on_exit - register a function to be called at normal process termination
int on_exit(void (*function)(int, void *), void *arg);
Since glibc 2.19:
Glibc 2.19 and earlier:
_BSD_SOURCE || _SVID_SOURCE
The on_exit() function registers the given function to be called
at normal process termination, whether via exit(3) or via return from
the program's main(). The function is passed the status argument
given to the last call to exit(3) and the arg argument from
The same function may be registered multiple times: it is called
once for each registration.
When a child process is created via fork(2), it inherits
copies of its parent's registrations. Upon a successful call to one of the
exec(3) functions, all registrations are removed.
The on_exit() function returns the value 0 if successful; otherwise it
returns a nonzero value.
For an explanation of the terms used in this section, see attributes(7).
This function comes from SunOS 4, but is also present in glibc. It no longer
occurs in Solaris (SunOS 5). Portable application should avoid this function,
and use the standard atexit(3) instead.
By the time function is executed, stack (auto) variables may
already have gone out of scope. Therefore, arg should not be a pointer
to a stack variable; it may however be a pointer to a heap variable or a
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