open file descriptors |
| belonging to the process are closed; any children of the process are |
| inherited by process 1, |
| .IR init , |
| and the process's parent is sent a |
| .B SIGCHLD |
| signal. |
| .LP |
| The value |
| .I status |
| is returned to the parent process as the process's exit status, and |
| can be collected using one of the |
| .BR wait (2) |
| family of calls. |
| .LP |
| The function |
| .BR _Exit () |
| is equivalent to |
| .BR _exit (). |
| .SH RETURN VALUE |
| These functions do not return. |
| .SH CONFORMING TO |
| POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD. |
| The function |
| .BR _Exit () |
| was introduced by C99. |
| .SH NOTES |
| For a discussion on the effects of an exit, the transmission of |
| exit status, zombie processes, signals sent, and so on, see |
| .BR exit (3). |
| .LP |
| The function |
| .BR _exit () |
| is like |
| .BR exit (3), |
| but does not call any |
| functions registered with |
| .BR atexit (3) |
| or |
| .BR on_exit (3). |
| Open |
| .BR stdio (3) |
| streams are not flushed. |
| On the other hand, |
| .BR _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 |
| .BR tcflush (3) |
| before calling |
| .BR _exit (). |
| Whether any pending I/O is canceled, and which pending I/O may be |
| canceled upon |
| .BR _exit (), |
| is implementation-dependent. |
| .SS C library/kernel differences |
| In glibc up to version 2.3, the |
| .BR _exit () |
| wrapper function invoked the kernel system call of the same name. |
| Since glibc 2.3, the wrapper function invokes |
| .BR exit_group (2), |
| in order to terminate all of the threads in a process. |
| .SH SEE ALSO |
| .BR execve (2), |
| .BR exit_group (2), |
| .BR fork (2), |
| .BR kill (2), |
| .BR wait (2), |
| .BR wait4 (2), |
| .BR waitpid (2), |
| .BR atexit (3), |
| .BR exit (3), |
| .BR on_exit (3), |
| .BR termios (3) |