void _exit(int status);
void _Exit(int status);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
or cc -std=c99
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 process 1, init, and the process's par-
ent is sent a SIGCHLD signal.
The value status is returned to the parent process as the process's
exit status, and can be collected using one of the wait(2) family of
The function _Exit() is equivalent to _exit().
These functions do not return.
SVr4, POSIX.1-2001, 4.3BSD. The function _Exit() was introduced by
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). Whether it flushes standard
I/O buffers and removes temporary files created with tmpfile(3) is
implementation-dependent. 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.
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 process.
Linux 2010-09-20 _EXIT(2)
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