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exit(3) [freebsd man page]

EXIT(3) 						   BSD Library Functions Manual 						   EXIT(3)

NAME
exit, _Exit -- perform normal program termination LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <stdlib.h> void exit(int status); void _Exit(int status); DESCRIPTION
The exit() and _Exit() functions terminate a process. Before termination, exit() performs the following functions in the order listed: 1. Call the functions registered with the atexit(3) function, in the reverse order of their registration. 2. Flush all open output streams. 3. Close all open streams. 4. Unlink all files created with the tmpfile(3) function. The _Exit() function terminates without calling the functions registered with the atexit(3) function, and may or may not perform the other actions listed. Both functions make the low-order eight bits of the status argument available to a parent process which has called a wait(2)-family function. The C Standard (ISO/IEC 9899:1999 (``ISO C99'')) defines the values 0, EXIT_SUCCESS, and EXIT_FAILURE as possible values of status. Cooper- ating processes may use other values; in a program which might be called by a mail transfer agent, the values described in sysexits(3) may be used to provide more information to the parent process. Note that exit() does nothing to prevent bottomless recursion should a function registered using atexit(3) itself call exit(). Such func- tions must call _Exit() instead (although this has other effects as well which may not be desired). RETURN VALUES
The exit() and _Exit() functions never return. SEE ALSO
_exit(2), wait(2), at_quick_exit(3), atexit(3), intro(3), quick_exit(3), sysexits(3), tmpfile(3) STANDARDS
The exit() and _Exit() functions conform to ISO/IEC 9899:1999 (``ISO C99''). BSD
September 9, 2002 BSD

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_EXIT(2)						     Linux Programmer's Manual							  _EXIT(2)

NAME
_exit, _Exit - terminate the calling process SYNOPSIS
#include <unistd.h> void _exit(int status); #include <stdlib.h> void _Exit(int status); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): _Exit(): _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L; or cc -std=c99 DESCRIPTION
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 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(). RETURN VALUE
These functions do not return. CONFORMING TO
SVr4, POSIX.1-2001, 4.3BSD. The function _Exit() was introduced by C99. NOTES
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. SEE ALSO
execve(2), exit_group(2), fork(2), kill(2), wait(2), wait4(2), waitpid(2), atexit(3), exit(3), on_exit(3), termios(3) COLOPHON
This page is part of release 3.53 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/. Linux 2010-09-20 _EXIT(2)

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