_EXITSection: Linux Programmer's Manual (2)
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NAME_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)):
DESCRIPTIONThe 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 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.
RETURN VALUEThese functions do not return.
CONFORMING TOSVr4, POSIX.1-2001, 4.3BSD. The function _Exit() was introduced by C99.
NOTESFor a discussion on the effects of an exit, the transmission of exit status, zombie processes, signals sent, etc., 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.
SEE ALSOexecve(2), exit_group(2), fork(2), kill(2), wait(2), wait4(2), waitpid(2), atexit(3), exit(3), on_exit(3), termios(3)
COLOPHONThis page is part of release 3.21 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.