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 2017-09-15 "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
42 value of \fIstatus & 0377\fP is returned to the parent
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.
111 The behavior is undefined if one of the functions registered using
121 removes registrations created using
130 is slightly more portable
131 (to non-UNIX environments) than the use of 0 and some nonzero value
133 In particular, VMS uses a different convention.
135 BSD has attempted to standardize exit codes; see the file
140 the exit status must be transmitted to the
142 There are three cases:
144 If the parent has set
150 the status is discarded and the child dies immediately.
152 If the parent was waiting on the child,
153 it is notified of the exit status and the child dies immediately.
156 the child becomes a "zombie" process:
157 most of the process resources are recycled,
158 but a slot containing minimal information about the child process
159 (termination status, resource usage statistics) is retained in process table.
160 This allows the parent to subsequently use
162 (or similar) to learn the termination status of the child;
163 at that point the zombie process slot is released.
165 If the implementation supports the
168 is sent to the parent.
169 If the parent has set
171 it is undefined whether a
175 .SS Signals sent to other processes
176 If the exiting process is a session leader and its controlling terminal
177 is the controlling terminal of the session, then each process in
178 the foreground process group of this controlling terminal
181 signal, and the terminal is disassociated
182 from this session, allowing it to be acquired by a new controlling
185 If the exit of the process causes a process group to become orphaned,
186 and if any member of the newly orphaned process group is stopped,
192 sent to each process in this process group.
195 for an explanation of orphaned process groups.
197 Except in the above cases,
198 where the signalled processes may be children of the terminating process,
199 termination of a process does
201 in general cause a signal to be sent to children of that process.
202 However, a process can use the
205 operation to arrange that it receives a signal if its parent terminates.
208 .BR get_robust_list (2),