1 .\" Copyright (C) 2001 Andries Brouwer <aeb@cwi.nl>.
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25 .\" FIXME . There are a lot of other process termination actions that
26 .\" could be listed on this page. See, for example, the list in the
27 .\" POSIX exit(3p) page.
29 .TH EXIT 3 2020-02-09 "Linux" "Linux Programmer's Manual"
31 exit \- cause normal process termination
34 .B #include <stdlib.h>
36 .BI "void exit(int " status );
41 function causes normal process termination and the least significant byte of
43 (i.e., \fIstatus & 0xFF\fP) is returned to the parent (see
46 All functions registered with
50 are called, in the reverse order of their registration.
51 (It is possible for one of these functions to use
55 to register an additional
56 function to be executed during exit processing;
57 the new registration is added to the front of the list of functions
58 that remain to be called.)
59 If one of these functions does not return
62 or kills itself with a signal),
63 then none of the remaining functions is called,
64 and further exit processing (in particular, flushing of
66 streams) is abandoned.
67 If a function has been registered multiple times using
71 then it is called as many times as it was registered.
75 streams are flushed and closed.
80 The C standard specifies two constants,
81 \fBEXIT_SUCCESS\fP and \fBEXIT_FAILURE\fP,
84 to indicate successful or unsuccessful
85 termination, respectively.
89 function does not return.
91 For an explanation of the terms used in this section, see
97 Interface Attribute Value
100 T} Thread safety MT-Unsafe race:exit
105 function uses a global variable that is not protected,
106 so it is not thread-safe.
108 POSIX.1-2001, POSIX.1-2008, C89, C99, SVr4, 4.3BSD.
110 The behavior is undefined if one of the functions registered using
120 removes registrations created using
129 is slightly more portable
130 (to non-UNIX environments) than the use of 0 and some nonzero value
132 In particular, VMS uses a different convention.
134 BSD has attempted to standardize exit codes
135 (which some C libraries such as the GNU C library have also adopted);
141 the exit status must be transmitted to the
143 There are three cases:
145 If the parent has set
151 the status is discarded and the child dies immediately.
153 If the parent was waiting on the child,
154 it is notified of the exit status and the child dies immediately.
157 the child becomes a "zombie" process:
158 most of the process resources are recycled,
159 but a slot containing minimal information about the child process
160 (termination status, resource usage statistics) is retained in process table.
161 This allows the parent to subsequently use
163 (or similar) to learn the termination status of the child;
164 at that point the zombie process slot is released.
166 If the implementation supports the
169 is sent to the parent.
170 If the parent has set
172 it is undefined whether a
176 .SS Signals sent to other processes
177 If the exiting process is a session leader and its controlling terminal
178 is the controlling terminal of the session, then each process in
179 the foreground process group of this controlling terminal
182 signal, and the terminal is disassociated
183 from this session, allowing it to be acquired by a new controlling
186 If the exit of the process causes a process group to become orphaned,
187 and if any member of the newly orphaned process group is stopped,
193 sent to each process in this process group.
196 for an explanation of orphaned process groups.
198 Except in the above cases,
199 where the signalled processes may be children of the terminating process,
200 termination of a process does
202 in general cause a signal to be sent to children of that process.
203 However, a process can use the
206 operation to arrange that it receives a signal if its parent terminates.
209 .BR get_robust_list (2),
216 This page is part of release 5.10 of the Linux
219 A description of the project,
220 information about reporting bugs,
221 and the latest version of this page,
223 \%https://www.kernel.org/doc/man\-pages/.