EXIT(3) BSD Library Functions Manual EXIT(3)NAME
exit -- perform normal program termination
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <stdlib.h>
void
exit(int status);
DESCRIPTION
exit() terminates a process. The status values EXIT_SUCCESS and EXIT_FAILURE can be used to indicate successful and unsuccessful termina-
tion, respectively.
Before termination it 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.
Following this, exit() calls _exit(2).
RESTRICTIONS
Standard C guarantees only that the values zero, EXIT_SUCCESS, and EXIT_FAILURE produce meaningful results. POSIX extends this to guarantee
that the least significant 8 bits of status are preserved and returned to the parent via wait(2). Values outside the supported range 0-255
are bitwise-truncated; therefore, negative values should not be used.
RETURN VALUES
The exit() function never returns.
SEE ALSO _exit(2), atexit(3), intro(3), tmpfile(3)STANDARDS
The exit() function conforms to ANSI X3.159-1989 (``ANSI C89'').
BSD January 2, 2012 BSD
Check Out this Related Man Page
EXIT(3) Linux Programmer's Manual EXIT(3)NAME
exit - cause normal program termination
SYNOPSIS
#include <stdlib.h>
void exit(int status);
DESCRIPTION
The exit() function causes normal program termination and the the value of status & 0377 is returned to the parent (see wait(2)). All
functions registered with atexit() and on_exit() are called in the reverse order of their registration, and all open streams are flushed
and closed. Files created by tmpfile() are removed.
The C standard specifies two defines EXIT_SUCCESS and EXIT_FAILURE that may be passed to exit() to indicate successful or unsuccessful ter-
mination, respectively.
RETURN VALUE
The exit() function does not return.
CONFORMING TO
SVID 3, POSIX, BSD 4.3, ISO 9899 (``ANSI C'')
NOTES
During the exit processing, it is possible to register additional functions with atexit() and on_exit(). Always the last-registered func-
tion is removed from the chain of registered functions, and invoked. It is undefined what happens if during this processing either exit()
or longjmp() is called.
The use of EXIT_SUCCESS and EXIT_FAILURE is slightly more portable (to non-Unix environments) than that of 0 and some nonzero value like 1
or -1. In particular, VMS uses a different convention.
BSD has attempted to standardize exit codes - see the file <sysexits.h>.
After exit(), the exit status must be transmitted to the parent process. There are three cases. If the parent has set SA_NOCLDWAIT, or has
set the SIGCHLD handler to SIG_IGN, the status is discarded. If the parent was waiting on the child it is notified of the exit status. In
both cases the exiting process dies immediately. If the parent has not indicated that it is not interested in the exit status, but is not
waiting, the exiting process turns into a "zombie" process (which is nothing but a container for the single byte representing the exit sta-
tus) so that the parent can learn the exit status when it later calls one of the wait() functions.
If the implementation supports the SIGCHLD signal, this signal is sent to the parent. If the parent has set SA_NOCLDWAIT, it is undefined
whether a SIGCHLD signal is sent.
If the process is a session leader and its controlling terminal the controlling terminal of the session, then each process in the fore-
ground process group of this controlling terminal is sent a SIGHUP signal, and the terminal is disassociated from this session, allowing it
to be acquired by a new controlling process.
If the exit of the process causes a process group to become orphaned, and if any member of the newly-orphaned process group is stopped,
then a SIGHUP signal followed by a SIGCONT signal will be sent to each process in this process group.
SEE ALSO _exit(2), wait(2), atexit(3), on_exit(3), tmpfile(3)
2001-11-17 EXIT(3)