exit - terminate a process
void exit(int status);
[CX] The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1-2017 defers to the ISO C standard.
The value of status may be 0, EXIT_SUCCESS, EXIT_FAILURE, [CX] or any other value, though only the least significant 8 bits (that is, status & 0377) shall be available from wait() and waitpid(); the full value shall be available from waitid() and in the siginfo_t passed to a signal handler for SIGCHLD.
The exit() function shall first call all functions registered by atexit(), in the reverse order of their registration, except that a function is called after any previously registered functions that had already been called at the time it was registered. Each function is called as many times as it was registered. If, during the call to any such function, a call to the longjmp() function is made that would terminate the call to the registered function, the behavior is undefined.
If a function registered by a call to atexit() fails to return, the remaining registered functions shall not be called and the rest of the exit() processing shall not be completed. If exit() is called more than once, the behavior is undefined.
The exit() function shall then flush all open streams with unwritten buffered data and close all open streams. Finally, the process shall be terminated [CX] with the same consequences as described in Consequences of Process Termination.
The exit() function does not return.
No errors are defined.
_Exit, atexit, exec, longjmp, tmpfile, wait, waitid
Austin Group Interpretation 1003.1-2001 #031 is applied, separating the _Exit() and _exit() functions from the exit() function.
Austin Group Interpretation 1003.1-2001 #085 is applied.
POSIX.1-2008, Technical Corrigendum 2, XSH/TC2-2008/0100  is applied.
return to top of page