_exit, _Exit - terminate the calling process
void _exit(int status);
void _Exit(int status);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
_POSIX_C_SOURCE >= 200112L
The function _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 using one of the
wait(2) family of calls.
The function _Exit() is equivalent to _exit().
These functions do not return.
POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD. The function _Exit() was
introduced by C99.
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
In glibc up to version 2.3, the _exit() wrapper function invoked the
kernel system call of the same name. Since glibc 2.3, the wrapper function
invokes exit_group(2), in order to terminate all of the threads in a
execve(2), exit_group(2), fork(2), kill(2),
wait(2), wait4(2), waitpid(2), atexit(3),
exit(3), on_exit(3), termios(3)
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