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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 19:40:15 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 19:40:15 +0000 |
commit | 399644e47874bff147afb19c89228901ac39340e (patch) | |
tree | 1c4c0b733f4c16b5783b41bebb19194a9ef62ad1 /man2/_exit.2 | |
parent | Initial commit. (diff) | |
download | manpages-399644e47874bff147afb19c89228901ac39340e.tar.xz manpages-399644e47874bff147afb19c89228901ac39340e.zip |
Adding upstream version 6.05.01.upstream/6.05.01
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'man2/_exit.2')
-rw-r--r-- | man2/_exit.2 | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/man2/_exit.2 b/man2/_exit.2 new file mode 100644 index 0000000..22cccd9 --- /dev/null +++ b/man2/_exit.2 @@ -0,0 +1,138 @@ +.\" This manpage is Copyright (C) 1992 Drew Eckhardt; +.\" and Copyright (C) 1993 Michael Haardt, Ian Jackson. +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.\" Modified Wed Jul 21 23:02:38 1993 by Rik Faith <faith@cs.unc.edu> +.\" Modified 2001-11-17, aeb +.\" +.TH _exit 2 2023-03-30 "Linux man-pages 6.05.01" +.SH NAME +_exit, _Exit \- terminate the calling process +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include <unistd.h> +.PP +.BI "[[noreturn]] void _exit(int " status ); +.PP +.B #include <stdlib.h> +.PP +.BI "[[noreturn]] void _Exit(int " status ); +.fi +.PP +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.PP +.BR _Exit (): +.nf + _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L +.fi +.SH DESCRIPTION +.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 +.BR init (1) +(or by the nearest "subreaper" process as defined through the use of the +.BR prctl (2) +.B PR_SET_CHILD_SUBREAPER +operation). +The process's parent is sent a +.B SIGCHLD +signal. +.PP +The value +.I "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 +.BR wait (2) +family of calls. +.PP +The function +.BR _Exit () +is equivalent to +.BR _exit (). +.SH RETURN VALUE +These functions do not return. +.SH STANDARDS +.TP +.BR _exit () +POSIX.1-2008. +.TP +.BR _Exit () +C11, POSIX.1-2008. +.SH HISTORY +POSIX.1-2001, SVr4, 4.3BSD. +.PP +.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). +.PP +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 +The text above in DESCRIPTION describes the traditional effect of +.BR _exit (), +which is to terminate a process, +and these are the semantics specified by POSIX.1 and implemented +by the C library wrapper function. +On modern systems, this means termination of all threads in the process. +.PP +By contrast with the C library wrapper function, the raw Linux +.BR _exit () +system call terminates only the calling thread, and actions such as +reparenting child processes or sending +.B SIGCHLD +to the parent process are performed only if this is +the last thread in the thread group. +.\" _exit() is used by pthread_exit() to terminate the calling thread +.PP +Up to glibc 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) |