_EXIT(2) Linux Programmer's Manual _EXIT(2)
_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)):
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
or cc -std=c99
The function _exit() terminates the calling process "immediately". Any open file descrip-
tors belonging to the process are closed; any children of the process are inherited by
process 1, init, and the process's parent 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 calls.
The function _Exit() is equivalent to _exit().
These functions do not return.
SVr4, POSIX.1-2001, 4.3BSD. The function _Exit() was introduced by C99.
For a discussion on the effects of an exit, the transmission of exit status, zombie pro-
cesses, 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.
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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Linux 2010-09-20 _EXIT(2)